Hydrologic and Hydraulic Analysis

Watershed Concepts provides hydrologic and hydraulic analysis in support of floodplain mapping, but can also conduct such traditional engineering analysis as dam break modeling and classification and bridge scour assessment.

Watershed Concepts can perform automated approximate hydrologic and hydraulic studies for a fraction of the cost of traditional studies. Watershed Concepts uses HEC-1 and HEC-RAS with our custom software to quickly calculate Time of Concentration, routing, curve numbers and storage volumes and to delineate basins, cross sections, takeoffs, and flood boundaries. Our approach integrates USGS data to create a more accurate HEC-1 model that requires less calibration and can be calibrated with more accurate variables.

Hurricane Floyd Flood Recovery Maps
Mecklenburg County Floodplain Study and DFIRM Creation

Flood Insurance Studies

Flood insurance studies typically involve detailed hydrographic analysis for the 10-, 50-, 100- and 500-year flood events on selected streams. Hydrologic and hydraulic analyses are revised, detailed stream studies are re-mapped, and “approximate” studies streams (Zone A) are analyzed and re-mapped. The analysis and the re-mapping tasks usually cover several hundred miles of stream in a county. Automation of many of these tasks allows for quick turn-around and a higher quality product due to the quality control features incorporated in our custom software and methodology.

Watershed Concepts has performed almost 40 Flood Insurance Studies for the Federal Emergency Management Agency in the southeastern U.S. since 1984.

Tropical Storm Allison Flood Recovery Data and Hazard Mitigation

Digital Floodplain Mapping

Watershed Concepts provides a variety of floodplain mapping services, including FEMA Letters of Map Revision, Flood Recovery Maps, and updating existing maps.

Watershed Concepts has developed a comprehensive process for redelineation of existing detailed study information. The process involves capturing data from various sources including Flood Insurance Rate Map panels, original study work maps, flood profiles, and floodway data tables and importing this data into our customized software. Extensive quality control checks are done to identify any inconsistencies in the current flood maps. Any necessary datum conversion is performed using our software to create a new database of water surface elevations based on the correct vertical datum. The converted flood elevation database is then used to automatically map updated floodplain boundaries based on the best available topographic mapping techniques.

Watershed Concepts has performed dozens of studies for Letters of Map Revision that were processed successfully. Watershed Concepts was contracted by the State of North Carolina to develop flood recovery maps.

Hurricane Floyd Flood Recovery Maps
Mecklenburg County Floodplain Study and DFIRM Creation

Flood Mitigation Plans

A natural extension of Watershed Concepts’ work in flood studies is flood mitigation planning. A typical mitigation plan evaluates the public and private buildings and infrastructure in relation to risks from natural hazards such as flooding. The plan can include recommendations for mitigation projects to reduce the overall risk of future damage and preparation of applications for grant funding.

Our staff at Watershed Concepts has developed several large mitigation plans in North and South Carolina and has extensive experience in successfully obtaining funding through federal programs.