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Society of American Military Engineers

(SAME) Fort Worth Post

Presenters• Edith Marvin, P.E., Director of Environment and

Development, NCTCOG

• Michael Morris, P.E., Director of Transportation,

NCTCOG

• Jerry Cotter, P.E., Chief Water Resources

USACE, Fort Worth District

March 1, 2021

Integrated Transportation and

Stormwater Infrastructure in the

Upper Trinity River

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WHAT IS NCTCOG? (NORTH CENTRAL TEXAS COUNCIL OF

GOVERNMENTS)

Voluntary association of member governments

Established in 1966 to assist member governments

in:

➢ Planning for common needs

➢ Cooperating for mutual benefit

➢ Strengthen their individual and collective power

➢ Coordinating for sound regional development

One of 24 COGs in Texas

A political subdivision of the state – non taxing entity

Governed by 18-member Executive Board

www.nctcog.org

2020 Population

of over 7.5 Million

– 4th largest

metro area in the

U.S.

3

A FUNDAMENTAL PROBLEM: REACTIVE APPROACH TO

MANAGING FLOOD RISK AND ENVIRONMENTAL IMPACTS

As development occurs, planning occurs for:

▪ Transportation infrastructure

▪ Wastewater infrastructure

▪ Water supply infrastructure

▪ Solid waste infrastructure

But what about stormwater infrastructure:

• Spotty requirements to mitigate increased

impervious area

• Minimal requirements to mitigate loss of

storage

• Minimal requirements to look at cumulated

watershed scale impacts

• Questionable standards, historic 100-year

What about environmental infrastructure:

• Negotiated impact by impact

• Frustration and misunderstandings

• Piece-meal rather than comprehensive

Case Study: Developing Area In North Fort Worth, Texas

Before After

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PROJECT AREA STATISTICS

• 126% increase in population

between 2020 and 2045

• 7,183 miles of stream

• 274,121 acres of FEMA 100

year floodplain (including lake

area)

• 19% increase in impervious

surface from 2006 to 2016

• 86 cities, 7 counties, 2 water

providers, 1 regional

wastewater provider

32%

4%60%

4%

Residential

Developed

Undeveloped

Open Water

2015 Land

Use (acres)

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REACTIVE APPROACHES ARE EXTREMELY DIFFICULT AND

COSTLY

6

BUILD UPON LONG-TERM SUCCESSFUL REGIONAL PROGRAMS:

Integrated Stormwater Management (iSWM) Resources

- Technical Manual - Criteria Manual

Trinity River Common Vision Corridor

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BUILD UPON LONG-TERM SUCCESSFUL REGIONAL PROGRAMS:

2017 REGIONALLY ENDORSED RECOMMENDED STANDARDS IN WATERSHED MANAGEMENT - For New

Development Within County Regulated Areas *

1 Design infrastructure to fully developed conditions with approved land-use maps if data is available

2Begin protection at the most upstream end of the watershed above Federal Emergency Management

Agency Limit of Detail Study

3 Maintain unfilled valley storage areas

4 Protect against and reduce erosive velocities

5 Match pre-developed site runoffs

6 Verify/require adequate downstream conveyance

7 Require freeboard from fully developed (if data is available) and changing watershed conditions

8 Define written operation and maintenance responsibilities

9 Size conveyance of street and storm systems adequately to safely convey traffic

10 Create stream buffers and preserve open space; limit clearing and grading

11 Consider regional (on or off stream) detention incentives

12 Implement Conservation and/or Cluster Development incentives

13 Encouraging low impact development techniques and/or green infrastructure

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State Recommendation:The January 2019 Interim Report to the 86th Texas Legislature from the House Committee on County Affairs contains a recommendation that the Texas Legislature should explore a regional approach to floodplain regulation, allowing counties that share watersheds to adopt similar regulations, as allowed by the Texas State Water Code.

https://house.texas.gov/_media/pdf/committees/reports/85interim/County-Affairs-Committee-Interim-Report-2018.pdf

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PLANNING INTEGRATION: PREVENTION VS. RESPONSE

Implementation (Products and Technical Tools)

Project Management and Organization

Plans to Offset Future Transportation and Indirect Development Impacts

Land Inventory and Site-Specific Design Considerations

Inventory of StormwaterManagement Structures

Inventory of Relevant Data

PR

OJ

EC

T T

AS

KS

& C

OS

T C

OM

PO

NE

NT

S

What: How:

• Integrate regional transportation planning,

regional stormwater management planning,

and environmental planning to develop

consolidated, adaptive infrastructure

• Create innovative regional partnerships

• Dissolve silos

• Create grant and loan

legislation (WRDA) for

implementation

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COST AND NUMBER OF FLOODING DISASTERS ARE INCREASING

Flooding Disasters are

Impactful• Flooding has impacted 99% of

counties in USA, (1996 to present)

• Increasing frequency of events

• 160 of 224 fatalities in TX occurred

2015-2017

• Increasing cost of flooding events

• ~$150B in Texas, (2015 to present)

• Response: Increasing U.S.

appropriations from $1B to $8B

annually

2010-2019 Flood Related Fatalities

Source: NOAA/NWS

224

Median

Recent Years

Frequency of Flooding Disasters

Source: NOAA

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WHY: INCREASING FREQUENCY AND MAGNITUDE OF

PRECIPITATION EVENTS

• Regional observed stormso USACE extreme storm database

o 24-hour rainfall for 10 mi2

• Grey band was design

standard (100-year) until

2018

• Blue X’s points are 2010-

2019 storms that exceed

100-yearo 20+ events exceeded the 100-yr

design standard (2010-2019)

NOAA

Atlas(2018)

NOAA

Atlas(2018)

TP40 Maximum

TP40 Minimum

Standard

Project

Flood

Previous

Active

Storm

Period

Recent

Active

Storm

Period

DFW 100-yr 24hr

DFW 100-yr 24hr

12

13

• 2010 Tropical Storm Hermine

• Extensive flooding

• No fatalities

• Buy-outs for 150 residences

• $17+ M

11” Rain 7-8” Rain over Rush Creek

FINANCIAL TOLL:

ARLINGTON, TEXAS

SEPTEMBER 2010

THE HUMAN TOLL

Houston, TXHouston, TX

Brazos River, 2016Brandon Wade/Star-Telegram via

AP Photos

Brazos River, 2016

Brazos River, TX

2016

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WHY: GROWTH AND DEVELOPMENT INCREASES FLOODING

Technologies to understand

impacts of growth and

development

• Floodplains are among the most

valuable ecosystems on earth,

they are also one of the most

threatened

• Growth and development

increases impervious cover and

runoff

• Growth and development depletes

storage

• Flooding is increased with

negative societal impacts

• Further research for impacts of

detention associated with

development ordinances

1990 – Trinity River DFW

Kazemi, Hamidreza

(Kasra. (2014).

Evaluating the

effectiveness and

hydrological

performance of

green infrastructure

stormwater control

measures.

10.18297/etd/1744

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WHY: UNCERTAINTIES AND INAPPROPRIATE RISKS

• Statistical Hydrology - The most commonly used

techniques to estimate flood and rainfall frequencies

rely on observations

• Need record length 3-4 times estimated return interval

• Short Observation Periods - On average TX has 50

years of stream record and 70 years of precipitation

records

• Significant variability and/or non-stationarity observed

in flood flow and rainfall frequency estimates

Perfect 100 year water surface

(80 yrs)

▪ 1:100 probability changes for blocks of years

▪ > 1:4 chance of being flooded over a 30 yearmortgage

▪ > 1:2 chance of flooding over life of the structure (80 years)

01

00

,00

02

00

,00

03

00

,00

0

1940 1950 1960 1970 1980 1990 2000 2010 2020

Flo

w (

cfs)

Years of Gage Record

Blanco River at Wimberley, Texas

100-Year Estimate

95% Confidence Limits

Annual Peak FlowsCurrent 100-yr

Estimate

1997 100-yr Estimate

12’

20’+

variation

30’

42’

49’

29’

Guadalupe River at Victoria Trinity River at Rosser

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METVUE - STORM SHIFT TECHNOLOGY

• Storm shift technologyo Provides impacts of larger actual regional storms

o Adjustments to critical infrastructure, e.g.

hospitals, sub-stations, ingress/egress

o Freeboard decisions

• Waco, TX completedo Issue: Uncertainty associated with determination

of flood potential (dams)

o Shifted several storms (30+ mi)

o Examined different operational constraints,

multiple scenarios

o Outcome: showed flood potential is greater than

100-year

• Mary’s Creek, DFW, TX areao Issue: Uncertainty associated with determination

of flood potential

o Shifted 2010 100-year± storm 10 miles

o Outcome: Flood potential is greater than

previously understood

• San Marcos underway

Mary’s Creek

Storm above

Benbook Lake FEMA 100-yr Floodplain

Potential Hazard Areas

based on Transposed Storm

• Current Effective FEMA Flow = 43,000 cfs

• Transposed Storm Flow = 60,000 cfs

TP40 - Maximum

TP40 - Minumum

2017

2015

2010

2015

2016

2016

20122014

2010

2010

0

5

10

15

20

25

30

35

40

24

-Ho

ur

10

Sq

. M

i. R

ain

fall D

ep

th (

in)

24-Hour Precipitation for 10 Square Miles

100-Year 24-hour

Average

24-hour 10 sq. mi.

Rainfall (1904 - 2009)

24-hour 10 sq. mi.

Rainfall (2010-2017)

Tropical Storm Patricia

Transposed rainfall

Potential Hazard Areas based

on Transposed Storms

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TRANSPORTATION AND STORMWATER ARE CLOSELY LINKED

Perspectives: • Development of transportation infrastructure precedes

urban growth and development

• Existing and needed low water crossings indicates a

need for better analysis and data for transportation

infrastructure

• Experiencing significant flood related damage to

transportation infrastructure

• Strong relationship between development and road

construction

• Experience non-stationarity of flood potential from

growth and development

• Transportation infrastructure expenditures are some

of the most significant

• Transportation infrastructure has a well established 5

year planning cycle

• Shouldn’t we consider planning stormwater

and environmental infrastructure?

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PREVENTION FOCUS

TRANSPORTATION

Advancing Projects Now

Structure Elevation

Mechanical Culverts

Parkway Detention

Improved Routing Algorithms

ENVIRONMENTAL FEATURES

Tree Farm Saturation

Real Time Filtration Recharging

Wetland/Stream Bed Credit Banking

STORMWATER

Reduce Downstream Flows

Detention

Plan for Peaks

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A working group of partners and stakeholders to carry out a

comprehensive planning effort in Wise County and portions of

Dallas, Denton, Ellis, Johnson, Parker, and Tarrant counties

WHO: Project Team Members

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US Housing and Urban

Development

NCTCOG

US Army Corps of Engineers

Federal Emergency Management

Agency

Tarrant Regional Water District

Regional Transportation

Council

Texas Water Development

Board

Technical Partner

Texas Floodplain Management Association

Education and Communication

Local Jurisdictions

Technical Partner

Trinity River Authority

Trinity River Common Vision

Committee

Policy and Technical Partner

Policy and Technical Partner

Policy and Technical Partner

Policy and Technical Partner

Technical PartnerTechnical PartnerTechnical Partner and Advisor

Project Oversight /Leadership

2020

CONTRIBUTIONS: Partners are critical to making this possible

$ ? $ GLO $ BLE✓

Project Funding Goal: $10 Million

Phased Implementation, If Necessary

$ PAS $ RTC $ FIF $ 3M ✓

Project Has Begun With Getting the Money

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21

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PARADIGM SHIFT

BENEFITS

Collaborative

Effort

Complement

Existing

Programs

Return on

Investment

Address Existing

Challenges with Flood Reduction

Efforts

Comprehensive Planning• Dissolve silos • Improve delivery of consolidated, adaptive

infrastructure before expected population growth• Minimizing duplication and providing resources

Complementing Existing Regional ProgramsNorth Central Texas Council of Governments Common Vision Program• Community management of Trinity River through DFW• Limit impact of development through Corridor Development

Certificate (CDC)• Flood warning systems• Enhanced state-of-the-art modeling toolsLong-Range Transportation Planning ProcessCompliance with State Laws

Creating Positive Financial Outcomes• Investment in stormwater infrastructure returns $5 to $7

for every $1 invested*• Lower community flood insurance premiums• Provides connected open space• Increased safety from flooding• Human health benefits• Recreation benefits*2017 “Natural Hazard Mitigation Saves” (National Institute of Building Sciences Multi-hazard Mitigation Council)

Creation of Resources and Tools to Support Communities• Limited resources, staff expertise, competing priorities, piecemeal

modeling• Develop tools that define waterways, stormwater features• Community avoids costs of development impacts, don’t loose

revenue

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Foundational

Analysis

Policies & Actions

Decisions

BENEFITS: PRODUCTS AND OUTCOMES

0 This

Effort

Community

Activities

Transportation Infrastructure

• Structure Elevation/ Culverts/Model Growth

• Transportation “LEED” Certified

• Green Parkway Widths/Detention

• Safety

• Technology/routing

• Better prioritization of low-lying structures

Flooding

• Numerical models (meteorology, hydrology, hydraulics)

• Reduced risk

• Regulatory products

• Designated stormwater areas

• Tree farms, Wetlands, Mitigation banks, Detention areas

Environmental Stewardship as Economic Asset

• Environmental areas

• Horse farms

• Preserve riparian areas

• Mitigation areas/wetland banking

• Eco-tourism

Other Planning Tools

• Stormwater infrastructure plans

• Emergency preparedness

• Emergency response

• Groundwater recharge

• Open space and connected open space

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WHERE ARE WE NOW?

REPLICATEINITIATE PLANNING

WORK

FUNDING

- $10 million price tag

- Congressional roundtable Summer

2019

- Moving forward on applications to federal

agencies

SCOPE AND SCHEDULE

- Under Development with partners

- Estimated 5 yearproject

PARTNERSHIPS AND WORKING

GROUP

- Federal

- State

- Local governments

- Water providers

- Universities

WE ARE HERE

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QUESTIONS & CONTACT

NCTCOG TransportationMichael Morris, P.E.(817) 695-9241MMorris@nctcog.org

NCTCOG Environment & Development

Edith Marvin, P.E.

817-695-9211

EMarvin@nctcog.org

U.S. Army Corps of Engineers

Jerry Cotter, P.E.

817-886-1549

Jerry.L.Cotter@USACE.army.mil