Floodplain Management
Flood Mitigation
Flood mitigation measures are actions intended to reduce the risk of damage to insurable structures as a result of flooding. These measures can include relocation of the structures in question, but this is not always feasible. As a result, engineered protective solutions such as floodproofing and levees may be sought. Depending on the situation, storage and detention facilities or improved drainage structures may also be of use. Because of the reduced risk of flood damage, flood mitigation can be a means of reducing insurance rates. It may also be required by local ordinance when making significant improvements to property located in the regulated floodplain.
Floodplain Modeling & Analysis
Floodplain modeling and analysis is performed in order to determine the flood risk to insurable structures. In the case of proposed development, floodplain modeling and analysis is used not only to determine the flood risk to any proposed structures, but it is also used to determine how the proposed development affects the risk of flooding to existing structures. The requirement of a flood risk analysis is determined by local ordinance and whether or not proposed development is located in a FEMA Special Flood Hazard Area (SFHA). Any development requiring such analysis that is in a FEMA SFHA will have to go through FEMA’s Letter Of Map Change (LOMC, e.g. CLOMRs and LOMRs) process.
Software Evaluation
Software for engineering analysis is sometimes developed in-house by consulting civil engineering firms. When provided to clients as a customized solution for their use, the integrity of the software and its analysis may come into question. Testing and evaluation is intended to assure as to the integrity of automated analyses.
Stormwater Management
BMP Design & Certification
Stormwater BMPs are engineered structural facilities that are constructed to remove sediments and nutrients from stormwater runoff. They are measures taken to mitigate the impact of development on downstream water quality that may be required according to a community’s status in the EPA Non-Point Discharge Elimination System (NPDES). In addition, these facilities may be required to detain or retain stormwater runoff in order to mitigate any increase in flood flow from proposed development as per local ordinance.
Bridge & Culvert Design
Bridges and culverts are often required in order to span streams with roadway. These structures must be sized to span the proposed road fill and to adequately pass storm flow without obstructing the road. Additionally, these structures must be protected from being undermined by scour and / or erosion. As a result, scour and / or erosion potential must be determined so as to know how far to extend foundations or if an energy dissipator should be included in the design. Exact design specifications will depend upon local standards and ordinance requirements.
Drainage System Design & Evaluation
Drainage systems can extend well beyond an individual property and are often maintained by local municipalities. These systems can develop problems as they evolve and age. Not all of these problems are reported, however. Modeling can help identify location and severity of these problems. When coupled with a prioritization system or protocol, such an evaluation can be used to target a Capital Improvements Program.
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