ADDRESSING FLOOD RISK:

A Path Forward for Texas After Hurricane Harvey
American Society of Civil Engineers – Texas Section:
Task Committee On Post-Hurricane Harvey Recommendations

FLOODED APARTMENT BUILDINGS IN PORT ARTHUR, TX FOLLOWING HURRICANE HARVEY, CREDIT: TASK COMMITTEE CHAIR, ANDREW WELLS

 Harvey flooding caused a major Houston-area arterial, the Sam Houston Tollway approaching
Interstate 10 in Memorial City, to completely shut down. Credit: iStock photo by Karl Spencer.

ABOUT THE AMERICAN SOCIETY OF CIVIL
ENGINEERS
This report was written by the Texas Section of the American Society of Civil Engineers
(ASCE): Task Committee on Post-Hurricane Harvey Recommendations. ASCE represents
more than 150,000 members of the civil engineering profession in 177 countries around the
world. Through the expertise of its active membership, ASCE is a leading provider of technical
and professional conferences and continuing education, the world’s largest publisher of civil
engineering content, and an authoritative source for codes and standards that protect the
public welfare.
Established in 1913, the Texas Section of ASCE represents nearly 10,000 members
throughout Texas. Headquartered in Austin, the Section is composed of 15 regional branches,
seven technical institute chapters and 17 student chapters (including one at each major
Texas university).

A PATH FORWARD FOR TEXAS AFTER HURRICANE HARVEY—PAGE 2

 About the Task Committee
The Task Committee on Post-Hurricane Harvey Recommendations was formed by members of the ASCE Houston and
Southeast Texas Branches whose communities have been severely impacted by flooding due to Hurricane Harvey. The
impetus to form this task committee came from a desire to improve flood management practices based on their personal
and professional experiences. The committee now includes members from across the State. Committee members, as
well as their various positions within ASCE, can be seen below.
All committee members are practicing engineers and serve on the committee on a volunteer basis.
COMMITTEE CHAIRMAN:
Andrew Wells EIT
Past President, Southeast Texas Branch

ASSISTANCE ALSO PROVIDED BY:
Lawrence Goldberg PE
President, Texas Section

COMMITTEE MEMBERS:
Curtis Beitel PE
Past President, Texas Section; Chair, Environmental &
Water Resources Institute, Texas Chapter
Michael Bloom PE
President, Environmental & Water Resources Institute,
Houston Chapter
Griselda Gonzales PE
Member, Government Affairs Committee, Texas Section
Liv Haselbach PhD, PE
Texas Section Director, Southeast Texas Branch

Kate Osborn EIT
President, Southeast Texas Branch
Gareth Young PE
President, Houston Branch
CONTRIBUTING ASCE STAFF MEMBERS:
Anna Denecke
Senior Manager, Infrastructure Initiatives, ASCE
Maria Matthews
Senior Manager, Grassroots Programs &
State Government Relations, ASCE
Becky Moylan
Senior Manager, Media Relations, ASCE

Michael Kelley PE
Member, Infrastructure Report Card Committee,
Texas Section
Brandon Klenzendorf PhD, PE
Vice President of Professional Affairs Elect, Texas Section

Lindsay O’Leary PE
Executive Director, Texas Section

Andres Salazar PhD, PE
Past President, Environmental & Water Resources Institute,
Houston Chapter

Document Review
This document was distributed to a large number of government agencies and organizations for review prior to publishing.
Many responded with valuable feedback. The Task Committee greatly appreciates these stakeholders’ time and has done
its best to incorporate their comments into this report.

ASCE TEXAS SECTION - PAGE 1

 EXECUTIVE SUMMARY
In the 2017 Report Card for Texas’s Infrastructure, the Texas Section of the American
Society of Civil Engineers (ASCE) graded the State’s overall flood control infrastructure a
“D.” This grade does not reflect the quality or adequacy of any individual local government’s
facilities, but is rather a statewide grade. To improve this grade, civil engineers made several
recommendations to lawmakers and the public, including increasing funding for flood control
infrastructure, flood warning systems, flood risk mapping, and enhancing state involvement in
these programs.
The issues identified in the 2017 Report Card for Texas’s Infrastructure were highlighted when
Hurricane Harvey made landfall as a category four hurricane near Rockport, Texas on August
25, 2017. The storm went on to impact over 40 counties in Texas, dropping more than 60
inches of rain in a matter of days on some areas and becoming the costliest natural disaster
in Texas history. It is the second most costly natural disaster in U.S. history, behind only
Hurricane Katrina.

Hurricane Harvey Massive Flooding
Columbus Texas small Town
destruction close up. Copyright:
RoschetzkyPhotographyBigStock

While eliminating the risk from
extreme storm events such as
Hurricane Harvey is impossible,
communities across the State can
reduce risks associated with larger
storms, reduce their impacts, and
improve recovery capabilities. Because
flood water does not respect political
boundaries, the Texas Section of ASCE
calls for improved communication and
coordination among local governments
within each watershed.

This report expands on the 2017 Report Card for Texas’s Infrastructure by exploring the existing
landscape of flood risk management in the State and identifies measures that can be taken to
better prepare for the next event. The report makes a series of recommendations to guide local,
state, and federal decision-makers to use in improving inland flood risk management throughout
Texas. It does not specifically address the issue of coastal flood risk management.

A PATH FORWARD FOR TEXAS AFTER HURRICANE HARVEY—PAGE 2

 Recommendations from ASCE Texas Section for a path forward after Hurricane Harvey include:
  DEVELOP A STATEWIDE FLOOD MITIGATION PLAN
The Texas Water Development Board should develop
and regularly update a statewide flood mitigation plan,
with input from all levels of government, citizens and
the private sector. The state legislature, in partnership
with localities and the federal government, should provide
funding to support projects identified in the statewide
flood mitigation plan. Investing in flood mitigation
infrastructure will save taxpayers money in the long
run; for every $1 invested in mitigation, $6 is returned,
according to the National Institute of Building Sciences.

  FUND DAM SAFETY
The state should provide additional funding for Texas’s
Dam Safety Program as well as a funding program for
dam improvements. A 2008 Audit Report found that,
“[The Texas Commission on Environmental Quality’s]
dam safety program, as currently designed and operating,
is not able to accomplish its statutory mandate to ensure
the safe construction, maintenance, repair, and removal of
dams in the State of Texas.” Increased funding is necessary
for this important program. Additionally, grants and loans
designed to assist owners with dam repair, abandonment,
or removal should be provided, either through the Dam
Safety Program or another administrative process.
  IMPLEMENT A STATEWIDE LEVEE SAFETY PROGRAM
The Texas Commission on Environmental Quality should
develop and implement a program for inventorying the
condition of all levees in Texas. Levees are owned by a
variety of local, regional and federal agencies, but the
inspection of non-federal levees is not widely available,
and their condition is often unknown. The state legislature,
in partnership with the federal government, should
establish a program to ensure the safe construction,
maintenance and repair of levees in Texas.
  FOCUS ON A WATERSHED APPROACH
Communities should take a watershed approach to
flood risk management. Communities within each Texas
watershed should coordinate their flood risk management
regulations and infrastructure plans so that upstream
activities don’t adversely impact downstream property

 

owners and localities. Coordinated activities should also be
used to plan and implement flood risk reduction programs
and projects that help reduce flood risks for everyone
within a watershed, not just those living in one community.
Neighboring watersheds should work together to create
regional planning groups, which in turn could be integrated
to create a statewide flood mitigation plan. This structure
would be similar to the existing state water planning
framework, which includes 16 regional planning groups.
Additionally, the State should establish minimum flood
risk management standards and give all local jurisdictions
sufficient authority to implement locally appropriate land
development and floodplain management regulations.
  EDUCATE CITIZENS ABOUT RISK
Entities with authority over floodplain management
should collaborate to implement a public outreach
program to educate the Texas population about flood risk
management and preparedness, including the roles of
public agencies during emergency conditions. Increased
education will help better inform residents about the
watershed they live in, what infrastructure may affect
their homes, and where to look for information during
an emergency. Additionally, more robust flood risk maps
that identify multiple risk levels, not just the boundary
between areas with greater than a one percent annual
chance of flooding and those with less, are needed.
Risk maps should also show risks from other types of
inundation, not just riverine flooding.
  EMPLOY ALTERNATIVE FLOOD MITIGATION
STRATEGIES

Continue to invest in the development and
deployment of alternative flood mitigation strategies,
including green stormwater infrastructure (also
known as “low impact development”). Technological

advancements in permeable pavement, green roofs, and
small-scale sedimentation and filtration ponds, as well
as the installation of rain gardens, vegetated swales, and
disconnecting flow paths can be effective tools to reduce
flood risk and increase resiliency when implemented on a
watershed basis. The natural environment should also be
considered as an asset for flood risk management purposes.

The report that follows includes detailed explanations of the recommendations listed above. 
ASCE TEXAS SECTION—PAGE 3

 Introduction
Hurricane Harvey made landfall as a category four
hurricane near Rockport, Texas on August 25, 2017.
The storm went on to impact over 40 counties in Texas,
dropping over 60 inches of rain in a matter of days in
some areas, becoming the costliest natural disaster in
Texas history and the second most costly natural disaster
in U.S. history, behind only Hurricane Katrina.

of any individual local government’s facilities, but is rather a statewide grade. The report found that flood preparedness, floodplain management and flood prevention
are largely the domain of local jurisdictions as the State
of Texas does not have a central authority to guide these
activities. While the major urban centers have implemented increasingly sophisticated flood risk management
programs and flood mitigation
systems, the needs of both large
cities and less populated counties
consistently outpace the funding
required to provide reliable flood
risk mitigation statewide. Enhancing state involvement in planning,
financing, and funding of flood risk
management activities will help
to improve the effectiveness of all
flood risk management activities
across Texas.

In addressing the challenges ahead,
it should be recognized that the
adverse impacts from extreme
events such as Hurricane Harvey
cannot be fully prevented. Likewise, the approach to flood risk
Estimated 5-day Rainfall during Hurricane Harvey along the U.S. gulf coast. Credit: Capital Weather Gang, Jordan Tessler.
management must change from
a philosophy of “control” to one
As the State rebuilds and looks to the future, the Texof “risk reduction.” This underscores the understanding
as Section of the American Society of Civil Engineers
that there is a limit to which any storm or natural disaster
(Texas Section) has developed a comprehensive set of
can be controlled and recognizes that there will always be
recommendations to improve inland flood risk mansome measure of risk no matter how extensive the State’s
agement, to enhance resiliency and to help mitigate
flood risk management system might be.
the adverse impacts of future storm events throughout
Throughout Texas, communities are reevaluating their
Texas. Coastal flooding is not specifically addressed. The
flood risk management strategies, their floodplain maps
committee tasked with writing this report is composed
and funding for flood risk reduction infrastructure. Buildof civil engineers throughout Texas, many of whom were
ing off the recommendations to raise the grade in the
personally affected by Hurricane Harvey.
2017 Report Card for Texas’s Infrastructure, this report
In the 2017 Report Card for Texas’s Infrastructure1, ASCE
proposes solutions applicable across all levels of governgraded Texas’s flood risk management infrastructure a
ment to address the issues highlighted by the results of
“D.” This grade does not reflect the quality or adequacy
Hurricane Harvey.
_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
1

Texas Section of the American Society of Civil Engineers (www.TexASCE.org/IRC), 2017. 2017 Report Card for Texas’ Infrastructure.

A PATH FORWARD FOR TEXAS AFTER HURRICANE HARVEY—PAGE 4

 The Task at Hand
The Federal Emergency Management Agency (FEMA)
defines a flood as a temporary condition of partial or complete inundation of two or more acres of normally dry land
area or two or more properties from overflow of inland or
tidal waters or unusual and rapid accumulation or runoff of
surface waters.2 Flooding is not a new phenomenon. For
thousands of years, people have sought to control the
flow of water during extreme weather events to protect
property and promote public safety. As infrastructure
designers, civil engineers seek to accomplish those same
goals today. However, as the population grows and Texas
continues to develop, it is increasingly likely that two or
more properties will be flooded rather than two or more
acres of land. This poses many challenges because the
very nature of development removes natural ecosystems
that serve to collect and infiltrate rainwater and thereby
reduce flood risk. Further, the introduction of infrastructure to collect rainwater can introduce new hazards when
they become overwhelmed. As a result, the sophistication of infrastructure must increase with increasing development. Similarly, flood risk management structures
and strategies must be able to keep pace with an ever
more spatially connected society.
According to the Texas Demographic Center, the population of Texas is projected to increase from 28 million
(January 1, 2017) to 54 million by 2050.3 This growth
will drive the construction of additional infrastructure,
homes, roads, businesses and other facilities. Local
governments control how and where many of these new
facilities will be constructed and what flood risk they will
experience. State government controls how state institutions locate and construct new facilities. Similarly, the
state governs where highways and certain roadways are
built and how they might impact flood risks.
In general, there are two interconnected infrastructure
strategies for managing rainwater. Stormwater infrastructure, which includes street curbs and drains, parking

lot inlets, and buried pipes and culverts, is designed to
handle rainwater that falls on developed land and transport it to streams, rivers or other water bodies. These
systems are typically designed for smaller, more frequent
storms and handle water on a neighborhood or city level.
While these systems still function during extreme events,
they are designed to handle smaller rain events, so they
are routinely overwhelmed by larger storms. This leads to
inundation and possible flooding. Conversely, flood risk
management infrastructure, such as detention facilities,
channels, dams and levees, is designed to handle rainwater that has already accumulated in water bodies. These
structures are designed to function during larger, more
extreme events and may handle water on a neighborhood, city or regional scale.
In addition to infrastructure, natural systems, such as
undeveloped river corridors, wetlands, prairies, and other
features can also serve a flood risk management function
by containing and infiltrating rain water, as well as providing an important buffer for communities from overland
flow. As such, the incorporation of natural ecosystem
components into a flood risk management strategy can
minimize flood risk and provide important benefits similar
to manmade infrastructure.

Stormwater infrastructure, flood
risk management infrastructure
and the natural environment work
together to reduce flood risks. The
task at hand is to better leverage
each of these assets to sustainably
reduce flood risk, increase public
safety and protect the environment for future generations.

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

  National Flood Insurance Program, FEMA (https://www.fema.gov/national-flood-insurance-program/definitions#F)

2

3

 2014 Texas Populations Projections, Texas Demographic Center (http://txsdc.utsa.edu/Data/TPEPP/Projections/)
ASCE TEXAS SECTION - PAGE 5

 FLOOD RISK MANAGEMENT IN TEXAS
Local cities and counties conduct most flood risk management activities in Texas. Local communities plan and
implement stormwater infrastructure projects; they devise
and implement flood risk management projects, sometimes in partnership with federal agencies; and they adopt
and enforce floodplain management rules for land development. By State law, cities and counties must participate
in the National Flood Insurance Program (NFIP), which
makes them eligible to receive federally subsidized flood
insurance and federal assistance. In return, each community agrees to adopt and enforce a minimum set of floodplain
development standards. Communities may also choose to
exceed the NFIP minimum criteria.
Flood risk management activities related to the NFIP are
led by the floodplain administrators in each community,
guided by the specific floodplain management regulations for urban development that community leaders have
selected according to their acceptable level of risk and local
conditions. The Texas Floodplain Management Association
(TFMA), a state chapter of the Association of State Floodplain Managers (ASFPM), provides training and certification for professionals working in the flood risk management
field in both the private and public sectors. Through the
auspices of ASFPM, which credentials nationally, TFMA has
credentialed over 2,000 Certified Floodplain Managers in
the state of Texas, more than any other state.

At the state level of government, the Texas Water Development Board (TWDB) provides limited funding
assistance for flood risk management projects to political
subdivisions of the State. This generally consists of small
grants and low-interest loans. The Texas Commission
on Environmental Quality (TCEQ) defines the stream
and environmental regulations in the State, either by
administering federal regulations on behalf of the U.S.
Environmental Protection Agency (EPA) or enacting the
State’s own rules for environmental regulations. TCEQ
also administers the statewide Dam Safety Program, which
monitors and inspects private and public dams. The Texas
Department of Emergency Management (TDEM) is
responsible for emergency preparedness and emergency
response activities that are associated with flooding and
other natural disasters. The General Land Office (GLO)
administers the state’s coastal management program,
receives and manages post-disaster recovery funds from
the U.S. Department of Housing and Urban Development,
and has developed a coastal resiliency master plan for the
state. There are also a number of river authorities in Texas,
created by state law, that are authorized to conduct drainage and flood risk reduction activities.
At the federal level, the U.S. Army Corps of Engineers
(USACE), U.S. Department of Agriculture (USDA) and
other federal agencies own, operate and/or regulate a

Inundation of the main spillway area of the U.S. Army Corps of Engineers’ Barker Reservoir
during emergency releases during Harvey. Credit: iStock photo by Karl Spencer.

A PATH FORWARD FOR TEXAS AFTER HURRICANE HARVEY—PAGE 6

 number (but by no means all) of Texas’s dams and levees.
In many instances, the USACE will construct infrastructure and then transition into a regulatory role after
passing ownership on to a local sponsor, such as a drainage district, to operate and maintain. In 2016, the Water
Infrastructure Improvements for the Nation (WIIN) Act
authorized the High-Hazard Potential Dam Rehabilitation program, which would help fund the repair, removal,
or rehabilitation of the nation’s non-federal, high-hazard potential dams. The Water Resources Reform and
Development Act (WRRDA) of 2014 created a new
National Levee Safety Initiative (NLSI). This program will
promote consistent safety standards, create levee safety
guidelines, and provide funding assistance to states for
establishing participating levee safety programs; however,
the authorized funds have yet to be fully appropriated.
FEMA administers the NFIP and develops Flood Insurance Rate Maps (FIRMs) that delineate special flood
hazard areas (regulatory floodplains) that have at least a
one percent chance of flooding annually, as well as other
flood risk information. These maps are not comprehensive in that they typically only include flooding along
major studied streams and do not consider all potential
sources of flooding. They also typically only represent
two risk levels; the one percent annual chance and the
0.2 percent annual chance.

While different public and private
entities use these maps for a variety
of purposes, they are strictly
developed and intended to be used
to assess compliance with NFIP
standards, which is necessary for
citizens in each community to
receive federally subsidized flood
insurance and federal assistance.
They are not meant to be comprehensive flood risk management tools.
FEMA is also responsible for overseeing the National
Dam Safety Program.

Additionally, FEMA sponsors the Interagency Flood
Risk Management (InFRM) team, which brings together
Federal partners with mission areas of hazard mitigation,
emergency management, floodplain management, natural resources management and conservation to determine
the needs of communities, define solutions and implement measures to reduce long term flood risk throughout
Arkansas, Louisiana, New Mexico, Oklahoma and Texas.
Partners include the USACE, the U.S. Geological Survey
(USGS) and National Weather Service (NWS) .4

COORDINATION AMONG STAKEHOLDERS AND
FLOOD RISK MANAGEMENT LEADERSHIP
Because flood risk management activities are defined at
the local level, with each community having some degree
of autonomy to set their own policies, regions with multiple
neighboring communities can end up with a collection of
flood risk management strategies and regulations that differ
in protection levels and land development requirements. The
common denominator is the NFIP minimum criteria, but
from there two adjacent communities may elect to enact
additional standards, which may or may not be consistent.
This is the case in the Greater Houston Area. Harris County
has 33 different municipalities, with the unincorporated areas under the jurisdiction of Harris County. Thus, there are

34 floodplain administrators in the county. Harris County
Flood Control District also designs, builds, and maintains
the primary channels and tributaries throughout the county.
Urban development extends to the adjacent Counties of
Montgomery, Fort Bend, Brazoria, and Galveston, which
adds to the number of communities enacting their own
flood management standards that affect the Houston area.
Although the boundaries of each community are well
defined, these boundaries do not correspond to watershed
boundaries and streams that traverse multiple communities.
This creates the need for collaboration and coordination.
Each adjoining community, although politically independent

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
4

Interagency Flood Risk Management (https://webapps.usgs.gov/infrm/)
ASCE TEXAS SECTION - PAGE 7

 of each other, should be somewhat consistent with their
neighbors in their approach to flood risk management.
When considering new development, it is important that
communities recognize that these developments are not isolated from the surrounding community or its infrastructure.
Not only does new development remove natural ecosystems
that buffer existing developments and infrastructure, but
merely by existing in a natural environment that is subject to
rainfall and runoff, it exposes people and property to flood
risk and can often increase risk levels for those upstream or
downstream, even if locally mitigated. Over time, this can
reduce the effectiveness of existing large flood risk management infrastructure, drive a requirement for upgrades,
or make it more expensive to implement new risk management systems. Since the owners of flood risk management
systems are often not the same entities who permit new
development, decisions are often not harmonized. This also
means that the those who pay to reduce risks and those who
benefit are not the same people.

TWDB is currently conducting a statewide flood assessment,
which seeks to estimate the total cost of all flood risk management projects across the state. Billions of dollars will be
needed to reduce flood risks in Texas to acceptable levels,
especially in areas that were developed prior to the creation of
the NFIP and the production of FIRMs. Flood risk management infrastructure projects must be devised on a watershed
basis, which requires multi-agency coordination and the
participation of all communities within that watershed.
Texas has been exemplary in water supply planning with the
development of a State Water Plan, which is updated on a
five-year cycle by regional stakeholder groups under the
administration of TWDB. However, no such statewide planning framework exists for flood risk management planning.
Recent flood events such as Hurricane Harvey, the Wimberley floods, and Brazos River floods, among others, have
highlighted the need for flood risk reduction projects in
urbanized areas. Such projects are not easy to implement

This is especially true for dams, which are given a hazard
rating of high, significant or low based on whether there
is probable loss of life, significant economic losses with no
expected loss of life, or minor damage to normally unoccupied buildings or land, respectively, if a dam fails. According
to the Texas State Soil and Water Conservation Board
(TSSWCB), approximately 50 percent of dams in Texas
built since 1948 under the Small Watershed Programs have
exceeded their 50-year life expectancy.5 By allowing new
development below these and other dams, even if local
mitigation rules are followed, communities may inadvertently increase the hazard rating of upstream dams, which can
require millions of dollars in renovations and repairs.
Most communities have a well-defined process to regulate
land development to avoid increases in flood risk and to
meet NFIP minimum requirements, however the NFIP’s
primary goal is to determine insurance premiums for properties located in different flood risk zones. The NFIP and
related policies do not define the infrastructure needed to
reduce flood risk. In other words, it is not within the scope
of the NFIP to define what infrastructure is needed in a
particular watershed to reduce flood risks. Such solutions
are developed in a regional context by local stakeholders
or in some cases with participation from the State and
Federal Government.

Various Watersheds in Harris County and neighboring counties. Source: Illustration
adapted from Harris County Flood Control District and the Texas Water Development
Board, prepared by Task Committee member Michael Bloom.

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
5

 TSSWCB Flood Control Program and USDA NRCS Watershed Program Maintenance, Repair and Rehabilitation; June 2016. Texas State Soil and
Water Conservation Board.
A PATH FORWARD FOR TEXAS AFTER HURRICANE HARVEY—PAGE 8

 as they require feasibility studies, reliable funding mechanisms and, as stated before, participation from multiple
communities. A statewide flood plan could identify specific
projects for future funding and implementation.
Following the philosophy of the State Water Plan—which
draws from 16 regional planning groups—the statewide
flood plan could be developed by regional planning groups,
composed of local agencies, and stakeholders each representing different interests, but which consider local contexts and priorities. Also, similar to the process of the State
Water Plan, a flood reduction project would need to be in
the statewide plan and determined feasible to be eligible for
funding or financing from TWDB. Planning regions should
be developed based on interconnected watersheds appropriate for the protection of life and assets. Closer to the coast,
they may be smaller than those in the State Water Plan;
however, planning regions may be able to cover a larger area
with the same effect in other parts of the State.
Planning activities should include all communities in a watershed, regardless of size or population, because stormwater and flood risk management in upstream communities
has a direct impact on those downstream. It should be
recognized that availability of funding and resources for
flood planning and mitigation are not distributed equally
among cities or regions. A comprehensive approach that
considers large and small communities would provide an
opportunity to identify not only projects, but also the
needs and resources required to implement the plan.
All projects should be selected based on a cost-benefit
analysis. This requires accurate and widely available data
and models. The TWDB currently serves as a repository
for information related to water planning throughout the
State. That role should be expanded to include flood risk
management data to help guide Federal, state and local
authorities throughout the planning process.
Besides collaborating to fund new projects, the State
should also monitor and fund repairs to current infrastructure. While Texas has a statewide dam safety program, it is
sorely underfunded. In 2008, the State Auditor’s Office
completed
an Audit Report on the Dam Safety Program
 

at TCEQ that concluded, “[TCEQ’s] dam safety program,
as currently designed and operating, is not able to accomplish its statutory mandate to ensure the safe construction,
maintenance, repair, and removal of dams in the State of
Texas.”6 This report has not been recently updated. Because of poor funding, only 259 of approximately 4,000
non-exempt dams were inspected in 2015.7
Texas also does not have a statewide levee safety program.
Many levees throughout Texas were originally used to protect
farmland, and now are protecting developed communities.
The reliability of these structures is unknown in many cases
and there is no dependable catalog of the location, ownership,
condition, or hazard potential of levees in Texas. Along the
lines of the Dam Safety Program, a levee safety program
could include funding for the inspection, construction oversight, maintenance and repair of levees across the State. Such
a program would also assist in the development of emergency
action plans in the case of a levee breach or failure.
In addition to building, inspecting and maintaining appropriate
infrastructure, the State should establish minimum flood risk
management standards and give all local jurisdictions sufficient
authority to implement locally appropriate land development
and floodplain management regulations. Minimum standards
should include a prohibition of positive net fill, which displaces
floodplain storage volume and increases flood risks for other
properties, require the mitigation of increased peak flow rates
from development, and require the routing and sizing of a flow
path for stormwater runoff generated during the one percent
annual chance event so that it does not inundate the occupied
space of any structures. It may be necessary to vary minimum
criteria by region, but consideration should be given to the
watershed that standards influence.
At the federal level, the 1968 National Flood Insurance
Act required that a Unified National Program (UNP)
for Floodplain Management be prepared. While several UNPs have been issued, the most recent version was
published in 1995 and its recommendations, including
the need for coordinated risk management at all levels of
government, have not been seriously addressed.8 Furthermore, much of the program does not reflect current needs
and must be updated.9

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
6

An Audit Report on the Dam Safety Program at the Commission on Environmental Quality, May 2008. Texas State Auditor’s Office, Report No. 08-032.

7

Texas Commission on Environmental Quality, June 2016 and January 2017. Interviews and data from Dam Safety Program. (www.tceq.tx.gov)

8

Traver, R. et al., 2017. Flood Risk Management: Call for a National Strategy. American Society of Civil Engineers.

9

 Galloway, Gerald E., and Lewis E. Link, 2012. A White Paper: The Need for a Unified National Program for Floodplain Management in the 21st
Century. Report prepared for the Federal Interagency Floodplain Management Task Force. Bethesda, MD: Abt Associates
ASCE TEXAS SECTION - PAGE 9

 Implementing an updated UNP would establish the roles
and responsibilities of federal agencies and provide a
framework for their interaction with state and local governments. This is critical for minimizing flood risk before

flooding events and having a coordinated post-disaster
response. As with the state flood plan, a UNP must give
adequate consideration to local priorities and represent the
spectrum of challenges faced around the country.

Recommendations
  Adjoining communities in a region should establish a

consistent set of flood risk management policies to
avoid large variations of land development and floodplain
management rules within the same watershed.

  Create a statewide flood plan to continuously

determine the needs of flood protection projects across
the state, estimate the costs, and propose funding
mechanisms and priorities. This plan should supplement
the current federal NFIP for flood risk management.

  Projects proposed in the statewide flood plan should

be formulated at the local level with participation
of local stakeholders, as activity at the local level
encourages collaboration among stakeholders and
establishes the roles for implementation.

  Multi-purpose projects that provide recreational,

  Establish a statewide database for flood risk

management information.

  Create a statewide levee safety program to ensure

the safe construction, maintenance and repair of
levees throughout Texas.

  Establish minimum, statewide flood risk

management standards.

  Update the 1995 UNP for Floodplain Management

to reflect current challenges and define the
relationship between various levels of government in
reducing flood risk.

  Develop a national vision and supporting framework

for flood risk management in the United States that
includes input from all levels of government.

flood risk management, and ecosystem preservation
and restoration functions should be considered in
any future statewide flood risk management plan.

Devastation of Hurricane Harvey in Pearland Texas USA with pile of debris
from flooding damaged. Huge heap of throw away belongings materials
garbage of ruined houses. Copyright: trongnguyen.

A PATH FORWARD FOR TEXAS AFTER HURRICANE HARVEY—PAGE 10

 COMMUNICATION OF FLOOD RISK
Flood control design, management, and planning are
typically based on statistical analyses of available historic rainfall data for a given geographic region. Statistical
models are used to characterize past rainfall into a recurrence interval or return period, such as a 100-year event.
The use of the term “100-year storm” has been debated
because it implies that a rainfall event of such magnitude
will happen only once every 100 years, but it is actually a
statistical artifact of the method that more precisely states
that there is a one percent probability of the event being
equaled or exceeded in any given year.
The methodology used to determine recurrence intervals
only considers data from past rainfall records and is only
as good as the data available as well as the accuracy of the
statistical methods used. Since the statistics are based on
historical rainfall record, they do not account for potential
changes in long-term, future rainfall trends. It should be
noted that some areas do not have sufficient historical
records to produce statistically significant results. In these
instances, expected flooding is interpolated from locations
with more data or through computer modeling. When
considered in conjunction with a changing climate, the
100-year event (or one percent chance event) may not
remain constant over time.
Communication is further complicated by the work engineers
must do to convert the rainfall amount to a runoff amount,
and, in turn, the river flood stage. Even if the rainfall statistics are periodically updated with new data, the calculation
of stormwater runoff and flood stage needs to account for
changing land use, which it often does not. As more areas are
developed, the amount of rainfall converted to stream runoff
increases. Therefore, the runoff flow rate associated with a
one percent annual chance event will increase as additional development occurs. Mitigation and planning for these
changes is required to provide a level of risk the public is willing
to accept for the given cost of that protection.
Over the last several years, there has been an ongoing
public discussion surrounding the applicability of floodplain
maps in southeast Texas. Much of the discussion since
Hurricane Harvey has revealed a fundamental misunderstanding of risks when reading FIRMs. Since the one percent flood level is used to determine whether a mortgage
lender will require flood insurance, many people see it as
a line distinguishing between areas that are susceptible to

flooding and areas that are not. However, the reality is that
all low-lying, coastal areas have some degree of flood risk.

In fact, there is statistically a 26 percent chance that a storm equal to or
greater than the one percent chance
event will occur over the duration of a
30-year mortgage and a 5.8 percent
chance that a 0.2 percent chance
event (“500-year event”) will occur
over that same 30-year mortgage.

FIRMs, are developed to calculate flood insurance rates
and to regulate compliance with NFIP standards. While
the maps sometimes include other information, their
main purpose is to illustrate areas that have at least a
one percent chance of flooding each year due to riverine
flooding (i.e. from streams, rivers and bayous) with drainage areas usually greater than one square mile. Below
dams, these areas are typically determined assuming that
dams will perform as designed.
However, flood waters can come from a variety of
sources during an extreme storm event. When storm
drains exceed their capacity, streets are designed to
function as a secondary drainage system to transport
water to streams, rivers and other natural water conveyors. Water will also flow over ground when the underlying
soil becomes completely saturated. As a result, water
can collect in localized, low lying areas that are outside of
floodplains shown on FIRMs.
Most dams are designed to contain runoff from a one
percent annual chance event. As a result, the release of
water from dams during large flood events is not typically
shown on FIRMs. However, higher flows could occur
downstream of a dam due to an uncontrolled release of
its reservoir if its embankment is breached. Areas that
could be inundated in the event of a dam breach are
mapped separately and included in an Emergency Action
Plan, which is required by TCEQ for each dam.
As previously mentioned, the one percent chance (100year) floodplain established in FIRMs is used to determine flood insurance premiums and whether a mortgage

ASCE TEXAS SECTION - PAGE 11

 Piles of construction demolition debris accumulate in a residential neighborhood two weeks after
Hurricane Harvey floodwaters subside (Port Arthur, Texas). Credit: Task Committee Chair Andrew Wells.

lender will require flood insurance on a loan as collateral.
While it may be appropriate for insurance companies,
lenders and government agencies to use this metric, it
is critical that residents and businesses are aware of the
limitations of these floodplain maps and educate themselves on their own flood risk. To that end, it is similarly
important that communities invest in mapping that

considers a number of risk categories and incorporates a
broad range of flooding sources as a part of their floodplain management strategy. This information could also
be a helpful tool for local planning and zoning boards as
they consider the development of different areas within
their communities.

Recommendations
  Update current floodplain maps and include multiple

risk levels with a more robust consideration of
flooding sources.

  Discuss events in a manner that emphasizes annual

risk rather than an event’s recurrence interval.

  Implement a public outreach program to help

residents and business owners interpret and better
understand the flood risk in their communities.

A PATH FORWARD FOR TEXAS AFTER HURRICANE HARVEY—PAGE 12

 COMMUNICATING WITH THE PUBLIC DURING
A FLOODING EVENT
Hurricane Harvey revealed several short comings in communicating flood emergency conditions to the public. Information related to flood forecasting, water elevation increases,
road closures, evacuations (mandatory or voluntary), and
other relevant information needed to be disseminated in a
timely manner and, equally as important, the public needed to
understand the information and take proper action.

Responders travel through flood waters at an inundated apartment complex, aiding
stranded residents on August 31, 2017 (Port Arthur, Texas). Credit: Task Committee
Chair Andrew Wells.

Although many residents have a working knowledge and
understanding of how drainage networks function, there is
a large portion of the community that does not know which
watershed they live in, what infrastructure may affect their
homes and where to look for information during an emergency. For example, when news stations began reporting that
releases from Addicks and Barker Reservoirs were increasing
with the corresponding increase in flooding, residents in other
watersheds unrelated to these reservoirs were unsure if such
releases would impact their homes. Similarly, upon the possibility of levee breaches, some residents did not know if their
homes were protected by a levee or which government entity
had jurisdiction over the levees that protected their homes.
Besides a county or a municipality, other public entities
with jurisdiction over drainage and flood control infrastructure include Municipal Utility Districts, Drainage Districts, and Levee Improvement Districts. The jurisdiction
that these entities have for flood risk reduction and flood
emergency management needs to be better defined and
communicated to the general public, so all stakeholders
and the public are better prepared and know where to look
for information during the next emergency.

Recommendations
  Implement a public outreach program to educate

the general public on fundamentals of flood risk
management and preparedness, including the roles
of public agencies during emergency conditions.

  Develop warning systems that can notify citizens of

  The Texas Department of Emergency Management

should coordinate with all local jurisdictions to create
and implement a statewide public outreach and
educational program with consistent messages and
information about what to do in a flood emergency.

the timing and degree of potential flood hazards.

ASCE TEXAS SECTION - PAGE 13

 THE WATERSHED APPROACH
Reducing community flood risks can take several forms,
depending on the design storm size and the area under
consideration. In general, stormwater infrastructure, such
as storm drains, is designed to handle water that falls on
developed land during smaller, routine storms and convey that runoff to existing water bodies; while flood risk
management infrastructure, such as dams and levees, are
designed to handle flows from existing water bodies and
mitigate flooding during large and extreme storm events.

Since flood risk management infrastructure is a recipient of water from
surrounding land and stormwater
infrastructure, the need for flood risk
infrastructure is directly related to
the effectiveness of land use strategies and stormwater management in
their respective watersheds.
The increase in population across Texas over the past several decades has been substantial. Between the 2000 and
2010 census, the Texas population grew from 20.9 to 25.1
million people—an increase of approximately 20 percent.10
The corresponding development has replaced many open
areas that naturally infiltrate water (and thus keep water
from flowing to adjacent land and water bodies) with impervious structures and surfaces that do not.
Most communities in Texas, though not all, currently allow
land development to occur as long as the highest rate of
stormwater runoff flowing off the newly developed area
(post-development flowrate) does not exceed the highest
rate of stormwater runoff that would have flowed off the
site before the development was constructed (pre-development flowrate). New developments achieve this rate
control approach using detention ponds, which temporarily
detain (hold) stormwater on the property and then slowly
release it over a long period of time such that the post-development flowrate does not exceed the pre-development
flowrate. This controls the rate of discharge, but not the
total volume of runoff, which is often increased when compared to a pre-developed state.

Alternatively, strategies labeled as Low Impact Development
(LID), or green stormwater infrastructure, have been
implemented across the country. They are known as “low
impact” because they reduce the frequency and likelihood
of adverse stormwater impacts (inundation, erosion, etc.)
to downstream properties by handling stormwater more
holistically. These approaches seek to control the total volume
of runoff (as well as flowrates) by attempting to mimic a
more natural hydrological cycle, promoting rainwater to
remain where it would have infiltrated or been detained
prior to development. In other words, LID encourages
developed land to manage stormwater in the same way
that it would have prior to development. This decreases
runoff volumes to downstream communities and can help
mitigate flooding.
LID strategies include: rain gardens, vegetated swales,
green roofs, rainwater harvesting, small-scale sedimentation and filtration ponds, permeable pavement, the
disconnection of flow paths and increased tree canopy.
These approaches have proven effective at improving the
water quality in developed areas, but due to their small size
and contributing drainage area have only demonstrated
the ability to mitigate stormwater flows up to approximately 10 percent chance storms. However, it should be
noted, that if implemented on a watershed basis, upstream
communities using LID would decrease the volume of
water discharged during storms greater than 10 percent
chance events and thus decrease the impact of storms
on downstream communities. Leadership in Energy and
Environmental Design (also known as LEED) has additional credits for using LID for the 98th percentile storms, so
larger controls through LID are developing.
LID has been mandated in other areas of the country—
many times for its ability to reduce stormwater runoff
volumes to address combined sewer overflow issues or its
benefits to stormwater quality, used to achieve waterbody
restoration goals—however, it has received little traction in
Texas at a statewide level. This is largely due to the tendency for relatively slow changes to design and construction
specifications, a lack of training in their implementation,
concerns about long-term maintenance, and a lack of
awareness on the local level.

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
10

U.S. Census Bureau. (www.census.gov)
A PATH FORWARD FOR TEXAS AFTER HURRICANE HARVEY—PAGE 14

 Photo of low impact development drainage system used in a single-family residential subdivision in the Houston area. Credit: R. G. Miller Engineers, Inc.

Funding for LID research to increase the ability to address
these issues in a sustainable and cost-effective manner
is required to fully implement a watershed approach to
stormwater management in Texas. A bill was submitted
in the 2017 Texas Legislature (HB 1536) that directed
TCEQ to include information about the use of LID in the
State in a biannual report already issued by TCEQ. The
bill required the report to include a list of communities
that allow the use of LID, an estimate of the number of
LID projects in the state; an estimate of the amount of
stormwater managed through LID in the state; an estimate
of the investment made in LID projects; an assessment of
the social, economic, and environmental benefits realized; a description of barriers to installing and using LID;

and recommendations to encourage the utilization and
deployment of LID. This bill did not pass during the 2017
legislative session.
As discussed, there is a limit to which LID or any other
stormwater system can mitigate flooding. At some rain
gages in southeast Texas, Hurricane Harvey produced 24hour rainfall totals that had a 0.5 percent to 0.1 percent
annual chance of occurrence.11 In extreme events, such as
Hurricane Harvey, it is not practical to design stormwater
systems to manage the peaks of these events. Consequently, there is always some risk of localized flooding,
whether LID or conventional stormwater systems are
implemented.

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
11

Harris County Flood Control District, 2017. Immediate Report No. 1: Hurricane Harvey, Storm and Flood Information. Houston, TX.
ASCE TEXAS SECTION - PAGE 15

 Once rainwater enters an existing water body, the approach to flood risk management significantly changes.
Where stormwater systems are required to force developed land to behave similarly to undeveloped land, flood
risk infrastructure is specifically designed to alter natural
water bodies to protect human life and property.
Flood risk management infrastructure includes dams,
levees, detention and retention basins, and other similar
infrastructure. Channel widening and straightening offer
other means of increasing the capacity of water bodies to
mitigate flooding. Flood risk management infrastructure
ranges in size from neighborhood level systems to large
regional ones and while some act to collect water, others
divert it. Thus, a hierarchy of flood risk management
infrastructure exists across a watershed.
Given the results of Hurricane Harvey, a significant
investment in flood risk management infrastructure will be
necessary. When considering any flood risk management
infrastructure, a project’s impact on the region’s waterflow
must be considered. This is particularly true for levees and
channel straightening, which may reduce flood risk in some
areas at the expense of increased risk in others. Dams
also intentionally inundate land for the purpose of water
storage. Selection of these projects should be based on a
cost-benefit analysis that considers, not only the community benefiting from the infrastructure, but all communities in the watershed.

While large infrastructure has proven effective during
many storm events, it is important to recognize that
one single piece of infrastructure cannot protect
communities from all hazards in all storm events.

Thus, proper flood risk management on a watershed basis must
consider the interconnected nature of water flow across a region
and incorporate resiliency at every
level of stormwater and flood risk
management infrastructure.
Protecting new and existing developments, communities
and those downstream from flooding during extreme
events is a challenging task. Due to an ever-increasing population, it is unreasonable to expect or require
development to cease. However, it is vital to consider the
impacts of localized decisions in a regional context. As
communities continue to develop post-Hurricane Harvey, they must recognize that they are a part of a larger
flood risk management system. Adopting holistic flood
risk management practices in conjunction with surrounding communities will maximize the value of investments,
minimize risk, add resiliency and promote sustainability.

Recommendations
  Consider stormwater and flood risk management

infrastructure at all levels of government in a
regional context based on watersheds.

  Incorporate resiliency into flood risk management

systems.

  Consider the value of open or undeveloped land as a

part of flood risk management strategies.

  Develop local ordinances that address the increase

in total stormwater runoff volume diverted from
developed areas as well as the increase in peak
flowrates.

  Assemble a state-wide case study report similar

to the one envisioned in HB 1536 (85th Regular
Session).

A PATH FORWARD FOR TEXAS AFTER HURRICANE HARVEY—PAGE 16

 ADDRESSING THE NEED
There have been 94 federally declared disasters in Texas
between 1953 and 2016, with 72 of these involving widespread, damaging flooding.12 Between 1999 and 2009,
approximately 47 percent of flood insurance claims in
Harris County occurred at locations with less than a one
percent annual chance of flooding.13 This suggests that
funding for more frequent updates to flood risk maps and
additional flood risk management projects are necessary.
Many of the existing floodplain maps have been developed by FEMA to regulate compliance with NFIP and
establish insurance premium levels. To that end, FEMA
has implemented an aggressive Risk Mapping Assessment
and Planning (RiskMAP) program across the nation, with
the goal of updating all FIRMs. The program requires state
or local participation in the mapping projects to receive
federal participation and funding. The target for local
participation is approximately 20 percent of project costs.
Additional funding is needed to increase the frequency of
map updates and to create maps that detail more risk levels throughout watersheds, from all sources of inundation.

Current TWDB funding activities are focused on water
supply with only a minor portion dedicated to flood mitigation
grants. Considering the devastation of recent floods and that
flood risk management falls within the mission of TWDB, it is
justifiable that TWDB funding be substantially increased
for financial support of flood risk management programs and
projects. Additionally, TWDB funding should be increased
to support the collection and creation of data necessary to
support flood risk management throughout Texas.
Presently, TWDB is conducting a State Flood Assessment.
The report’s goal is to assess statewide flood risks, estimate
mitigation costs, and recommend an approach for future
of flood planning in the state. It is expected to be released
in December 2018, just before the start of the 86th legislative session.
In addition to stormwater runoff, flooding can be caused
by uncontrolled releases or breaches of the many dams
throughout the State. There are 1,373 high hazard dams,

As has been discussed, flood risk management takes place on
a variety of scales and by all levels of government. Flood risk
management activities include everything from local storm
drains and site detention ponds, to channel improvements and
regional detention facilities, to dams and reservoirs. Except for
dams and levees, which are owned by a variety of public and private entities, local governments are responsible for stormwater
management and flood mitigation projects under the current
floodplain management structure. However, various pressures
have caused a decrease in funding in many communities.
Apart from limited grants requiring a 50 percent match
and low-interest loans, Texas does not substantially fund or
finance flood risk management activities or infrastructure.
Several state agencies administer Federal grants but provide
no financial assistance to meet local match requirements.
The total for all grant funding received by Texas from FEMA
through 2016 was 298 flood mitigation projects totaling
over $408 million.14 Local communities have provided the
local matching funds for all of those projects.

Women in Houston Heights on Sunday, August 27, 2017. Credit: Candace Brakewood

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
12

 Federal Emergency Management Agency. Disaster Declarations for Texas. (https://www.fema.gov/disasters/grid/state-tribal-government/24)

13

 Highfield, W. E., et al., 2013. “Examining the 100-year floodplain as a metric of risk, loss, and household adjustment.” Risk analysis: an official publication
of the Society for Risk Analysis, 33(2), 186-191.

14

 Federal Emergency Management Agency, August 2016. Flood Insurance Statistics, National Flood Insurance Program.
ASCE TEXAS SECTION - PAGE 17

 588 significant hazard dams, and 5,283 low hazard dams in
Texas15. In 2016, the TCEQ Dam Safety Program estimated
the rehabilitation cost for the State’s non-federal high-hazard dams at $2.5 billion16. This estimate covers all high hazard
dams (including USDA’s Natural Resources Conservation
Service dams) that need rehabilitation, other than dams
owned by the USACE, Bureau of Reclamation and International Boundary Water Commission. Additionally, continued
growth in rural areas downstream of dams is resulting in
changes to hazard classification for some dams. This will cause
changes in requirements for the dams, possibly resulting the
need for rehabilitation of these structures.
Funding for the rehabilitation or repair of hazardous dams
must be obtained by the owners, many of which are private
entities that cannot afford these projects. As Texas continues
to grow, State and local governments must prioritize funding
for dam inspection, maintenance, repair and rehabilitation as
these structures protect life and property during all flooding
events. Local governments with land development permitting
authority should consider any dams in developing areas, how
the new development might impact the dam hazard rating
and the flood risk exposure levels for those above and below
the dam. Similar considerations should be given to levees,
which are not currently regulated by the State.
While TCEQ administers the Dam Safety Program, no initiative exists to inventory levees or fund their maintenance
and repair. Given recent levee breaches and failures,

it is reasonable for the state to provide funding for levee
inspection, construction oversight, maintenance and repair
through a levee safety program.
In 2007, Congress called for the President to conduct a
national flood vulnerability assessment, however Congress
has not funded such a measure in the 11 years since. In 2014,
Congress created a new National Levee Safety Initiative
(NLSI) as a part of the Water Resources Reform and
Development Act (WRRDA). WRRDA authorized $395
million for the NLSI; however, the funds have not been fully
appropriated, nor has the program been identified in the
Presidential Budget Request as a priority. In 2016, the Water Infrastructure Improvements for the Nation (WIIN) Act
authorized the High Hazard Potential Dam Rehabilitation
program, which will help fund the repair, removal, or rehabilitation of the nation’s non-federal, high-hazard potential
dams. This program has never been funded. Over the past
year, the need for such initiatives has become all the more
relevant—not only for Texas, but the nation as well.

According to a National Institute
of Building Sciences report,
every $1 invested in flood risk
mitigation yields $6 in return.17

As the State rebuilds from Hurricane Harvey, all levels
of government must consider flood risk mitigation as
investments and prioritize its funding.

Recommendations:
  Increase funding for flood risk management

  Increase funding for the TCEQ Dam Safety

  Continue participation in FEMA’s RiskMAP program

  Create a state loan or grant funding program for

infrastructure across all levels of government.
and create maps that show more detail about the
gradation of risk levels throughout watersheds, from
all sources of inundation. The State should also identify
resources to assist communities with this effort.

  Develop a robust statewide funding plan for flood

risk management, which acknowledges local, state
and federal responsibilities.

Program.

dam repair, abandonment, or removal.

  Provide state funding for inspection, construction

oversight, maintenance and repair of levees.

  Fully fund a national flood vulnerability assessment,

the NLSI and the High Hazard Potential Dam
Rehabilitation Program outlined in WIIN.

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
15

 Texas Commission on Environmental Quality, July 2018. Correspondence with Dam Safety Officials.

16

 Texas Commission on Environmental Quality, June 2016 and January 2017. Interviews and data from the Dam Safety Program. (www.tceq.texas.gov)

17 

National Institute of Building Sciences, 2015. Developing Pre-Disaster Resilience Based on Public and Private Incentivization. Washington, DC.

A PATH FORWARD FOR TEXAS AFTER HURRICANE HARVEY—PAGE 18

 CONCLUSION
The population of Texas is expected to increase by approximately 25 million people in the next 30 years. Development
in areas potentially subject to flooding can be expected to
increase to accommodate the demand for homes, businesses, and public infrastructure. Without a robust strategy that
equitably shares responsibility and funding between various
government agencies and stakeholders, the risk and costs of
periodic flooding will continue to increase across Texas.
While eliminating the risk associated with extreme storm
events such as Hurricane Harvey is impossible, communities across the State must be able to appropriately
assess the risk associated with large storms and mitigate
against their impacts. This report has outlined a number
of issues that have come to light during recent floods
and, specifically, Hurricane Harvey. The Texas Section of
the American Society of Civil Engineers recommends:

Because flood water does not respect political boundaries, the most important qualities of effective policy
solutions in these areas are communication and coordination among responsible parties. As Texas rebuilds from
Hurricane Harvey, it is critical that communities realize
the cumulative impacts of individual stormwater and
flood risk management projects on the overall system.
While it is recommended that state funding for flood
management significantly increase, it should be recognized that many decisions affecting flooding are made at
the neighborhood, city and county levels. To minimize
the impacts of flooding, all levels of government must be
more actively engaged in the strategic development and
implementation of forward thinking flood risk mitigation
systems.

  developing a statewide flood mitigation plan;
  funding dam safety;
  implementing a statewide levee safety program;
  focusing on a watershed approach;
  better educating citizens about flood risks; and
  employing alternative flood mitigation strategies.

Hurricane Harvey floodwaters approach the rims of process and treatment basins at a
Houston area wastewater treatment plan. Credit: iStock photo by Karl Spencer.

ASCE TEXAS SECTION - PAGE 19

 GLOSSARY
EMERGENCY ACTION PLAN (EAP)
A formal document that identifies potential emergency
conditions at critical infrastructure and specifies preplanned
actions to be followed to minimize property damage and loss
of life should those conditions occur. The EAP contains
procedures and information to assist the infrastructure
owners in issuing early warning and notification messages to responsible downstream emergency management
authorities. It also should include inundation maps to show
the emergency management authorities the critical areas
for action in case of an emergency.

LOW IMPACT DEVELOPMENT (LID)
An approach to stormwater management that seeks to
control the total volume of runoff, as well as peak flowrates,
by attempting to mimic the natural hydrological cycle.

FLOOD 
A temporary condition of partial or complete inundation
of two or more acres of normally dry land area or of two or
more properties from overflow of inland or tidal waters or
unusual and rapid accumulation or runoff of surface waters.

ONE PERCENT CHANCE EVENT (100-YEAR
EVENT)
A storm event that has at least a one percent chance of occurring each year, commonly referred to as a 100-year event.

FLOODPLAIN 
Any land area susceptible to being inundated by floodwaters from any source.
FLOOD RISK MANAGEMENT INFRASTRUCTURE
Facilities designed to reduce the likelihood of inundation
from high rainfall events. Examples include dams, levees
and retention basins.
FLOOD RISK MANAGEMENT 
The operation of an overall program of corrective and
preventive measures for reducing flood damage, including but not limited to, emergency preparedness plans,
infrastructure projects, regulations, and codes.
HAZARD 
A risk to human safety, property or the environment.
HAZARD CLASSIFICATION (OF DAMS)
Defines the risk should a dam fail. A hazard classification of
high indicates a probable loss of life; a hazard classification
of significant indicates significant economic losses with no
expected loss of life; and a hazard classification of low indicates only minor damage to normally unoccupied buildings
or land with no expected loss of life if a dam fails.
INFILTRATE 
To absorb into soil

NET FILL 
The difference between soil or materials placed below the
floodplain elevation minus that removed from below the
floodplain elevation. Positive net fill increases the volume
of soil in the floodplain and thus raises the one percent
annual chance flood elevation.

RECURRENCE INTERVAL 
The inverse of the probability that the event will be exceeded in any one year. For instance, a 100-year event has
a one percent chance of being exceeded in a given year.
RESILIENCY 
The ability of a system to recover quickly from a natural disaster.
RIVERINE FLOODING 
Flooding originating from existing water bodies—such a
streams, rivers and bayous—that extend beyond their banks.
STORMWATER INFRASTRUCTURE 
Facilities designed to convey, hold, and route rainwater
which drains or travels across the ground from and within
developed areas to a natural waterbody. Examples include
storm drains and LID systems.
SUSTAINABILITY 
A set of economic, environmental and social conditions
in which all of society has the capacity and opportunity to
maintain and improve its quality of life indefinitely without
degrading the quantity, quality or the availability of economic, environmental and social resources. Sustainable development is the application of these resources to enhance
the safety, welfare, and quality of life for all of society.
WATERSHED 
An area of land that shares a common outlet for all of the
water that falls on it.

A PATH FORWARD FOR TEXAS AFTER HURRICANE HARVEY—PAGE 20

  

Flooding in Port Arthur, Texas on August 30, 2017. Credit: Task Committee Chair Andrew Wells.
ASCE TEXAS SECTION - PAGE 21

 512-472-8905
TexASCE.org
office@TexASCE.org

ASCE Texas Section is one of the largest and most active sections of the American
Society of Civil Engineers. Established in 1913, the Texas Section represents nearly
10,000 members throughout Texas. Headquartered in Austin, the Texas Section
unites 15 Branches, seven Technical Institute Chapters, and 17 Student Chapters
including one at each major Texas university. ASCE Texas Section belongs to ASCE’s
Region 6, which includes the Mexico, New Mexico, and Oklahoma Sections. ASCE
has over 150,000 global members.
Texas civil engineers are leaders in their comxmunities building a better quality of
life across the street and around the world.

Texas Section ASCE

Texas Section ASCE

@TexASCETweets

asce_texassection

Flood Protection Sandbags with flooded homes in the background.
Copyright: Mbruxelle.

TexASCE.org