Our engineers are highly skilled in the use of computer models for drainage design. We commonly use HY-8 for culvert design, StormCAD for storm sewer design, and the hydrodynamic model CHAN for outlet systems consisting of interconnected ponds, pipes and channels with tailwater control. CHAN’s hydrology module utilizes SCS methodology for generation of hydrographs for flow routing.
DMC will perform hydraulic analysis to determine location, alignment, material and size of required drainage structures and pipes. At a minimum, designs will adhere to the applicable Drainage Authority requirements, specifications, and details. Potential sediment and debris issues are taken into consideration. Prior to final design submittals, we normally develop preliminary pipe profiles to evaluate any potential conflicts and to provide value engineered designs.
DMC is experienced in all aspects of FEMA flood plain and floodway modeling. We routinely utilize Hec-Ras and Hec-2 modeling software to establish flood plain and floodway boundaries and water surface elevations. We additionally perform No-Rise modeling and certifications, where we demonstrate no rise in flood elevations from existing flood elevations and post development flood elevations. We are experienced in preparation of Letters of Map Revision (LOMR) and Conditional Letters of Map Revision (CLOMR), for revision of regulatory flood plain and floodway limits.
DMC will survey cross-sections at a site and obtain existing flood flows from existing hydrology if available. Where existing hydrology is not available, we will perform hydrology calculations to establish flood flows.