Stormwater management involves the evaluation and design of components such as storm water conveyance systems, open channels, natural channels, Best Management Practices (BMP’s), and hydraulic analysis for flood studies. Stormwater management design begins with an evaluation of the watershed and development of expected discharges for specific storm events. Storm drainage systems are designed to convey stormwater safely away from structures and roadways. Hydraulic analyses are completed to predict floodwater elevations and their impacts on structures and property. Stormwater Best Management Practices (BMP’s) are designed for water quality and quantity management benefits. Ward Consulting Engineers have over twenty five (25) years of stormwater management analysis and design experience and have staff professionals trained in the latest stormwater management practices.
Ward Consulting Engineers Provides the Following Services:
Watershed analysis
Watershed are characterized to gain information on the drainage basin and to predict past and future trends. Characterization includes determining the size, land use, percent impervious surfaces and a description of the geology and soils. Specific data to be collected during a watershed analysis includes: Topographic mapping, NRCS soils mapping, FEMA floodplain mapping, existing land use and zoning and future plans for development. The hydrology of the watershed is determined by evaluating the characteristics and applying them to engineering models such as the Rational Method, SCS TR-55, HEC-1, HEC-HMS, and local Urban/Rural Regression Equations. WEC has extensive expertise in watershed analyses.
Storm drainage system design and upgrade retrofits
Stormwater conveyance system design involves the determination of watershed hydrology to size the appropriate system. Stormwater systems are designed for roadways, residential, and commercial developments. Existing storm drainage systems are often taxed by growing watersheds and increasing flows. Overloaded systems can cause structural and roadway flooding. Evaluation of the existing system capabilities provides an understanding of system components that are undersized or restricted. System upgrades such as larger pipes, increased slopes, ponds with in the system, and better structure entrance conditions can be determined. WCE has extensive experience providing storm system design and evaluation of upgrades for municipalities.
Flood studies
Flood studies are performed to evaluate the hydraulics of rivers and to establish corresponding water surface elevations for selected storm water events. Rivers and streams regulated by the Federal Emergency Management Agency (FEMA) require Conditional Letter of Map Approval (CLOMR) and Letter of Map Approval (LOMR) approval of any mapping or water surface elevations changes due to proposed impacts. Local ordinances and regulations also apply to streams. Impacts such as structures for road crossings and fill can impact the floodway and floodplain of streams. Ward Consulting Engineers, P.C. has been performing flood studies for over 25 years for the following impacts on both FEMA regulated and non-regulated streams utilizing the HEC-2 and HEC-RAS step backwater program:
Bridges for roadways and pedestrian trails
Culverts
Proposed fill
Stream bank improvements/stabilization
Stream relocation with dimension, pattern and profile changes
Pedestrian trail boardwalks
Establishment of new floodway and floodplain limits on non-regulated streams for new commercial and residential developments
Stormwater BMP design
Stormwater Best Management Practices (BMP’s) are implemented as a way of treating or limiting pollutants in stormwater runoff. An important source of pollutants is stormwater runoff from urban and developing areas that can degrade water quality. BMP’s can use plants and soil for the removal of pollutants from stormwater through filtration and facilitation of chemical and biological processes. They can allow particulate pollutants to settle and provide consumption of pollutants by plants, algae and bacteria in the water. Other functions can include the reduction of frequency and severity of flooding events and provide wildlife habitat. Some of these practices are listed below:
