integrated transportation and stormwater infrastructure in the
TRANSCRIPT
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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.
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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
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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
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• 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
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-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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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) [email protected]
NCTCOG Environment & Development
Edith Marvin, P.E.
817-695-9211
U.S. Army Corps of Engineers
Jerry Cotter, P.E.
817-886-1549