Draft Environmental Assessment
City of New Orleans
Mirabeau Water Garden Storm Water
Management and Flood Mitigation Project
FEMA-1607-DR-LA
Orleans Parish, Louisiana
Hazard Mitigation Grant Program
Project 1607-0120
December 2018 U.S. Department of Homeland Security
Federal Emergency Management Agency, Region VI
Louisiana Recovery Office
1500 Main Street
Baton Rouge, LA 70802
Mirabeau Water Garden Stormwater Management and Flood Mitigation Project Draft Environmental Assessment i
APPENDICES ..................................................................................................................................... III
LIST OF TABLES ..................................................................................................................................... III
LIST OF FIGURES ..................................................................................................................................... III
1.0 INTRODUCTION ........................................................................................................................... 1
1.1 Project Authority ...................................................................................................1 1.2 Background ...........................................................................................................1 1.3 Purpose and Need .................................................................................................5
2.0 ALTERNATIVES ........................................................................................................................... 5
Alternative 1 - No Action Alternative ..............................................................................5 Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent
Pool ...........................................................................................................6 Alternative 3 - Mirabeau Water Garden: Basin Storage Using Existing
Topography (Preferred Alternative) .........................................................8
3.0 AFFECTED ENVIRONMENT AND POTENTIAL IMPACTS ....................................................... 11
3.1 Land Use .............................................................................................................11 3.1.1 Regulatory Setting ..................................................................................11 3.1.2 Existing Conditions .................................................................................12 3.1.3 Environmental Consequences .................................................................12
3.2. Geology, Soils, and Topography ........................................................................12 3.2.1 Regulatory Setting ..................................................................................12 3.2.2 Existing Conditions .................................................................................13 3.2.3 Environmental Consequences .................................................................15
3.3 Water Quality ......................................................................................................16 3.3.1 Regulatory Setting ..................................................................................16 3.3.2 Existing Conditions .................................................................................17
3.3.3 Environmental Consequences .................................................................18 3.4 Wetlands .............................................................................................................19
3.4.1 Regulatory Setting ..................................................................................19
3.4.2 Existing Conditions ................................................................................20 3.4.3 Environmental Consequences .................................................................20
3.5 Floodplains & Hydrology ...................................................................................21
3.5.1 Regulatory Setting ..................................................................................21 3.5.2 Existing Conditions .................................................................................22 3.5.3 Environmental Consequences .................................................................24
3.6 Coastal Resources ...............................................................................................26
3.6.1 Regulatory Setting ..................................................................................26 3.6.2 Existing Conditions .................................................................................28 3.6.3 Environmental Consequences .................................................................28
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment ii
3.7 Biological Resources ..........................................................................................28 3.7.1 Regulatory Setting ..................................................................................28 3.7.2 Existing Conditions .................................................................................29 3.7.3 Environmental Consequences .................................................................30
3.8 Air Quality ..........................................................................................................30 3.8.1 Regulatory Setting ..................................................................................30 3.8.2 Existing Conditions .................................................................................31 3.8.3 Environmental Consequences .................................................................31
3.9 Noise ...................................................................................................................32
3.9.1 Regulatory Setting ..................................................................................32 3.9.2 Existing Conditions .................................................................................33 3.9.3 Environmental Consequences .................................................................33
3.10 Traffic and Parking .............................................................................................34
3.10.1 Regulatory Setting ..................................................................................34 3.10.2 Existing Conditions .................................................................................34
3.10.3 Environmental Consequences .................................................................35 3.11 Historic and Cultural Resources .........................................................................35
3.11.1 Regulatory Setting ..................................................................................35 3.11.2 Existing Conditions .................................................................................36 3.11.3 Environmental Consequences .................................................................37
3.12 Socioeconomics and Environmental Justice .......................................................37 3.12.1 Regulatory Setting ..................................................................................37
3.12.2 Existing Conditions .................................................................................38 3.12.3 Environmental Consequences .................................................................38
3.13 Hazardous Material .............................................................................................40
3.13.1 Regulatory Setting ..................................................................................40
3.13.2 Existing Conditions .................................................................................41 3.13.3 Environmental Consequences .................................................................41
3.14 Public Safety .......................................................................................................43
3.14.1 Regulatory Setting ..................................................................................43 3.14.2 Existing Conditions .................................................................................43
3.14.3 Environmental Consequences .................................................................43
4.0 CUMULATIVE IMPACTS ............................................................................................................ 44
4.1 Environmental Consequences .............................................................................47
5.0 CONDITIONS AND MITIGATION MEASURES .......................................................................... 53
6.0 AGENCY COORDINATION AND PUBLIC INVOLVEMENT ...................................................... 55
6.1 Agency Coordination ..........................................................................................55 6.2 Public Involvement .............................................................................................56
7.0 CONCLUSION ............................................................................................................................ 58
8.0 LIST OF PREPARERS ............................................................................................................... 59
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment iii
9.0 BIBLIOGRAPHY ......................................................................................................................... 60
APPENDICES
Appendix A Site Photographs
Appendix B Mirabeau Water Garden Storm Water Management and Flood Mitigation 100%
Design Report
Appendix C September 2017 Proposal for Hydrogeological Investigation
Appendix D Agency Communications
Appendix E 8-Step
Appendix F Hydrology and Hydraulics Model Results
Appendix G Phase I Environmental Site Assessment of the 1200 Block of Mirabeau Avenue
Appendix H Draft Finding of No Significant Impact (FONSI)
Appendix I Public Notice
LIST OF TABLES
Table 1. The probability of a 2-, 5-, or 10-year event occurring within four different time
periods ..................................................................................................................... 2
Table 2. Description of Aquifers Found Below the Filmore Neighborhood. ..................... 18 Table 3 Average Noise Levels by Vehicle......................................................................... 34
Table 4: Demographic and Economic Information for the Census Tract In Which the Project
Area is Located and for Orleans Parish. (USEPA, 2017) ..................................... 39
Table 5 Projects Identified as Having Potential to Contribute to Cumulative impacts ..... 48
LIST OF FIGURES
Figure 1: Location of Orleans Parish, Louisiana, shown in red, in relation to other Parishes
in the State............................................................................................................... 2 Figure 2: 2015 USGS topographic map with project area outlined in yellow (National
Geographic Society, ESRI et al., 2013) .................................................................. 3
Figure 3: Aerial image with proposed project area shaded in green (National Geographic
Society, ESRI et al., 2013). ..................................................................................... 4
Figure 4 Alternative 2 - Treatment Cell Storage and Permanent Pool (Waggonner & Ball
Architects, 2015). .................................................................................................... 7 Figure 5 Key Features of Alternative 3 - Pond Storage Using Existing Topography
(Preferred Alternative) (Waggoner & Ball, 2018; Waggonner & Ball Architects,
Sherwood Design Engineers, and Carbo Landscape Architecture, 2018). ............. 9
Figure 6 Depiction of Selected Design Performance During a 10-Year Return Interval, 24-
Hour Duration, Rainfall Event (Waggonner & Ball Architects, Sherwood Design
Engineers, and Carbo Landscape Architecture, 2018). ......................................... 11
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment iv
Figure 7 Generalized Geologic Map of Louisiana Indicating the general project location in
green (Snead, 2008). ............................................................................................. 14 Figure 8 National Wetlands Inventory Map with Project Area Outlined in Red (U.S. Fish &
Wildlife Service, 2017). ........................................................................................ 21
Figure 9 Flood Insurance Rate Map (FIRM) 22071C0114F Showing Project Area (Federal
Emergency Management Agency, 2016). ............................................................. 23 Figure 10 Phase I ESA summary map of known hazardous material site near project location.
............................................................................................................................... 42 Figure 11 A map showing FEMA-funded projects within the Cumulative Impacts Study area.
............................................................................................................................... 46
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment v
ACRONYMS AND ABBREVIATIONS
ABFE Advisory Base Flood Elevation
APE Area of Potential Effects
BFE Base Flood Elevation
BMP Best Management Practice
CAA Clean Air Act
CBRA Coastal Barrier Resources Act
CBRS Coastal Barrier Resources System
CEQ Council on Environmental Quality
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
CFR Code of Federal Regulations
CFS Cubic Feet per Second
CNO City of New Orleans
CO Carbon Monoxide
CUP Coastal Use Permit
CWA Clean Water Act
CZMA Coastal Zone Management Act
dB Decibel
dBA A-Scale Weighted Sound Pressure Level in Decibels
DA Department of the Army
DFIRM Digital Flood Insurance Rate Map
DPS Drainage Pumping Station
EA Environmental Assessment
EHP Environmental and Historic Preservation
EIS Environmental Impact Statement
ESA Endangered Species Act
EO Executive Order
FEMA Federal Emergency Management Agency
FIRM Flood Insurance Rate Map
FONSI Finding of No Significant Impact
FPPA Farmland Protection Policy Act
GCR General Conformity Rule
GOHSEP Governor's Office of Homeland Security and Emergency Preparedness
HMGP Hazard Mitigation Grant Program
HP Historic Preservation
HUD United States Department of Housing and Urban Development
LAC Louisiana Administrative Code
LDEQ Louisiana Department of Environmental Quality
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment vi
LDNR Louisiana Department of Natural Resources
LDOTD Louisiana Department of Transportation and Development
Leq Equivalent Noise Level
LPDES Louisiana Pollutant Discharge Elimination System
Mgal Millions of Gallons
MGD Million Gallons per Day
NAAQS National Ambient Air Quality Standards
NGVD North Geodetic Vertical Datum
NEPA National Environmental Policy Act
NFIP National Flood Insurance Program
NHPA National Historic Preservation Act
NMFS National Marine Fisheries Service
NPDES National Pollutant Discharge Elimination System
NRHP National Register of Historic Places
NRCS Natural Resources Conservation Services
O3 Ozone
OPA Otherwise Protected Area
OSHA Occupational Safety and Health Act
PA Programmatic Agreement
Pb Lead
PCB Polychlorinated Biphenyl
POLs Petroleum, Oil, and/or Lubricants
PL Public Law
RCRA Resource Conservation and Recovery Act
SARA Superfund Amendment and Reauthorization Act
SHPO State Historic Preservation Office/Officer
SO2 Sulfur Dioxide
SOV Solicitation of Views
SPOC Single Point of Contact
STAPLEE Social, Technical, Administrative, Political, Legal, Economic and
Environmental
SWBNO Sewerage & Water Board of New Orleans
SWPPP Storm Water Pollution Prevention Plan
TMDL Total Maximum Daily Load
TSCA Toxic Substances Control Act
USACE United States Army Corps of Engineers
USDA United States Department of Agriculture
USEPA United States Environmental Protection Agency
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment vii
USFWS United States Fish and Wildlife Service
USGS United States Geological Survey
Mirabeau Water Garden Stormwater Management and Flood Mitigation Project Draft Environmental Assessment 1
1.0 INTRODUCTION
1.1 Project Authority
Hurricane Katrina made landfall on August 29, 2005 near Buras, Louisiana, with sustained winds
of more than 125 mph. The subsequent storm surge damaged levees and entered the city of New
Orleans from various coastal waterways. President George W. Bush declared a major disaster for
the state of Louisiana due to the damages and signed a disaster declaration authorizing the
Department of Homeland Security’s Federal Emergency Management Agency (FEMA) to provide
federal assistance to communities. FEMA is administering this disaster assistance pursuant to the
Robert T. Stafford Disaster Relief Emergency Assistance Act (Stafford Act, Public Law [PL] 93-
288). Section 404 of this act authorizes FEMA’s Hazard Mitigation Grant Program (HMGP) to
provide funding for state and local governments to implement long-term hazard mitigation
measures after major disaster declarations.
The City of New Orleans (CNO), through the Governor’s Office of Homeland Security and
Emergency Preparedness (GOHSEP), applied for funding through FEMA’s HMGP for projects
that would reduce flooding in the area during rain, flooding, and extreme weather events.
This Environmental Assessment (EA) report has been prepared pursuant to the National
Environmental Policy Act of 1969 (NEPA), the President’s Council on Environmental Quality
(CEQ) regulations for implementing NEPA Regulations for Implementing the Procedural
Provisions of the National Environment Policy Act of 2005, promulgated at Title 50 of the Code
of Federal Regulations, Sections 1500 through 1508 (40 CFR 1500-1508), and FEMA’s
procedures for implementing NEPA (FEMA Instruction 108-1-1). The purpose of this EA is to
analyze potential environmental impacts that the proposed Mirabeau Water Garden Storm Water
Management and Flood Mitigation project (referred to as the Mirabeau Water Garden throughout
this assessment) would have on the environment. FEMA will use the findings in this EA to
determine whether to prepare an Environmental Impact Statement (EIS) or a Finding of No
Significant Impact (FONSI).
1.2 Background
As a result of Hurricane Katrina, the city of New Orleans suffered unprecedented damage from
flood waters and high winds. The Mirabeau Water Garden project area was included in the
damaged area. Orleans Parish is in southeastern Louisiana and includes the city of New Orleans,
as shown in Figure 1.
The Mirabeau Water Garden project area is located within the Filmore neighborhood of New
Orleans, between Bayou St. John and the London Avenue Canal. The proposed project is located
on a vacant, 25-acre site at 1200 Mirabeau Avenue. The project area is located between Mirabeau
Avenue (northern boundary); Cartier Avenue (eastern boundary); Owens Boulevard (southern
boundary); and St. Bernard Avenue (western boundary). Approximate coordinates of the property
corners are listed below.
Northwest Corner latitude 30.006672 degrees North, longitude 90.082082 degrees West
Northeast Corner latitude 30.006843 degrees North, longitude 90.079240 degrees West
Southeast Corner latitude 30.003612 degrees North, longitude 90.078813 degrees West
Southwest Corner latitude 30.003438 degrees North, longitude 90.081829 degrees West
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 2
Figure 1: Location of Orleans Parish, Louisiana, shown in red, in relation to other Parishes in the State.
The Filmore neighborhood has received extensive flooding in the past and continues to flood
during 2-, 5-, and 10-year, 24-hour duration, rainfall events. Contrary to its name, a 2-year event
does not necessarily occur every 2 years, nor does a 10-year event necessarily occur every 10
years. Table 1 shows the probabilities of 2-, 5- or 10-year rainfall events.
Table 1. The probability of a 2-, 5-, or 10-year event occurring within four different time periods
2-year event 5-year event 10-year event
Probability within 1 year 50% 20% 10%
Probability within 2 years 75% 36% 19%
Probability within 5 years 96.9% 67.2% 41%
Probability within 10 years 99.9% 89.3% 65.1%
The proposed project area is the former location of the Sisters of St. Joseph Convent. The convent
occupied the site from 1950 to 2005. After the convent and adjacent buildings were damaged by
the flooding in Hurricane Katrina, the Sisters relocated. Eventually, the buildings were demolished
in 2008, and the 25-acre property is now a vacant greenspace (Figure 2 and Figure 3). Currently,
the site is fenced off and is not accessible for public use. The Congregation of St. Joseph agreed
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 3
Figure 2: 2015 USGS topographic map with project area outlined in yellow (National Geographic Society,
ESRI et al., 2013)
to donate this land to the City of New Orleans (CNO) via a 99-year lease, on the condition that the
property be used to benefit the city by preserving and protecting the environment, improving the
quality of life, and reducing the risk of flooding for neighborhood residents. Accordingly, CNO
aspires for the Mirabeau Water Garden to become both an example of sustainable water
management for the lowland flood-prone areas of the city, as well as an educational destination
for residents to learn about water storage, filtration, and ecology. Photographs of the project site
can be found in Appendix A.
The Mirabeau Water Garden Project is one of 91 projects identified in the City of New Orleans
Hazard Mitigation Plan. As part of the effort to update the 2010 Hazard Mitigation Grant Program
Mitigation Plan, an updated and expanded planning process was used to review and update the
plan to ensure broad representation from the community. Stakeholders for this planning effort
included non-profits, community organizations, environmental groups, and regional governmental
agencies with an interest in and/or responsibility for hazard mitigation planning. In addition to a
CNO City Hall Working Group and Advisory Committee, two additional groups were convened
for the purpose of holding discussions specific to their responsibilities (i.e., Public Safety Group
and Non-Profits and Community Organizations Group).
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 4
Figure 3: Aerial image with proposed project area shaded in green (National Geographic Society, ESRI et
al., 2013).
The CNO Hazard Mitigation Plan includes 91 mitigation actions that meet the goals established
by CNO, meet one or more of the FEMA mitigation action categories, and will reduce or eliminate
risks to human life and property from one or more of the identified hazards in the plan. After the
final list of hazard mitigation actions was established, the City Hall Working Group and Advisory
Committee used the Social, Technical, Administrative, Political, Legal, Economic, and
Environmental (STAPLEE) methodology to evaluate and prioritize the mitigation actions for the
2015 Plan. This methodology was used to examine opportunities (benefits) and constraints (costs)
of implementing each action from the perspective of all seven of the STAPLEE criteria. By using
the STAPLEE methodology, CNO was able to evaluate and prioritize mitigation actions to
determine whether the actions addressed specific goals and objectives and where the actions are
appropriate for Orleans Parish. The Mirabeau Water Garden Project received a ranking of “High,”
similar to that of other Green Infrastructure drainage projects within the same drainage basin and
throughout New Orleans (City of New Orleans, 2015).
CNO had broad public involvement and used many vehicles to gain insight on the public’s
thoughts and to consider recommendations made by the public. A summary of these meetings is
provided in Section 7.2 Public Involvement.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 5
1.3 Purpose and Need
FEMA provides grants to states and local governments to implement long-term hazard mitigation
measures through the HMGP. The purpose of the HMGP is to reduce the loss of human life and
property due to natural disasters and to enable mitigation measures to be implemented during
recovery from a disaster. The Mirabeau Water Garden project has been proposed by the City of
New Orleans for HMGP funding to mitigate flood risks in municipal areas.
The purpose of this project is to reduce damages to property in the project vicinity during 2-, 5-,
and 10-year, 24-hour duration, rainfall events by reducing the load on Drainage Pump Station
(DPS) 3 and Drainage Pump Station 4, which drain neighborhood runoff into the London Avenue
Canal.
Beginning in the early 20th century, swampy, low-lying areas in the city were drained to
accommodate further development. The Filmore neighborhood was developed intensely during
the latter half of the 20th century, particularly after World War II. Currently, the vast majority of
the area remains below sea level and is located in the National Flood Insurance Program (NFIP)
Special Flood Hazard Area (SFHA). A SFHA is the area where the NFIP's floodplain management
regulations must be enforced, and the area where the mandatory purchase of flood insurance
applies. Additionally, the existing drainage system (i.e., traditional subsurface drainage connected
to outfall canals and pumping stations) can often be overwhelmed during 5- and 10-year rainfall
events. Consequently, in addition to being one of the most affected areas during Hurricane Katrina,
the Filmore neighborhood is typically exposed to flood hazards resulting from thunderstorms and
other intense rain events. The project is needed to protect structures, facilities, and residents in the
Filmore neighborhood from damages resulting from 2-, 5-, and 10-year, 24-hour duration, rainfall
events.
2.0 ALTERNATIVES
A basic principle of NEPA is that the federal government must consider reasonable alternatives to
a proposed action. Considering alternatives helps avoid unnecessary impacts and allows analysis
of reasonable ways to achieve the stated purpose. To warrant detailed evaluation, an alternative
must be reasonable. As determined by CEQ, “reasonable alternatives include those that are
practical or feasible from the technical and economic standpoint and using common sense, rather
than simply desirable from the standpoint of the applicant” (CEQ 1981). The following sections
identify alternatives considered by CNO that are subject to detailed evaluation in this EA. Two
alternatives were developed to address the purpose and need stated in the preceding section. The
three alternatives that are evaluated throughout this EA are:
Alternative 1 – No Action Alternative
Alternative 2 – Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
Alternative 3 – Mirabeau Water Garden: Pond Storage using Existing Topography (Preferred
Alternative).
Alternative 1 - No Action Alternative
The No Action Alternative is included to identify the baseline conditions against which potential
impacts of implementation alternatives are evaluated. The No Action Alternative represents the
baseline condition of the environment if the proposed action is not implemented. Under the No
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 6
Action Alternative, the proposed drainage improvements would not be constructed in the project
area and the neighborhood would continue to experience flooding effects similar to those that have
occurred during past events. This alternative will be evaluated throughout this EA.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
The design of Alternative 2 includes the following elements to collect and detain storm water,
biologically treat it, and infiltrate it into the subsurface or discharge it to city storm drain system
at controlled rates. This alternative is represented in the 30% design report, dated May 2015
(Waggonner & Ball Architects, 2015), and Figure 4 shows the approximate layout of this design
alternative.
Two subsurface pump forebays in the northwest and southeast corners of the project area to
transfer water from the city storm water collection system
Rock-lined swales to divert surface runoff to project area
Water treatment cells and a permanent pool
Rain garden and bioswale designed to remove silt and pollution from surface runoff
Detention/infiltration basin to percolate water into the subsurface
Parking lot with subsurface storage
Weirs and berms to control excess overflow back to city storm water collection system
Key elements of this design concept are multiple underground and aboveground water storage
areas that would progressively fill to retain surface runoff and storm water at the site. This plan
uses pumping to control the flow of water into the site.
The northwest pump would lift water into a row of water treatment cells, thence into a permanent
pool aligned roughly west-to-east along the center of the site. The pool and some greenspace areas
would also be available for public use. The southeast pump would evenly distribute that flow into
a storm water storage basin.
Rainfall that accumulates directly onto the site would be collected via perimeter bioswales and
rain gardens. A dedicated collector system would also direct to a subsurface retention tank
constructed beneath the proposed southern parking area. A proposed berm along the southern
portion of the site would also retain water aboveground for percolation into the subsurface.
This design alternative uses the natural landscape (e.g., mounds, native vegetation, etc.) to
distribute water throughout the site. To be eligible for FEMA HMGP, applicants must sign a
maintenance agreement, agreeing to maintain the proposed improvements for the life of project.
A project-specific Operations and Maintenance Plan was also developed, that includes the
following inspection, periodic testing, cleaning, and maintenance activities, as appropriate.
Mechanical equipment (e.g., pumps and valves)
Flow control features (e.g., weirs, debris screens, settling chambers
Vegetation and landscaping (e.g., mowing, weeding, pruning, herbicide application)
General site housekeeping
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 7
Alternative 2 meets the purpose and need of the action and will, therefore, continue to be evaluated
throughout this EA.
Figure 4 Alternative 2 - Treatment Cell Storage and Permanent Pool (Waggonner & Ball Architects,
2015).
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 8
Alternative 3 - Mirabeau Water Garden: Basin Storage Using Existing Topography
(Preferred Alternative)
The primary components of this alternative are two separate water retention basins (Mirabeau
Basin and Owens Basin). Mirabeau Basin is graded to allow retention of approximately 8.5 million
gallons (Mgal) of storm water storage. Owens Basin is graded to accommodate 2.5 Mgal of
storage. The basins are designed to provide storage above the water table with no liner, allowing
for infiltration of water into the subsurface. This alternative creates a floodable landscape that can
react and adapt to various levels of inundation up to a 10-year return interval, 24-hour duration,
rainfall event.
This alternative also preserves much of the existing vegetation and topography in the design,
avoiding removal of many of the native tree species that have grown on the property for decades.
The shapes of the basins were designed to protect existing trees and to minimize excavation by
taking advantage of existing grades. Several vegetative clusters and existing trees on the property,
augmented with new plantings, would be retained to reflect the historic Pine Island Barrier Sands
geologic trend that underlies much of the site. The proposed layout for the site is depicted in
Figures 5 and 6.
The site would be accessible to the public via Mirabeau Avenue from the north and Owens
Boulevard from the south, where parking areas would be surfaced with pervious pavers and gravel
to further aid infiltration of surface runoff. Boardwalks and gravel paths would provide both
maintenance and public access throughout the site. The existing topography (including an area of
higher ground where the St. Joseph buildings once stood), vegetative clusters, and a large, open
field would provide ample room for future public use of the site (Waggoner & Ball, 2018). The
applicant plans to incorporate future instructional signage and educational programs into the site
(Figure 5).
The drainage scope for this design alternative includes diversion of storm water runoff from the
city storm drain system into two large retention basins and from adjacent streets into perimeter
bioswales. Storm water from the city storm drain system beneath Mirabeau Avenue would be
diverted by gravity flow into a forebay at the northwest corner of the site, where a vortex separator
would retain and remove settleable solids and floating oils/debris. From the separator, storm water
would flow to a wet well, where it would then be pumped into the Mirabeau Basin, located along
the western portion of the site. Figure 6 depicts water storage and water circulation pattern during
a 10-year storm.
Bioswales are designed to improve captured storm water quality by gravity settling of suspended
solids and by filtration through plants and soils to further remove floating and suspended
contaminants. Surface runoff from surrounding streets, diverted by perimeter berms to these
bioswales, would also infiltrate into the subsurface. Parking and walking areas paved with
pervious pavers and gravel would also capture and infiltrate runoff at the site.
Water from the city storm drain system beneath Owens Boulevard and Cartier Avenue would begin
to fill the Owens Basin by gravity flow from Owens Boulevard. The Owens Basin, in the
southeastern portion of the site, would be connected to the adjacent Mirabeau Basin by a pair of
culvert pipes. The pipes are designed with flap gates that only allow flow from Owens Basin to
Mirabeau Basin when water surface elevations in Owens Basin exceed those in Mirabeau Basin.
The flap gates prevent backflow from Mirabeau Basin back to Owens Basin. Water from a 10-year
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 9
storm event will fill the Owens and Mirabeau Basins to an elevation of approximately 3.5 feet
below National Geodetic Vertical Datum (-3.5 feet NGVD).
The Mirabeau Basin inlet pump is designed to automatically prevent basin water elevations from
exceeding a maximum elevation of -3.5 feet NGVD. An overflow structure in the north weir
provides a discharge path in case the system continues to fill from direct runoff into the basins.
Figure 5 Key Features of Alternative 3 - Pond Storage Using Existing Topography (Preferred Alternative)
(Waggoner & Ball, 2018; Waggonner & Ball Architects, Sherwood Design Engineers, and Carbo
Landscape Architecture, 2018).
The overflow weir is designed to slowly discharge water from the basins back into the city storm
drain system, providing time for infiltration from the basins directly into the subsurface.
This alternative also includes a perimeter underdrain system to control infiltration into the
surrounding groundwater. The underdrain system is designed to collect excess water from
bioswale zones and overflow catch basins around the basins and direct it to the Mirabeau Basin
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 10
wet well. Water from the wet well would also serve as a water source for plant irrigation water
and recirculation through the site during dry periods.
Excess water from the underdrain wet well may also be diverted to the city storm water collection
system by automatic level-controlled pump. Integration of the perimeter underdrain and an
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 11
Figure 6 Depiction of Selected Design Performance During a 10-Year Return Interval, 24-Hour Duration,
Rainfall Event (Waggonner & Ball Architects, Sherwood Design Engineers, and Carbo
Landscape Architecture, 2018).
associated groundwater control/monitoring system into the site design provides a system to
monitor and control groundwater elevations.
To be eligible for FEMA HMGP, applicants must sign a maintenance agreement, agreeing to
maintain the proposed improvements for the life of project. A project-specific Operations and
Maintenance Plan was also developed, that includes the following inspection, periodic testing,
cleaning, and maintenance activities (as appropriate).
Mechanical equipment (e.g., pumps, flow controllers, vortex separator)
Flow control features (e.g., weirs, valves, drains)
Vegetation and landscaping (e.g., path/boardwalk maintenance, mowing, weeding, pruning,
herbicide application)
General site housekeeping
Alternative 3 meets the purpose and need of the action. This action alternative will therefore
continue to be evaluated throughout this EA.Comparison of Alternatives
Alternative 3, the preferred alternative, reduces construction, operation, and maintenance costs
associated with second set of pumps included in Alternative 2, while keeping the same overall
benefits. Unlike Alternative 2, the preferred alternative would not include a permanent pool.
However, the preferred alternative would include the addition of walkways to allow for
maintenance of the site.
3.0 AFFECTED ENVIRONMENT AND POTENTIAL IMPACTS
This section describes the existing environmental and socioeconomic conditions potentially
affected by the proposed action, as well as the potential environmental and socioeconomic impacts
of implementing the proposed action or its alternative. This section also provides information on
the existing condition at the site to serve as a baseline against which to identify and evaluate
environmental and socioeconomic changes likely to result from implementation of the proposed
action or its alternative.
3.1 Land Use
This section describes the existing land use setting in the project area and its vicinity, as well as
any potential impacts that would occur with each proposed action.
3.1.1 Regulatory Setting
The Comprehensive Zoning Ordinance (CZO) is the law that governs land use throughout the City
of New Orleans. The CZO includes lists of permitted land uses for each of the City’s zoning
districts, in addition to height limits, setback requirements, urban design standards, operational
rules, and other regulations. The CZO is broken into a series of Articles that cover citywide
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 12
standards, individual zoning district regulations, and the processes for variances, conditional use
permits, and other land use reviews.
3.1.2 Existing Conditions
Land use in urbanized portions of the Filmore neighborhood consists primarily of single and multi-
family residences with a component of commercial and industrial businesses. Public uses include
Interstate Highway 610 (I-610), rights-of-way for rail access to industrial businesses along I-610,
elementary and secondary schools, cemeteries, playgrounds, and City Park. Commercial activities
line the major thoroughfare of Paris Avenue. The 25-acre project area, a single property at 1200
Mirabeau Avenue, is zoned entirely as S-RS (Suburban Single-Family Residential). Currently the
site is fenced off and is not accessible for public use.
3.1.3 Environmental Consequences
Alternative 1 – No Action
No land use changes are proposed under the No Action Alternative.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
Implementation of Alternative 2 would change the existing land use of the project site to a water
garden and storm water management facility. The CZO zoning designation might be changed
accordingly from S-RS (Suburban Single-Family Residential) to OS-N (Neighborhood Open
Space). The proposed Water Garden would store, manage, and treat (by solids settling and
biological filtration) storm water runoff. Additionally, this alternative would include the
construction of a permanent pool and the planned use of some greenspace areas as potential
recreational areas. Consequently, Alternative 2 would include visual and structural improvements
to the project site and would provide additional recreational opportunities for residents.
Alternative 3 -Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
Implementation of the preferred alternative would also change the existing land use of the project
site to a water garden and storm water management facility. The CZO zoning designation might
be changed accordingly from S-RS, Suburban Single-Family Residential to OS-N, Neighborhood
Open Space. Similarly to Alternative 2, the proposed Water Garden would store, manage, and treat
(through solids settling and biological filtration) storm water runoff. Planned use of some
greenspace areas would include potential recreational areas. This land use change should be
discussed in community settings and throughout the public involvement process. Alternative 3
(Preferred Alternative) would include visual and structural improvements to the project site and
would provide additional recreational opportunities for residents.
3.2. Geology, Soils, and Topography
3.2.1 Regulatory Setting
The Farmland Protection Policy Act (FPPA) (PL 97-98, Sections 1539-1549; 7 USC Section 4201,
et seq.) was enacted in 1981 and is intended to minimize the impact federal actions have toward
the unnecessary and irreversible conversion of farmland to non-agricultural uses. This law assures
that, to the extent possible, federal programs and policies are administered in a way that is
compatible with state and local farmland protection policies and programs. To implement the
FPPA, federal agencies are required to develop and review their policies and procedures every two
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 13
years. The FPPA does not authorize the federal government to regulate the use of private or non-
federal land or, in any way, affect the property rights of owners.
For purposes of the FPPA, farmland includes prime farmland, unique farmland, and farmland of
statewide or local importance. Prime farmland is characterized as land with the best physical and
chemical characteristics for production of food, feed, forage, fiber, and oilseed crops (Natural
Resources Conservation Service, U.S. Department of Agriculture, 2016). Farmland subject to
FPPA requirements does not currently have to be used for cropland; it also can be forest land,
pastureland, or other land, but not water or built-up land.
3.2.2 Existing Conditions
The project area is situated in the Mississippi River delta plain in a heavily urbanized geographic
setting and a subsurface geologic setting of alluvium deposits from the river (Figure 7). The delta
plain typically consists of land that was historically flooded on a periodic basis and that was
covered with vegetation. Depending on elevation and degree of salinity, cypress-tupelo swamp,
freshwater marsh, brackish marsh, or saltwater marsh are found on the delta plain. The delta plain
is typically interspersed with bays, tidal channels and lakes.
Extensive development of the greater New Orleans metropolitan area (including the project area)
throughout the 20th century has transformed the project area into a suburban area where periodic
flooding is no longer caused by the Mississippi River overtopping its banks. Periodic inundation
of the project area and vicinity by fresh waters from the river or by brackish waters from Lake
Pontchartrain is now controlled by an extensive levee system designed by United States Army
Corps of Engineers (USACE) to protect the New Orleans area (including the project area) from
flooding caused by hurricane storm surges. Periodic flooding in the project area can still occur if
heavy rainfall generates storm water runoff at rates that exceed storm water removal rates of the
municipal storm water collection and removal system, operated by Sewerage & Water Board of
New Orleans (SWBNO).
Surface soils present within the project area are mapped by Natural Resources Conservation
Service (NRCS) as Schriever clay (0-1 percent slopes). This soil has a shallow depth to the
saturated zone (generally 0.5 foot), high clay content, high shrink-swell potential, unstable
excavation walls, low strength, and potential for flooding. The Schriever clay is a hydric soil
(Natural Resources Conservation Service, U.S. Department of Agriculture, 2016). The Pine Island
Barrier Sand is the first encountered water-bearing geologic zone at the project area. In the
southern part of the project area, this lithologic zone outcrops at the ground surface, but it is
generally first encountered across the project site at a depth of 5 feet below ground surface, under
an overlying, confining clay unit. The average thickness of the Pine Island Barrier Sand zone in
the project area is about 40 feet. This permeable unit is in direct contact with many surface water
sources in the vicinity of the project area, including Bayou St. John, drainage canals, ditches,
sewers, storm water pipes, and direct rainwater infiltration.
Prior to construction of drainage canals and flood control levees, the topography of Orleans Parish
varied from a high of about 15 feet above sea level on natural levees to sea level. Typical landforms
present, from high to low elevation, were the natural levees to back swamps to coastal marshes to
the gulf or other water body (U.S. Geological Survey, 1939, 1951, 1965, 1966, 1983, 1998, 1999,
2012, 2015). The project area was originally characterized as cypress swamp.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 14
According to a preliminary hydrogeology evaluation report provided as an appendix to the April
13, 2018, Final Design Report (Appendix B), current groundwater levels fluctuate approximately
around 3 to 4 feet below surface level. The lowest groundwater levels correspondent with typical
depth of sewer and storm drainage pipes (12 feet below sea level) in the site vicinity, and the
hydraulic head elevation (i.e., artesian groundwater pressure in the Pine Barrier Sand zone) is often
above the bases of the overlying clayey deposits. The Mirabeau project area is a groundwater
discharge area; the shallow groundwater is recharged by surface water infiltration into the
subsurface, and groundwater discharge (seepage) from the subsurface is controlled by evaporation
and groundwater drainage into the underground infrastructure (storm drainage and sewer pipes in
the surrounding streets.
Figure 7 Generalized Geologic Map of Louisiana Indicating the general project location in green (Snead,
2008).
Flow rates and volumes of groundwater seepage to the surface are not known; this information is
necessary to analyze the impact of surface water storage on the surrounding area (Waggonner &
Ball Architects, Sherwood Design Engineers, and Carbo Landscape Architecture, 2018).
Additional geotechnical and hydrogeological investigations are planned, according to a
preliminary groundwater investigation proposal provided by CNO (Appendix C), but a detailed
investigation scope or specific implementation schedule has not yet been provided. That
investigation would include collection of samples and geotechnical analyses to characterize
groundwater conditions of the site and site vicinity. Geotechnical investigation results would be
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 15
evaluated by the applicant to characterize groundwater seepage and infiltration flow rates and
volumes to refine the design of groundwater seepage collection systems, if required.
3.2.3 Environmental Consequences
Alternative 1 – No Action
The scope of the No Action Alternative includes no construction activities in the project area.
Therefore, this alternative would have no effects differing from the baseline condition on geology,
soils, or topography, and no effects on prime, unique, statewide, or locally important farmland
would occur. The corresponding no change in frequency of local flooding could result in further
erosion of soils within the project area and offers no change in control of flooding to surrounding
properties and structures.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
Per a response from United States Department of Agriculture (USDA), dated January 19, 2017,
the proposed construction areas are in urban areas and, therefore, are exempt from the rules and
regulations of the FPPA – Subtitle I of Title XV, Section 1539-1549. This response is included in
Appendix D.
Construction activity would result in adverse direct impacts from localized soil disturbance
because of clearing and grubbing activities (where needed) and installation of the drainage
improvement infrastructure. Soils would also be exposed during grading and trenching activities.
Direct and indirect beneficial impacts to soils in the project area and the greater Filmore
neighborhood would occur during the operation of the Mirabeau Water Garden as storm water
would be stored onsite, and slowly released into the groundwater and storm sewer system.
Additionally, mandatory compliance by CNO and its contractors with applicable local, state, and
federal causing less sedimentation.
Impacts to the groundwater will require further analysis after the proposed groundwater
investigation is complete. According to the groundwater proposal provided as Appendix C, the
CNO will need to implement a control mechanism or other best management practices (BMPs) to
maintain groundwater table elevation in and around the project area that will not contribute to
excessive groundwater seepage to the surface (Waggoner & Ball, 2018), but a detailed scope or
specific implementation schedule has not been provided. Results of this testing will be made
publicly available through the New Orleans Department of Public Works. CNO is also required to
coordinate with Louisiana Department of Environmental Quality (LDEQ) regarding the results of
their investigation.
Alternative 3 -Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
Per a response from USDA, dated January 19, 2017, the proposed construction areas are in urban
areas and therefore are exempt from the rules and regulations of the FPPA – Subtitle I of Title XV,
Section 1539-1549. This response is included in Appendix D.
Construction activity would result in adverse direct impacts from localized soil disturbance
because of clearing and grubbing activities (where needed) and installation of the drainage
improvement infrastructure. Soils would also be exposed during grading and trenching activities.
Under the preferred alternative less soil disturbance would occur as the contouring of the ponds
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 16
would use the existing topography. Indirect and direct beneficial impacts would be similar to those
described under Alternative 2.
This alternative proposes a perimeter underdrain system to control groundwater seepage into the
project site and surrounding area. According to the applicant’s groundwater investigation
proposal (Appendix C), additional subsurface sampling and analyses are planned to more fully
characterize groundwater conditions at the project site and to collect design information to refine
anticipated flow rates and pipe sizes for the proposed perimeter underdrain system. Updates to
the perimeter underdrain final design, based on the subsurface investigation, would be
incorporated into the project around the mid-point of construction. Results of this testing would be
made publicly available through the New Orleans Department of Public Works. CNO is also
required to coordinate with LDEQ regarding the results of an investigation of this type.
3.3 Water Quality
3.3.1 Regulatory Setting
Section 401 of the Clean Water Act (CWA) requires state certification of all federal licenses and
permits in which there is a “discharge of fill material into navigable waters.” The certification
process is used to determine whether an activity, as described in the federal license or permit,
would impact established site-specific water quality standards. A water quality certification from
the issuing state agency, LDEQ in this case, is required prior to the issuance of the relevant federal
license or permit.
The National Pollutant Discharge Elimination System (NPDES) program was created by
Section 402 of the CWA. This program authorizes the United States Environmental Protection
Agency (USEPA) to issue permits for the point source discharge of pollutants into waters of the
U.S. Through a 2004 Memorandum of Agreement, the USEPA delegated its permit program for
the state of Louisiana to LDEQ. The ensuing Louisiana Pollutant Discharge Elimination System
(LPDES) program authorizes individual permits, general permits, storm water permits, and
pretreatment activities that result in discharges to jurisdictional waters of the state.
Under Section 303(d) of the CWA, states, territories and authorized tribes, are required to develop
lists of impaired waters. These are waters for which technology-based regulations and other
required controls are not stringent enough to meet the water quality standards set by states. The
law requires that states establish priority rankings for waters on the lists and develop Total
Maximum Daily Loads (TMDLs) for these waters. A TMDL includes a calculation of the
maximum amount of a pollutant that can be present in a waterbody and still meet water quality
standards.
The LPDES requires permits for the discharge of pollutants/wastewater from any point source into
waters of the State. Per the CWA, the term “point source” is defined as “any discernible, confined,
and discrete conveyance such as a pipe or a ditch.” All point source discharges of pollutants to
waters in the state of Louisiana are subject to a LPDES permit issued by LDEQ. Additionally,
LDEQ requires a Storm Water Pollution Prevention Plan (SWPPP) for land disturbing activities
greater than one acre. For land disturbing activities greater than five acres, LDEQ requires the
following submittals.
SWPPP
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 17
Notice of Intent to operate under LDEQ General Permit currently in effect for storm water
discharges associated with construction activity
Notice of Completion of activities under the LDEQ General Permit, after completion of work
The City of New Orleans currently manages storm water discharges under a NPDES Municipal
Separate Storm Sewer System (MS4) permit. The NPDES MS4 permit requires permittees to
develop and implement a comprehensive Storm Water Management Program (SWMP) that must
include pollution prevention measures, treatment or removal techniques, monitoring, use of legal
authority, and other appropriate measures to control the quality of storm water discharged to the
storm drains and thence to waters of the United States (MS4 Permit Number LAS000301).
3.3.2 Existing Conditions
The project area is in the drainage basin of DPS 3. The drainage system for the project area consists
of catch basins and drop-inlets that receive surface runoff from the project area, surrounding
properties, and streets. Runoff that enters drop-inlets is conveyed underground to DPS 3 and into
the London Avenue Canal that flows north into Lake Pontchartrain. The London Avenue Canal is
not listed on USEPA’s 303(d) list of impaired waters (U.S. Environmental Protection Agency,
2014).
Regionally, the greater New Orleans area obtains potable groundwater from the Gonzales-New
Orleans aquifer, a much deeper aquifer with the majority of groundwater withdrawals. Other
groundwater resources in the New Orleans area include the shallow Mississippi River point-bar
deposits, the Gramercy aquifer, the Norco aquifer, and the deeper “1,200-foot” sand of the New
Orleans aquifer. Primary drinking water sources for Orleans Parish are the Mississippi River and
the Gonzales-New Orleans aquifer, and some of the shallow aquifers (above the Gonzales-New
Orleans aquifer) could be a viable emergency source of potable water in the area (Table 2)
(Prakken, 2009). In 2010, the total average amounts of water withdrawal were 602 million gallons
per day (MGD) from the Mississippi River and 13 MGD from aquifers.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 18
Table 2. Description of Aquifers Found Below the Filmore Neighborhood.
Aquifer or aquifer system
(clay units separating aquifers
are not listed) Aquifer Characteristics Water Quality
Shallow point-bar deposit aquifers
Up to 150 feet thick; found
inside the Mississippi River
bends
Freshwater in areas
adjacent to the river
Other shallow sand aquifers of
New Orleans area
50 to 100 feet thick; shallower
than 200 feet below ground
surface; discontinuous
Saltwater
Gramercy aquifer
Up to 150 feet thick; top is
generally found at 100 to 250
feet below ground surface
Saltwater
Norco aquifer
50 to 150 feet thick; top is
generally found at 250 to 350
feet below ground surface
Mostly saltwater except
for a narrow area along
Lake Pontchartrain
Gonzales-New Orleans aquifer
150 to 300 feet thick; top is
found between 400 to 700 feet
below ground surface;
continuous throughout the
area
Freshwater with
saltwater in the southern
and western part of the
area
“1,200-foot” sand (aquifer)
about 100 feet thick; top is
found approximately 750 feet
below ground surface
Saltwater
Currently, groundwater in the Pine Island Barrier Sands (discussed in Section 4.2.2) beneath the
project area flows toward the northeast. The shallow groundwater observed in the Pine Island
Barrier Sand is not a viable drinking water resource. Several impermeable units separate the Pine
Island Barrier Sand from deeper permeable units which may be potable aquifers).
3.3.3 Environmental Consequences
Alternative 1 – No Action
The No Action Alternative would have no effects differing from the baseline condition on water
resources in the project area and Orleans Parish.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
Short-term adverse impacts to surface water and water quality from the implementation of
Alternative 2 could arise from soil disturbance and surface runoff during construction. However,
mandatory LPDES permitting for the proposed construction activities at the project location is
intended to minimize those impacts. Because the proposed land disturbing activities would be
greater than five acres, the applicable LPDES general permit would require a SWPPP, submittal
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 19
of a Notice of Intent (NOI) to LDEQ prior to commencement of construction activities, and
submittal of a Notice of Completion to LDEQ after completion of construction activities.
Long-term, beneficial impacts to water quality of surface water and groundwater are expected
during the operation of the Mirabeau Water Garden Project. Planned retention of water onsite,
reduced storm water flow rates into the municipal storm water collection system, and reduced
sediment loads into surface water are all benefits that directly result from this alternative, as are
increased rates of groundwater infiltration. No significant impacts to surface waters or water
quality are therefore anticipated under Alternative 2.
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
Short-term adverse impacts to surface water and water quality from the implementation of
Alternative 3 could arise from soil disturbance and surface runoff during construction. However,
mandatory LPDES permitting for the proposed construction activities at the project location is
intended to minimize those impacts. Because the proposed land disturbing activities would be
greater than five acres, the applicable LPDES general permit would require a SWPPP, submittal
of a Notice of Intent (NOI) to LDEQ prior to commencement of construction activities, and
submittal of a Notice of Completion to LDEQ after completion of construction activities.
Proper design of this alternative would be based on results of the subsurface investigation proposed
in Appendix C. This alternative proposes a perimeter underdrain system to control groundwater
seepage into the project site and surrounding area. According to the applicant’s groundwater
investigation proposal, additional subsurface sampling and analyses are planned to more fully
characterize groundwater conditions at the project site and to collect design information to refine
anticipated flow rates and pipe sizes for the proposed perimeter underdrain system. Updates to the
perimeter underdrain final design, based on the subsurface investigation, would be incorporated
into the project around the mid-point of construction. Results of this testing will be made publicly
available through the New Orleans Department of Public Works. CNO is also required to
coordinate with LDEQ regarding the results of their investigation.
Long-term, beneficial impacts to water quality would be similar to those described for
Alternative 2, and no significant impacts to surface waters or water quality are anticipated under
the Preferred Alternative.
3.4 Wetlands
3.4.1 Regulatory Setting
Wetlands are defined as “those areas that are inundated or saturated by surface or groundwater at
a frequency and duration sufficient to support, and that under normal circumstances do support, a
prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally
include swamps, marshes, bogs, and similar areas” (33 CFR 328.3[b]) (United States Department
of Defense, Department of the Army, Corps of Engineers, 1986). USACE, through its permit
program, regulates the discharge of dredged or fill material into waters of the United States,
including wetlands, pursuant to Section 404 of the CWA. USACE regulates the discharge of
dredged or fill material into waters of the U.S., including wetlands, pursuant to Sections 401 and
404 of the Clean Water Act (CWA). In addition, USEPA has regulatory oversight of the USACE
permit program, allowing USEPA under CWA Section 404c to veto USACE-issued permits where
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 20
there are unacceptable environmental impacts (United States Environmental Protection Agency,
2018).
Executive Order (EO) 11990, Protection of Wetlands, directs federal agencies to minimize the
destruction, loss, or degradation of wetlands and to preserve and enhance the values of wetlands
for federally funded projects. FEMA regulations for complying with EO 11990 are found at
44 CFR 9, Floodplain Management and Protection of Wetlands.
3.4.2 Existing Conditions
According to the National Wetlands Inventory map available from United States Fish and Wildlife
Service (USFWS), no wetlands exist at the site (Figure 8). This classification is based on aerial
imagery and thus this area may or may not be classified as a wetland during a wetland
determination. A wetlands determination has not been conducted for this site. The Filmore
neighborhood has been protected by a levee and drained by canals since before 1938 (U.S.
Geological Survey, 1939, 1951, 1965, 1966, 1983, 1998, 1999, 2012, 2015).
3.4.3 Environmental Consequences
Alternative 1 – No Action
The No Action Alternative would include no construction activities in the project area. Therefore,
this alternative would have no adverse impacts on wetlands.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
Because the project area has been drained and is completely built up, implementation of
Alternative 2 would have no adverse effects on wetlands. The proposed project would create new
wetlands within the project area. These new wetlands would provide a natural space to retain storm
water runoff and to provide a natural filter for removal of pollutants from storm water. The
proposed wetlands would also provide aesthetic, educational, and ecological value to the area
resulting in long-term beneficial impacts.
A Solicitation of Views (SOV) was sent to USACE; per correspondence dated May 5, 2017,
USACE does not require a Department of Army permit under Section 404 of the Clean Water Act.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 21
Figure 8 National Wetlands Inventory Map with Project Area Outlined in Red (U.S. Fish & Wildlife
Service, 2017).
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
Because the project area has been drained and is completely built up, implementation of the
Preferred Alternative would have no adverse effects on wetlands. The long-term beneficial impacts
under the Preferred Alternative would be similar in nature, but greater in effect, to those described
for Alternative 2, because the Preferred Alternative would create more wetlands. These proposed
wetlands would provide a natural space to retain storm water runoff and to provide a natural filter
for removal of pollutants from storm water. The wetlands would also provide aesthetic,
educational, and ecological value to the area resulting in long-term beneficial impacts.
An SOV was sent to USACE. Per correspondence dated May 5, 2017, USACE does not require a
Department of Army permit under Section 404 of the Clean Water Act.
3.5 Floodplains & Hydrology
3.5.1 Regulatory Setting
Executive Order 11988, Floodplain Management, requires federal agencies to avoid direct or
indirect support or development within or affecting the 1 percent annual chance special flood
hazard area (i.e., 100-year floodplain) whenever there is a practicable alternative (for “Critical
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 22
Actions,” within the 0.2 percent annual chance special flood hazard area, or the 500-year
floodplain). FEMA used NFIP Flood Insurance Rate Maps (FIRMs) to determine the flood hazard
zone for the proposed project location. FEMA regulations for complying with EO 11988 are
codified in 44 CFR Part 9, Floodplain Management and Protection of Wetlands.
This EA forms part of the “Eight-Step Planning Process” (44 CFR 9.6) that decision-makers must
use when considering projects either located within the floodplain or with the potential to affect
the floodplain. The Eight-Step Planning Process: assesses the action regarding human
susceptibility to flood harm and impacts to wetlands; analyzes principle flood problems, risks from
flooding, history of flood loss, and existing flood protection measures; and includes public notice
and opportunity for the public to have early and meaningful participation in decision-making and
alternative selection. If impacts cannot be avoided, the Eight-Step Planning Process includes
requirements to incorporate measures to minimize and mitigate potential risks from flooding and
impacts to wetlands as appropriate.
Under 44 CFR Part 9, FEMA is required to avoid activities in a floodplain unless it is the only
practicable alternative. If a proposed project in the floodplain is the only practicable alternative,
then FEMA must minimize the impacts to the floodplain and the impacts from floods to the facility
or structure being proposed. Minimization techniques apply to the location of structures, facilities
equipment, and building contents in floodplain areas. This could include elevating facilities or
structures above the base flood elevation. Minimization techniques may include flood-proofing
structures or facilities.
3.5.2 Existing Conditions
The Parish of Orleans enrolled in the NFIP on October 19, 1971. The project area is partially
located within Special Flood Hazard Area Zone "AE", Elevation 1, and 0.2 percent chance of
annual flood, per Digital Flood Insurance Rate Map Panel Number 22071C0114F, dated
September 30, 2016 (Figure 9).
In July 2005, prior to Hurricane Katrina, FEMA initiated a series of flood insurance studies for
many of Louisiana’s coastal parishes as part of the Flood Map Modernization Effort through
FEMA’s National Flood Insurance Fund. These studies were necessary because the flood hazard
and risk information shown on the effective Flood Insurance Rate Maps (FIRMs) was developed
during the 1970s. Since that time, the physical terrain had changed considerably, including the
significant loss of wetland areas. After Hurricanes Katrina and Rita, FEMA expanded the scope
of work to include all of coastal Louisiana. The magnitude of impacts caused by the two hurricanes
reinforced the urgency to obtain additional flood recovery data for the coastal zones of Louisiana.
More detailed analysis was possible because new data obtained after the hurricanes included
information on levees and levee systems, new high-water marks, and new hurricane parameters.
During an initial post-hurricane analysis, FEMA determined that the 100-year, or 1 percent annual
chance, storm flood elevations on FIRMs for many Louisiana communities - including the
community where the project area is located - were too low or were not adequate for protection.
These storm flood elevations are referred to as Base Flood Elevations (BFEs). FEMA created
recovery maps showing the extent and magnitude of the surges from Hurricanes Katrina and Rita,
as well as information on other storms over the past 25 years. The 2006 advisory flood data shown
on the recovery maps for the Louisiana-declared disaster areas indicated high-water marks
surveyed after the storm, flood limits developed from these surveyed points, and Advisory Base
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 23
Figure 9 Flood Insurance Rate Map (FIRM) 22071C0114F Showing Project Area (Federal Emergency
Management Agency, 2016).
Flood Elevations (ABFEs). These recovery maps and other advisory data were developed to assist
parish officials, homeowners, business owners, and other affected citizens with their recovery and
rebuilding efforts.
Updated preliminary flood hazard maps from an intensive 5-year mapping project guided by
FEMA subsequently were provided to all Louisiana coastal parishes. These maps, released in
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 24
early 2008, known as Preliminary Digital Flood Insurance Rate Maps (DFIRMs), were based on
the most technically advanced flood insurance studies ever performed for Louisiana, followed by
multiple levels of review. The DFIRMs provided communities with a more scientific approach to
economic development, hazard mitigation planning, emergency response, and post-flood recovery.
USACE has completed work on a Hurricane and Storm Damage Risk Reduction System
(HSDRRS) for the Greater New Orleans area (United States Department of Defense, Department
of the Army, Corps of Engineers, 2011), which includes the project area. This 350-mile system of
levees, floodwalls, surge barriers, and pump stations reduce the flood risk associated with a storm
event. In September 2011, USACE provided FEMA with assurances the HSDRRS is capable of
defending against a storm surge with a 1 percent annual chance event of occurring in any given
year (United State Department of Defense, Department of the Army, Corps of Engineers, 2012).
The areas protected include portions of St. Bernard, St. Charles, Jefferson, Orleans, and
Plaquemines Parishes. FEMA has revised the preliminary DFIRMS within the HSDRRS to
incorporate the reduced flood risk associated with the system improvements.
In November 2012, FEMA revised the 2008 preliminary DFIRMS within the HSDRRS to
incorporate the reduced flood risk associated with the system improvements. The preliminary
DFIRMs were subsequently revised in 2013 and 2014. On September 30, 2016, the 2014 Revised
Preliminary DFIRMs for Orleans Parish became effective. The 2016 Effective DFIRMs are the
best available flood risk data for Orleans Parish.
The drainage system for Orleans Parish consists of many features typical of large urban cities in
the United States, and some features that are unique because much of the area is below sea level.
As in any urbanized area, catch basins and drop-inlets receive surface runoff from rooftops, yards
and streets, and excess runoff runs downslope overland and/or in the streets to areas of lower
elevation.
Runoff that can enter drop-inlets flows underground in small-diameter pipes (i.e., 36 inches or less
in diameter)), called the tertiary system. The tertiary system collects local flows and conveys them
to the secondary system, 36 inches to 60 inches in diameter, where several of these local flows
combine and are conveyed to the primary system.
Generally, pipes or box culverts larger than 60 inches in diameter are considered to be part of the
primary system. Large underground concrete box culverts, as large as 16 feet wide by 11 feet
high, convey primary system flows from the Filmore neighborhood to the suction basin at pumping
stations DPS 3 and DPS 4. Both stations pump directly to the tidal waters of Lake Pontchartrain
via the London Avenue Canal. As previously stated in this EA, the existing drainage system in the
Filmore neighborhood is often overwhelmed during heavy rainfall events, largely due to excessive
runoff flow rates.
3.5.3 Environmental Consequences
Alternative 1 – No Action
The scope of the No Action alternative includes no upgrades to the current drainage infrastructure,
and localized flooding would continue to impact the area as urban development increases and
current drainage systems continue to age, with corresponding reductions in drainage capacity.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 25
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
As required by Section 9.6 of EO 11988, the Eight-Step Planning Process was conducted for this
EA. The findings of the process indicate that no adverse impacts to or within the base floodplain
are anticipated. A copy of the Eight-Step documentation for this project is included in Appendix
E.
Alternative 2 would provide flood mitigation and increased storm water storage capacity for the
Filmore neighborhood. The project would have no discernible benefit or cost during a 1%
(100-year) flooding event in the Mirabeau Basin. Significant benefits and costs are associated with
this project for more frequent, lower-discharge, 24-hour-duration rainfall events (2-year, 5-year,
and 10-year). The drainage basin containing the project area does not have any inflows coming in
from outside, so no “upstream” impacts are considered. This project alternative is designed to
decrease storm water runoff flowrates, particularly those associated with more frequent, lower-
discharge, 24-hour rainfall events (2-, 5-, and 10-year return intervals) in the Mirabeau basin.
Storm water flow rates from the project area would be reduced through a series of on-site collection
mitigation actions, diversion of storm water loads to pumping stations DPS 3 and DPS 4, leading
to smaller discharge flows to the London Avenue Canal. Downstream impacts would be
minimal/negligible as these receiving channels carry a significantly higher flow, with later flow-
rate peaking times. Additional benefits include the capture of on-site rainfall, and infiltration of
surface runoff into the soils, which would also contribute to the reduction of local subsidence
issues associated with lowered ground water tables.
Construction of the Mirabeau Water Garden Storm water Management and Flood Mitigation
Project would therefore improve the floodwater storage capacity of the floodplain by increasing
the amount of infiltration to groundwater. The action could potentially support development in the
floodplain by reducing flood hazards in the project area; however, the project area is an already
densely populated urban area with little room for further development.
Per 44 CFR 9.11(d)(6), no project should be built to a floodplain management standard that is less
protective than what the community has adopted in local ordinances through their participation in
the NFIP. The project is in compliance with Chapter 78 of the City of New Orleans Code of
Ordinances, The Flood Damage Prevention Ordinance, according to a letter from the CNO
Floodplain Administrator, dated May 1, 2017.
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
As required by Section 9.6 of EO 11988, the Eight-Step Planning Process was conducted for this
EA. The findings of the process and of this floodplain assessment indicate that no adverse impacts
to, or within, the base floodplain are anticipated.
Despite some design differences, the preferred alternative is expected to have similar beneficial
impacts to the floodplain as Alternative 2. Alternative 3 would provide flood mitigation and
increased storm water storage capacity in the Filmore neighborhood.
The project would have no discernible benefit or cost during a 1% probability (100-year) rainstorm
flooding event in the Mirabeau Basin. The benefits and costs associated with this project are for
more frequent, lower-discharge events (2-, 5-, and 10-year return intervals). The Filmore drainage
basin does not have any inflows coming in from outside, so no “upstream” impacts are considered.
The project scope is designed to decrease storm water flow rates, and particularly, to reduce storm
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 26
water surface elevations for these more frequent, lower-discharge events (2-, 5-, and 10-year return
intervals) in the Mirabeau basin. These storm water flow rate and water level reductions would be
effected through a series of on-site collection mitigation actions, diversion of storm water loads
from pumping stations DPS 3 and DPS 4, thus resulting in smaller discharge flow rates to the
London Avenue Canal. Per the final upstream/downstream analysis, indicated in the applicant’s
H&H study report (Appendix F), the project would reduce water surface elevations and the number
of flooded off-site structures during the 2-, 5-, and 10-year flooding events in the Mirabeau basin.
Additional benefits include the capture of on-site rainfall, and infiltration of surface runoff into the
soils, which would also contribute to the reduction of local subsidence issues associated with
lowered ground water tables.
Construction of the Mirabeau Water Garden Storm water Management and Flood Mitigation
Project would therefore improve the floodwater storage capacity of the floodplain by increasing
the amount of infiltration to groundwater. The action could potentially support development in the
floodplain by reducing flood hazards in the project area; however, the project area is an already
densely populated urban area with little room for further development.
Alternative 3 would have similar direct and indirect impacts as Alternative 2. The function of this
proposed alternative of the Mirabeau Water Garden Storm Water Management and Flood
Mitigation project would be the same or very similar to that of Alternative 2 and is a practicable
and desirable alternative. Additionally, the hydrology and hydraulics modeling results report
(Appendix F) states that,
This project reduces the storm runoff load on the existing storm sewer system. Upstream
areas are expected to receive immediate benefits for various storms, and additional
benefits from this project as the typically constricted storm sewer flow is improved by
replacement of currently undersized storm sewer pipes with larger pipes included in the
City capital improvements program. The downstream system would receive immediate
benefits as the storm runoff flow burden on the serving storm sewer and pump stations
are reduced. The flow from this area flows DPS 3 and DPS 4. Both of these pump stations
outlet to the London Avenue Canal. The pump stations are maintained by the Sewerage
and Water Board of New Orleans. There are no anticipated negative impacts to the
upstream or downstream watersheds as a result of this project. (MSMM Engineering,
LLC, 2018)
Per 44 CFR 9.11(d)(6), no project should be built to a floodplain management standard that is less
protective than what the community has adopted in local ordinances through their participation in
the NFIP. The project is in compliance with Chapter 78 of the City of New Orleans Code of
Ordinances, The Flood Damage Prevention Ordinance, according to a letter from the CNO
Floodplain Administrator, dated May 1, 2017.
3.6 Coastal Resources
3.6.1 Regulatory Setting
The Coastal Zone Management Act (CZMA) of 1972 (16 USC 1451, et seq.) is administered by
the Department of Commerce’s Office of Ocean and Coastal Resource Management within the
National Oceanic and Atmospheric Administration (NOAA). It applies to all coastal states and to
all states that border the Great Lakes. The CZMA was established to help prevent any additional
loss of living marine resources, wildlife, and nutrient-enriched areas; alterations in ecological
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 27
systems; and decreases in undeveloped areas available for public use. The CZMA gives states the
authority to determine whether activities of governmental agencies are consistent with federally-
approved coastal zone management programs. Each state coastal zone management program must
include provisions protecting coastal natural resources, fish, and wildlife; managing development
along coastal shorelines; providing public access to the coast for recreational purposes; and
incorporating public and local coordination for decision-making in coastal areas. This voluntary
federal-state partnership addresses coastal development, water quality, shoreline erosion, public
access, protection of natural resources, energy facility siting, and coastal hazards.
The Federal Consistency provision, contained in Section 307 of the CZMA, allows affected states
to review federal activities to ensure that they are consistent with the state’s coastal zone
management program. This provision also applies to non-federal programs and activities that use
federal funding and that require federal authorization. Any activities that may have an effect on
any land or water use or on any natural resources in the coastal zone must conform to the
enforceable policies of the approved state coastal zone management program. NOAA’s regulations
in 15 CFR Part 930 provide the procedures for arriving at or obtaining a consistency determination.
The CZMA requires that coastal states develop a State Coastal Zone Management Plan or program
and that any federal agency conducting or supporting activities affecting the coastal zone conduct
or support those activities in a manner consistent with the approved state plan or program. To
comply with the CZMA, a federal agency must identify activities that would affect the coastal
zone, including development projects, and review the state coastal zone management plan to
determine whether a proposed activity would be consistent with the plan.
3.6.1.1 Louisiana State and Local Coastal Resources Management Act of 1978
Pursuant to the CZMA, the State and Local Coastal Resources Management Act of 1978 (RS
49:214.21, et seq., Act 1978, No. 361) is the state of Louisiana’s legislation creating the Louisiana
Coastal Resources Program (LCRP). The LCRP establishes policy for activities including
construction in the coastal zone, defines and updates the coastal zone boundary, and creates
regulatory processes. The LCRP is under the authority of the Louisiana Department of Natural
Resources (LDNR) Office of Coastal Management (OCM). Per the CZMA, all proposed federal
projects within the coastal zone must undergo a Consistency Determination by OCM for that
project’s consistency with the state’s Coastal Resources Program, i.e., LCRP (Louisiana
Department of Natural Resources, 2016).
3.6.1.2 Coastal Barrier Resources Act of 1982
The Coastal Barrier Resources Act (CBRA) of 1982 (16 USC 3501 et seq.), administered by
USFWS, was enacted to protect sensitive and vulnerable barrier islands found along the U.S.
Atlantic, Gulf, and Great Lakes coastlines. The CBRA established the Coastal Barrier Resources
System (CBRS), which is composed of undeveloped coastal barrier islands, including those in the
Great Lakes. With limited exceptions, areas contained within a CBRS are ineligible for direct or
indirect federal funds that might support or promote coastal development, thereby discouraging
development in coastal areas.
Otherwise Protected Areas (OPAs) are a category of coastal barriers within the CBRS. OPAs are
undeveloped coastal areas established under Federal, State, or local law or held by a qualified
organization, primarily for wildlife refuge, sanctuary, recreational, or natural resource
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 28
conservation purposes. Flood insurance is restricted in OPAs, though OPAs may receive other
forms of Federal Assistance.
3.6.2 Existing Conditions
All of Orleans Parish, including the Mirabeau project area and the Filmore neighborhood, is within
the regulated coastal zone of Louisiana. It is located entirely within fast lands, which are defined
by the Louisiana State Legislature as “lands surrounded by publicly owned, maintained, or
otherwise validly existing levees, or natural formations, as of the effective date of this Act or as
may be lawfully constructed in the future, which levees or natural formations would normally
prevent activities, not to include the pumping of water for drainage purposes, within the
surrounded area from having direct and significant impacts on coastal waters” (State of Louisiana,
2006). The area is located within the Louisiana Coastal Management Zone (LCMZ) and may
require a Coastal Use Permit (CUP) application. The project area is not located in, or connected
to, a CBRS Unit or otherwise protected area (OPA).
3.6.3 Environmental Consequences
Alternative 1 – No Action
The No Action Alternative would have no effect on the Louisiana Coastal Zone. No permit would
be required.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
In a letter dated September 28, 2012, the Louisiana Office of Coastal Management determined that
the granting of financial assistance is fully consistent with the Louisiana Coastal Resources
Program. Per a letter dated April 26, 2017, the Louisiana Office of Coastal Management has
determined in accordance with the State and Local Coastal Resources Management Act of 1978,
as amended (La. R.S. 49:214.34.a), the proposed activity is exempt and a Coastal Use Permit is
not required. This determination is valid for 2 years from the date of this letter. If the proposed
activity is not initiated within this 2-year period, this determination would expire and the applicant
would be required to submit a new application.
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
In a letter dated September 28, 2012, the Louisiana Office of Coastal Management determined that
the granting of financial assistance is fully consistent with the Louisiana Coastal Resources
Program. Per a letter dated April 26, 2017, the Louisiana Office of Coastal Management has
determined in accordance with the State and Local Coastal Resources Management Act of 1978,
as amended (La. R.S. 49:214.34.a), the proposed activity is exempt and a Coastal Use Permit is
not required. This determination is valid for 2 years from the date of this letter. If the proposed
activity is not initiated within this 2-year period, this determination would expire and the applicant
would be required to submit a new application.
3.7 Biological Resources
3.7.1 Regulatory Setting
The Endangered Species Act (ESA) of 1973 (16 USC 1531-1543) prohibits the taking of listed,
threatened, and endangered species unless specifically authorized by permit from USFWS or
National Marine Fisheries (NMFS). “Take” is defined in 16 U.S.C. 1532(19) as "to harass, harm,
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 29
pursue, hunt, shoot, wound, kill, trap, capture, or collect or attempt to engage in any such conduct.”
“Harm” is further defined to include significant habitat modification or degradation that results in
death or injury to listed species by significantly impairing behavioral patterns such as breeding,
feeding, or sheltering (50 CFR 17.3).
Section 7(a)(2) of the ESA requires the lead federal agency to consult with either USFWS or
NMFS, depending which agency has jurisdiction over the federally listed species in question, when
a federally funded project either may have the potential to adversely affect a federally listed
species, or a federal action occurs within or may have the potential to impact designated critical
habitat. The lead agency must consult with USFWS, NMFS, or both (Agencies) as appropriate and
will determine if a biological assessment is necessary to identify potentially adverse effects to
federally listed species, their critical habitat, or both. If a biological assessment is required, it will
be followed by a biological opinion from USFWS, NMFS, or both depending on the jurisdiction
of the federally listed species identified in the biological assessment. If the impacts of a proposed
federal project are considered negligible to federally listed species, the lead agency may instead
prepare a letter to the Agencies with a “May Affect, but Not Likely to Adversely Affect”
determination requesting the relevant agency’s concurrence. This EA serves to identify potential
impacts and meet the ESA Section 7 requirement by ascertaining the risks of the proposed action
and alternatives to known federally listed species and their critical habitat, as well as providing a
means for consultation with the regulatory agencies.
Unless otherwise permitted by regulation, the Migratory Bird Treaty Act (MBTA) of 1918
(16 USC 703-712) prohibits pursuing; hunting; taking; capturing; killing; attempting to take,
capture, or kill; possessing; offering for sale; selling; offering to purchase; purchasing; delivering
for shipment; shipping; causing to be shipped; delivering for transportation; transporting; causing
to be transported; carrying or causing to be carried by any means whatever; receiving for shipment,
transportation, or carriage; or exporting; at any time or in any manner, any migratory bird or any
part, nest, or egg of any such bird, that is included on the list of protected bird species. USFWS is
responsible for enforcing the provisions of the MBTA.
3.7.2 Existing Conditions
The project area is currently a 25 acre greenspace within a developed urban area. The site has
trees, grasses, and shrubs commonly found and maintained in the adjacent urban areas including
an existing grove of oak trees. The vegetation species and animal species present in the area
typically can adapt to an urban/developed environment. These species include raccoon (Procyon
lotor), eastern gray squirrel (Sciurus carolinensis), rabbits (Sylvilagus sp.), rodents (Mus sp. and
Rattus sp.), and various species of birds, snakes, turtles, and amphibians. The site is terrestrial and
has been previously disturbed. No state or federal parks, wildlife refuges, scenic streams, or
wildlife management areas are located within the bounds of the project area.
According to the USFWS website and an official species list provided by the USFWS Louisiana
Ecological Services Field Office (U.S. Fish and Wildlife Service, 2017), multiple species listed on
the Federal Endangered Species List occur or potentially occur in Orleans Parish (Appendix D).
Most of these species are aquatic and are thus not expected to be present. Two endangered bird
species, the Piping Plover and the Red Knot, are also known to occur or potentially occur within
Orleans Parish.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 30
3.7.3 Environmental Consequences
Alternative 1 – No Action
The No Action Alternative would include no construction activities in the project area and the
opportunity to provide a more diverse habitat in the area to increase biodiversity in the project area
would be lost. This alternative would result in no significant impacts to urban vegetation or animal
species.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
FEMA has determined Alternative 2 would not affect listed species or modify designated critical
habitat in accordance with USFWS stamped letter dated February 08, 2017, and LDWF letter,
dated February 10, 2017 (Appendix D). Long-term beneficial impacts to biological resources
would occur at the site because an increase in habitat variability would have a subsequent increase
in biodiversity at the site. The introduction of shallow aquatic environments would provide habitat
for species of amphibians, reptiles, birds, small mammals, and insects that currently do not inhabit
the site.
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
FEMA has determined the Preferred Alternative would not affect listed species or modify
designated critical habitat in accordance with USFWS stamped letter dated February 8, 2017, and
LDWF letter dated February 10, 2017 (Appendix D).
Long-term beneficial impacts to biological resources would be similar to those described for
Alternative 2, but additional beneficial impacts would be realized under the Preferred Alternative
as more aquatic habitat would be created.
3.8 Air Quality
3.8.1 Regulatory Setting
The Clean Air Act of 1970 (with 1977 and 1990 Amendments)
The Clean Air Act (CAA) (42 Section 7401 et seq.) regulates air emissions from stationary and
mobile sources. This law tasks the USEPA with establishing primary and secondary air quality
standards. Primary air quality standards protect the public’s health including the health of
“sensitive populations, such as people with asthma, children, and older adults.” Secondary air
quality standards protect the public’s welfare by promoting ecosystem health, preventing
decreased surface visibility, and reducing damage to crops and buildings. The USEPA has also set
National Ambient Air Quality Standards (NAAQS) for the following six criteria pollutants:
Carbon Monoxide (CO), Lead (Pb), Nitrogen Oxides (NOx), Ozone (O3), Sulfur Dioxide (SO2), and particulate matter less than 10 micrometers (PM10).
According to 40 CFR Section 93.150(a): “No department, agency or instrumentality of the federal
government shall engage in, support in any way, or provide financial assistance for, license or
permit, or approve any activity which does not conform to an applicable implantation plan.” In
addition, the followings section adds: “A federal agency must make a determination that a federal
action conforms to the applicable implementation plan in accordance with the requirements of this
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 31
subpart before the action is taken”. As a result, when FEMA provides financial assistance for a
project located in a NAAQS “non-attainment area” for any one of the six criteria pollutants, the
CAA requires and evaluation of the applicability of the General Conformity Rule (GCR).
The GCR currently applies to federal actions that are taken in designated nonattainment or
maintenance areas, with the following exceptions.
(1) Actions covered by the Transportation Conformity Rule
(2) Actions with associate emissions clearly at or below specified de minimis levels
(3) Actions listed as exempt in the rule
(4) Actions covered by an approved “presumed to conform” list (see 40 CFR Section 93.153[c])
GCR de minimis emission thresholds were created by the USEPA with the intent of limiting the
need for General Conformity determination when actions generate minimal emissions. These
thresholds are defined in 40 CFR Section 93.153(b) and represent the maximum level of allowable
emissions to remain within the de minimis exemption, in tons per calendar year for each criteria
pollutant or its precursor compound. De minimis levels for nonattainment areas in Louisiana,
identified in Title 33, Chapter III, Section 1405.B of the Louisiana Administrative Code (LAC
33:III.1405.B), are identical to those defined in the federal statute.
3.8.2 Existing Conditions
According to The EPA Greenbook (U.S. Environmental Protection Agency, 2017a), Orleans
Parish falls with the Southern Louisiana-Southeast Texas Interstate Air Quality Control Region.
In 2015, Orleans Parish achieved attainment of the NAAQS for ozone (O3). Based on past criteria,
Orleans Parish also achieved attainment of NAAQS for carbon monoxide (CO) levels, sulfur
dioxide (SO2), lead (Pb), particulate matter less than 2.5 micrometers (PM2.5), and nitrous oxides
(NOx). Therefore, Orleans Parish has no GCR obligations.
3.8.3 Environmental Consequences
Alternative 1 – No Action
The No action alternative would include no construction activities in the project area. Therefore,
this alternative would result in no adverse impacts to air quality.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
A temporary increase in vehicle emissions would result from construction trucks and equipment
during the construction of Alternative 2. However, no long-term or significant impacts to air
quality are anticipated. Currently, Orleans Parish is classified as in NAAQS attainment and has no
general conformity determination obligations.
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
As with Alternative 2, a temporary increase in vehicle emissions would result from construction
trucks and equipment during the construction of the proposed project under the preferred
alternative. However, no long-term or significant impacts to air quality are anticipated for the
preferred alternative. Currently, Orleans Parish is classified as in NAAQS attainment and has no
GCR determination obligations, per a letter from LDEQ dated May 16, 2017 (Appendix D).
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 32
To reduce emissions of air pollution from equipment during construction, fuel-burning equipment
times should be kept to a minimum and engines should be properly maintained. Airborne dust
control measures should be implemented during construction as well.
3.9 Noise
3.9.1 Regulatory Setting
Noise is defined as unwanted sound, indicating that perceived noise impacts are inherently
subjective. Measured in terms of air pressure, sound intensity spans several orders of magnitude.
As a result, the response of the human ear to sound is best represented by a logarithmic scale rather
than a linear scale.
The basic unit of measure on this logarithmic scale is the decibel (dB), and various weighted dB
scales (A, B, C) are used to approximate how people perceive different types of sounds (U.S.
Federal Transit Administration, 2006) (U.S. Environmental Protection Agency, 1974). Noise level
(volume) is generally measured in dB using the A-weighted sound pressure level (dBA). The A-
weighted scale is an adjustment to be consistent with that of human hearing, which is most
sensitive to frequencies around 4,000 hertz (roughly comparable to the highest note on a piano)
and less sensitive to low frequencies (below 100 hertz).
In addition to the instantaneous measurement of sound levels, the duration of sound is important.
Sounds that occur over a long period of time are more likely to be an annoyance or cause direct
physical damage or environmental stress. One of the more commonly used noise metrics that
considers duration as well as sound power level is the equivalent noise level (Leq). The Leq is
defined as the steady A-weighted level equivalent to the same amount of energy as that contained
in the actual time-varying levels over a period of time. Typically, Leq is summed over a 1-hour
period (U.S. Federal Transit Administration, 2006).
Average acceptable day-night sound levels fall in a range between 50 dBA in quiet suburban areas
to 70 DBA in noisier urban areas (U.S. Environmental Protection Agency, 1974). The day-night
sound level is a cumulative metric that accounts for the total sound energy occurring over a 24-
hour period, with nighttime noise (occurring from 10 pm to 7 am) more heavily weighted to reflect
community sensitivity during nighttime hours. A sound level of 75 dBA is generally considered
unacceptable in urban areas, with 85 dBA being unacceptable in industrial areas (United States
Department of Housing and Urban Development [HUD], 2018).
Sound is federally regulated by the Noise Control Act of 1972, which charges the USEPA with
preparing guidelines for acceptable ambient noise levels. USEPA guidelines, and those of many
other federal agencies, state that outdoor sound levels more than 55 dBA are “normally
unacceptable” for noise-sensitive land uses including residences, schools, or hospitals (U.S.
Environmental Protection Agency, 1974).
Within Orleans Parish, the noise control program is administered through the combined efforts of
the Department of Health and the Police Department. Orleans Parish has regulations concerning
noise in the Code of Ordinances, Chapter 66, Article IV, 66-136. It is unlawful to operate power
equipment between the hours of 10:00 pm and 7:00 am on weekdays, and between 10:00 pm and
8:00 am on weekends. However, installation and maintenance of public and private utilities, as
well as construction activities for which a permit has been issued, are limited to work between the
hours of 7:00 a.m. and 6:00 p.m. in areas that are zoned as residential. During those hours, none
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 33
of the noise produced by machinery less than 5 horsepower shall exceed 75 dBA, and machinery
over 5 horsepower shall not exceed 82 dBA.
The City of New Orleans Noise Ordinance (Section 66) places restrictions on any source of sound
exceeding the maximum permissible sound level based on the time of day and the zoning district
within which the sound is emitted. A number of exemptions exist for certain types of activities,
however. In accordance with the City’s Noise Ordinance Section 66-138, noises “from
construction and demolition activities for which a building permit has been issued by the
department of safety and permits are exempt from” maximum permissible sound level restrictions
“between the hours of 7:00 a.m. and 11:00 p.m., except in those areas zoned as RS [Single-Family],
RD [Two-Family], or RM [Multi-Family] residential districts. Construction and/or demolition
activities shall not begin before 7:00 a.m. or continue after 6:00 p.m. in areas zoned as RS, RD, or
RM residential districts, or within 300 feet of such residential districts. Mufflers on construction
equipment shall be maintained” (City of New Orleans, 2018).
3.9.2 Existing Conditions
The proposed project is located within a residential area and surrounded by sensitive receptors
(i.e., homes, schools, medical facilities, and churches). As such, the average day-night sound
pressure levels would be expected to be between the 40 dBA to 50 dBA range due to the residential
and public-use nature of the area.
3.9.3 Environmental Consequences
Alternative 1 – No Action
Under the No Action Alternative, there would be no short- or long-term impact on the noise
environment because no construction would occur.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
Alternative 2 would not cause any long-term noise impacts to the surrounding area. Construction
activities would cause a short-term increase in noise levels. However, they would not exceed noise
levels stated in parish ordinances (82 dBA). Equipment and machinery utilized on the project sites
would be expected to meet all local, state, and federal noise regulations. All activities located in
RS, RD or RM zones, or within 300 feet of such residential districts shall not begin before 7:00
a.m. or continue after 6:00 p.m. Due to the temporary nature of these activities and the applicable
City of New Orleans Noise Ordinance, noise would not exceed the maximum permissible sound
level based on the time of day and the zoning district within which the sound is emitted, and long-
term noise effects would not occur.
Noise associated with construction projects is difficult to predict because heavy machinery is
constantly moving in irregular patterns. However, the approximate sound levels associated with
each noise source (i.e., each piece of heavy equipment) are listed in the “Transit Noise and
Vibration Impact Assessment” manual (U.S. Federal Transit Administration, 2006). Table 3 lists
average noise levels by vehicle type. The noise impacts associated with construction of the
Mirabeau Water Garden would occur during daylight hours, and the vast majority of the noise
would be created from sources more than 50 feet from inhabited structures.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 34
Table 3 Average Noise Levels by Vehicle
Equipment Usage Factor (%)1 Typical Noise Level (dBA) 50 feet from Source2
Air Compressor 40 81
Backhoe 40 80
Mobile Crane 16 83
Excavator 40 85
Loader 40 85
1 (U.S. Federal Highway Administration , 2006)
2 (U.S. Federal Transit Administration, 2006)
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
The Preferred Alternative would not cause any long-term noise impacts to the surrounding area.
Construction activities under this alternative are expected to be similar to those described in
Alternative 2, and would, therefore, cause a similar, short-term increase in noise levels. However,
because offsite noise receptors are located more than 50 feet from the sound sources, they would
not experience noise levels that exceed the applicable limit stated in parish ordinances (82 dBA).
3.10 Traffic and Parking
3.10.1 Regulatory Setting
The City of New Orleans Department of Public Works maintains approximately 1,547 miles of
streets and 149 bridges in the City of New Orleans including all the streets in the project area.
According to the Department of Public Work’s website; “The Department of Public Works’
mission is to construct and maintain the highest quality of safe and sustainable transportation
facilities for users of vehicular, bicycle, pedestrian and rail transportation, in order to improve the
quality of life and create opportunities for economic development for all New Orleanians” (City
of New Orleans, 2017). Louisiana Department of Transportation and Development (LDOTD) is
responsible for developing and maintaining public transportation, state highways, interstate
highways under state jurisdiction, airports and heliports, railways, waterways, and bridges located
within the state of Louisiana.
3.10.2 Existing Conditions
The project area is bounded by Mirabeau Avenue to the North, Cartier Avenue to the east, Owens
Boulevard to the south, and St. Bernard Avenue to the west. Since the project area encompasses
nearly the entire block bounded by these four streets, no cross-streets exist for consideration. The
four streets bounding the project location are in various states of disrepair following repeated
flooding events.
The only roadway with available traffic data from either LDOTD or New Orleans Regional
Planning Council (NORPC) is Mirabeau Avenue. Based on 2008 statistics, the average daily
traffic (ADT) count at the corner of Mirabeau and Wisner Boulevard was 1,824 vehicles per day
in 2008. Where Mirabeau Avenue crosses the London Avenue Canal, average traffic counts were
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 35
much higher. The Mirabeau Avenue ADT at London Canal was 3,978 vehicles per day in 2008.
Since Mirabeau Avenue is a divided roadway, only eastbound traffic might experience any
incidental issues.
3.10.3 Environmental Consequences
Alternative 1 – No Action
The No Action Alternative would include no construction activities in the project area. Therefore,
this alternative would have no impact on traffic or roadways at any location near the site.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
Implementation of Alternative 2 would require heavy trucks and machinery for moving large
volumes of soil and bringing in materials such as hay bales, silt fencing, geotextiles, stakes, plants,
and hardware. A temporary increase in construction traffic may affect traffic circulation patterns
and motorists’ perception of traffic movement. There would be temporary disruptions in traffic
flow of the streets bordering the project area (Mirabeau Avenue, Cartier Street, Owens Boulevard,
and St. Bernard Avenue). No significant increase in traffic is expected under Alternative 2.
The contractor would be responsible for handling all traffic control and warning in accordance
with the Manual of Uniform Traffic Control Devices (23 CFR 655, subpart F), including placing
signs and signals in advance of construction activities in order to alert pedestrians and motorists
of the upcoming work and traffic pattern changes (e.g., detours or lanes dedicated for construction
equipment egress). There may be times when certain streets would be closed to all but local traffic
and rerouting of through traffic to alternate roads might become necessary. The contractor would
be expected to provide a traffic control schedule prior to commencing construction.
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
Impacts to traffic and parking from implementation of the Preferred Alternative would be similar
to those described for Alternative 2, because the project area and construction intensity would be
similar.
3.11 Historic and Cultural Resources
3.11.1 Regulatory Setting
The consideration of impacts to historic and cultural resources is mandated under Section 101(b)4
of NEPA as implemented by 40 CFR 1501-1508. Section 106 of the National Historic Preservation
Act (NHPA) requires Federal agencies to take into account their effects on historic properties (i.e.,
historic and cultural resources, including American Indian Cultural Sites) and allows the Advisory
Council on Historic Preservation an opportunity to comment. Additionally, it is policy of the
Federal government to consult with Indian Tribal Governments on a Government-to-Government
basis as required in EO 13175. FEMA has chosen to address potential impacts to historic
properties through the Section 106 consultation process of NHPA as implemented through 36 CFR
Part 800.
The “Section 106 process” requires the identification of historic properties that may be affected by
the proposed action or alternatives within the project’s Area of Potential Effects (APE). Historic
properties, defined in Section 101(a)(1)(A) of the NHPA, include districts, sites (archaeological
and religious/cultural), buildings, structures, and objects that are listed in or determined eligible
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 36
for listing in the National Register of Historical Places (NRHP). Historic properties are identified
by qualified agency representatives in consultation with interested parties
To fulfill its Section 106 responsibilities, FEMA has initiated consultation on this project in
accordance with the Louisiana Programmatic Agreement Among the FEMA, the Louisiana State
Historic Preservation Officer (SHPO), the Governor’s Office Of Homeland Security and
Emergency Preparedness (GOHSEP), and Participating Tribes (PA), executed on December 21,
2016 (Federal Emergency Management Agency, Louisiana State Historic Preservation Officer, the
Governor’s Office Of Homeland Security and Emergency Preparedness, Participating Tribes,
2016). The PA streamlines the Section 106 review process for all FEMA funded projects in
Louisiana
3.11.2 Existing Conditions
Cultural resources in the project area were identified by reviewing the NRHP database; the
Louisiana Cultural Resources Map provided by the Louisiana Division of Archaeology, historic
map research, FEMA’s internal Section 106 files, a site visit (conducted on May 18, 2016) and a
Phase I Cultural Resources Investigation (completed in April 2016).
The Mirabeau Gardens Drainage area is located along the backslope of the Mississippi River’s
natural levee and historically would have been characterized as backswamp or marsh until forced
drainage of the area into newly created drainage canals began in the twentieth century. The
development of the “Lakeshore” area of New Orleans began slowly and primarily occurred near
the lakefront area and to the east of the London Avenue Canal. It was not until the 1940s when
the St. Bernard Housing Development opened that the neighborhood near the project area began
to develop.
The subdivisions that now make up the Filmore neighborhood (Bayou Vista / Parish Oaks) were
not developed until after 1945, when soldiers returning home from World War II created a housing
demand nationwide. New Orleans, like many urban areas in the United States developed rapidly
during the pos-war building boom. Sometime between 1940 and 1951, houses began to appear
along Cartier Avenue (Sanborn Fire Insurance Map of New Orleans, Volume 10 1937, updated
1951; Sanborn Map Company). After 1951, residential development continued around the project
area and in 1952 construction was completed on the Novitiate House for The Sisters of St. Joseph
of Medaille located on the north end of the 25-acre tract of land where the Mirabeau Drainage
Garden is proposed. Subsequently, the Sisters of St. Joseph commissioned the construction of a
Provincial House (in 1956) and an Infirmary (in 1981).
Following Hurricane Katrina in 2005, the Mirabeau Garden tract and the surrounding project area,
like much of New Orleans, was inundated with flood waters. The Sisters of St. Joseph began work
to clean up the campus; however, in June 2006, the Provincial House was struck by lightning and
caught fire. The campus was subsequently demolished in 2008 and only remnants related to the
former Sisters of St. Joseph facility remain within the project area (including streets, sidewalks,
drains, a small stone grotto, and a portion of terrazzo floor bearing the crest of the Sisters of St.
Joseph and the walled entrance).
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 37
3.11.3 Environmental Consequences
Alternative 1 – No Action
Implementing the No Action Alternative would result in the continuation of flooding in the project
area including any cultural resources. This alternative does not include a FEMA undertaking;
therefore, FEMA has no further responsibilities under Section 106 of NHPA.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
A Phase I Cultural Resources survey of the project area was conducted. The survey resulted in a
negative findings report, meaning no archaeological properties eligible for listing the NRHP were
identified and no further investigation is necessary. Subsequently, FEMA determined no standing
structures within or adjacent to the project area are listed on or eligible for listing on the NRHP
and no historic properties would be affected by the construction of the Mirabeau Water Garden.
FEMA consulted with the SHPO and affected Tribes regarding the undertaking in a letter dated 2
June 2016. FEMA received SHPO concurrence with the determination that no historic properties
would be affected on 10 June 2016. Consultation with affected Tribes (the Alabama-Coushatta
Tribe of Texas, Chitimacha Tribe of Louisiana, Choctaw Nation of Oklahoma, Coushatta Tribe of
Louisiana, Jena Band of Choctaw Indians, Mississippi Band of Choctaw Indians, Muscogee Creek
Nation; Seminole Nation of Oklahoma, Seminole Tribe of Florida, and the Tunica-Biloxi Tribe of
Louisiana) was conducted per 36 CFR 800.2(c)(2)(i)(B). The Muscogee Creek Nation (MCN)
submitted written concurrence with the determination. The remaining Tribes did not respond
within the regulatory timeframes; therefore, in accordance with Stipulation II.C.4 of the PA and
36 CFR part 800.5(c)1.
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
The Phase I Cultural Resources survey and determination of no historic properties is applicable to
Alternative 3. Since no historic properties were identified within the APE, Alternative 3, like
Alternative 2, would not affect any historic properties.
3.12 Socioeconomics and Environmental Justice
3.12.1 Regulatory Setting
EO 12898 Federal Actions to Address Environmental Justice in Minority Populations and Low-
Income Populations requires a federal agency to “make achieving environmental justice part of its
mission by identifying and addressing, as appropriate, disproportionally high human health or
environmental effects of its programs, policies, and activities on minority populations and low
income populations.”
Environmental Justice is defined as “the fair treatment and meaningful involvement of all people-
regardless of race, color, national origin, culture, education, or income—in the development,
implementation, and enforcement of environmental laws, regulations and policies.” (Federal
Emergency Management Agency, 2012). FEMA further defines fair treatment as “no racial, ethnic,
or socioeconomic group should bear a share of negative consequences resulting from industrial,
municipal, and commercial operations, or the execution of federal, state, local and tribal
environmental programs and policies”.
According to the CEQ (Council on Environmental Quality, 1997a), a minority individual is a
member of the following population groups: American Indian or Alaskan Native, Asian or Pacific
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 38
Islander, Black, not of Hispanic origin, or Hispanic. A minority population is identified where
either a) the minority population of the affected area exceeds 50 percent or b) the minority
population percentage of the affected area is meaningfully greater than the minority population
percentage in the general population. Race and ethnicity are two separate categories of minority
populations. A minority population can be defined by race, by ethnicity, or by a combination of
the two distinct classifications.
3.12.2 Existing Conditions
The immediate project area is uninhabited with no housing units located within its boundaries. The
project area consists of 25 acres within the 416-acre US Census Bureau Census Tract 33.02 (census
tract). Therefore, the demographic data available for this census tract has been used for the analysis
of Socioeconomic and Environmental Justice effects. Census Tract 33.02 is located within zip code
70122. Demographic data presented below was acquired online using the USEPA Environmental
Justice Screening and Mapping Tool (USEPA, 2017).
The population of the entire census tract is 3,476 individuals. Of these, 1,356 individuals (39%
percent of the total population) are considered low-income, which is 8 percentage points less than
the overall percentage for Orleans Parish. The minority population in the census tract comprises
92 percent of the population, and 88 percent of the population identified as African-American,
while the remaining 12 percent is comprised of Hispanic, Caucasian, and Asian people, as well as
some that identify as belonging to two or more races. The minority population in the census tract
is 21 percentage points higher than the overall minority population of Orleans Parish. Also, the
census tract has a substantially higher percentage of owner-occupied homes, and a lower
unemployed percentage, than does Orleans Parish. Additionally, of those 16 years or older, the
census tract unemployment rate of 3 percent is lower than the 6 percent of all individuals in Orleans
Parish. This census information is summarized in Table 4.
3.12.3 Environmental Consequences
In compliance with EO 12898, the following key questions were addressed regarding potential
Environmental Justice concerns:
Is there an impact caused by the proposed action? Yes
Is the impact adverse? No
Is the impact disproportionate? No
Has an action been undertaken without considerable input
by the affected low-income and/or minority community? No
Alternative 1 – No Action
Because the proposed projects would not be implemented, the No Action Alternative would not
cause disproportionally high human health or environmental effects on minority populations
and/or low income populations. Flooding of streets could prevent community members from
leaving their homes and going to work or school causing loss of income and absences from school.
With each flooding event, community resources must be spent to repair and restore damaged
properties and vehicles.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 39
Table 4: Demographic and Economic Information for the Census Tract In Which the Project Area is
Located and for Orleans Parish. (USEPA, 2017)
2011-2015
Estimate for
Mirabeau Water
Garden Census
Tract 33.02
Percentage
of
Population
in Mirabeau
Water
Garden
Census Tract
33.02
2011-2015
Estimate for
Orleans Parish
Percentage of
Population in
Orleans
Parish
Total Population 3,476 100% 376,738 100%
Minority Population 3,192 92% 268,144 71%
Households 1,234 Not
Provided 153,140 Not Provided
Housing Units 1,504 Not
Provided 191,951 Not Provided
Owner-Occupied
Housing Units
987 80%
70,853 46%
Renter-Occupied
Housing Units
247 20%
82,297 56%
Low Income 1,356 39% 177,067 47%
Population Ages 16-64 2,688 Not
Provided 307,039 Not Provided
Labor Force Employed
(civilian) 1,733 65% 190,715 62%
Labor Force
Unemployed (civilian) 90 3% 19,523 6%
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
Storm water management is a problem throughout the city of New Orleans. As part of the effort
to update the 2010 Hazard Mitigation Grant Program Mitigation Plan, an updated and expanded
planning process was used to review and select sites for FEMA HMGP funded drainage projects
as well as other projects. Sites, including the Mirabeau Water Garden project, were selected based
on many factors including flood risk, available land, drainage rates. This planning process included
various stakeholders from across the city of New Orleans and is described in the in the background
and public involvement sections of this EA.
Implementing Alternative 2 would have long-term beneficial effects for the residents surrounding
the project area regardless of their racial makeup or economic situation. The Filmore neighborhood
has been susceptible to flooding events in the past. Drainage improvements would reduce
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 40
resources expended on flooding response and recovery. Public Notice to the affected communities
has been and would continue to be provided.
Under Alternative 2, there could be short-term, minor adverse impacts on populations living in the
project area during construction of the project. Impacts might include increased noise levels and
traffic disruptions associated with construction activities. Noise and traffic disruptions would be
temporary and consistent with construction activities typically found in urban areas.
The implementation of Alternative 2 would not have disproportionately high adverse impacts on
minority or low-income groups in the project area.
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
As with Alternative 2, the Preferred Alternative would have long-term positive effects for the
residents of the project area regardless of their racial makeup or economic situation. Under
Alternative 3, there could be short-term, minor adverse impacts on populations living in the project
area during construction of the project. Impacts might include increased noise levels and traffic
disruptions associated with construction activities. Noise and traffic disruptions would be
temporary and consistent with construction activities typically found in urban areas.
Implementation of the Preferred Alternative would not have disproportionately high adverse
impacts on minority of low-income groups in the project area. The CNO maintains a resilience
website, https://nola.gov/resilience/ where it updates project information. The CNO has also held
several public meetings for citizens to voice their concerns regarding the project, including a
meeting in August 2017 at the nearby Arthur Ashe School on Gardena Drive. Information
regarding these meetings may be found in the Public Involvement section of this EA. CNO is
required to update the community of any future test results that have the potential to impact the
community.
3.13 Hazardous Material
3.13.1 Regulatory Setting
The management of hazardous materials is regulated under various federal and state environmental
and transportation laws and regulations, including but not limited to the Resource Conservation
and Recovery Act (RCRA); the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA); the Toxic Substances Control Act (TSCA); the Emergency Planning and
Community Right-to-Know provisions of the Superfund Amendment and Reauthorization Act
(SARA); the Hazardous Materials Transportation Act; and the Louisiana Voluntary Investigation
and Remedial Action statute. The purpose of the regulatory requirements set forth under these
laws is to ensure the protection of human health and the environment through proper management
(identification, use, storage, treatment, transport, and disposal) of these materials. Some of the
laws provide for the investigation and cleanup of sites already contaminated by releases of
hazardous materials, wastes, or substances.
TSCA (codified at 15 USC 53), authorizes the USEPA to protect the public from “unreasonable
risk of injury to health or the environment” by regulating the introduction, manufacture,
importation, sale, use, and disposal of specific new or already existing chemicals. Existing
chemicals include any chemical currently listed under Section 8(b), including polychlorinated
biphenyls (PCBs), asbestos, radon, lead-based paint, chlorofluorocarbons, dioxin, and hexavalent
chromium.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 41
TSCA Subchapter I, “Control of Toxic Substances” (Sections 2601-2629), regulates the disposal
of PCB-containing products, sets limits for PCB levels present within the environment, and
authorizes the remediation of sites contaminated with PCBs. Subchapter II, “Asbestos Hazard
Emergency Response” (Sections 2641-2656), authorizes the USEPA to impose requirements for
asbestos abatement in schools and requires accreditation of those who inspect asbestos-containing
materials. Subchapter IV, “Lead Exposure Reduction” (Sections 2681-2692), requires USEPA to
identify sources of lead contamination in the environment, to regulate the amounts of lead allowed
in products, and to establish state programs that monitor and reduce lead exposure.
3.13.2 Existing Conditions
A Phase I Environmental Site Assessment of the 1200 Block of Mirabeau Avenue was conducted
in 2015 (Appendix G). Environmental Data Resources, Inc. (EDR) provided a Phase I
Environmental Site Assessment report of known hazardous material sites near the project area
(Figure 10). Based on records produced by EDR, the Phase I Environmental Site Assessment
concluded that there were no hazardous conditions present that could disrupt or become disturbed
by construction activities on the site. A review of LDEQ and USEPA databases confirmed the
assessment. A list of nearby sites analyzed as part of the Environmental Site Assessment is
provided below (Materials Management Group, Inc., 2015)
1. One nearby RCRA Small Quantity Generator was identified:
Bob’s Foreign Car Service, 1553 Wakefield Place, located 0.235 miles east of the project site.
LDEQ Agency Interest (AI) Number associated with this facility is 6202. The most recent
available report associated with this facility is dated April 5, 1995.
2. One US Brownfield site was identified:
Gas Station, 1555 Mirabeau Avenue, located 0.233 miles east-northeast of the project site. No
LDEQ AI Number associated with this facility could be identified.
3. EDR records included one dry cleaner within 0.25 miles of the project site:
Soap Opera, 1530 Mirabeau Avenue, located 0.203 miles east-northeast of the project site.
LDEQ AI Number associated with this facility is 39496. The most recent available report
associated with this facility is dated April 25, 1995
4. EDR identified four historical automotive service stations within 0.25 miles of project site.
5. EDR identified three historical dry cleaners within 0.25 miles of the project site.
3.13.3 Environmental Consequences
Alternative 1 – No Action
The No Action alternative would include no construction activities in the project area. Therefore,
this alternative would not disturb or contact any hazardous materials or create any potential hazards
to human or environmental health.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
A review of conditions indicated that no hazardous materials are likely present at the project site.
Hazardous materials typically related to construction activities (e.g., petroleum, oils, and/or
lubricants [POLs]) may be used during the conduction of the Mirabeau Water Garden. Short-term
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 42
Figure 10 Phase I ESA summary map of known hazardous material site near project location.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 43
adverse impacts associated with the use of POLs during construction could occur if these materials
are spilled or leaked onto the ground surface at the project area. If POLs spill or leak during
construction, appropriate measures would be used to properly clean the area where the spill or leak
occurred, in accordance with state and federal SWPPP implementation requirements. During
operation of the Mirabeau Water Garden, hazardous materials may be used for general
maintenance, including, but not necessarily limited to, pesticides, herbicides, paints, and POLs.
No significant quantities of hazardous materials would be stored at the project site, and no
significant effects of hazardous material use are anticipated.
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
Because construction and operations under the preferred alternative would be similar to those
under Alternative 2, impacts from hazardous materials are expected to be similar to those described
under Alternative 2. Hazardous materials typically associated with construction activities (e.g.,
POLs) may be used during the conduction of the Mirabeau Water Garden. Short-term adverse
impacts associated with the use of POLs during construction could occur if these materials are
spilled or leaked onto the ground surface at the project area. If POLs spill or leak during
construction, appropriate measures would be used to properly clean the area where the spill or leak
occurred, in accordance with state and federal SWPPP implementation requirements. During
operation of the Mirabeau Water Garden, hazardous materials may be used for general
maintenance, including, but not necessarily limited to, pesticides, herbicides, paints, and POLs.
No significant quantities of hazardous materials would be stored at the project site, and no
significant effects of hazardous material use are anticipated. CNO is required to update the
community of any future groundwater or soil tests results that have the potential to impact the
community.
3.14 Public Safety
3.14.1 Regulatory Setting
As a matter of public health and safety, an integrated mosquito management approach is used by
the CNO Mosquito, Termite, and Rodent Control Board. The need for organized mosquito
abatement operations in the city of New Orleans has been driven by a habitat uniquely suited to
produce overwhelming mosquito populations, disease epidemics, and public outcry. Historically,
these efforts have proved successful with no human cases of Yellow fever reported in the city of
New Orleans after 1905. In the years that followed, public attention turned from Yellow fever to
Malaria. Formal malaria eradication efforts, led by the United States Department of Health Public
Health Service, continued in New Orleans until 1954.
3.14.2 Existing Conditions
The project location does not collect standing water that could breed mosquitoes.
3.14.3 Environmental Consequences
Alternative 1 – No Action
The No Action alternative would include no construction activities in the project area. Therefore,
this alternative would not create any additional standing water that could breed mosquitoes.
Alternative 2 - Mirabeau Water Garden: Treatment Cell Storage and Permanent Pool
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 44
As a matter of public health and safety, an integrated mosquito management approach is used by
the CNO Mosquito, Termite, and Rodent Control Board. This involves vector population
surveillance, public education, larval mosquito habitat reduction, and chemical control of larval
and adult mosquitoes. Larval source reduction (i.e., the physical elimination of larval breeding
sites) involves inspection and removal of man-made containers, clutter, and trash. For sites that
cannot be removed or drained, biorational larvicides (i.e., pesticides that are relatively non-toxic
to people with few environmental side effects) are used to target early mosquito stages. Adult
mosquitoes can be treated at the yard-, block-, or residential level using a variety of equipment.
An understanding of the basic biology of mosquitoes and the factors that influence their density is
used to effectively implement Integrated Pest Management for mosquito control. Integrated Pest
Management incorporates a continual process of monitoring, sampling, and surveillance to observe
changes in the mosquito population density, diversity, ecology, and behavior.
The aim of vector monitoring is to define a guide for effective and efficient mosquito control
interventions. Mosquito surveillance can target any life stage; egg, larvae, pupae, adult. Green
infrastructure projects such as the proposed Mirabeau Water Garden are included in routine survey,
surveillance, and mosquito control sites.
Additionally, a 501(c)3 non-profit organization, Bayou Land Resource Conservation and
Development (RC&D) Council, has partnered with the New Orleans Mosquito Rodent & Termite
Control Board and with Water Works L3C, a low-profit limited-liability company (L3C), to aid in
mosquito control specifically in green infrastructure projects. According to their website, the goals
of the project aim to:
Monitor green infrastructure sites to ensure that these areas are: draining properly,
improving water quality parameters, and are not providing mosquito breeding habitats
Increase citizen understanding of green infrastructure (GI) opportunities and limitations
Increase citizen engagement with GI from the lot to the neighborhood level
Provide managers with technical guidance which will inform MS4 program and support
design criteria identified in local policies and ordinances.
Alternative 3 - Mirabeau Water Garden: Pond Storage Using Existing Topography (Preferred
Alternative)
As similarly described for Alternative 2, with implementation of Alternative 3, an integrated
mosquito management approach would be used by the CNO Mosquito, Termite, and Rodent
Control Board. Green infrastructure projects such as the proposed Mirabeau Water Garden are
included in routine survey, surveillance, and mosquito control sites.
4.0 CUMULATIVE IMPACTS
The most severe environmental degradation may not result from the direct effects of any particular
action, but from the combination of effects of multiple, independent actions over time. As defined
in 40 CFR 1508.7 (CEQ Regulations), a cumulative effect is the impact on the environment that
results from the incremental impact of the action when added to other past, present, and reasonably
foreseeable future actions regardless of what agency (federal or non-federal) or person undertakes
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 45
such other actions. Principles of cumulative effects analysis are described in the CEQ guide,
“Considering Cumulative Effects under the National Environmental Policy Act” (Council on
Environmental Quality, 1997b). CEQ guidance on cumulative impacts analysis states that,
“For cumulative impacts analysis to help the decision-maker and inform interested parties,
it must be limited through scoping to effects that can be evaluated meaningfully. The
boundaries for evaluating cumulative impacts should be expanded to the point at which the
resource is no longer affected significantly or the impacts are no longer of interest to
affected parties” (Council on Environmental Quality, 2006).
Not all potential issues identified during cumulative effects scoping need be included in an EA.
Because some effects may be irrelevant or inconsequential to decisions about the proposed action
and alternatives, the focus of the cumulative effects analysis should be narrowed to important
issues of national, regional, or local significance. To assist agencies in this narrowing process,
CEQ (Council on Environmental Quality, 1997b) provides a list of several basic questions to be
considered, including:
(1) Is the proposed action one of several similar past, present, or future actions in the same
geographic area?
(2) Do other activities (governmental or private) in the region have environmental effects similar
to those of the proposed action?
(3) Have any recent or ongoing NEPA analyses of similar or nearby actions identified important
adverse or beneficial cumulative effect issues?
(4) Has the impact been historically significant, such that the importance of the resource is defined
by past loss, past gain, or investments to restore resources?
It is normally insufficient when conducting a cumulative effects analysis to merely analyze effects
within the immediate area of the proposed action. Geographic boundaries should be expanded for
cumulative effects analysis and conducted on the scale of human communities, landscapes,
watersheds, or airsheds. Temporal frames should be extended to encompass additional effects on
the resources, ecosystems, and human communities of concern. A useful concept in determining
appropriate geographic boundaries for a cumulative effects analysis is the project impact zone, that
is, the area (and resources within that area) that could be affected by the proposed action. The area
appropriate for analysis of cumulative effects will, in most instances, be a larger geographic area
occupied by resources outside of the project impact zone (Council on Environmental Quality,
1997b).
The proposed project area is centered at latitude 30.003405, longitude -90.082120 in zip code
70122. FEMA established the list of resource categories to analyze cumulative effects based upon
how the project affected certain resources analyzed within this EA and determined the
environmental resources that have the potential for cumulative effects include; socioeconomic and
the floodplain or hydrology. FEMA has determined that the affected portions of the SWBNO
drainage basins constitute an appropriate boundary for a cumulative impact analysis of the
proposed action and the alternatives since the storm water for the project area outfalls to both DPS
3 and DPS 4. This study area is comprised of three parts: the western section of DPS 4 drainage
area from the Inner Harbor Navigation Canal to the London Avenue Canal, the northern section of
DPS 3 drainage area above Harrison Avenue, and the undesignated district from Mirabeau Avenue
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 46
to Stars and Stripes Boulevard (Figure 11). The study area for cumulative impacts is approximately
7.4 square miles and includes zip codes 70122, 70126 and 70148. This area was chosen largely
Figure 11 A map showing FEMA-funded projects within the Cumulative Impacts Study area.
due to potential impacts to the floodplain or watershed. Other projects that have the potential to
have a socioeconomic impact, such as traffic, noise, and air quality were analyzed within the study
area but a closer range, within a radius of 0.5 miles from the project site.
In Orleans Parish, over 8,000 FEMA program-funded emergency protective measures, repair
projects and hazard mitigation projects have occurred, are occurring, or are reasonably foreseen to
occur to buildings, recreational and educational facilities, public utilities, and waterways in the
time period August 2005 through June 2017. Figure 11 depicts 90 FEMA-funded undertakings
that fall within or intersect the study area, representing an obligated amount of over $88.8 million
for two FEMA disasters. Eighty-six of the 90 project sites inside the study area were Public
Assistance grants, and the majority of these were educational facilities.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 47
Grants for Public Assistance projects fell under two categories: Category B, Emergency Protective
Measures (37%) and Category E, Public Buildings (59%). Three of the 90 FEMA-funded project
sites are associated with HMGP storm water management projects:
Dillard University Mitigation Project – A link to additional information about this project is:
https://www.fema.gov/ar/media-library/assets/documents/117620
Pontilly Water Mitigation – A link to additional information about this project is:
https://www.fema.gov/media-library/assets/documents/161710
Bayou St. John Drainage Project – A link to additional information about this project is:
https://www.fema.gov/media-library/assets/documents/151962
The Bayou St. John project drains into the same pump stations as the Mirabeau Water Garden
project. FEMA is also funding nearly 2 billion dollars of infrastructure improvements throughout
the city of New Orleans to include road and utility repair and replacement. Table 5 represents
projects FEMA has identified that have the potential to affect resources cumulatively with this
project including the planned infrastructure work within a 0.5-mile radius from the project site.
4.1 Environmental Consequences
The proposed and foreseeable mitigation projects are expected to fulfill the purposes of the projects
by mitigating flooding up to the 10-year, 24-hour storm and therefore reducing the loss of property
during these events. The number and size of NFIP claims is expected to be reduced within the
project areas. The combined population of the HMGP project areas comprises approximately 14
percent of the population in the affected drainage basins of DPS 3 and DPS 4 (United States
Enviromental Protection Agency, 2017). However, additional benefits are projected to occur
outside the project areas. The project analyzed in this EA is also intended to reduce the load on
DPS 3 and DPS 4. Additional benefits include the capture of on-site rainfall, water infiltration
into soils in a subsidence prone area, and the creation of wetlands (Waggoner & Ball, 2018).
In summary, the cumulative effect of these present, past, and reasonably foreseeable future actions
is not anticipated to result in a significant impact to environmental resources. Each of the projects
analyzed either aims to restore or improve the function of pre-existing infrastructure within an
urban setting or proposes redevelopment consistent with current zoning requirements, with
minimal impacts to the natural and human environment occurring cumulatively with the proposed
project. Likewise, the project in combination with other drainage projects within the study area
would have a positive impact on the natural and human environment by reducing flooding and
restoring floodplain values.
Mirabeau Water Garden Stormwater Management and Flood Mitigation Project Draft Environmental Assessment 48
Table 5 Projects Identified as Having Potential to Contribute to Cumulative impacts
Project
Name/Status
Lead
Agency Location Description
Cumulative
Impact Rationale
Gentilly
Resilience
District
CNO,
FEMA,
SWBNO and
HUD
Throughout
drainage basin 4
Designed spaces to
capture rainwater using
green infrastructure and
other techniques
Minimal/
beneficial
The project is designed to improve floodplain conditions by
improving natural values of floodplain and drainage in the
basin.
Mirabeau Water
Garden
FEMA
(HMGP),
CNO, and
HUD
1200 Mirabeau
Avenue
Installation of educational
components at the
Mirabeau Water Garden
Minimal/
beneficial
Project would promote floodplain and storm water
sewerage educational opportunities to the residents of New
Orleans.
Bayou St. John
(Hagan Lafitte)
Drainage
Project
FEMA
Portion of the
Bayou St. John
neighborhood
bordered by North
Broad Street,
Orleans Avenue,
Bayou St. John,
and the St. Louis
Canal / Lafitte
Greenway
Installation of green and
gray drainage
infrastructure including
an underground water
storage feature at Warren
Easton Park
Minimal/
beneficial
Minimal impact, Cultural Resource Impacts are site
specific. Similar to Mirabeau this project is designed to
reduce flow into DPS 3 and DPS 4 and therefore should
have a positive impact on the floodplain
Pontilly Storm
water
Mitigation
FEMA
(HMGP),
and CNO
Pontchartrain
Park and Gentilly
Woods
neighborhoods
Installation of green and
gray drainage
infrastructure
Minimal/
beneficial
The project is designed to improve floodplain conditions by
improving natural values of floodplain and drainage in the
basin.
Dillard
University
Drainage
Project/in
construction
FEMA
(HMGP)
2601 Gentilly
Blvd.
New Orleans, LA
70122
Upgrades to surface and
subsurface campus
drainage system, linked to
the London Avenue Canal
Minimal /
beneficial
The project is designed to improve floodplain conditions by
improving natural values of floodplain and drainage in the
basin.
SWBNO
Reconstruction/
Elevation and
Hardening of
Nine Sewage
Pump Stations/
complete
FEMA/
SWBNO
Throughout the
City
Reconstruction, elevation
and hardening of nine
sewage pump stations
Minimal This project is designed to mitigate against flooding.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 49
Project
Name/Status
Lead
Agency Location Description
Cumulative
Impact Rationale
SWBNO Pump
Stations USACE
Throughout
Orleans Parish
Drainage pump station
repairs and elevation Minimal
The project is designed to mitigate against flooding and
work in tandem with the proposed and considered
alternatives.
Filmore South
Group A
infrastructure
repairs Future
(2017- 2018)
CNO and
FEMA
St. Bernard Ave,
Gardena, Riviera,
Mirabeau,
Bancroft,
Wakefield,
Westbrook, Paula
Repairs of damaged
roads, sidewalks, and
curbs
Minimal
Construction would not affect drainage in the area and
would cumulatively have a positive impact on
infrastructure within the project area. Project would have
some temporary impacts to traffic. This would be
minimized by BMP.
Filmore South
Group B Future
(2017- 2018)
CNO and
FEMA
Cartier Ave. and
Owens Blvd,
Gardena Dr., St.
Bernard Avenue,
Davey and
Cadilla St.
Repairs and replacement
of utilities, sidewalks, and
road
Minimal
Construction would not affect drainage in the area and
would cumulatively have a positive impact on
infrastructure within the project area. Project would have
some temporary impacts to traffic. This would be
minimized by BMP.
Filmore South
Group C Future
(2020-2021)
CNO and
FEMA
Seville Drive,
Bancroft Drive,
and Granada
Drive
Repairs and replacement
of utilities, sidewalks, and
road
Minimal
Construction would not affect drainage in the area and
would cumulatively have a positive impact on
infrastructure within the project area. Project would have
some temporary impacts to traffic. This would be
minimized by BMP.
Filmore South
Group D Future
(2021-2022)
CNO and
FEMA
Davey, Cadillac,
Carnot, Gardena,
Wellington,
Kennon,
Randolph, Pratt,
St. Bernard
Repairs and replacement
of utilities, sidewalks, and
road
Minimal
Construction would not affect drainage in the area and
would cumulatively have a positive impact on
infrastructure within the project area. Project would have
some temporary impacts to traffic. This would be
minimized by BMP.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 50
Project
Name/Status
Lead
Agency Location Description
Cumulative
Impact Rationale
Repairs and
reconstruction
of critical
physical
infrastructure
(Past, Present
and Future)
FEMA
Throughout
Orleans Parish
metropolitan area
including Orleans,
Jefferson, St.
Bernard,
Plaquemines, St.
Tammany, St.
Charles, and St.
John the Baptist
parishes
Repairs, reconstruction,
and improvements to
critical infrastructure such
as hospitals, schools, fire
stations, utilities,
government buildings and
detention centers
Minimal
Project is conditioned to comply with minimum NFIP
floodplain regulations as adopted by the local community
and would thereby reduce risk and increase protection from
future damage. Effects to cultural resources considered to
be not adverse or are minimized or mitigated through
consultation.
Response to
Hurricanes
Katrina and Rita
USACE
Orleans, St.
Bernard,
Jefferson,
Plaquemines, St.
Mary’s,
Terrebonne, and
Lafourche
Parishes
Evaluates emergency
actions to unwater New
Orleans Metropolitan
Area; rehabilitate
federally authorized
levees, and restore non-
federal levees and pump
stations (Orleans, St.
Bernard, Jefferson and
Plaquemines Parishes);
and flood flight
operations (St. Mary’s,
Terrebonne, and
Lafourche Parishes)
Negligible
Adverse impacts to resources (wetlands) required
compensatory mitigation and are much different from those
in the currently proposed action; there are no wetland
resources associated with proposed action; no impact on
proposed action
Lafitte
Greenway
Corridor
FEMA N. Lopez Bridge,
N. Lopez Street
Restoration of bridge and
installation of bicycle and
pedestrian paths
Negligible
Construction would not affect drainage in the area and
would cumulatively have a positive impact on
infrastructure within the project area. Effects to adjacent
cultural resources considered to be not adverse or would be
minimized or mitigated through consultation.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 51
Project
Name/Status
Lead
Agency Location Description
Cumulative
Impact Rationale
City of New
Orleans City-
Wide Road
Repairs
CNO and
FEMA
New Orleans
City-Wide
Repairs, replacements,
and improvements to
roads and components
damaged as a result of
Hurricane Katrina.
Elements include
upgrades to current codes
and standards including
mitigation measures to
reduce the risk of future
damages in the next
flood.
Negligible
Construction would not affect drainage in the area and
would cumulatively have a positive impact on
infrastructure.
New Orleans
Sewer and
Water Board
Water Supply
and Sanitary
Sewer System-
Wide Repairs
SWBNO New Orleans
City-Wide
Repairs and
improvements to water
and sanitary sewer system
components damaged as a
result of Hurricane
Katrina. Elements include
upgrades to current codes
and standards including
mitigation measures to
reduce the risk of future
damages in the next
flood.
Negligible
Project is conditioned to comply with minimum NFIP
floodplain regulations as adopted by the local community
and would thereby reduce risk and increase protection from
future damage
Laffite Housing
Development HANO
3801 St. Bernard
Avenue
Repair and Replacement
of the Lafitte Housing
Development
Negligible
Project is conditioned to comply with minimum NFIP
floodplain regulations as adopted by the local community
and would thereby reduce risk and increase protection from
future damage
Public
Assistance
Grant funded
Emergency
Protective
Measures
(2005-2008)
FEMA
33 projects
throughout study
area (see Figure
10)
Emergency Protective
Measures implemented to
protect life and property
before, during and after
Hurricane Katrina
Negligible
Emergency Protective Measures had minimal impact to
resources, they are intended to preserve life and property
during and after a disaster. They are typically temporary in
nature and impact existing infrastructure
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 52
Project
Name/Status
Lead
Agency Location Description
Cumulative
Impact Rationale
Public
Assistance
Grant funded
Public
Buildings
(2005-2021)
FEMA
53 projects
throughout study
area (see Figure
10)
Repairs, reconstruction,
and improvements to
critical infrastructure such
as hospitals, schools, fire
stations, utilities,
government buildings and
detention centers
Negligible
Project is conditioned to comply with minimum NFIP
floodplain regulations as adopted by the local community
and would thereby reduce risk and increase protection from
future damage. Effects to cultural resources considered to
be not adverse or are minimized or mitigated through
consultation.
Mirabeau Water Garden Stormwater Management and Flood Mitigation Project Draft Environmental Assessment 53
5.0 CONDITIONS AND MITIGATION MEASURES
Construction of the proposed action at the 1200 Block of Mirabeau Avenue was analyzed based
on the consultations and review undertaken as part of the EA. The finding of the EA is that no
significant long-term adverse impacts would occur to geology, soils, and topography; water
resources (including wetlands and waters of the U.S.); floodplains; coastal resources; biological
resources; hazardous materials and sites; socioeconomics, environmental justice, and the
protection of children; traffic and parking; air quality, greenhouse gases and climate change; noise;
or historic and cultural resources. However, as a part of construction activities, short-term soils,
traffic, air quality, and noise impacts might occur. These short-term adverse impacts would be
mitigated through the implementation of Best Management Practices (BMPs). FEMA has
therefore concluded that implementing the proposed action, including the conditions and
mitigation measure listed in this, and other sections of the EA, meet the requirements for a FONSI
and the preparation of an EIS is not required.
The following conditions must be met as part of the implementation of the project. Failure to
comply with these conditions may jeopardize federal funds. The applicant is required to comply
with all federal, state, and local laws, EOs, and regulations. Failure to do so will jeopardize federal
funding.
The applicant would be required to comply with all federal, state, and local laws, EOs, and
regulations. Failure to do so will jeopardize federal funding.
The contractor would employ appropriate measure to eliminate or reduce any potential soil
sloughing, erosion or wind-blown soils through the implementation of appropriate BMPs
To reduce the emission of air quality pollution from equipment during construction, fuel-
burning equipment times should be kept to a minimum and engines should be properly
maintained. Dust minimization measures should be implemented during construction as well.
A Storm Water Pollution Prevention Plan (SWPPP) utilizing BMPs should be developed once
a detailed flood mitigation alternative is selected to mitigate any adverse impact that the storm
water runoff from the construction activities would have on the waters surrounding the
Mirabeau area.
A Louisiana Pollution Discharge Elimination (LPDES) permit is required in accordance with
the Clean Water Act and the Louisiana Water Quality Regulations. The applicant shall require
its contractor to prepare, certify, and implement a construction SWPPP approved by LDEQ to
prevent sediment and construction material transport from the project site. The applicant shall
comply with all conditions of the required permit. All coordination pertaining to these activities
should be documented and copies forwarded to the state and FEMA as part of the permanent
project files.
Since this project would require temporary lane closures and involves some disruption of
normal traffic in the project area, the contractor would keep an open dialogue with the public
and utilize the appropriate signage to indicate rerouted traffic and closed streets. The contractor
would also comply with all federal, state, and parish laws and regulations regarding
construction in high traffic areas.
The contractor would coordinate construction activities with the local floodplain administrator
for a floodplain development permit and all activities would be conducted in compliance with
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 54
relevant, applicable, and required local codes and standards designed to reduce the risk of
future flood loss; minimize the impacts of floods on safety, health, and welfare; and preserve
floodplain values.
Applicant is required to make the results of the planned groundwater and geotechnical analysis
publicly available through the New Orleans Department of Public Works. CNO is also required
to coordinate with LDEQ regarding the results of their investigation.
Subject to results of the planned groundwater and geotechnical analysis, the applicant is
required to implement a control mechanism or other BMPs, as appropriate, to maintain a
groundwater table elevation in and around the project area that will not cause excessive
groundwater seepage to the surface (Waggoner & Ball, 2018)
If the proposed activity is not initiated by April 26, 2019, the applicant is responsible for
coordinating with and obtaining any required permit(s) from the LDNR OCM prior to initiating
work.
To ensure no impacts to local or regional air quality, the contractor would comply with all
applicable federal, state, and/or local air pollution control requirements, including using water
or other chemicals (applied daily or as needed to each construction site, debris piles, bare soils,
etc.) and covering any open-bodied haul trucks to control dust. Emissions from the burning of
fuel by internal combustion engines would temporarily increase the levels of some of the
criteria pollutants, including CO2, NO2, O3, and PM10, and non-criteria pollutants such as
VOCs. To reduce these emissions, running times for fuel-burning equipment should be kept to
a minimum and engines should be properly maintained. Mitigation of increased, short-term
noise levels during construction should include limited construction time periods, proper
maintenance of construction equipment, and the selection of noise-dampening construction
techniques
Project construction would involve the use of potentially hazardous materials (e.g., gasoline,
diesel, brake and hydraulic fluid, cement, caustics, acids, solvents, and paint) and may result
in the generation of small volumes of hazardous wastes. Appropriate measures to prevent,
minimize, and control spills of hazardous materials must be taken and generated hazardous or
non-hazardous wastes are required to be disposed in accordance with applicable federal, state,
and local regulations.
The construction contractor, in accordance with all applicable laws and regulations, would
conduct all substantial construction equipment maintenance at off-site locations. On-site
equipment repairs (within the established construction or staging area) would be limited to
routine daily maintenance and repair. A 24-Hour Spill Response Program would also be
implemented if required by state or local authorities. All construction-related debris would be
recycled or disposed of at an approved landfill in accordance with all applicable federal, state,
and parish laws and regulations. Similarly, any hazardous wastes generated during construction
activities would be disposed of in accordance with all federal, state, and local regulations. If
any solid or hazardous wastes, or soils and/or groundwater contaminated with hazardous
constituents are encountered during the project, notification to LDEQ’s Single Point of Contact
(SPOC) at 225-219-3640 is required. Additionally, precautions must be taken to protect
workers from these hazardous constituents in accordance with all applicable Occupational
Safety and Health Act (OSHA) worker safety regulations.
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 55
Unusable equipment, debris and material shall be disposed of in an approved manner and
location. In the event that significant items (or evidence thereof) are discovered during
implementation of the project, applicant shall handle, manage, and dispose of petroleum
products, hazardous materials and/or toxic waste in accordance to the requirements and to the
satisfaction of the governing local, state and federal agencies. Applicant is responsible for
securing LDEQ permits for temporary debris staging and volume reduction sites associated
with this project prior to project closeout. Failure to provide FEMA with LDEQ approval may
jeopardize project funding eligibility.
The LDNR Office of Conservation should be contacted at 225-342-5540 if any unregistered
wells of any type are encountered during construction work.
For pipelines and other underground hazards, Louisiana One Call should be contacted at 800-
272-3020 at least 48 hours prior to commencing any subsurface excavation or drilling
operations.
Offsite location of activities such as borrow, disposal, haul-roads, detour-roads, and work
mobilization site developments may be subject to Department of the Army (DA) regulatory
requirements and may have an impact on a DA project (e.g., flood protection levees).
Avoid engaging in construction activities within 660 feet of a bald eagle or golden eagle nest
during nesting and fledging where there is no visual buffer, or 330 feet where there is a visual
buffer, as nesting eagles are quite sensitive to human activities during these times.
If human bone or unmarked grave(s) are present within the project area, compliance with the
Louisiana Unmarked Human Burial Sites Preservation Act (RS 8:671 et seq.) is required. The
applicant shall notify the law enforcement agency of the jurisdiction where the remains are
located within 24 hours of the discovery. The applicant shall also notify FEMA and the
Louisiana Division of Archaeology at 225-342-8170 within 72 hours after the discovery.
If during the course of work, archaeological artifacts (prehistoric or historic) are discovered,
the applicant shall stop work in the vicinity of the discovery and take all reasonable measures
to avoid or minimize harm to the finds. The applicant shall inform their HMGP contacts at
FEMA and GOHSEP, who will in turn contact FEMA Historic Preservation (HP) staff. The
applicant will not proceed with work until FEMA HP staff completes consultation with the
SHPO, and others as appropriate.
6.0 AGENCY COORDINATION AND PUBLIC INVOLVEMENT
6.1 Agency Coordination
Louisiana Department of Environmental Quality (LDEQ)
Louisiana Department of Natural Resources (LDNR)
Louisiana Department of Wildlife and Fisheries (LDWF)
Environmental Protection Agency (EPA)
United States Army Corps of Engineers (USACE)
United States Department of Agriculture (USDA)
City of New Orleans Floodplain Administrator
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 56
Louisiana State Historic Preservation Officer (SHPO)
U.S. Fish and Wildlife Service (USFWS)
Alabama Coushatta Tribe of Texas (ACTT)
Choctaw Nation of Oklahoma (CNO)
Chitimacha Tribe of Louisiana (CTL)
Coushatta Tribe of Louisiana (CT)
Eastern Shawnee Tribe of Oklahoma (ESTO)
Jena Band of Choctaw Indians (JBCI)
Kialegee Tribal Town (KT)
Mississippi Band of Choctaw Indians (MBCI)
Muscogee Creek Nation (MCN)
Seminole Tribe of Oklahoma (SNO)
Seminole Tribe of Florida (STF)
Tunica Biloxi Tribe of Louisiana (TBTL)
6.2 Public Involvement
A public meeting was held on Thursday, November 28, 2016, between 6:00-8:00 pm at Dillard
University Community Resource Center, 3301 Orleans Annette Street, New Orleans, Louisiana to
present the 30% design to the community and solicit feedback. Another public meeting was held
on August 5, 2017 at Arthur Ashe School, 1456 Gardena Drive, New Orleans, Louisiana to present
the 90% design. The project was also presented to the Resilience Project Design Committee
Meeting on June 30, 2016 at 2:30 PM, September 25, 2016 at 3:30 P.M. and December 13, 2016
at 1:30 p.m. in the 8 Floor Conference Room, at the CNO City Hall, 1300 Perdido Street, New
Orleans, Louisiana. Members of the committee include representatives from several City entities
including Sewerage and Water Board, Parks and Parkways, and the Planning Commission. These
meetings were also open to the public. Public comments and the Committee Member’s comments
were considered and addressed during the meeting or incorporated into the design documents
and/or maintenance plan.
The Mirabeau Water Garden is one of 91 projects identified in the City of New Orleans Hazard
Mitigation Plan. As part of the effort to update the 2010 Hazard Mitigation Grant Program
Mitigation Plan, an updated and expanded planning process was used to review and update the
plan to ensure broad representation from the community. Stakeholders for this planning effort
included non-profits, community organizations, environmental groups, and regional governmental
agencies with an interest in and/or responsibility for hazard mitigation planning. In addition to a
CNO City Hall Working Group and Advisory Committee, two additional groups were convened
for the purpose of holding discussions specific to their responsibilities (i.e., Public Safety Group
and Non-Profits and Community Organizations Group).
The CNO City Hall Working Group met eight times between June and October 2015. The purpose
of each meeting was as follows:
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 57
June 26, 2015 Overview/Hazards: overview of the hazard mitigation planning process;
review the 2010 Plan; hazards activity to rank hazards and discuss
correlation to 2010 risk assessment.
July 13, 2015 Assets and Goals: share draft maps and discuss data sources; exercise to
develop updated goals for 2015 Plan.
July 31, 2015 History of Impacts: update on risk assessment; discuss proposed goals;
hazards exercise to discuss what could have been done to reduce impacts of
different hazards in past 5 years.
August 13, 2015 Risk Assessment: update on risk assessment; overview of hazard impacts.
September 14, 2015 Mitigation Strategies: mitigation actions activity to determine how actions
fit under updated goals.
September 25, 2015 Capabilities/Implementation: capability assessment and mitigation action
implementation activities to determine process for city departments to
implement mitigation strategies.
October 9, 2015 Hazards Ranking/Draft Review: activity to rank hazards; review draft of
2015 Plan Update.
October 23, 2015 Final Draft Review: review of final 2015 Plan Update prior to submittal to
GOHSEP.
The Advisory Committee met four times between July and October 2015. The purpose of each
meeting was as follows.
July 8, 2015 Assets, Goals, Capabilities.
August 5, 2015 Risk Assessment.
September 18, 2015 Mitigation Strategies.
October 7, 2015 Implementation and Draft Review
Community involvement in the development of the Hazard Mitigation Plan update was
coordinated with an ongoing public engagement process through the CNO for the Resilient New
Orleans Strategy and National Disaster Resiliency Competition (NDRC). Community members
were informed of the planning process through a press release, as well as the City’s Hazard
Mitigation website (http://www.nola.gov/hazard-mitigation/). A survey was circulated to the
general public in August and September of 2015 and received over 130 responses and a public
comment form was posted on the City’s Hazard Mitigation website.
One community meeting was organized and held in conjunction with the NDRC public
engagement process. The community engagement meeting, held on October 19, 2015, included
public presentations of the risks, hazards, strategies, and implementation. Comments from the
public were cataloged and noted. Comments were used to inform mitigation action strategy
rankings. Community involvement in the Public Meeting included:
Receiving information about the hazard mitigation project planning process,
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 58
Sharing specific concerns about each phase of the planning effort,
Reviewing the recommendations from the Planning Group,
Identifying community priorities for hazard mitigation project planning.
A preliminary list of mitigation project actions, including 2010 mitigation actions that are ongoing
and potential new mitigation projects, was presented to the CNO Hazard Mitigation staff for its
review and then to the City Hall Working Group and Advisory Committee. The City Hall Working
Group and Advisory Committee provided feedback on the proposed actions, including their input
regarding the placement of the actions relative to the goals. The list of actions was also made
available to the community in October 2015.
Public notice of the availability of the draft EA is published on Wednesday, December 26, 2018;
Friday, December 28, 2018; and Wednesday, January 2, 2019 in the Times-Picayune, the journal
of record for Orleans Parish, as well as in The Advocate – New Orleans Edition on Wednesday,
December 26, 2018; Thursday, December 27, 2018; and Friday, December 28, 2018.to alert the
public that the Draft EA and draft Finding of No Significant Impact (FONSI) are available for
review at the New Orleans Public Library – Main Branch, located at 219 Loyola Avenue, and at
the Norman Mayer Branch located at 3001 Gentilly Blvd, both in New Orleans, LA . Additionally,
there will be a 30-day comment period beginning on Wednesday, December 26, 2018 and
concluding on Friday, January 25, 2019 at 4 pm. Once the public comment period for the Draft
EA is completed, comments will be addressed and incorporated into the EA as appropriate. A
copy of the draft FONSI is provided in Appendix H, and a copy of the Public Notice is attached in
Appendix I.
Electronic versions of the draft EA and draft FONSI can be viewed at FEMA's website at
http://www.fema.gov/resource-document-library. Comments may be mailed to:
DEPARTMENT OF HOMELAND SECURITY-FEMA EHP
MIRABEAU WATER GARDEN PROJECT
1500 MAIN STREET
BATON ROUGE, LOUISIANA 70802.
Comments may be emailed to: [email protected] or faxed to: 225-346-5848. Verbal
comments will be accepted or recorded at 225-267-2962. All comments must be received by
Friday, January 25, 2019 at 4 pm. If no substantive comments are received, the draft EA and
associated draft FONSI will become final.
7.0 CONCLUSION
The findings of this EA conclude that the proposed action at the proposed site would result in no
significant adverse impacts to the natural and human environment, including geology,
groundwater, floodplains, public health and safety, hazardous materials, socioeconomic resources,
environmental justice, or cultural resources.
During project construction, short-term impacts to soils, surface water, transportation, air quality,
and noise are anticipated and conditions have been incorporated to mitigate and minimize the
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 59
effects (see section 6, conditions and mitigation measures). No long-term adverse impacts are
anticipated from the proposed project. Therefore, FEMA finds the proposed action meets the
requirements for a FONSI under NEPA and the preparation of an EIS will not be required.
8.0 LIST OF PREPARERS
This EA was prepared under the direction of FEMA. Individuals who contributed to the
preparation of this document are:
Jerame Cramer Environmental Liaison Officer, FEMA
Tiffany Spann-Winfield Deputy Environmental Liaison Officer, FEMA
Amber Martinez Supervisory Historic Preservation Specialist, FEMA
LeSchina Holmes Lead Environmental Protection Specialist, FEMA
Melanie Pitts Supervisory Environmental Protection Specialist, FEMA
Robert E. Leslie, Jr., PE, CFM Hydraulic Civil Engineer, FEMA
Joey Chauvin Environmental and Historic Preservation Advisor, FEMA
Randy Norris Acclivity Associates
Darren Mitchell Acclivity Associates
Timothy Hall Technical Advisor, Quaternary Resource Investigations
Ron Moore Project Manager, Quaternary Resource Investigations
L. Rivers Berryhill Environmental Scientist, Quaternary Resource Investigations
Mirabeau Water Garden Storm Water Management and Flood Mitigation Project Draft Environmental Assessment 60
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