Concept Plan Development Incorporating Flood Mitigation into an Ecosystem Restoration Project

Concept Plan Development

Incorporating Flood Mitigation into

an Ecosystem Restoration Project

2nd National Flood Workshop: February 29, 2012

Westside Creeks Restoration Project

Historical Background - Significance

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2nd National Flood Workshop: Westside Creeks Restoration

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Historical Background - Flooding

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Historical Background - Flooding

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5

Historical Background - Channelization

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Historical Background - Channelization

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Existing Condition - Discharges

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Martinez Creek (DA = 7.3 mi2)

Alazan Creek (DA = 17.5 mi2)

Apache Creek (DA = 40.3 mi2)

San Pedro Creek (DA = 44.9 mi2)

Frequency (years)

Austin Urban Regression

Effective FIS


Effective FIS


Effective FIS


Effective FIS

1.5 (interpolated) 2,437 -- 3,978 -- 6,228 -- 6,672 --

2 3,113 -- 5,221 -- 8,419 -- 9,046 --5 5,161 -- 8,996 -- 15,083 -- 16,266 --

10 6,811 10,236 12,025 16,314 20,423 25,362 22,051 26,53625 9,236 -- 16,469 -- 28,251 -- 30,535 --50 11,336 15,633 20,269 24,393 34,856 40,474 37,687 42,563

100 13,581 18,191 24,304 27,935 41,831 46,726 45,232 49,312

Bankfull Discharge •The formative flow of water that characterizes the morphology (shape) of a fluvial channel

•Typically associated with a 1.5-year return period flow

Flood Depth0 – 1’

1 – 2’

2 – 5’

5 – 10’

10+’8

Existing Condition - Floodplain

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Existing Condition - Habitat

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Existing Condition - Base Flow

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Existing Condition - Neighborhoods

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Design Process - Catalyst Sites

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Design Process - Fluvial Geomorphology

Flat Stream Slope

>>> Increasing Sediment Supply >>>

Moderate Stream Slope

Steep Stream Slope

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• Natural Succession takes place over centuries

• This goal of this project is to take the Westside Creeks from barren flood channels to a “climax community” in ~50 years

Design Process - Vegetation

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Design Process - Flood Mitigation

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Concept Plan - Aerial View

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Type A: This restoration alternative defines locations where the extents of stream modifications are expected to remain essentially within existing ROW limits and publicly owned property.

Type B: In locations where additional property may be required to meet flood mitigation needs, the restoration alternative is shown with potential ROW expansion into existing privately owned properties. Flood mitigation is being coordinated with the Master Planning efforts in the San Antonio River basin and the dredging project in Elmendorf Lake.

Degrees of Restoration Intensity

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The first phase recommended for implementation includes 9 stream reaches (4 Type A and 5 Type B) and trails along the entire Westside Creeks, totaling approximately $300M.

Of these Phase 1 projects, 4 were selected as initial demonstration projects (Totaling $50M, + $10M for trails on all other stream reaches, in coordination with the Linear Trails Initiative):

Project Phasing

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Alazán Reach 1 (Type A) Apache Reach 1 (Type B) Martínez Reach 2 (Type B) San Pedro Reach 2*

(Type A)

Concept Plan - Cross Sections

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AL-1

AL-2

AL-3

AL-4

AL-5

AL-6

AL-7

AP-1

AP-2

AP-3

AP-4

AP-5

MA-1

MA-2

MA-3

MA-4

MA-5

SP-1

SP-2*

SP-3

SP-4

SP-5

SP-6

SP-7

Concept Plan - Phasing

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78,400,000$

Type A (restricted ROW) 8,950,000$

Trails only 235,000$


Type B (expanded ROW) 9,860,000$




84,600,000$






85,300,000$






42,400,000$


*Type A (restricted ROW) 15,800,000$





Trails only 1,780,000$

291,000,000$

-5% 276,000,000$ 15% 335,000,000$

DescriptionPhase 1

Cost

Reach 4 - Leal to Confluence with Martinez Creek

Reach 5 - Confluence with Martinez Creek to Colorado

Reach 2 - Lombrano to Poplar

Reach 3 - Poplar to Leal

Alazán

Reach 1 - Josephine Tobin Dr. to Lombrano

Reach 1 - General McMullen to 19th Street

Reach 2 - 19th street to Chihuahua

Apache

Reach 6 - Colorado to Missouri Pacific Railroad

Reach 7 - Missouri Pacific Railroad to San Pedro Confluence

Martínez

Reach 1 - Hildebrand to IH 10 (Upstream)

Reach 5 - Missouri Pacific Railroad to San Pedro confluence

Reach 3 - Chihuahua to Trinity

Reach 4 - Trinity to Missouri Pacific Railroad

Cost Contingency Range:

Phase 1 Recommendation

Westside Creeks TOTAL

Reach 7 - Nogalitos to San Antonio River Confluence

Reach 5 - Camp to Southern Pacific Railroad (downstream of IH-35)

Reach 6 - Southern Pacific Railroad (downstream of IH-35) to Nogalitos

Reach 3 - Durango to Culvert End/ Tunnel Outfall (South of El Paso St.)

Reach 4 - Culvert End/ Tunnel Outfall (South of El Paso St.) to Camp

Reach 1 - Tunnel Inlet to Travis

Reach 2 - Travis to Durango

San Pedro

Reach 4 - Lombrano to Ruiz

Reach 5 - Ruiz to Confluence with Alazan Creek

Reach 2 - IH 10 (Downstream) to Sabinas

Reach 3 - Sabinas to Lombrano

Concept Plan - Cost Estimate

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Schedule

Maintain Community Support for the Project (Action Item 1) x x x

Develop Public Agency Funding and Partnership Agreements (Action Item 2) x x x x x x x x x x x x x x x x x x x x x

Implementation of Phase 1A Projects (~$60M)(Action Item 3) Project #1: Alazán Reach 1

Planning x x x x x xDesign x x x x x x x x xPermitting and Property Acquisition x x x x x xUtility Adjustment x x x x x xBidding and Construction x x x x x x x x x x x x x x x x x x x x x x x x

Project #2: Martínez Reach 5Planning x x x x x xDesign x x x x x x x x xPermitting and Property Acquisition x x x x x xUtility Adjustment x x x x x xBidding and Construction x x x x x x x x x x x x x x x x x x x x x x x x

Project #3: Apache Reach 1Planning x x x x x x x x x x x xDesign x x x x x x x x x x x xPermitting and Property Acquisition x x x x x x x x x x x x x x xUtility Adjustment x x x x x x x x x x x x x x xBidding and Construction x x x x x x x x x x x x x x x x x x x x x x x x

Project #4: San Pedro Reach 2 - Coordination with Federal Courthouse (~$100K)Implementation of Trails Only - Fifteen Reaches

Planning x x x x x xDesign x x x x x xPermitting and Property Acquisition x x x x x xBidding and Construction x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

Develop Cooperating Governmental and Private Agreements (Action Item 4) x x x x x x x x x x x x x x x x x x x x x x x x

Develop Revised Planning Details for Groups B & C Projects (Action Item 5)

Completion of Remaining Phase 1 Recommended Projects (~$240 M)(Action Item 6)Phase 1B: 3 Reaches (~$100M) x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x *Phase 1C: 3 Reaches (~$140M) x x x x x x x x x x x x x x x *

Dedicated Activities *Additional 5-15 years depending upon available fundingIntermittent Activities

2011 2012 2013 2014 2015 2016 2017

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Report Introduction Plan Context Community Vision Existing Conditions Stream Restoration

Approach Economic Development Restoration Concept Implementation Glossary

Conceptual Plan Documents

Appendix Historic Resources Public Meeting Minutes Existing Conditions Stable Channel Design Cost Estimates

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For More Information

[email protected]

+1 (512) 457-7884 (office)

+1 (210) 381-3390 (mobile)

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