Services

New Concrete Spillways – One of the most common problems is not only a deteriorating spillway structure, but one that does not have sufficient capacity to adequately pass major storm flows. In this case, repairs may include modification of the spillway (i.e., widening or raising the walls and slabs). In most circumstances, this will result in a new concrete structure or a modification or enlargement using reinforced concrete. There are many types of spillways including a drop spillway, a sloped spillway apron, or a stepped spillway. For those with a straight drop, a small cantilevered section can be added for aesthetic appearance.

Protection of Water Quality – During construction, water quality is a major concern to all regulatory agencies. Therefore, construction will almost always include sedimentation and erosion controls such as silt fence, hay bales and stone check dams. In addition, work frequently takes place within the limits of the adjoining water body, which then necessitates a cofferdam. A cofferdam may take many forms, such as steel sheeting, a large neoprene membrane that holds water, temporary earth fill, or large and small sandbags. The type used will depend on soil conditions at the site, accessibility, depth to submerged excavation limits

Dam Breaching – There have been many instances for which clients have chosen to breach a dam, rather than reconstruct embankments, walls, spillways and intake or outlet structures. This can be based on an economic decision, a request from regulatory agencies (usually to encourage fish passage or to remove an unsafe structure), or an aesthetic and environmental solution to a troubling facility. In making such a decision, however, owners must be aware that it is not without cost, usually due to a buildup of sediment on the upstream side of the dam and the logistics of removing materials from within water bodies and water courses. Once breached, stream embankments and remaining portions of the structures will have to be stabilized to prevent erosion and the transport of sediment to downstream locations.