J&A’s Hydrologic and Hydraulic Engineering Department has the experience and expertise to make recommendations that are cost effective, environmentally friendly, and reduce downstream impacts. We have performed numerous flood studies to FEMA standards using HEC-1, HEC-2 and HEC-RAS programs. J&A utilizes GIS information to determine watershed parameters, soil-types, ground cover, impermeable areas, digital terrain models, etc. We have provided data collection for stormwater systems, cross sections, stream evaluations, photo archives, and mapping needed to determine water surface elevations, hydraulic grade lines, floodway limits, and finish floor elevations.

We evaluate the site conditions and clients needs to determine the best solution to mitigate the downstream impacts to the pre-developed conditions. Our engineers have experience with a wide range of hydraulic/hydrologic computer programs to model closed pipe and open channel systems, including Haestad Methods StormCad, PondPak, HEC packages listed previously, Flowmaster, Hydro, Hydrain, and HydroCad. We have provided designs for local developments as well as regional retention/detention lakes for large industrial parks. We have assisted cities and various clients with design solutions to mitigate flooding of streets and homes. Many of our detention designs include a “first flush” wetland area for water quality treatment, low impact designs, rain gardens, or other measures to reduce impacts from developments.

Stormwater Management Services:

  • Floodplain and Floodway Analysis
  • Flood Studies for unstudied tributaries and creeks
  • LOMA, LOMR-F, CLOMR, & CLOMR-F preparation
  • Stormwater Master Planning
  • GIS Data Collection and Inventory Mapping
  • Stormwater Management Planning and System Design
  • Stream and Wetland Permitting & Mitigation Design
  • Flood Mitigation Plans
  • ADEM/NPDES Permit Applications and Monitoring
  • Erosion and Sediment Control Plans
  • Open channel and bank stabilization design
  • Closed pipe design, sizing storm pipe structures and surcharge analysis
  • Stormwater Quality design and constructed wetlands designs
  • Regional and local Detention/Retention  Systems
  • Above and below ground stormwater storage and treatment systems