Dams, Reservoirs and Hydraulic Structure Design Experience

DAMS, RESERVOIRS and HYDRAULIC STRUCTURES

The following are typical examples of Surface Water Impoundment projects accomplished or underway by Denmon Engineering. DE involvement ranged from being the lead firm for the project team to develop complex reservoir projects to providing technical and engineering assistance to complete:

Site Evaluation and Selection
H & H Studies
- Storm Routing
- Firm Water Yields
- Dam Safety
- Stage Reductions
- Additional Hydraulic Control
Geotechnical and Foundations
Structural Studies
Environmental and Permitting
Master Planning
Cost Estimating and Feasibility Studies
Ancillary Facilities
Construction Management
Regulatory Coordination

Representative examples of the dams and reservoir projects accomplished by DE are listed below:

Poverty Point Reservoir

The Poverty Point Reservoir in Richland Parish, Louisiana near the Town of Delhi is an ideal example of the capacity for the DE Team to advance complex projects on a "short tract" schedule. This project, which is near completion, is a surface impoundment of approximately 2, 700 acres intended as a water supply and recreation facility. The estimated cost is in the vicinity of $15 million dollars.

The development faced significant obstacles in that it is located in close proximity to the Poverty Point Commemorative Area that has received a federal designation Aerial View of Poverty Point

as a national monument and has world wide archeological significance. In addition, the project is located within the proposed critical habitat of the Louisiana Black Bear that is a threatened species under the Endangered Species Act.

Rising above these obstacles, the DE Team started work on the project in 1991. All regulatory permits were gained and construction began in 1996. The project is scheduled for completion in 2002. This is an extremely short project schedule and the DE Team proved to be up to the challenge.

Bundick Lake Additional Spillway

DE was selected as the lead consultant for an improvement project on the existing Bundick Lake in Beauregard Parish, Louisiana, where adjacent improved residential and commercial property is suffering from flood damage incurred through fluctuating pool stages of the lake. DE performed the necessary hydraulic and hydrologic studies to model the lake surface during rainfall, up to and including the probable maximum flood and designed the alternative solution best suited for the project. Since the initial work, the DE Team has carried the project through surveying, preliminary engineering studies, conceptual design and is currently working on the construction plans for a 1,200-foot spillway addition estimated at a cost of approximately $18 million dollars.

Bayou DeChene Reservoir

The DE Team was selected to plan, design and assist in construction management of a new 1,100 acre reservoir located in Caldwell Parish, Louisiana. This project is similar to the Poverty Point Reservoir project. DE has carried the project through the initial engineering and environmental studies necessary to justify the reservoir and to detail the construction and environmental considerations. DE is presently preparing plans and specifications for several phases of the project. The overall project is estimated to cost approximately $12 million dollars.

Bayou D'Arbonne Lake Additional Spillway

The DE Team was selected to provide engineering and environmental services similar to the Bundick Lake project above. At present, DE has completed the hydraulic and hydrologic computer model studies to project the lake profiles for all events up to and including the probable maximum flood. DE has also determined the slab elevation for approximately 700 residential and commercial structures around the lake and has completed the engineering and feasibility studies required to document the best suited alternative for limiting the pool elevations as a means of minimizing adjacent property damage.

Red River Navigation Project Three Tributary Lakes Study

DE acted as a subconsultant to Espey, Huston & Associates, Inc. which provided the surveying, structural and civil engineering, environmental, and geotechnical engineering necessary to determine the adverse impacts to the three dams forming Black, Saline, and Nantucket Lakes, which are adjacent to the Red River, as a result of the elevated river stages created by the Red River Navigational project and to formulate the alternatives for mitigating any such adverse impacts.

Shallow Water Reservoir for Duty Ferry Farms

The DE Team was selected to design a 550-acre shallow water reservoir intended for wildlife, particularly waterfowl, in Catahoula Parish, Louisiana. The reservoir was constructed utilizing earthen levees, control structures, and the pumping capabilities necessary to fill the reservoir in the fall to accommodate waterfowl feeding and nesting and allow the reservoir to be drained in the Spring for regrowth of natural wetland plants.

Spring Lake Dam Rehabilitation

Denmon Engineering along with its geotechnical subconsultant, Burns Cooley Dennis, provided technical support to PBS&J who were ultimately selected to provide engineering and environmental studies to rehabilitate the Spring Lake Dam on the Southwest Texas State University Campus in San Marcus, Texas. Work completed to date includes the preparation of a preliminary engineering report which addresses problems and solutions at the Spring Lake Dam. Currently, the dam suffers excessive piping and leaking and a large cavern has eroded under the stop-log control structure and stilling basin.

The preliminary engineering report indicates that the project should be broken into two phases. The first phase should be an emergency phase that should isolate the control structure with the coffer dams, and reinstate the foundation with pumped concrete grout.

The second phase would rehabilitate the dam proper by clearing and grading, installation of a filter cloth and a rock rip-rap blanket to control piping and seeping and to add stability, install a toe trench drain to collect normal seepage and to completely replace the reinforced concrete control structure with a gated structure. Estimated cost approximately $5 million dollars.

Castor Creek Reservoir

The DEC Team was recently selected to provide all planning, engineering, environmental and surveying services required to develop a major reservoir project located in Central Louisiana to be known as the "Castor Creek Reservoir." This will be a principal reservoir project estimated to have approximately 34,000 acres of surface at pool stage with an average depth of 12 feet and a maximum depth of 60 feet. The proposed lake will have a drainage area of approximately 775 square miles and contain approximately 425,000-acre feet of water at normal pool stage.

The project to be handled by the DEC Team will be comprehensive including the planning, design and construction of the dam, control structures, access roads, required relocations, recreation facilities and other appurtenances normally associated with such a complex project.

It is planned that the reservoir will be used to provide drinking water for a large area in Central Louisiana and provide significant fishing and other recreational opportunities. The lake is anticipated to have approximately 250 miles of shoreline and expected to be the center stone for a major development that is to include parks, golf courses, marinas and other developments.

West Ouachita Reservoir

Denmon Engineering has also recently been selected to provide site selection and all planning, engineering, environmental and surveying services required to develop a potable water supply and recreational reservoir complex for west Ouachita Parish, Louisiana. The project will be comprehensive including the planning, permitting, design and construction of the dam, control structures, access roads, required relocations, recreation facilities and other appurtenances normally associated with such a complex project. Estimated Project Cost: $25 million

Off-Channel Reservoir Project for the Pierce Ranch Water Right

Denmon Engineering provided the Lower Colorado River Authority (LCRA) engineering and technical assistance to evaluate engineering and cost particulars relative to constructing a 25,000 acre-foot off-channel reservoir to maximize total yield from the Pierce Ranch Water Right, of which they were evaluating the purchase.

Two engineering studies were conducted which evaluated the design particulars and cost to construct a reservoir on several specific sites and the hydraulics necessary to divert water to and from the Colorado River. Studies were also conducted to determine if construction of such a reservoir in the flood plain would have a significant impact on flooding in the nearby Town of Wharton. LCRA has successfully concluded the purchase.

Lometa Reservoir

Denmon Engineering provided all engineering and technical services for an 80-acre off-channel reservoir for potable water in Lampasas County, Texas. DE performed all H & H studies, geotechnical investigations, civil and structural engineering for the reservoir complex which included an earthen dam, concrete outlet works and emergency spillway.

The reservoir did not have sufficient drainage area and storage to provide needed water supply. A water intake structure, pumping plant and pipeline was designed to supplement the reservoir from the Colorado River approximately eight (8) miles distant. The project is currently under construction with Denmon Engineering providing construction management and inspection.

Pope Westminister Force Main and Stilling Basin

DE prepared engineering studies and construction plans and specifications for a 72/96-inch concrete cylinder force main to carry the discharge from a 300 cfs pumping station through a residential neighborhood into Bayou DeSiard. Owing to the lack of a suitable discharge site, designed and constructed a reinforced concrete stilling basin beneath a major street intersection, one of the streets being a major arterial traffic route along the top bank of Bayou DeSiard. Discharge velocities were very critical on this project as it discharged into the Bayou DeSiard in the vicinity of the raw water intake for the City of Monroe�s drinking water supply. Estimated cost approximately $2 million dollars.

East Parkview Flood Prevention Project

DE prepared preliminary engineering studies and construction plans and specifications to construct a flood prevention project in the City of Monroe consisting of a back water prevention levee (dam), reinforced concrete collection system and a major storm water pumping station. Estimated cost approximately $2.5 million dollars.

Forsythe/Chauvin Flood Prevention Project

DE prepared engineering studies and construction plans and specifications to build a major back water flood prevention project consisting of approximately 6,200 linear feet of earthen levee (dam) with a reinforced concrete overflow spillway structure and a 40 cfs pumping station with reinforced concrete stilling basin. Estimated cost approximately $2 million dollars.

Wilson Point Pumping Plant

DE prepared construction plans and specifications to build a 75 cfs pumping station where the mainline Mississippi River levee crossed a major drainage cannel draining over 10,000 acres. Pumping Plant consisted of a reinforced concrete structure on a concrete pile foundation with two diesel driven 75 cfs pumps, discharge pipes and controls. Estimated cost approximately $1 million dollars.

Boeuf River Reclamation Project

DE prepared engineering studies and construction plans and specifications to rehabilitate a 20 mile stretch of Boeuf River which included the construction of 3 steel sheet pile and rock rip-rap overflow weirs and channelization of approximately 4.5 miles of channel at a estimated cost of approximately $1.6 million dollars.