Flood Control Studies
Flood control projects can range from mapping flood lines to delineating flood vulnerable areas or evaluating potential financial damages. EHG uses a multi-disciplinary approach involving:

• statistics for flood & rainfall frequencies using CFA or IDF curves
• hydrology for flood volume, peak & timing using OTTHYMO, SWMHYMO or OTTWSWMM
• hydraulics for flood levels and routing; erosion & sedimentation (HEC-2, EXTRAN, MOBED); ice jam formation & break-up
• geotechnical engineering for bank and channel stability; scour at bends and bridges
• Geographic Information Systems (GIS) for flood proofing and/or damage evaluations using SPANS or ArcView™

Short and long-term results are mapped and clearly documented for presentation to decision makers and to members of the public.

Erosion & Sedimentation
Potential erosion damages to hydraulic structures and bridge foundations are well known but economical damages from siltation in reservoirs, flood ways and estuaries are also increasingly recognized. Studies must consider:

• monitoring of bed and wash loads combined with soundings of sediment deposits
• computer models such as HEC-6 (-RAS) and MOBED; calibrated to match field data
• bio-engineering methods to control long-term erosion naturally by stabilizing banks

EHG's participation in many legal cases dealing with flooding & erosion affirms its expertise.

Bridges & Hydraulic Structures
Bridge and culvert hydraulic designs also require a multi-disciplinary approach (see Flood Control Studies) as well as careful attention to ensure long-term stability:

• bridge abutment and pier design's effect on local and downstream scour and deposition
• headwater or tailwater control as well as conditions inside/over the culvert or bridge
• tidal & storm surge impacts in coastal areas
• modifiers such as armor stones, abutments, headwalls and energy dissipators (at outlet)

Computer models such as HEC-2 (-RAS), MOBED and CulvertMaster® are used to evaluate alternative designs and alignments for various design flows.

Coastal Engineering
Coastal engineering near lake or ocean shore-lines and environments requires a sound understanding of:

• wind set-up and wave action on shorelines
• tidal action on bays and estuaries
• littoral transport and environmental impacts
• field testing techniques (using non-toxic dyes) to verify computer or physical model results