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SWM-SY-no dateDENTON CREEK WATERSHED TEXAS FEASIBILITY STUDY PROPOSAL Executive Summary U.S. Army Corps of Engineers Page 1 Fort Worth District THE PROCESS: • The Sponsor(s) decides to participate in a flood damage reduction or multi- purpose water resource development cost - shared study. • The Upper Trinity River Feasibility Study Executive Committee of the North Central Texas Council of Governments ( NCTCOG) endorses the measures selected by the Sponsor(s) for more detailed studies as part of the final phase of the feasibility study. • A proposed work plan for each identified measure that is to be investigated is prepared. Potential study activities will include, but not limited to hydrologic and hydraulic modeling, engineering design, environmental assessments, recreational needs, and economic feasibility studies of the specific measure. • The Corps of Engineers, the NCTCOG, and the Sponsor(s) sign a Feasibility Cost Sharing Agreement (FCSA) outlining the agreed upon studies, costs, and scheduling. • The Sponsor(s) provides the local share of funding to the NCTCOG for the detailed studies described in the FCSA. • An evaluation team made up of local public entities participate with the Corps of Engineers and NCTCOG staff to investigate each measure. Public Involvement activities will be conducted concurrently throughout the study. Executive Summary U.S. Army Corps of Engineers Page 2 Fort Worth District WHAT CAN THE FORT WORTH DISTRICT DO FOR YOUR AREA? FEMA MODELING AND MAPPING - You will receive a state of the art Hydrology & Hydraulics model for the Denton Creek Watershed, which is compatible with the new Trinity River Model. Updated FEMA maps will be prepared, coordinated, and submitted for the Denton Creek Watershed. ENVIRONMENTAL RESTORATION - If an environmental restoration project is determined feasible, an implementable plan to restore riparian forest vegetation along the old and new creek channels would be RECREATIONAL FACILITIES - FLOOD DAMAGE REDUCTION - developed. Additional benefits would include water quality improvements (lower water temperature) and erosion control along the creek. Recreational facilities can be added to a feasible environmental restoration or flood damage reduction project. Recreational facilities can include hike and bike trails, footbridges, picnic facilities, and parking areas. Denton Creek trails could tie into the Trinity Trails Corridor, providing a recreational and transportation link to the developing regional system. If a flood damage reduction project is constructed, you will receive a reduced flood damage threat to floodplain residents, reduced streambank erosion, and can qualify for reduced flood insurance premiums for portions of the creek. FUNDING - You will receive Federal matching funds for the study and, if a project is implemented, the Federal government will cost share in the design and construction of the project. Executive Summary Page 3 U.S. Army Corps of Engineers Fort Worth District 03,T `930 9 Q 190 ; DFWR 3, v A 1 { L � f t �^ n 7 a• .� M1 re r v s �•. 3 '0 31 ` r TxDOT: No Xentral Texa f.Ooverhm FEMA MODELING AND MAPPING Fort Worth District extensive expertise in the preparation of hydrology and hydraulic models and mapping for Federal Emergency Management Agency (FEMA) projects ensures a quality and cost effective product. The District's recent efforts directed toward the preparation of the Corridor Development Certificate (CDC) and FEMA modeling and mapping for the Upper Trinity River Feasibility Study are two examples of our capabilities. H &H Modeling The new Denton Creek Watershed H &H models will be based in the new HEC -RAS system. This model will be compatible with the new H &H model for the Trinity River, which was developed for the Upper Trinity River Feasibility Study. These models will also be applicable for use in the Corridor Development Certificate (CDC) program. FEMA Mapping The revised floodplain maps will be coordinated with FEMA to gain their approval and certification. The new maps will incorporate the same base mapping as the CDC process and, therefore, will be compatible or seamless when meshed together. Executive Summary U.S. Army Corps of Engineers Page 5 Fort Worth District ENVIRONMENTAL RESTORATION The Fort Worth District interdisciplinary team possesses the broad expertise in environmental restoration which can be utilized in the progect design to provide successful revegetation and other land management activities resulting in a diversified and productive wildlife habitat in a timely and cost effective manner. Restoration of Vegetation Possible restoration activities along Denton Creek could include: riparian forest stand development and improvement using native trees, shrubs and vines; and development of wetland/shallow water /moist soil areas. Various riparian restoration opportunities exist along Denton Creek downstream to its confluence with the Elm Fork of the Trinity River. Water Quality Vegetative growth is preferred over concrete or other impervious cover for a number of reasons. First, it serves to remove pollutants from stormwater. Grasses, wetland plants and other groundcovers act as a filter for urban and agricultural pollutants washed from surfaces by rain. Pollutants are physically removed by vegetation as well as broken down by microorganisms in the soil. Thus, vegetative buffer strips could be developed between urban lands and Denton Creek in order to protect the watershed from pollutants such as oil, grease, fertilizers, pesticides and other compounds which enter the stream directly with stormwater. In addition to the ability to remove pollutants from stormwater, vegetation provides shading to protect streams from large temperature increases in the summer and provides habitat for local wildlife. Erosion Control Slopes can be stabilized with a combination of hard materials, including rocks and logs, along with living plants such as willow, the roots of which hold soil together, while its branches trap sediment and slow stream velocities. Executive Summary U.S. Army Corps of Engineers Page 6 Fort Worth District RECREATIONAL FACILITIES The Fort Worth District posses extensive expertise and experience in the planning, design, and construction of recreational facilities. Aesthetically pleasing, user friendly recreational features can be added to the project in a timely and cost effective manner. Hike & Bike Trails The construction of a concrete hike/bike trail is one possibility. The trail could begin at Grapevine Lake and follow the stream corridor in a general easterly direction, crossing the creek via new footbridges at various locations to provide access to existing and proposed recreational facilities along either side of the corridor. At the eastern end of the project, the trail could join the Trinity Trails. The Trinity Trails Corridor will be a continuous strip of public land that can accommodate hike, bike, equestrian and nature trails. It will serve as the primary link for recreational opportunities within a "world- class" Regional Trinity River Greenway. Trails within the corridor spine, and along connecting spurs, will provide alternate transportation routes to parks, schools, work, and shopping areas. Other Facilities Park shelters and picnic tables could be placed within the project area. Lighted, off - street parking areas can be included for access to the trails and picnic areas. Park benches, drinking fountains and hose bibs, trash receptacles, and signage could also be included at the picnic areas and along the trail system. Executive Summary U.S. Army Corps of Engineers Page 7 Fort Worth District FLOOD DAMAGE REDUCTION The Fort Worth District's technical expertise in the planning, design, and construction of flood damage reduction projects includes work on numerous major flood control projects, such as the Dallas Floodway and on 26 multipurpose lakes located throughout the state. This experience can be applied to develop effective solutions to the watershed's flooding problems. Flood Damage Threat The flood threat along the Denton Creek Watershed could be reduced by structural measures, non- structural measures and/or combinations of these two features. Such improvements would qualify the affected area for a reduction or elimination of National Flood Insurance Program (NFIP) premiums and the potential for increased property values and development. Stream Bank Erosion Section 14 of the 1946 Flood Control Act allows the Corps of Engineers to address small flood or erosion threats to public works and public facilities by construction or repair of emergency stream bank and shoreline protection. The implementation of a streambank erosion project would have the benefit of preventing further stream bank erosion along the creek. Executive Summary U.S. Army Corps of Engineers Page 8 Fort Worth District FUNDING The Corps of Engineers has a variety of programs, derived from various Congressional authorities, to undertake the study, design, and construction of projects in the interest of developing and managing the Nation's water resources. The project purposes can include: navigation, flood damage reduction, environmental restoration, stream bank erosion protection, and recreation. FEASIBILITY STUDY COST SHARING The local sponsor must provide 50 percent of the total Feasibility Study costs; up to one -half of these local sponsor costs can be work in -kind. The Feasibility Cost - Sharing Agreement establishes the conditions of the "contract" between the Federal government and the local sponsor. It also defines a specific scope of work to be performed in the Feasibility Study. PROJECT COST SHARING Environmental Restoration: The current Federal policy on cost - sharing for ecosystem restoration features is 65 percent (Federal) and 35 percent (non - Federal) for implementation (preconstruction engineering and design, construction), and 100 percent non - Federal for operation, maintenance, repair, rehabilitation, and replacement. Flood Damage Reduction Structural Projects: For structural flood control related features, the non - Federal sponsor(s) must provide all lands, easements, rights -of -way, relocations, and disposal areas (LERR &D) for the project. The Sponsor's total cost will vary between 35 and a maximum of 50 percent of the total project cost including the five percent cash contribution. If the total percentage is higher or lower than these percentages, the difference in cash is to be contributed or credited. Nonstructural Projects: The non - Federal cost on nonstructural projects is 35 percent of the total project cost. The Sponsor is responsible for the LERR&D portion of the project requirements but is not required to contribute any amount of cash during construction of the project, if the LERR&D is at least 35 percent of the total project cost. Recreational Facilities Recreational development, including lands required for public access, health, and safety, are cost- shared on an equal (50 \50 percent) basis between Federal and non - Federal public interests. The Federal share is capped at a maximum of 10 percent of the Federal flood control and environmental restoration feature costs Executive Summary U.S. Army Corps of Engineers Page 9 Fort Worth District WHY FORT WORTH DISTRICT? • The District has widespread expertise in the planning, design, and construction of water resource projects which utilize innovative solutions with multiple outputs. • The District possesses proven technical capabilities in preparing FEMA models and mapping. • The District can design compatible recreational facilities into the project. • The District can provide between 50% to 65% of the design and construction funds for feasible projects. Executive Summary U.S. Army Corps of Engineers Page 10 Fort Worth District