TRINITY RIVER WATERSHED

TRINITY RIVER WATERSHED
MULTI-OBJECTIVE PLANNING AND MANAGEMENT
ALTERNATIVES

Prepared by J. Glenn Eugster
Alexandria, Virginia


March 17, 1994






































Introduction:

In January 1994 representatives of citizen groups interested in the development of alternatives to the plan recommended by the U.S. Corps of Engineers for the Dallas Floodway Extension area contacted this office and requested technical advise on multi-objective river corridor planning. These groups are interested in learning about successful, locally based river conservation and flood-loss reduction approaches that would be applicable to the Floodway Extension.

The groups are also interested in public and private sources of financial and technical assistance which could be used to develop and implement a comprehensive and coordinated plan for the Upper Trinity River corridor.

On February 10 - 13, a site reconnaissance of the Trinity River watershed in Dallas was conducted. In addition to examining the area, a series of discussions were arranged with public and private organization representatives to seek information and insights about the area.

This report summarizes the conclusions reached from a review of available literature, the site visit and discussions with public and private interests.





Overview:

Dallas's past and present is very much connected to the Trinity River and the City's economic function as a trade center. The Trinity and trade were the primary reasons why French travelers from Louisiana penetrated to the Dallas area to exchange goods with Native American tribes in 1712.
Although the Trinity has been used for trade, industry, commerce, shipping, transportation, plant and wildlife habitat and recreation the river's tendency to flood has been a frequent source of concern for City residents. Eighteen major floods have reportedly occurred in Dallas since 1841 with the 1908 flood noteworthy in that it displaced 2,000 people from their homes.

In 1910, in response to that flood, the City commissioned George Kessler, a city planning engineer, to prepare plans for Dallas and the floodplain of the Trinity. By 1928 a Levee Improvement District had reclaimed 10,553 acres of land for industry, leveeing a new river channel "to free the City from the damage of floods". Today, as in the 1920's, industry, trade and the potential flood waters of the Trinity River continue to attract the attention of Dallas's leaders.

Dallas is one of many cities across the United States which are rapidly changing. Technological changes to transportation, communication and computers have begun to alter the role and function of many of our commercial downtown business districts. A

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multitude of partial centers, called "edge cities", are developing outside of our old downtown cores. As businesses move to these edge cities they often take with them population, jobs, tax bases and support services. This change in the role of older cities has created serious urban problems and required city leaders to explore new economic alternatives.

Because of it's unique natural, cultural, recreation and economic values and functions, the Trinity River continues to be an important focus of future plans for Dallas. It is a central feature of the City's Natural Open Space Plan and of the Dallas County Open Space Plan. A corridor downstream from the floodway has been designated as the Trinity River State Park. A Trinity River Park plan for the area between the existing levees has been approved by the City Council; and a modification of this plan with on-channel lakes has been proposed by the New Trinity Coalition.

The Dallas Plan advocates the development of a comprehensive master plan for the Trinity River Corridor in Dallas. Hiking and biking uses of the corridor are proposed by the Dallas County Trails Plan, and vehicular uses will be considered in the Trinity Turnpike Study, which is scheduled to begin in the near future. Flooding problems are being addressed by the Dallas Floodway Extension Study and by the "Common Vision" study of the Upper Trinity River Basin.









Trinity River

Despite the visionary qualities of the 1910 Kessler Plan, and subsequent efforts, the floodplains of the Trinity River are subject to regular and naturally occurring floods.

Experiences over the years, within Dallas and in other areas, clearly illustrate that
development within the floodplain is always at risk no matter how extensive or creative the structural engineering solutions are.

As Dallas's interest focuses on solutions to the flooding of the Trinity River, City, State and federal governments and the private sector are faced once again with the challenge of developing ways to protect the people and businesses of Dallas from floods.

Two efforts are currently examining ways to reduce flood losses. The Dallas Floodway Extension Study, led by the U.S. Army Corps of Engineers, is considering projects that could be implemented downstream from the existing floodway and levee system. Another effort, the Upper Trinity River Feasibility Study, involves the Corps, nine cities and three counties. Local participation is being coordinated by the North Central Texas Council of Governments. This study is seeking a "Common Vision" of strategies for flood damage reduction, water quality, environmental enhancement and recreation in the Upper Trinity watershed.

Both efforts are exploring structural and non-structural alternatives for flood damage reduction. The recommendations for each of these projects will significantly shape the use of the Trinity River, its floodplain and other land and water uses within the City of

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Dallas and other communities within the watershed.

Flood damage is of great concern to communities across the United States. Communities such as Dallas, state and federal government agencies and the private sector have gone to great effort and expense to protect people and property from flood damage. Recurring and significant flood damage motivated the creation of the Federal Interagency Floodplain Management Task Force to prepare for the Congress a
"Unified National Program for Floodplain
Management." The report, released in 1992, re-examined the definition of floodplain management and concluded that
" floodplain management is a decision-making process driven by the goal of achieving wise use of lands subject to flooding. "Wise use" is compatible with: 1) the risk to human life and property posed by flooding; 2) floodplain natural resource functions such as water quality functions and biological resource functions.

The report indicates that, "Compatibility of floodplain use with risks to life and property is achieved through the three strategies of modifying susceptibility to flooding, modifying flood waters, and modifying the impact of flooding. Compatibility with natural resource functions is achieved through the two strategies of floodplain preservation and restoration".

One of the variety of "tools" which are being used to accomplish each of the previously noted strategies is multi-objective river corridor/ watershed planning/ management. The multi-objective approach has been the topic of Congressionally requested regional public meetings, draft




legislation, demonstration projects and conferences. The concept intends to recognize all of the legitimate beneficial public and private uses of river corridors/ watersheds and seeks to encourage coordinated decisions which result in the maximum public and private benefit with the least adverse impact on significant river resource values and functions.

The goals for multi-objective planning and management include an attempt to simultaneously achieve all or many of the following:

* Reduce present and potential flood and stormwater losses.
* Reduce present and potential erosion losses and sedimentation problems.
* Protect and enhance water quality from point and non-point sources of pollution by reducing these sources and increasing the capacity of the river and it's adjacent wetlands to absorb pollution.
* Protect and improve river water quality for public supply/ use.
* Protect and enhance fish, waterfowl, and other wildlife by protecting habitat, food chain support, migratory routes, water supply, etc.
* Protect and enhance recreational opportunities for the river and related lands.
* Promote waterfront regeneration and appropriate economic revitalization for the adjacent floodplain.
* Protect and enhance historic and cultural values.





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Alternatives and Recommendations:

A variety of federal, City, County and other documents were reviewed as part of this assistance. The following comments/ recommendations/ issues are identified to serve as a focus for further discussions as alternatives are considered within ongoing planning projects.

Dallas Floodway Extension Study

The Dallas Floodway Extension Study focuses on floodplain management of the Trinity River watershed downstream from the existing levees. The Trinity River in this study is being examined separately from the larger river basin/ watershed.

Such a subarea focus, although responsive to important concerns, does not recognize the interdependencies of the upstream and downstream portions of the Trinity River. It is unclear, from available information, how a successful strategy for Dallas flood damage reduction can be developed without tying proposed decisions into the larger upper watershed-wide strategy.

The Extension Study identifies Overbank Swale alternatives as a major solution to future flooding in Dallas. Although swales are common in some of Dallas's floodplain areas, these natural and man-made drainage conduits are typically much smaller in size.

The proposed Overbank Swale raises the following questions which are worthy of additional discussion.

* Has this approach, at this scale, been used successfully before?
* If so, where?




* Is it possible to consolidate the Dallas Floodway Extension Study with the Trinity River Feasibility Study to examine the full range of flood-loss reduction alternatives for Dallas?


Multi-objective Alternatives

The Overbank Swale would require extensive clearing of bottomland hardwood forests and the filling of wetlands. This type of construction would destroy a large portion of the Trinity River corridor, significant open space and wildlife habitat and reduce the viability of the existing corridor to perform ecological functions.

In addition, the proposed alternatives do not appear to consider opportunities for natural valley storage (using existing and/ or restored wetlands) or strategies that incorporate economic regeneration/ revitalization elements.

Alternatives could be developed which examine multi-objective goals such as:
* Protection of fish, waterfowl and wildlife habitat/ corridors.
* Economic revitalization strategies which emphasize the natural and cultural heritage of Dallas and the Trinity River (ie. multi-objective heritage corridor).
* Natural valley storage which uses the capacity of existing or restored wetlands/ riparian areas to help reduce floods.
* Restoration of degraded land areas for new uses compatible with flood-loss reduction.
* Promotion and use of natural and cultural areas for ecological and cultural tourism.


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Non-Structural and Greenway Assistance

The Trinity River Feasibility Study is examining a range of structural and non-structural alternatives for flood-loss reduction in the upper watershed including Dallas. These alternatives, and the process that the Corps and the COG are using could
be helpful to expand the range of
alternatives being considered in the Dallas Floodway Extension Study.

* Can the NCTCOG and the Corps be requested to help the Dallas Floodway Extension Study to develop non- structural alternatives including natural valley storage, greenways and composite strategies?


Greenway Alternatives

The public and private interests involved in the Dallas Floodway Extension Study have an opportunity to identify non-structural floodplain management alternatives to be considered in the ongoing study. Alternatives which could be submitted include:

* Natural valley storage which includes the use of existing wetlands and the restoration of wetlands in riparian areas and existing floodways.

* A multi-objective river corridor/
watershed approach which attempts to simultaneously achieve flood protection, economic development, transportation, recreation-open space and historic preservation-adaptive reuse goals.

* A greenway which includes the



coordinated use of active and passive recreation and open space areas, including trails.

The Association of State Floodplain Managers is an excellent source of
information on multi-objective river
corridor/ watershed planning and
management. Contact Alison Nicholson, Region 6 Director at 501-682-3982.


Wetlands and Open Space

The Rochester Park and White Rock Creek confluence areas have been recognized as significant open space opportunities by the 1976 Congressionally mandated "National Urban Recreation Study" prepared by the U.S. Department of the Interior's National Park Service. Included within this area are publicly and privately owned bottomland hardwood forests which have been recognized as a priority wetland type by the U. S. Environmental Protection Agency's Wetlands Division in Washington, D.C.

The proposed Overbank Swale alternative has the potential to significantly impact/ destroy the open space and wetland values and functions of this portion of the Trinity River floodplain. The existing values and functions which these land and water areas provide warrant additional research and information to ensure that nationally/ regionally significant natural areas will not be lost.

* The Region 6 office of the U.S. EPA and the National Park Service could be requested to provide technical information and planning assistance in wetlands identification, wetlands
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value and function analysis, bottomland hardwoods and open space and recreation values. Contact Beverly Etheridge of the Wetlands Division of EPA at 214-655-2263 and Jodi Hernandez of NPS at 817-695-9228.

Open Space Acquisition

The State of Texas and the Dallas County Open Space Board have recognized the importance of the Rochester Park and White Rock Creek confluence area and have recommended that public funds be used to permanently protect this important open space area. In addition to State and local funds it may be possible, because of the State and local commitment and the resource values and functions, to secure additional outside funds to purchase, protect, manage and use this area. Additional sources of funding to consider include:

* Conservation Fund, 1800 N. Kent Street, Suite 1120, Arlington, VA. 22209. Contact Ed McMahon 703-525-6300. In Texas call Dan McNamara 512-477- 1712.

* National Fish and Wildlife Foundation, Main Interior Bldg., 18th and C Streets, NW Room 2556, Washington, D.C. 20240. Contact Sara Nicholas 202-343- 1040.

* Management Institute for Environment and Business, 1220 Sixteenth Street, NW Washington, D.C. 20036. Contact Michelle Mauthe Harvey 202-833-6556.






Trinity River Forum

Numerous plans have been done recently, or are being prepared now, for the Trinity River area in Dallas. Many of these plans contain specific ideas for the future use of the Trinity's floodplain. Each of these proposals represents a portion of a "vision" for Dallas and the Trinity River. It would
be useful, and timely, to bring all of the major interests who are preparing these plans together with each other and community leaders to discuss; 1) how the plans/ visions relate to each other; 2) common elements within each proposal that the Dallas community can agree on and support.

Publicize the Trinity

The values and functions of the Trinity River watershed are unique assets for a city the size of Dallas. Much of the natural and cultural heritage of Dallas is revealed along
the river and people should be encouraged to visit and enjoy the existing public areas and attractions of the Trinity. May is a time when attention is given to the values and functions of wetlands and riparian areas as part of the annual "American Wetlands Month" celebration.

* For information call the Wetlands Protection Hotline 1-800-832-7828.

In June each year the values and functions of rivers and streams are recognized as part of "American Rivers Month".

* For information call American Rivers, Inc. 202-547-6900.



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Specific local events or activities could be coordinated with these National celebrations
to encourage people to take time to enjoy, and learn more about, the special natural and cultural qualities of Dallas and the Trinity River watershed.


Summary:

Protecting the people and property of Dallas from future floods requires a multidisciplinary approach to managing the waters, adjacent floodplain and wetlands of the Trinity River watershed. Such an approach needs to be basin-wide, integrated with other related plans and sensitive to the concerns of people in the area.

It should be realized that the future use of the Trinity River in Dallas must be achieved through multi-objective use of the river and its adjacent corridor rather than simply allocating segments of the Trinity for single purpose uses.




































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