EE&T has an annual contract with the City of Newport News, VA to provide consulting engineering services for stormwater management issues, including water quality assessment and enhancement. Work under this contract not only addresses stormwater runoff and flood control strategies, but also integrates water quality enhancement strategies and monitoring as required under current regulations.
Our stormwater management experience also includes extensive runoff modeling for the City of Newport News; the Regional Landfill in Suffolk, VA; and the Refuse Derived Fuel Facility in Portsmouth, VA.
Our capabilities in the area of stormwater are multidisciplined through our knowledge of current water quality issues both regionally and related to specific BMP performance for a specific stormwater application. We can provide the technical support to justify stormwater quality and/or quantity issues as well as provide the hard design for channels, drains, erosion control, detention ponds, inlet/outlet structures or related issues. We have designed closed conduit collection systems ranging from 12-in. to 72-in. diameter as well as open channel conveyance systems. Most recently we have completed design of a 13 mgd stormwater pumping station and a large diameter (60-in.) tunneled crossing of railroad tracks for stormwater conveyance.
Our comprehensive experience in water and wastewater engineering lends itself very well to a project such as this one where undoubtedly utility relocation design will be required. Our experience includes gravity sewer and force main designs ranging in size from 8 to 72 in. Our design staff has worked on Virginia Department of Transportation projects with a specific focus on utility relocation.
Proven technical experience in the following areas are also necessary to successfully complete stormwater projects:
- Best Management Practice (BMP) and Drainage Facility Design
- Familiarity with Regulations (local drainage regulations, Virginia Erosion and Sediment Control Standards, Chesapeake Bay Preservation Act, NPDES and VPDES Stormwater Discharge Permitting)
- Water Quality Assessment and Enhancement Strategies
EE&T’s experience in these areas are outlined below:
Best Management Practice (BMP) and Drainage Facility Design -EE&T engineers have evaluated the effectiveness and assessed the suitability of an array of BMPs for minimization of potential adverse impacts due to increased runoff quantities and for preservation and improvement of water quality, and have designed BMPs for a wide variety of projects. For example, we have conducted an in-depth assessment of impacts due to increased volumes of stormwater runoff and water quality impacts for three future landfill sites as part of an environmental impact statement (EIS) for SPSA. Effects of BMP implementation were investigated for three alternate landfill sites with each site having unique water quality and quantity impacts.
Familiarity with Regulations -EE&T places significant importance on keeping abreast of the latest regulatory guidelines in all areas of civil/sanitary engineering at the federal, state, and local level. Preparation of the EIS for SPSA involved extensive regulatory research and working relationships at all of these levels. Regulatory compliance with the requirements of the Chesapeake Bay Preservation Act and the Virginia Erosion and Sediment Control Standards, among others, was essential for completion of the project. EE&T has also provided technical assistance to clients in the area of NPDES/VPDES Stormwater Discharge Permitting.
Water Quality Assessment and Enhancement Strategies-Expertise in assessing potential water quality impacts and developing mitigation measures is invaluable in evaluating drainage/erosion problems. As important, or more so, than competence in performing computations to quantify stormwater runoff and properly size drainage control structures, an understanding of water quality implications is essential to the study of complex drainage and erosion problems. Water quality was a central issue of the EIS that EE&T prepared for SPSA. A thorough investigation of probable and potential water quality impacts and minimization of such impacts through implementation of BMPs comprised a critical part of these projects. The completion of the Comprehensive Water Quality Assessment of the Chowan River Basin yielded data that was instrumental in development of a statewide phosphorus reduction management plan in Virginia, is further evidence of our expertise in the area of water quality. Our water quality assessment work has ranged from paper studies to assess soil loss and land use contaminant inputs, to instream studies of regional land use or site specific BMP effectiveness. Our work on high profile projects in southeastern Virginia has provided our staff with up-to-date technical knowledge and ability to apply state-of-the-art design for stormwater quality management.
Hydrology/Hydraulic Analysis -EE&T completed modeling, design, and construction services for a major stormwater improvement project for the City of Newport News. This project involved modeling of stormwater flows in a 361 acre urban area for 10, 25, and 100 year storm events. The objective of the project was to relieve flooding concerns at nominal rainfall events. The recommended improvements designed by EE&T included new stormwater collection piping (24 to 72 in. diameter) through densely populated urban areas. Rehabilitation of existing roads and relocation of natural gas, water, sewer, and electrical utilities were extensive components of this project.
Stormwater Sewer Systems —EE&T has performed hydraulic analysis to design stormwater piping from 8-in. to 72-in. in diameter. Storm sewer design has included the use of corrugated metal, PVC, precast concrete, and corrugated polyethylene pipe materials. Overall, storm sewer design and construction projects have included pipe conveyance systems, outfalls, river outlet structures, velocity dissipators, catch basins, manholes, and other appurtenant work. In addition to storm sewer design, EE&T personnel have applied similar design techniques on over 100 miles of sanitary gravity sewer.
Culverts and Bridges —EE&T personnel have designed precast concrete and field assembled corrugated metal culverts and bridges over seasonal waterways and environmentally protected streams. Design services include hydraulic analysis required to select the appropriate size and shape of culvert, material selection, design of foundation and wing walls, roadway/guide rail considerations, and acquisition of all required local, state, and federal permits.
Open Channel Waterways —EE&T personnel have designed open channel waterways for residential subdivisions, commercial, institutional and light industrial complexes, water treatment plant facilities, water storage tank overflows, yard waste composting facilities, and golf courses. Applying pre-packaged software and project specific spreadsheets, EE&T has designed channels utilizing a variety of materials including concrete, asphalt, and rip-rap, as well as earthen/grass lined swales.
Stormwater Holding Ponds —EE&T personnel have designed stormwater retention facilities utilizing established software (HEC-2), including a project for a residential community utilizing available land on an existing public golf course. Design of stormwater retention facilities includes systems to serve numerous residential subdivisions and where necessary, included provisions for the phased construction of the stormwater facilities.
Stormwater Treatment —Stormwater treatment facilities include the conceptual design of the treatment if seasonal high turbidity overflows from four upland reservoirs. Treatment methods investigated by EE&T personnel include sedimentation ponds (with and without polymer addition), use of mobile swirl concentrators (centrifuges), and gravity piping to alternate discharge point.
Existing Utility Coordination and Relocation —While it is always desired to avoid relocating existing utilities, it is not always practical or possible when working in urban areas. Our engineers have experience designing water utility lines from 4- to 54-in. in diameter, sewer lines up to 48-in. as well as electrical, natural gas, cable television, and telephone utility relocation. Three separate recent projects for the City of Newport News, VA included relocation of water lines (6- to 20-in. diameter), sewer lines (up to 18-in. diameter), natural gas, utility poles, underground electrical (20,000 volt primary power), and cable television. Our engineers are also experienced in construction issues such as residential access, acquisition of new easements, and road construction/modification, all of which require public coordination and scheduling.