Historically, low-head dams have been built to generate power and support industrial, agricultural, and community water supplies. In our most recent blog, Indiana American Water discusses the benefits of removing low-head dams across communities in Indiana.
What Exactly Is a Low-Head Dam?
First introduced in the 1800s and early 1900s, low-head dams were a quick and easy way to support industries including agriculture, sawmills, and grain mills. They were constructed using readily available materials including timber and stone which made them cheaper and more efficient to build than complex dam projects. In more recent times, low-head dams were constructed using concrete to produce hydropower and support municipal and industrial water supplies across communities in Indiana and other states.
Low-head dams typically extend from one riverbank to the other. They partially block the waterway, which creates a backup of water behind the dam. When the water reaches the wall, it flows over the drop-off.
The dams have created lasting impacts on the environment, such as altering water flows, trapping sediment, and altering the natural habitat of fish and other aquatic organisms. They are a safety hazard to boaters and swimmers due to the strong currents created at the spillway or downstream of the dam.
What Are the Benefits of Removing Low-Head Dams?
Removal projects can improve safety, open up access to the river for recreational uses, and diversify the waterway’s biodiversity. Currently, there is a movement in Indiana and nationally to remove these types of dams if they are no longer needed. Some of the most important benefits of low-head dam removal include:
Increasing Safety
Safety is one reason local communities and public utilities remove low-head dams. According to the Association of State Dam Safety Officials, the state of Indiana documented 25 deaths near or at low-head dams from 2010 to May 2020. Another 17 people were reported injured and 50 people were rescued at low-head dams. The hydraulic forces created by low-head dams can create recirculating currents in the stream. The water movement of a low-head dam is similar to that of a washing machine and can push people underwater and spin them around.
Restoring Habitat
Removing low-head dams restores the natural stream ecosystem. These dams change free-flowing river habitats into pond-like habitats where certain types of fish and aquatic life do not fare as well. The removal of these structures typically improves habitat and fish species diversity in the affected areas.
Improving Water Quality
Over time, low-head dams can trap sediment and nutrients, creating conditions favorable to algae growth and lowering dissolved oxygen levels in the stream. The health of aquatic ecosystems is improved with low-head dam removal.
Enhanced Recreational Activities
By allowing the waterway to flow naturally, low-head dam removal can open up a whole new world of recreational activities in communities across Indiana. Improved water quality and restored habitat can make rivers and streams popular places for residents to visit. Removal of these dams can allow water enthusiasts additional recreational opportunities such as canoeing, kayaking, boating, and fishing.
Source: the71percent.org
Photo Credit: pexels-adam-sondel
Categories: Indiana, General