“After the Floods: Texas Rising”€¦ · TEXAS FLOODPLAIN MANAGEMENT ASSOCIATION 2015 Fall Technical Summit – Sept. 2 - 4, 2015 Hyatt Regency Houston “After the Floods: Texas

TEXAS FLOODPLAIN MANAGEMENT ASSOCIATION

2015 Fall Technical Summit – Sept. 2 - 4, 2015

Hyatt Regency Houston

“After the Floods: Texas Rising”

SUMMIT AGENDA

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WEDNESDAY – SEPTEMBER 2, 2015 7:30 am - 5:00 pm 12:00 pm - 1:00 pm

SUMMIT REGISTRATION LUNCH ON YOUR OWN

WORKSHOPS

8:00 am – 5:00 pm

WORKSHOP 1: FLOODPLAIN MANAGEMENT 101

Instructor: Shawn Snyder, CFM, Texas Water Development Board

Floodplain Management 101 covers the basic tenets of the NFIP and the minimum administrative requirements to

successfully implement a community FPM program. Participants will learn the fundamentals of individual and local

responsibilities for managing flood risks and loss through proper permitting and planning. Topics covered include: NFIP

Basics, Maps & Flood Insurance Studies, The Floodplain Manager's Role, and NFIP Compliance. This workshop is

targeted at new floodplain managers with less than two years of experience.

8:00 am – 5:00 pm

WORKSHOP 2: INTERMEDIATE FLOODPLAIN MANAGEMENT (NFIP 201)

Instructors: Jack Graham, CFM, FEMA Region VI; Dale Hoff, CFM, FEMA Region VI

This workshop will focus on what the local floodplain administrator should know and do during the day-to-day conduct

of the community's flood damage prevention program. The importance of the local ordinance will be emphasized. The

majority of the course will involve the permitting process, how to establish an effective system, permitting requirements,

inspections, and follow-up to ensure development has met the provisions of the community's ordinance. Letters of Map

Change (LOMCs) will be discussed. At the end of the course, we will briefly cover other aspects of floodplain

management, to include post flood activities, the elevation certificate, etc.

8:00 am – Noon

WORKSHOP 3: UNDERSTANDING FEMA’s ELEVATION CERTIFICATES

Instructors: Jibrael (Jib) Ahmad, EPLS, CFM and Michael Hoover, RPLS, LSLS, CFM, McKim & Creed

This workshop will cover the Elevation Certificate – FEMA 81-31 (F-053) including:

What is an Elevation Certificate? (EC)Home or business in a high risk area? Who needs an EC? Flood Insurance Reform

Act of 2012 (Biggert-Waters) and Homeowner Flood Insurance Affordability Act of 2014 (HFIAA). Definitions and

discussion to include: Base Flood, Base Flood Elevation (BFE), Flood Insurance Rate Map (FIRM), Pre-Firm, Post Firm,

Lowest Floor Elevation (LFE) verses Top of bottom floor (C2a), Basement (subgrade living room/ elevator well/ work

pits) (C2a), Bottom of lowest horizontal structural member (V Zones) (C2c), Attached Garage (C2d), Lowest elevation

of machinery or equipment servicing building (C2e), Lowest Adjacent Grade (LAG) (C2f), Highest Adjacent Grade

(HAG) C2g), Lowest elevation of deck or stairs, including structural support (C2h), Vertical Datum’s - NGVD29 (The

Sea Level Datum of 1929) and NAVD88, Necessary conversion if FIRM is referenced to NGVD29, Vertcon

(CORPSCON), FIS data, Adjustments – how do they affect your elevations, Benchmarks – Sources: Local (HCFCD),

Federal (NGS), other Subsidence concerns. Also preparing and reviewing an Elevation Certificate: A Brief Overview and

Practical Application: Using a FIRM with the FIS data and profiles to fill out Elevation Certificates to include Instruction

Guides: FEMA E273 (Managing Floodplain Development through the NFIP) and FEMA 480 (Study Guide & Desk

Reference for Local Officials.)





SUMMIT AGENDA

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8:00 am – Noon

WORKSHOP 4: HOW TO REVIEW A 2D MODEL

Instructors: Mitch Blum, HDR Engineering; Wayne Tschirhart, PE, PMP, CFM, San Antonio River Authority

For floodplain managers, tools and analyses that help garner a more complete understanding of floodplain hydrodynamics

are invaluable to comprehensive floodplain administration. In recent years, 2D modeling of complex systems has become

more and more common as computer software and hardware have evolved. You are a local floodplain administrator and

a consultant has just dropped off a report and a DVD with a 2D model of the existing and proposed floodplain conditions

for you to review. Where do you start? What common elements do you look for in your review? How well does this

model represent study area hydraulics? What pieces of information do you need to complete your review? After reviewing

the report and the workmaps, consider the justification for using a 2D model. Does 2D automatically mean better? Just

because we can use it – should we? The workshop agenda includes discussion on the following review considerations:

Reporting, model runs, terrain, model geometry and parameterization, internal and external boundary conditions,

calculations and tolerances, and modeling outputs.

1:00 pm – 5:00 pm

WORKSHOP 5: ISSUES IN URBAN (ZONE X) FLOODING

Instructor: Steven E. Eubanks, PE, CFM, City of Fort Worth

While the National Flood Insurance Program (NFIP) has led to the dedication of numerous resources to understand,

model, map, regulate and manage flooding and floodplains along streams and rivers, many urban areas deal with extensive

flooding problems in areas served by storm sewers or storm drains. Long-term solutions are a challenge to develop

because of high costs and only sporadic flood damage. While there may be a large public outcry when flooding occurs,

by the time mitigation plans are developed, funding them is no longer a community priority. Further, correcting the

deficiencies is often far more complex than simply finding funding for more pipe capacity.

This workshop will discuss a broad range of urban flooding issues, from understanding urban hydrology, evaluating the

downstream impacts with large conveyance systems, and using hydrodynamic 2D analysis for mapping inundation. Also

addressed will be considerations for detention and other flood mitigation strategies such as buyouts to create open space

corridors and removing storm drains to restore streams. Economic pressures for revitalization efforts and for the

protection and reclamation of developable land will also be evaluated as a means to either gain or lose community support.

This workshop is also intended as an open forum to discuss particular problems and solutions to urban flooding being

dealt with by various communities.

1:00 pm – 5:00 pm

WORKSHOP 6: PLANNING 101 – THE DEVELOPMENT AND FORMULATION OF FLOOD DAMAGE

REDUCTION AND STORMWATER PLANS

Instructor: Burton Johnson, PE, CFM, Burton Johnson Engineering

“Planning” is an activity that engineers often engage in. Planning studies, in some form or fashion, form the basis of

virtually all of our projects, and drive the decisions on how we invest in protecting our communities from flooding and

improving our drainage. Given this, it is odd that planning is given minimal attention in the training of engineers,

hydrologists, and floodplain managers. While planning studies rely heavily upon technical investigations and

understanding, planning itself is not a technical activity. This workshop will present an approach to flood damage

reduction and storm water planning that is vested in an organized and deliberate process designed to identify optimum

plans that are effective at meeting objectives, constructible, affordable, economic, and acceptable.





SUMMIT AGENDA

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1:00 pm – 5:00 pm

WORKSHOP 7: REVIEW PROCESS AND REQUIRED DATA FOR HCFCD LOCAL REVIEW AND

LOMR DELEGATION

Instructors: Todd Ward, PE, CFM, and Brian Edmonson, PE, CFM, Harris County Flood Control District

The purpose of this workshop is to inform the engineering community about the review process and required data for

Local Review and LOMR Delegation Review submittals in Harris County.

The presentation will cover GIS standards, modeling standards, regulatory documentation requirements, and more. Model

Management at HCFCD will also be presented and the goal of that program is to manage a master set of current and

accurate hydrologic and hydraulic models and their supporting data. HCFCD is the first CTP approved by FEMA to begin

the systematic model and map maintenance process.

8:00 am – Noon

FIELD TRIP – PROJECT BRAYS

The Brays Bayou Flood Damage Reduction Project (Project Brays) is the largest, most extensive flood damage

reduction initiative ever to be managed by the Harris County Flood Control District (HCFCD). Designed to reduce

the risk of flood damage, the project will benefit thousands of residents and businesses along Brays Bayou. Project

Brays consists of more than 75 projects throughout the entire 31 miles of Brays Bayou. In fact, upon completion,

the mapped 1% (100-year) floodplain is anticipated to be removed from tens of thousands of structures.

This $480 million project is a cooperative effort between the HCFCD and the U.S. Army Corps of Engineers. This

powerful partnership allows the HCFCD to work hand-in-hand with the federal government to leverage funds and

local expertise.

Project Brays is a multi-disciplinary, collaborative approach that uses the latest in engineering technology and

techniques under the guidance of local professionals. The HCFCD is utilizing and combining several tools to

address today’s flood risk along Brays Bayou. These tools include:

Channel Modifications – Approximately 21 miles of the bayou channel will be widened and/or deepened

to increase its storm water carrying capacity by 15 to 30 percent

Bridge Modifications/Replacements – Approximately 30 bridges will be replaced, extended or modified

to increase storm water flow

Storm water Detention Basins – Creation of four regional storm water detention basins that will detain

more than 3.5 billion gallons (10,000 AC-FT) of water upon completion

6:00 pm – 9:00 pm

TFMA TEXAS NATIONAL CFM EXAM

THURSDAY – SEPTEMBER 3, 2015

7:30 am – 5:30 pm

SUMMIT REGISTRATION

8:00 am - 8:15 am

SUMMIT OPENING PLENARY SESSION

WELCOME: Roy Sedwick, CFM, TFMA Executive Director; Jessica Baker, PE, CFM, PMP, TFMA President





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8:15 am – 9:00 am

THE NATIONAL FLOOD INSURANCE PROGRAM FLOOD LOSS PREVENTION SOLUTIONS

Presenter: Bill Laughlin, CFM, SmartVent Products

The Biggert-Waters Act and Homeowners Flood Insurance Affordability Act (Grimm-Waters 2014) are changing the

landscape of the NFIP and this course will provide valuable insight into simple flood mitigation retrofit solutions your

residents or clients may be able to benefit from and lower their properties’ flood risk. We will review FEMA and ICC

flood venting regulations and how flood vents affect the lowest floor rating for your customers, in many cases lowering

premiums by 80%. We will review the Elevation Certificate and what the numbers on the form mean to a premium. This

upbeat course, full of case studies and service tips will have you understanding the solutions to rising NFIP rates and the

benefits of compliant, sustainable construction.

9:00 am – 9:30 am

THE COMING OF 2D MODEL REVIEW

Presenter: Mitch Blum, HDR Engineering

As floodplain managers desire to get a more complete understanding of flooding problems, 2D modeling of complex

situations has become more and more commonplace, as demonstrated in the large number of 2D modeling presentations

at recent TFMA conferences. In the past, limitations on computational hardware and software, expensive proprietary 2D

modeling software, few models on FEMA’s approved list for use in the NFIP have limited the number of 2D submittals

to floodplain administrators. With the release of HEC-RAS 5.0, many of these traditional barriers will be broken

down. Because it is HEC-RAS, the new version is automatically on FEMA’s approved list (no waiting period); it is free

for anybody to download and use; unique computational solutions provide increased efficiency lowering run times. It

will eventually preclude the use of ArcGIS, which also removes cost barriers. Many will start using it – but will they use

it well? Just because they can use it, should they? Many riverine systems can and should still be modeled with 1D. This

session will also discuss reasons for 2D based on applicable sections of FEMA’s Appendix C.

9:30 am – 10:00 am

BREAK

10:00 am – 10:15 am

NOAA ATLAS 14 FOR THE STATE OF TEXAS

Presenter: Max Strickler, U.S. Army Corps of Engineers

The Hydrometeorological Design Studies Center (HDSC) within the Office of Hydrologic Development of National

Oceanic and Atmospheric Administration’s (NOAA) National Weather Service (NWS) is updating precipitation

frequency estimates. Updated precipitation frequency estimates, accompanied by additional relevant information, are

published in NOAA Atlas 14 “Precipitation-Frequency Atlas of the United States”. The update for the state of Texas

would be published as Volume 11 of NOAA Atlas 14.

Precipitation frequency estimates from NOAA Atlas 14 serve as the de-facto standards for a wide variety of design and

planning activities under federal, state, and local regulation. They are essential in the design of highways, culverts,

bridges, parking lots, etc. Engineers may use them to design storm water-runoff facilities, to estimate the volume of

detention basins and size detention-basin outlet structures, and to estimate the volume of sediment or amount of erosion.

They are also used to delineate floodplains and regulate the development in floodplains for the National Flood Insurance

Program, and so on.

All NOAA Atlas 14 deliverables are accessible through the Precipitation Frequency Data Server (PFDS). The PFDS

provides a convenient user-interface to help identify a location of interest. Estimates can be viewed and printed on-the-

fly in a tabular or graphical form or users can download grids of the estimates for use in their own applications.





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10:15 am – 10:30 am WATERSHED-BASED INNOVATIONS: “SCALING-UP” RISK MAP FIRST ORDER APPROXIMATION ANALYSIS

Presenters: Jennifer Knecht, FEMA Region VI; Elizabeth Levitz, CFM, and Chris Levitz, CFM, RAMPP

In FEMA Region 6, the RAMPP team has completed a FOA analysis for the Lower Brazos Watershed (HUC-8 12070104)

in Texas as a part of Discovery. As part of Phase 2 of the Flood Risk Project, RAMPP has completed 274 miles of Zone

A study and 36 miles of limited detail study leveraged from the FOA completed during Discovery. Several hundred miles

of FOA streams are also being considered for use in the validation of existing approximate studies. These reaches are

currently supported by effective studies, which are mostly not valid based on the Coordinated Needs Management Strategy

(CNMS) standards. Reach networks for the new studies were selected based on community concerns voiced during

Discovery or near population centers to maximize benefit. This presentation will highlight:

1. Steps taken during Discovery to ensure the FOA was usable for future stages of the Flood Risk Project;

2. How FOA must be meaningful and credible data to allow FEMA to make informed decisions about whether to “scale-

up” the FOA;

3. Discuss scalability constraints of the FOA;

4. Review selection process for studies to be “scaled-up” from FOA in the Lower Brazos Watershed;

5. Discuss successes and lessons learned from “scaling-up” of the FOA for the Lower Brazos Watershed.

10:30 am – 11:00 am

FLOOD FORECASTING AND ALERTING: CONSIDERATIONS FOR THE FUTURE AT EVERY LEVEL

Presenter: Kevin Shunk, PE, CFM, City of Austin

Timely and accurate notification to the public about impending flooding can greatly reduce the risk to life and property.

However, flood forecasting and alerting are very challenging and complex tasks. Some flood forecasts can be made days

ahead of the flood while other creeks can only be forecast minutes or hours in advance of causing devastating damage.

Tools that our industry uses to predict floods include Doppler radar, rain gauges, stream gauges, radar adjustment

software, and a variety of floodplain models. Technology has greatly improved our ability to predict floods, yet we have

shown that we still need to improve. An inaccurate forecast or poorly phrased alert message, can be as devastating as not

having one at all. Once a flood forecast has been determined, the message needs to get to the public. Crafting that message

and selecting the people to receive it has proven to be as important as the forecast itself. And then there’s the delivery.

Options are available that include public emergency alerts, local emergency notification systems, television and radio

media, text messaging, emails, phone calls, and door knocking. This presentation will look at the current state of flood

forecasting and alerts in the City of Austin. It will also discuss ways your community can help its citizens to be safer the

next time it rains.

11:00 am – 11:30 am

FLOODING 101 FOR THE COMMUNITY EMERGENCY RESPONSE TEAM (CERT)

Presenter: Matt Porcher, CFM, City of Austin

The Community Emergency Response Team (CERT) program is a FEMA-sponsored organization that trains volunteers

on how to respond during disasters. After the devastating 2013 Halloween Flood, Austin CERT members volunteered at

the Austin Emergency Operations Center and the neighborhood Flood Assistance Center. The members are very familiar

with the importance of “Turn Around, Don’t Drown,” so City of Austin staff thought it would be good to offer training

on other aspects of flooding. Since CERT members tend to be very engaged in the community, they would be perfect

“flooding ambassadors” who understand concepts like watersheds, impervious cover, floodplains, the importance of flood

insurance and could help their neighbors when these issues come up. In March 2015, City of Austin staff hosted a half-

day training event called “Flooding 101” for Austin CERT members, with presentations and hands-on activities. The

training was a great success, and now the material is being turned into a class called “Flood Safety,” which will be part

of the basic CERT curriculum for all new members.





SUMMIT AGENDA

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11:45 am – 1:30 pm LUNCHEON AND GENERAL MEMBERSHIP MEETING

TECHNICAL CONCURRENT SESSIONS

TRACK A – HCFCD & USACOE UPDATES

2:00 – 2:45 pm

A1 USE OF 1D/2D MODELING AND RISK MAPPING

Presenters: Ataul Hannan, PE, CFM and Todd Ward, PE, CFM, Harris County Flood Control District

Larry Voice, CFM, Federal Emergency Management Agency

There are many hydrologic and hydraulic models available for flood modeling, and these models can be simple,

complex, steady state, unsteady state, and two-dimensional (2-D) models. The modelers have to make choices in

selecting the appropriate software based on condition of study site, the level of analysis, professional experience and

cost so that they can understand the extent of flooding and accordingly map the floodplain or risk. These advance models

give lot of additional information about depth, vector flow, and conveyance zone to make a better decision.

This paper shows our effort to understand a complex overflow phenomena and coming up with a Flood Insurance Rate

Map that better represents the flooding conditions. The overflow area is mapped zone AE with curvilinear BFE lines. A

typical FIS profile has been replaced with an elevation grid map. The elevation grid map is produced from 1% annual

chance water surface elevation generated from the 2D modeling.

2:45 – 3:30 pm

A2 AN OVERVIEW OF THE HARRIS COUNTY FLOOD CONTROL DISTRICT’S VOLUNTARY HOME

BUYOUT PROGRAM AND THE ASSOCIATES AVOIDED FLOOD DAMAGES RESULTING FROM

THE 2015 MEMORIAL DAY WEEKEND FLOOD EVENT

Presenter: James Wade, CFM, Harris County Flood Control District

The Harris County Flood Control District’s (District) Voluntary Home Buyout program began in 1985. Since that time

nearly 3,000 flood-prone properties have been purchased. As a result, over 1,000 acres have been restored to their natural

and beneficial function as a floodplain and millions of dollars in flood damages avoided. These properties will never

flood again – the only properties for which we can make such a guarantee. This presentation will provide an overview of

the District’s Voluntary Home Buyout program with a focus on the associated avoided flood damages resulting from the

2015 Memorial Day weekend flood event.

3:30 pm – 4:00 pm

BREAK

4:00 – 4:30 pm

A3 MEMORIAL DAY FLOOD EVENT ANALYSIS IN BRAYS BAYOU UNDERGOING FLOOD

IMPROVEMENT PROEJCTS

Presenters: Brian Edmondson, PE, CFM, and Nasiha Alibegovic, CFM, Harris County Flood Control District

On Memorial Day weekend our community experienced a high intensity storm event that in several locations resulted

in rainfall exceeding the 100-year storm. In Brays Bayou, the most intense rainfall occurred in the upper reaches which

resulted in flooding and property damage. In the aftermath of the storm, Harris County Flood Control District (HCFCD)

used Memorial Day weekend flood data and several techniques to estimate the location and severity of flooding.

Additionally, HCFCD attempted to quantify the partial benefit of the ongoing Project Brays flood improvements. This

presentation will review the various approaches used to estimate the impact of the Memorial Day flooding and the benefit

of so far completed flood control elements of Project Brays.





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4:30 – 5:30 pm

A4 COASTAL TEXAS REGIONAL COMMUNITY FLOOD RISK MANAGEMENT (FRM) SYSTEMS

PERFORMANCE EVALUATION STUDY

Presenters: Edmond Russo, PhD. PE, D. CE, D. NE, D. WRE, Eduardo Irigoyen, Rob Thomas, PE, and

Mario Beddingfield, PE, CFM, U.S. Army Corps of Engineers

A series of extreme precipitation and flooding events that occurred in the coastal populated regions of Texas during May-

June, 2015, caused extensive property damages, impairment of infrastructure functions, and losses of life. While regional

FRM systems are in some cases implemented and under continued improvement, these losses represent potential

vulnerabilities of intended system risk reduction performance. It is imperative to formulate technical and planning

approaches that are adequate to inform FRM systems performance evaluation for future use in developing a

comprehensive, integrated plan for improved FRM, ecosystem restoration, and recreation. This panel session and

presentations will discuss an ongoing study to assess the coastal Texas regional community FRM systems, identify

potential improvements, and recommend a long term planning approach to implement those improvements. The overall

goal of this effort is to coordinate with local, state and federal agencies and stakeholders to identify interested

cities/counties to collaborate in developing a detailed methodology and plan to assess and improve coastal Texas regional

community FRM systems performance.

TRACK B – HYDROLOGY & HYDRAULICS

2:00 – 2:30 pm

B1 BENCHMARKING 2D MODELS IN THE UNITED STATES FOLLOWING THE UK ENVIRONMENT

AGENCY’S 2D TESTING PROCEDURE- HEC-RAS 5.0 VERSUS INFOWORKS ICM

Presenters: Thomas C. Davies, PE and Mayank Mehta, PE, CFM, Jacobs Engineering Group

This presentation will directly compare HEC RAS 5.0 to the United Kingdom’s Environment Agency (EA) benchmarking

test program for software packages titled “Benchmarking the latest generation of 2D hydraulic modeling packages”.

Specifically, in detail, this evaluation compares InfoWorks ICM 2D to the beta version of HEC-RAS 5.0. Additionally

the original EA Benchmarking test covered fifteen (15) different software packages, so results are referenced for the

whole test group also.

The models were run through seven of eight applicable unique test runs, with a couple of sub-tests within the main test

categories. These tests covered a variety of simple to more complex 2D modeling issues. Some of the tests were not

applicable to HEC-RAS 5.0 because they focused on urban storm water network modeling and were therefore not

applicable to HEC-RAS 5.0, as it is strictly a riverine modeling package.

The test data was supplied by the Environment Agency and imported into HEC-RAS 5.0 and InfoWorks ICM. Run times,

model manipulation and other run specific issues are documented and presented.

The test results are compared to all the models with specific comparisons to InfoWorks ICM due to its extensive use in

Texas for complex storm water projects. The presentation highlights the direct comparison of results and points out

several key areas of emphasis the average user should be aware of in modeling riverine systems with 2D modeling

software.

Included in this presentation is a checklist of typical Go/No-Go criteria for whether 2D modeling of river systems is

applicable and if HEC-RAS 5.0 is suited to the situation. A review of current release capabilities and limitations will also

be presented.





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2:30 – 3:00 pm

B2 UTILIZING 1D/2D MODELING TO EVALUATE AND DESIGN DEVELOPMENT INFRASTRUCTURE

IN THE CYPRESS CREEK/ADDICKS OVERFLOW

Presenters: Chris Doherty, PE, CFM and Steven Golz, PE, CFM, Brown & Gay Engineers

In northwest Harris County, Texas, the primary watersheds between IH-10 and US-290 are Cypress Creek and Addicks

Reservoir. Cypress Creek flows from west to east in this area, and has limited capacity to contain all of its tributary

runoff. Runoff in excess of an approximate 10-year storm frequency event spill over the southern watershed divide into

the Addicks Reservoir watershed, and its three primary tributaries: Langham Creek, Bear Creek, and South Mayde Creek.

This overflow has been historically observed from Cypress Creek, with subsequent flows out of Bear Creek to South

Mayde Creek. Currently, a physical map revision (PMR) of the overflow area by Harris County Flood Control District

(HCFCD) is in review at FEMA that includes a 1D/2D model of the overflow area utilizing the computer program

XPSWMM 2D.

As land development for the metropolitan Houston area progresses into the Cypress/Addicks overflow area, much greater

detail is needed to adequately plan for and design systems to maintain existing conveyance and floodplain storage. New

development projects will require appropriate conveyance channels, mitigation basins, and detention basins in order to

develop in the overflow area without causing an impact to adjacent and downstream property. HCFCD established

guidelines that require any development in the overflow area utilize a 1D/2D model to show no impacts to surrounding

communities as a result of proposed development.

The 3,602-acre Elyson development is the first Master Planned community to develop in this overflow zone. The design

engineers spent significant coordination time with HCFCD, as they developed regulatory guidelines and an efficient

review process. A combination of unsteady HEC-RAS and 1D/2D XPSWMM 2D were used to model and design the

improvements for the 692-acre Elyson Phase 1 Development. A system of collection and conveyance channels, floodplain

storage and detention basins were designed to show no impact to the surrounding community as a result of the 692-acre

development placing fill in the overflow zone.

3:00 – 3:30 pm

B3 PROGRESSING OF HYDROLOGIC AND HYDRAULIC MODELING

Presenters: Adam Willard, EIT and Yousef Husain, PE, CFM, Brown & Gay Engineers

BGE was retained by Atmos Energy to study and design various drainage issues that impacted existing high pressure gas

infrastructure in areas throughout Texas. For each of the sites, BGE conducted a field investigation, obtained soil samples,

prepared base Hydraulic/Hydrologic Models, and developed alternative solutions, including corresponding cost estimates.

Descriptions of the individual sites, the issue at each project site, and the BGE solution will be discussed in detail including

Line S Site, Line X Site, and Line L sites.

3:30 pm – 4:00 pm

BREAK





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4:00 – 4:30 pm

B4 2D STORMWATER MODELING & MOBILE LiDAR

Presenter: Matt Manges, PE, CFM, Lockwood, Andrews & Newnam

We, as drainage professionals, have been lead to believe that more and higher density data will always lead to better

results than traditional data collection. More data for master planning and modeling is always better, right? Storm water

modeling and design have been drastically improved with the widespread availability and increased accuracy of terrain

data brought forth with aerial LiDAR over the past two decades. Will the recent advancements in mobile LiDAR

availability provide similar benefits to our practice of drainage engineering and analysis?

Aerial LiDAR has long been the standard for urban drainage analysis, but recently, mobile LiDAR has become another

tool in the drainage engineer’s toolbox for data collection. Mobile LiDAR, often collected by vehicle or standalone

instruments, has enabled topographic data collection surpassing the level of detail typically provided by aerially collected

LiDAR. This presentation will discuss the challenges of integrating mobile LiDAR into a traditional 2D storm water

master plan workflow and the benefits of this new data source. We will highlight lessons learned from a 2D hydrodynamic

master planning study under way in Oak Ridge North, Texas that utilizes both mobile and traditional aerial LIDAR.

4:30 – 5:00 pm

B5 2D STORMWATER ANALYSIS EQUALS BIG SAVINGS IN DRAINAGE RELIEF FOR THE TOWN OF

ADDISON

Presenters: Maria C. Martinez, PE, CFM and Walter Skipwith, PE, D.WRE, Halff Associates

Jason Shroyer, EIT, Town of Addison

The Hutton Branch watershed is located northwest in the Town of Addison draining 613.6 acres. Most of the Addison

Airport lies within the Hutton Branch watershed. The remaining watershed is comprised of predominantly commercial

and industrial developments with some residential development. The watershed is virtually built out with only a few

isolated vacant parcels.

The watershed is served by a storm drainage system that conveys runoff to Hutton Branch in the City of Carrollton to the

west of the Town of Addison. In 2012, Halff conducted an exploratory study to develop a Conceptual Storm water Master

Plan in order to determine an estimate of the cost of service for a storm water utility for the Town. The evaluation of the

existing storm drainage system was based on traditional storm drainage design methods. As a result of the exploratory

study, $16.4 million in drainage relief needs were identified in the Hutton Branch watershed

In order to better understand the severity of the flooding problems in the Hutton Branch watershed and to investigate

drainage relief alternatives, a more detailed storm water study was developed in 2014 – 2015. This study of Hutton Branch

utilized 2-Dimensional storm sewer modeling to simulate existing flooding conditions and help develop solutions to

mitigate the flood problems. The more rigorous analysis helped to better define the problem areas and alternatives. The

detailed study indicated that flood risk to the airport, other public facilities and private property in the basin was minimal

and could be handled with appropriate flood emergency management tools. As a result, the Town of Addison realized a

potential savings of more than $16 million in storm drainage relief costs in the Hutton Branch watershed as compared to

storm drainage relief analysis by traditional methods.





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5:00 – 5:30 pm

B6 THE BELEAGUERED FIGURE 15

Presenter: Craig Lofton, PE, CFM, U.S. Army Corps of Engineers

This presentation deals with the rapidly changing paradigms associated with development of frequency-based

hypothetical storms for application in watershed runoff modeling used for Flood Insurance Studies and in developing

design discharges for flood conveyance infrastructure components. The primary intent is to enhance participants’

understanding of the differences between how so-called Point Rainfall depths are converted to represent Area-Averaged

depths, depending upon which of two common types of statistical precipitation datasets is considered.

The classical approach, applied by the National Weather Bureau when developing the 1961 Technical Paper Number 40

(TP-40), results of which are presented therein as Figure 15 (Area-Depth curves), is based upon a frequency analysis of

site- and area-specific precipitation gauging station records. The area-specific analyses were based upon data from

available dense networks of gauging stations. The associated relationship between Point Rainfall and Area-Averaged

depths deals specifically with the period-of-records’ spatial statistical distribution over the dense network area and was

developed independently among the evaluated storm durations. Figure 15 represents a composite of many years’ worth

of widely spatially varied storms over the network area. Each plotted trend line is unrelated to the spatial volumetric

distribution of any given storms which had/have occurred. In contrast, the paradigm shift is toward consideration that

area reduction curves could/should be more so based upon the patterns of spatial distributions of (predominantly) large

regional storms in the record. The presentation will provide an overview of both positive and negative technical

considerations of the two approaches. Open dialog with the participants is encouraged.

* The views presented are based solely upon the experience of the presenter and do not necessarily represent any official

positions adopted and/or proposed by the U.S. Army Corps of Engineers.

TRACK C – CRS & HAZARD MITIGATION PLANNING

2:00 – 3:30 pm

C1-2 THE COMMUNITY RATING SYSTEM (CRS) AND HAZARD MITIGATION PLANNING (PART 1)

Presenters: Janine Ellington, CFM and Cathy Meek, CFM, LRA, Lockwood Andrews & Newnam

Topic: Flood mitigation and effective floodplain management are key aspects to meeting goals and objectives of CRS.

All are based upon encouraging communities to go beyond minimum requirements of the NFIP. This workshop will

explore flood mitigation activities aligned with achieving CRS credits, integrating Hazard Mitigation Action Plan

(HMAP) projects into CRS, Public Information Activities, and grant funding opportunities.

3:30 pm – 4:00 pm

BREAK

4:00 – 5:30 pm

C3-4 THE COMMUNITY RATING SYSTEM (CRS) AND HAZARD MITIGATION PLANNING (PART 2)

Presenters: Janine Ellington, CFM and Cathy Meek, CFM, LRA, Lockwood Andrews & Newnam

Continuation of session C1.





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TRACK D – FLOOD CONTROL CONCEPTS & ETHICS

2:00 – 2:30 pm

D1 A RACE AGAINST TIME: AN EMERGENCY BANK STABILIZATION ON KEE BRANCH

Presenters: Scott Hubley, PE, CFM and David Coffman, PE, CFM, Freese and Nichols

Amy Cannon, PE, CFM, City of Arlington

This presentation will give an overview of the Kee Branch Emergency Bank Stabilization project in Arlington, Texas.

Freese and Nichols, Inc. (FNI) assisted the City of Arlington in developing an emergency design for a stream bank failure

that was threatening a recently installed sanitary sewer line. The ultimate solution involved a unique bio-technical

approach that protects the sewer line while maintaining stream aesthetics and reducing potential downstream erosion

impacts. This presentation will give an overview of the failure, geomorphic conditions impacting the channel, fast paced

project timeline, environmental permitting, and construction process.

2:30 – 3:00 pm

D2 STREAM RESTORATION TOOLS DEVELOPED FOR THE SAN ANTONIO RIVER WATERSHED

Presenters: LeeAnne Lutz, PE, San Antonio River Authority; Gian Villarreal, PE, CPSWQ, CFM, Michael Baker

Natural rivers and stream systems provide recreation and economic development opportunities, floodwater storage, water

quality filters, and habitat for numerous species, both in channel and in the floodplain. They also serve as conveyors of

storm water and floods that can result in erosion of stream bed and banks, property and infrastructure damage, impaired

water quality, and require regular, sometimes costly maintenance. The San Antonio River Authority (SARA) has a vested

interest in stream and river health and is committed to the protection of natural stream resources within the San Antonio

River Basin. SARA’s Stream Restoration Program began in 2009 with a mission to improve the health of the San Antonio

River Basin by protecting and improving the physical, chemical, and biological functions of stream systems though

preservation, restoration and education.

This presentation will provide an introduction to several of the design tools that have been developed as part of SARA’s

Stream Restoration and Holistic Watershed Master Plan Programs to help the stream restoration community identify,

design, and implement stream restoration projects. The presentation will include the Natural Channel Design Manual,

Stream Restoration Potential Assessments, Regional Curves, and Reference Reach Tools.

The Natural Channel Design Manual provides design methodology and geomorphic assessment protocol for natural

channel design projects. The Stream Restoration Potential Assessments provide an assessment of the conditions of natural

streams under three categories that include Preservation, Restoration and Rehabilitation, and engineered or modified

streams based on existing constraints. The assessment is based on a desktop analysis, Rosgen Stream Classification,

stream stability, riparian buffer condition and width, and threats from adjacent land use or development. The Regional

Curves and Reference Reach Tools provide additional information that can be used to help guide the design of stream

restoration projects. The presenters will provide information about the tools and how they can be applied to help

implement stream restoration projects.





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3:00 – 3:30 pm

D3 ASSESSING INTERNAL DRAINAGE AND PUMP STATION CAPACITY FOR A TEXAS COASTAL

LEVEE SYSTEM

Presenters: Cory Stull, PE, CFM and Ashley Schneider, EIT, CFM, Freese and Nichols

Located on the Gulf of Mexico at the mouth of the Brazos River, the City of Freeport has many areas protected from both

coastal and Brazos River flooding by levees that rely on pump stations to drain the internal system during large storm

events. The Velasco Drainage District (VDD) is in charge of maintaining and operating this system of levees and pump

stations. Spurred by FEMA coastal remapping efforts, as well as the expansion of Port Freeport, there was a need to better

understand the internal drainage of North Freeport and assess the capacity of the existing pump stations, previously sized

based on a study by the U.S. Army Corps of Engineers in 1965. Additionally, there were uncertainties as to whether the

pump stations still had adequate capacity to meet the original goals of the project, which would address questions

concerning possible need to modify the current pump stations.

Currently, the Port of Freeport is in the process of expanding their facilities to meet additional demands, and part of the

new development includes modifications to the outfall canal for one of the main system pump stations. To better

understand the functionality of the overall system and pump station capacities, the VDD requested that a detailed hydraulic

analysis be done for the North Freeport area in order to evaluate the performance of these various system components.

The goal of this project was to analyze the area in sufficient detail to understand the flood risk for existing conditions

behind the levees, estimate modifications to the system to meet flood protection goals, calculate discharges from the

system in order to adequately size drainage infrastructure for the expansion of the port, and provide recommendations for

handling future development based on the results.

This presentation will emphasize the importance of understanding the cause of flooding for internal drainage systems

behind levees and will provide discussion on pump capacity assessments when determining how to plan for and regulate

future development.

3:30 pm – 4:00 pm

BREAK

4:00 – 5:00 pm

D4 ENGINEERING ETHICS FOR DEVELOPING IN FLOOD-PRONE AREAS

Presenters: Lacey Bodnar, EIT, CFM and Rich Gallegos, PE, CFM, Costello, Inc.

Development in areas prone to flooding requires engineers and planners to balance several ethical considerations that

produce tradeoffs. For example, land owners have a right to utilize their property, as granted in the 5 th Amendment (“Nor

should property be taken for public use without just compensation”). This Amendments prevents the government from

“taking” private property, either outright or through excessive regulations.

The right of people to utilize their property, even in areas prone to flooding, may be in conflict with the primary ethical

responsibility of engineers, which is to “hold paramount the safety, health and welfare of the public” (ASCE Code of

Ethics). This clearly mandates that civil engineers protect the public from risk of death or injury. Development in flood-

prone areas often places people at risk though. On September 18th, 2008, the thousands of residents remaining on

Galveston Island during Hurricane Ike undoubtedly felt very real and frightening threats to their welfare. The ethical issues

presented by this example at first seem in conflict; not to infringe on the right of a person to utilize his or her property, as

granted in the 5th Amendment, and to protect people’s health, safety, and welfare during natural disasters.

By using performance based design standards, practicing low impact development, and engaging in community education

and outreach, I believe civil engineers can balance the ethical tradeoffs of developing in areas prone to flooding.





SUMMIT AGENDA

13 of 21

5:00 – 5:30 pm

D5 RED BLUFF DAM: MODEL TESTED, MOTHER NATURE APPROVED

Presenters: Sunit Deo, PE, CFM and Cristopher Parker, PE, CFM, HDR Engineering

Red Bluff Dam is a large high-hazard dam located on the Pecos River approximately 6 miles south of the state line in

Texas. Constructed in 1936, the dam is owned by the Red Bluff Water Power Control District in Pecos, Texas and serves

as irrigation water supply for seven irrigation districts. The 9,200-foot long 106-foot high earthfill dam has a history of

seepage issues, and was also found to be hydraulically inadequate during Texas Commission on Environmental Quality

(TCEQ) dam inspections and evaluations in 2008.

In 2009, the Owner embarked on a dam safety update program including a new H&H evaluation, development of an

Emergency Action Plan (EAP) including unsteady dam breach analyses, design and construction of spillway

improvements, and a foundation grouting program. The H&H evaluation, based on new dam safety rules by TCEQ,

confirmed that the dam could not safely pass the required design flood, and was in fact hydraulically inadequate. To bring

the dam into compliance, numerous capacity improvement alternatives were evaluated. The final design consisted of

widening 1,200 feet of the principal spillway channel and raising the dam crest using a 1.6 feet high concrete parapet

wall, minimizing construction impacts to the nearby community. The spillway widening was finished in August 2013.

The concrete parapet wall construction will begin in mid-2015 now that the 1st Phase of foundation grouting is complete.

Shortly after the principal spillway improvements were completed, a historical flood event occurred over multiple days

from remnants of Tropical Storm Odile. This was the largest flood event to hit Red Bluff since 1987 and the 4 th largest

flood of record. Up to 15 inches of rainfall fell on some parts of the watershed. The new EAP was activated by the Owner

and the newly improved principal spillway was engaged. After being in severe and prolonged drought conditions, the

Owner’s new dam safety improvements and processes were subjected to an unexpected test.

In the end, Red Bluff Dam survived its first major storm of this century with no damage, and the Owner was able to test

the EAP in a real emergency response situation.

TRACK E – FLOODPLAIN MAPPING

2:00 – 2:30 pm

E1 PRESERVATION OF A HISTORIC SWING BRIDGE IN A COASTAL TIDAL SURGE ZONE E.

ROUNDBUNCH ROAD OVER COW BAYOU, ORANGE COUNTY, TEXAS

Presenter: Chris Doherty, PE, CFM, Brown & Gay Engineers

The East Roundbunch Road Bridge over Cow Bayou is a historic-eligible swing bridge located in a coastal tidal surge

zone. Cow Bayou, a tributary to the Sabine River upstream from Sabine Lake, has been straightened and dredged from

its historic meandering plan form for navigational purposes. The existing bridge is in poor repair, and is being

rehabilitated by TxDOT through its off-system highway bridge program.

The design team coordinated with the local community, which resulted in a decision to raise the elevation of the

rehabilitated bridge and approach embankments to provide greater navigational clearance when the swing bridge is closed.

The design hydraulic analysis included HEC-RAS modeling of the riverine flow to show no-adverse-impact, and a

foundation scour analysis for both riverine and tidal storm surge conditions.

The analysis used historical data from Hurricane Rita (2005) in a similarly situated environment to determine the rate of

rise of the storm surge on the Gulf side of the bridge embankment. Unsteady HEC-RAS was utilized to estimate the flow

rate and velocity through the bridge for the design storm surge event. Scour calculations were performed for the approach

piers and for the 22-foot diameter complex-foundation center pivot pier.





SUMMIT AGENDA

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2:30 – 3:00 pm

E2 DEFINING FLOOD INUNDATION AREAS USING SSURGO DATA

Presenters: J. Furnans, PhD, PE, PG, CFM, Intera Incorporated

N. Sangwan, MSE; V. Merwade, PhD

Floods are the most damaging of all natural disasters, adversely affecting millions of lives and causing financial losses

worth billions of dollars every year across the globe. Flood inundation maps play a key role in assessment and mitigation

of the potential flood hazards. However, there are several communities in Texas and within the larger United States for

which the flood risk maps have not been published yet, as the current flood inundation mapping methods are typically

very expensive and time consuming.

The objective of this study was to develop and examine an economical alternative approach to floodplain mapping using

widely available soil survey data. In this study, floodplain maps were developed for the entire states of Texas and Indiana

by identifying the flood-prone soil map units based on their attributes recorded in the SSURGO database. For validation,

the flood extents predicted by these maps were compared with the extents predicted by other floodplain maps, including

Federal Emergency Management Agency (FEMA) issued Flood Insurance Rate Maps (FIRM), flood extents observed

during past floods, and other flood maps derived using Digital Elevation Models (DEMs). In general for Indiana,

SSURGO based floodplain maps were found to be largely in agreement with the other flood inundation maps. They were

generally as effective as flood maps derived using DEMs in their predictions of flood extents. Although there was

comparatively greater agreement between the FEMA maps and the observed flood extents, SSURGO floodplain maps

could predict most of the observed flood extents with a median overlap of 72% between the two flood extents. Results

for Texas are still pending analysis at this time, yet will be available at the time of the presentation. For Indiana at least,

with a slight loss in accuracy, the SSURGO approach offers an economical and fast alternative for floodplain mapping.

In particular, it has potentially high utility in areas where no detailed flood studies have been conducted.

3:00 – 3:30 pm

E3 LOCAL FLOOD INUNDATION MAPPING – NOW WHAT? CASE STUDY OF THE MLK TOD

PROJECT AREA – CITY OF AUSTIN

Presenters: Glen Taffinder, PE, CFM, City of Austin; Kim Patak, PE, CFM, Env SP, CPESC, Freese and Nichols

The Martin Luther King Boulevard Transit Oriented Development (MLK TOD) is a redeveloping area in east Austin that

is adjacent to the City’s Metrorail. In 2012 the City, in conjunction with Freese and Nichols, Inc. (FNI), completed a

hydraulic capacity assessment of the existing storm water infrastructure (surface and subsurface systems) within the MLK

TOD using a two‐dimensional hydraulic model. The detailed assessment identified numerous local flood inundation areas

(not resulting from creek flooding) that are outside the City’s right‐of‐way and that would be underestimated by adhering

to the minimum requirements for an existing drainage assessment described in the Drainage Criteria Manual (DCM). The

areas of inundation included a large open space property that is ripe for development.

Fast forward three years and a developer is pursuing this open space tract. The City is in a position to provide detailed

surface and subsurface capacity and flooding information to assist the developer in appropriately designing drainage

improvements to the tract. However, this kind of information has not been available in the past and the City does not have

a mechanism to require permit reviewers to make the information regulatory and relies on Capital Improvement staff to

communicate with permitting staff to convey information. Thus, the City is charting new waters in how to use the results

of more detailed local flood analysis in working with private landowners and developers.

This presentation will discuss the City’s current development policy for drainage analysis and its’ potential need to evolve

using local flood mapping. The MLK TOD development will be presented, including lessons learned and current and

future coordination efforts. The presenter’s intent is to encourage audience participation and discussion related to local

flood modeling, regulation, and partnering.





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3:30 pm – 4:00 pm

BREAK

4:00 – 4:30 pm

E4 CHANGE IN RISK IN A FAST GROWING AREA – A CASE STUDY

Presenters: Hector Olmos, PE, CFM, Freese and Nichols; Shashi Kumar, PE, CFM, City of Sugar Land

This presentation will emphasize the importance of having accurate maps and tools in order to better estimate current risk,

better manage the floodplain, better invest funds, and be prepared for major storm events. The recent floods from

Memorial Day were used to validate the models, ensuring an accurate depiction of the flood risks. Fort Bend County is

one of the fastest growing counties in the country, experiencing significant development in the last decade in both

incorporated and unincorporated areas. In an effort to better represent flood risk, FEMA updated the flood hazard maps

and models in 2006. These maps and models have been used for the past decade to accomplish floodplain management

efforts, issue permits, and design infrastructure. The studied area encompasses a complex system comprised of the Brazos

River, several natural waterways, man-made channels, diversion structures, dams, gated structures, natural overflow areas,

levees, pump stations, and a relatively flat topography.

Because of the significant amount of new development and the complexity of the drainage system, the maps and models

created to represent this area no longer provide the most accurate representation of flood risk. Additionally, there are

restrictions on allowable water levels at key levee outfalls that protect over 6 billion dollars in infrastructure, and the

current models no longer provide a reliable predictive tool to assess these allowable levels.

Currently, there are several developments underway in the studied area, with others in the process of being permitted, all

while the City and the County are designing and constructing new infrastructure such as roads, bridges, and flood control

structures to accommodate the new development. Most of this infrastructure and development is being designed based on

the effective FEMA models, or variations of these existing models. Due to the many changes that have taken place in the

watershed, uncertainty is introduced to the final performance of these structures. This uncertainty leads to the following

questions. Will these structures meet the initial intent of the design? Will a new development result in unanticipated

impacts to downstream areas?

Freese and Nichols has been working with the City of Sugar Land, Fort Bend County Drainage District, and other regional

stakeholders in updating the hydrologic and hydraulic models for this area in order to better define the risk and make

better informed decisions for the design of future infrastructure and analysis of new developments. The new tools are

based on publicly available software that accurately represent the drainage network and provide flexibility when

evaluating local storms, floods on the Brazos, or a combination of both.

4:30 – 5:00 pm

E5 FLOOD ACCURACY – MODELS, MAPS, REALITY

Presenter: Thomas Mountz, PE, D.WRE, CFM, LJA Engineers

This presentation is intended to stimulate dialogue between Floodplain Mangers and Engineers concerning the accuracy

of the models and maps used to regulate floodplains and Flood Hazard zones and the reality of how and why floods

occur. Do they really follow the floodplain lines as mapped? How accurate are the models and FH zones in reality? There

is no exact answer and that is why this dialogue should occur. Floodplain Managers need to be aware of the uncertainties

inherent in the modeling and mapping. Engineers need to be aware of the needs of the community and federal officials

to be as accurate as possible for insurance and emergency management needs. Therefore an understanding of the needs

and concerns on both sides of the accuracy issue is important. Now we are entering “muddy waters” again with 2D and

unsteady models that many public officials have no experience with and that may be too accurate for real-time

management. What are the advantages to this advanced form of modeling? This presentation will open the discussion

of these issues and how they impact community regulations of floodplains.





SUMMIT AGENDA

16 of 21

5:00 – 5:30 pm

E6 STORM WATER EVALUATION ENHANCEMENT TOOL (SWEET) FOR THE CITY OF HOUSTON

Presenters: Paresh Lad, City of Houston

William Conlan, PE, CFM and Manuel Razo, GISP, CFM, Klotz Associates

In 2010, the voters in Houston passed Proposition 1 (the ReBuild Houston Initiative) to create a dedicated drainage

and street renewal fund. The fund was created to provide enhancement, improvement and ongoing renewal of

Houston’s drainage and streets. SWEET was created as a method to allow for the prioritization of the capital

improvement projects of ReBuild Houston by taking in various datasets that the city was collecting and combining

them to develop “hot spots” of need-based areas. SWEET is a toolbar created to run inside of ArcGIS and aggregate

the various datasets to produce a map and table prioritizing areas of the city needing attention without any political

or personal influence. One of the datasets used in the aggregation process is the city’s sufficiency of its drainage

infrastructure. These drainage areas were originally only available for the areas served by storm sewer and not

roadside ditch. Klotz Associates automated a process to delineate watersheds for areas served by roadside ditches

using ArcHydro and Python scripts to manipulate survey data to fill the gaps in the data creating a complete dataset

and then create an “adequacy” determination based on capacity versus potential flow.

TRACK F – FLOODPLAIN MANAGEMENT STRATEGIES

2:00 – 2:30 pm

F1 MOBILITY 35 – CAPITAL AREA IMPROVEMENT PROGRAM DRAINAGE IMPACT STUDY

Presenters: Florian Baltoi, PE and Travis Kaatz, EIT, Friese & Associates

The I-35 corridor through the Austin area is the most congested highway in Texas and ranks in the first 25 worst congested

corridors in the nation. The I-35 segment through downtown Austin was built more than 50 years ago and now has a

traffic of more than 200,000 vehicles per day with the majority of traffic being local.

The Capital Area Improvement Program, funded by TxDOT, City of Austin, and the State of Texas, is meant to improve

the traffic situation within a 28-mile section between SH 45N and SH 45 SE. The Future Transportation Corridor proposal

is for an additional freeway lane in each direction of the highway and involves widening of the main lanes footprint. Other

improvements pertain to access lanes, additional frontage road segments, bicycle and pedestrian paths, roundabouts and

updated intersection designs.

The 28-mile section proposed for improvements crosses 16 watersheds with 67 identified outfalls. K Friese & Associates

undertook a Preliminary Drainage Study for seven segments within the 28-mile highway section, to determine if the

existing crossing structures meet the current TxDOT hydraulic design criteria, evaluate the potential hydrological and

hydraulic impacts within and outside of the ROW and recommend mitigation measures.

To assess the existing onsite and offsite drainage conditions, topographic data, as built drawings, and hydrologic and

hydraulic models were used. Outfalls were identified along the corridor and a criteria was set to select the outfalls for

further analyses. Detention storage systems in the form of ponds and underground oversized conduits were proposed to

minimize the impacts to the receiving channels and properties. Flow mitigation models were generated using EPA SWMM

with the 100-yr, 24-hr event as the design storm, for pre-project, post-project without mitigation, and post-project with

mitigation conditions. The existing stream crossing structures were evaluated for capacity using HEC-RAS or HY-8

hydraulic models. Effective FEMA hydraulic and hydrologic models were utilized to assess floodplain impacts for FEMA

Mapped Zone AE stream crossing. The presentation will discuss some of the federal and state policies and guidelines as

they relate to TxDOT drainage projects, and address technical methodologies, with examples, used in completing the

study.





SUMMIT AGENDA

17 of 21

2:30 – 3:00 pm

F2 THE NEXT GENERATION OF AHPS SERVICES

Presenter: Dave Schwertz, CFM, Houston/Galveston National Weather Service

Advanced Hydrologic Prediction Service (AHPS) is a web based suite of accurate and information-rich river forecast

products. They display the magnitude and uncertainty of occurrence of floods or droughts, from hours to days and months,

in advance. These graphical products are useful information and planning tools for many economic and emergency

managers. These new products enable government agencies, private institutions, and individuals to make more informed

decisions about risk based policies and actions to mitigate the dangers posed by floods and droughts.

Impelled by experiences with major floods in 1993 in the Midwest, the Des Moines river basin was selected as a test site

for AHPS product development. The successful demonstration of AHPS on the Des Moines River was favorably received

by local water resource and emergency management agencies. The devastating floods in the upper Midwest and Plains

states in 1997 provided an increased sense of urgency. AHPS was implemented nationwide in the early 2000’s and today

covers more than 2,500 locations in the continental United States and Alaska.

The original suite of products included the observed and forecast hydrograph, categorical flood information, crest history,

impacts, and a map showing the location of the station. Improvements in the intervening years have included long term

probabilistic forecasts and inundation maps. Most recently the FEMA Flood Hazard Layer has been added to the map and

this summer short term ensemble forecasts (probabilistic) will be available.

This presentation will discuss the history of the AHPS program and current products available. It will also discuss near

term improvements to the program as well as longer term development goals.

3:00 – 3:30 pm

F3 HIGH WATER ALERT LIFESAVING TECHNOLOGY

Presenter: Frank Gutierrez, High Sierra Electronics

This presentation will examine Bexar County’s HALT system, High Water Alert Lifesaving Technology. The HALT

system is a tool to warn drivers when there is too much water over the road to drive through safely.

Flooding causes more deaths and property damage in the U.S. than any other severe weather‐related event. The reason

that so many people drown during flooding is because few of them realize the incredible power of water. A mere six

inches of fast‐moving water can knock over an adult. It takes only two feet of rushing water to carry away most vehicles,

which includes pickup trucks and sport utility vehicles.

Texas is prone to extremely heavy rains and flooding with half of the world record rainfall rates (accumulations in forty‐eight hours or less). It also has the distinction of being the state with the most flood‐related deaths in the past thirty‐six

years. Bexar County in central Texas, about 190 miles west of Houston, is particularly vulnerable because storms stall

along the Balcones escarpment. This region is known as the Hill Country and has earned the nickname "flash flood alley".

Due to this geography, floods are a natural hazard and a regular occurrence.

This presentation will demonstrate how HALT uses a sensor to detect rising water and, once the water reaches an unsafe

level, how the system automatically warns drivers to turn around with either flashing lights or a combination of flashing

lights and barrier gates. It will also illustrate how Bexar County citizens have access to a map on the www.bexar.org

website that provides real‐time status of the fifty-two HALT locations, so drivers can see which roads are safe to travel.

And lastly, discussion will focus on Bexar County’s collaboration with the City of San Antonio and the reasons why they

use multi‐agency coordination to promote public safety during flood events.





SUMMIT AGENDA

18 of 21

3:30 pm – 4:00 pm

BREAK

4:00 – 4:30 pm

F4 EMERGENCY PREPAREDNESS AS MITIGATION

Presenter: Rita Anderson, Freese and Nichols

In May 2015, Fort Bend County was impacted by minor flooding from the Brazos River and heavy rains including

localized amounts of over 11 inches in approximately six hours. This presentation describes how one levee district

implemented an emergency preparedness plan to mitigate impacts form this event. Fort Bend County Levee Improvement

District #2 protects over $4 billion in assets including Sugar Land city government centers, large shopping centers,

hospitals, and public safety facilities. Levees in Texas are operated and maintained by a Special Political Jurisdiction

known as Levee Improvement Districts (LIDs).

The LID Board members are appointed by the County Judge and, typically, there is no staff. The LIDs rely on consultants

and contract services for routine operations. In 2011, Fort Bend LID #2 determined that their existing emergency

procedures were inadequate but found little guidance to assist in developing an emergency program. The LID’s journey

to develop a preparedness program incorporating the on-site operators, determining authority and responsibilities for

consultants, and providing guidance for decisions making during emergencies was been long and sometimes arduous.

The success of this journey was illustrated in the District’s quick response to the May floods indicates the impacts of

preparedness in mitigating flood damage.

4:30 – 5:00 pm

F5 CITY OF AUSTIN LITTLE WALNUT CREEK FLOOD IMPROVEMENTS CASE STUDY

Presenters: Bryan Martin, PE, CFM, Brown & Gay Engineers; Thuan Nguyen, PE, CFM, City of Austin

Little Walnut Creek, from Metric to Rutland in North Austin, represents a 1,250 acre, highly urbanized watershed posing

a significant flood hazard to adjacent residential homes, apartments, and bridge crossings. To help alleviate the flooding

to interior structures and to reduce the extents of the floodplain footprint within this reach the City of Austin Little Walnut

Creek project proposes a large diameter storm drain system to significantly reduce the amount of creek flow during the

10-, 25-, and 100-year storm events.

This flood solution will capture and divert approximately 2,000 cfs of overflow from Little Walnut Creek and convey this

overflow via a large diameter box culvert system to a regional detention facility located within Quail Creek Park. This

flow diversion concept was selected over other traditional flood hazard reduction strategies such as buyouts, regional

detention, and improved channel conveyance.

This presentation will outline why the flow diversion concept was recommended for implementation and discuss the many

design and modeling challenges involved with this type of project. Design and modeling topics include: effective design

of the flow diversion capture system; installation of a large diameter box culvert within an existing street right-of-way;

interconnection of local storm drains; effective dissipation of the diversion outlet energy within Quail Creek Park;

determination of downstream impacts and mitigation measures; modeling of complex hydraulic structures with use of 1D

HEC, dynamic 2D and 3D CFD models; coordinating and obtaining approvals from local, state, and federal jurisdictions;

reducing long term operations and management requirements; and maintaining public safety.





SUMMIT AGENDA

19 of 21

5:00 – 5:30 pm

F6 ONION CREEK FLOOD MITIGATION BUYOUT PROJECT

Presenter: Pam Kearfott, PE, CFM, City of Austin

The Halloween Flood of 2013 was a historic disaster for many Texas neighborhoods in Travis County and the City of

Austin. This flood of record produced a peak flow of 140,000 cubic feet per second and turned Onion Creek and several

adjacent neighborhoods into a raging river. Following the early morning hours of October 31, the recovery and mitigation

processes began for the City and the more than 1,000 families impacted by the event.

These hardest hit neighborhoods in the Onion Creek watershed originally consisted of 855 properties at risk of flooding

in a 100-year storm event. In addition to the Halloween Flood of 2013, this area of Lower Onion Creek had also

experienced flooding in 1998 and 2001. The City began partnering with the U.S. Army Corps of Engineers (Corps) in

1998 to evaluate several flooding problems in the City of Austin, the City of Sunset Valley, and Travis County, including

lower Onion, and to identify potential solutions to those problems. As early as 1999, the City began acquiring properties

in this area while the Corps was conducting their study. The Corps study evaluated both structural and non-structural

solutions. Because of the depth and extent of the floodplain in this area, the Corps study determined that even the most

extensive structural solution to the flooding problem would not be more effective than acquiring the flood-prone properties

and relocating the families to areas safe from flood hazards. In 2007, the Water Resources Development Act authorized

the continued partnership between the City and the Corps to acquire 483 properties at the highest risk of flooding in this

area. Unfortunately, it would take several more years for federal funding to become available for the Corps. Despite the

lack of federal funding, the City proactively continued acquiring properties in the project area relying almost solely on

local funding. By the end of October 2013, the City, with the assistance of some funding from FEMA’s Hazard Mitigation

Grant Program, had acquired 323 properties in the Corps project area.

Immediately following the Halloween Flood, the City put forth great efforts to pull together funding to offer recovery

buyouts to many of the 532 properties that remained at risk, the majority of which were substantially damaged by the

flood. Cost savings from completed projects elsewhere in the City were used, and other planned projects were indefinitely

delayed so that their funding could be used for these buyouts. In 2014, the first federal funding for this project was

approved which has allowed the City to begin the acquisition process on additional properties in the Corps project area. In

June and September 2014, City Council also approved close to $100M to offer buyouts to the remaining properties at risk

in lower Onion Creek outside the Corps project area.

A flood of the magnitude of the Halloween storm, one of the largest ever in the City of Austin, tends to clarify a city’s

flood risk priorities and prompt community, government and political action. The City has worked hard to capitalize on

this focus through the acceleration of the floodplain mitigation buyout project in Onion Creek. This presentation will

provide a brief overview of the Halloween Flood, its immediate impacts, and the City’s initial response; and discuss the

City’s buyout project and associated preparedness and mitigation strategies.

5:30 pm - 7:30 pm

NETWORKING SOCIAL





SUMMIT AGENDA

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FRIDAY – SEPTEMBER 4, 2015 SUMMIT CLOSING PLENARY SESSION

8:00 am – 8:30 am

WIMBERLEY – WITNESSING THE FLOOD

Presenters: John Espinoza, PE, CFM, MS Engineering

Cindy Engelhardt, PE, CFM and Mike Moya, PE, CFM, Halff Associates

Flooding occurred throughout Texas and Oklahoma during Memorial Weekend 2015. This presentation will focus on the

flooding that occurred from the Blanco River and impacted the City of Wimberley. The presentation will be given from

the perspective of witnessing the event including what happened prior to the flood, during the flood, and after the flood.

From this experience there were many flood related topics that were identified that may not always be considered by

floodplain managers.

In addition, there is on-going study being conducted along the Blanco River. This presentation will summarize current

findings and correlation with the Memorial Day flooding event.

8:30 am – 9:00 am

MEMORIAL DAY FLOODING IN HARRIS COUNTY

Presenter: Jeff Lindner, Harris County Flood Control District

Week after week of heavy rainfall saturated grounds and brought rivers to bank full going into the Memorial Day holiday

weekend. Hydrologic conditions were extremely favorable for significant run-off and flash flooding and on the evening

of Memorial Day the atmospheric ingredients aligned to produce 8-11 inches of rainfall in a 3-6 hour period over portions

of Harris County. Widespread and devastating flooding ensued with thousands of structures and 7,000 to 10,000 vehicles

flooded. By the morning of May 26th, a state of emergency had been declared for the City of Houston and a request for

disaster declaration was submitted to the state. Seven fatalities resulted from the flooding in Harris County. The

presentation will give on overview of the flooding, the coordinated use of public messaging during the flooding, and the

lessons learned from one of the most significant flood events to impact Harris County since April 2009.

9:00 am – 9:30 am

UTILIZATION OF FLOOD MODELS TO ASSIST EMERGENCY RESPONDERS: EXPANDING THE

SITUATIONAL AWARENESS OF THE VICTORIA EMERGENCY OPERATION CENTER

Presenters: John Johnston, PE, CFM, City of Victoria; Richard McBrayer, Victoria Office of Emergency

Management; Chief Tanner Drake, City of Victoria; Jill Trevino, PE, CFM, Freese and Nichols

The 2015 Memorial Day Thunderstorms affected numerous river basins across the state. In Victoria, the National Weather

Service, the City, County, and Office of Emergency Management collaborated to prepare for the forecasted flood wave.

Emergency management personnel often use tools such as local river gauges to guide their response to river flooding. In

an effort to provide a more comprehensive understanding of potential inundation limits, the local floodplain administrator

asked Freese and Nichols, Inc. (FNI) to conduct a hydraulic analysis of the Guadalupe River in Victoria County. In less

than 24 hours, floodplain extents associated with different elevations at the local gauge were provided to the emergency

management personnel. The end product was a Google Earth tool that was used by first responders to understand and

identify potential areas of distress.

This presentation will focus on how to provide situational awareness to emergency management teams on a county-wide

basis, utilize existing models to assess anticipated inundation, and provide tools that non-engineers can use to direct their

responses.





SUMMIT AGENDA

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9:30 am – 10:00 am

BREAK

10:00 am – 10:40 am

FROM DROUGHT TO THE FLOOD OF THE CENTURY

Presenters: Jerry Cotter, PE and Helena Mosser; U.S. Army Corps of Engineers

The months of May and June of 2015 brought unprecedented rainfall to the state of Texas. USACE and its flood risk

management partners operated the flood control systems across the state preventing billions in flood damages. During

this flooding period, many USACE projects were filled to capacity with surcharge operations resulting at nine

projects. USACE prepared inundation mapping across the state for TDEM participated in after action flood risk studies.

10:40 am – Noon

FLOOD PANEL DISCUSSION

Panel: David Mauk, CFM. Bandera County River Authority and Groundwater District

Joe Arellano, CFM, National Weather Service

Jeff East, US Geological Survey (USGS)

Throughout the Summit, various presentations were given regarding the Memorial Weekend Floods including what

happened and actions taken. However, these presentations could have also resulted with questions. To help address your

questions, we assembled a panel of experts including representatives from various agencies and our communities. Be

ready to ask your questions and/or make your observations.

Noon

CLOSING REMARKS

Roy Sedwick, CFM; TFMA Executive Director

Jessica Baker, PE, CFM, PMP; TFMA President

SUMMIT ADJOURN

FUTURE TFMA CONFERENCES:

28th Annual TFMA Spring Conference 2016 Fall Technical Summit

March 8 - March 11, 2016 August 30 - September 2, 2016

Omni Galleria Hotel, Houston Hyatt Lost Pines Resort, Austin/Bastrop


April 25 - April 28, 2017 August 29 - September 1, 2017

Dallas Renaissance Hotel, Richardson Hyatt Hill Country Resort, San Antonio


March 6 - March 9, 2018 August 28 - August 31, 2018

Horseshoe Bay Resort, Horseshoe Bay/Austin Hyatt Hill Country Resort, San Antonio

Documents

“After the Floods: Texas Rising”€¦ · TEXAS FLOODPLAIN MANAGEMENT ASSOCIATION 2015 Fall Technical Summit – Sept. 2 - 4, 2015 Hyatt Regency Houston “After the Floods: Texas