Many existing dams were built according to dam safety standards that were far less stringent at the time of construction than they are now. Development has increased in and around existing dams since the time of their construction. Floodplain mapping regularly performed and updated by the Federal Emergency Management Agency indicates an increasing number of residences and other structures previously thought to be constructed above floodplains are now projected to be in flood-prone areas based on current mapping and methodology. Furthermore, the increase in impervious surfaces causes runoff from rain events to be more rapidly and more pronounced. This leads to increased risk of flash floods occurring immediately following storm events which previously did not result in flooding. The need to operate a dam in ways that don’t put the public at risk is as critical as it has ever been. However, many owners of dams lack the financial resources to adequately address maintenance and repairs, let alone a major rehabilitation of a deficient dam.
Whether dams are regulated or un-regulated, they typically require development and implementation of a consistent maintenance program. Problems dam owners can expect to encounter during the life of their dam include development of seeps or boils, erosion and sloughing of embankments, obstructions of spillways or outlets, and deterioration of steel (particularly corrugated metal pipe) and concrete structures and other appurtenances such as gates, spillway channels, risers, culverts, headwalls and wing walls. Many of these problems begin as minor maintenance-related issues, but if left unchecked, they can deteriorate into a more severe problem that jeopardizes the stability of the dam and that presents a risk to public safety in areas near the dam. State-regulated dams are typically required to have regular inspections by a licensed professional engineer and an Operations & Maintenance (O&M) plan to address these and other issues. However, smaller, presently non-regulated dams and their owners may not know what they should do to manage and mitigate the risks of these common conditions. In addition, many dam owners are not aware what resources are available to them to help defray the cost of major rehabilitation of their dam.
A good resource is the Association of State Dam Safety Officials (ASDSO). This organization, made up of dam safety officials from several states across the country, was formed in 1983 to help improve dam safety. Their website offers several types of resources, including technical details, emergency action planning, webinar offerings, workshops, dam and levee safety information, and even offers information to help owners of publicly-owned dams find and apply for low-interest loans and other funding, such as grants, to help safely manage their dams. For more information about ASDSO and their mission, click here.
Since regulatory authority over smaller municipal and privately-owned dams exists largely at the state level, your state government’s dam safety division also provides valuable information and resources to owners of dams within that state.
For more information about funding, click here. These resources will provide you with helpful guidance on what programs may be available in your local area.
For more information about dams and what your responsibilities are as a dam owner, contact ECS Principal Engineer Joseph Meiburger, P.E., or Principal Engineer Peter O’Hara.