Here’s why dam removal is necessary today

Image: Sierra Club

Have you ever thought about what happens to aquatic life when a dam is built on a river? Unaltered rivers have varying high and low flows based on the season, and the fish and other aquatic life in these rivers are accustomed to these varying flows. When a dam is built, it disrupts this water flow, leaving the fish in unnatural environments that can drastically impact their ecosystems. But beyond water flow, there are many other reasons why dams are harmful to the environment.

The consequences of dams

Aside from disrupting the natural and varying flows of the river, dams also change the temperature and nutrient levels of rivers. Water collects above low-head dams, causing nutrients to build up in these pools, preventing them from being distributed throughout the water properly. When the nutrients pool on top of a dam, this also alters the water temperatures. Aquatic life are not used to these temperature and nutrient changes.

It is also natural for waterways to experience the depositing of sediment evenly throughout the river. When dams are placed in rivers they slow down the flow of water, allowing sediment to build up on the backside of dams. This can increase siltation of important spawning and feeding habitat.

It’s no secret that dams are enormous features that disconnect the natural flow of rivers. This also disrupts the natural life cycles of aquatic species. Migrating fish can’t pass dams, leaving fish populations isolated. Dam removal opens miles of new habitat to the many aquatic species that depend on free-flowing water to thrive and reproduce.

Many people believe that dams are essential for flood control, but only a small percentage of dams provide flood control. The dams that make up this small percentage are dams that were specifically made for this purpose. The rest of them can be removed without flooding consequences.

Anyone who loves the outdoors should be in favor of dam removal. Poorly maintained dams are a safety hazard for those who use rivers for recreation. Besides, who wants to go kayaking only to run into a dam you can’t pass?

Dam removal may sound like a pricey project, but maintenance costs for old dams typically outweigh the cost of removing one. Property values are much higher on free-flowing rivers too. Lastly, rivers that are threatened by risks of flooding would reap greater economic benefits from removing a dam as opposed to flood damage.

Dam removal

Here are the benefits of dam removal:

• The removal of dams will quickly restore the waterway to its natural flow variations and restore the natural bank habitat.
• Dam removal will restore evenly distributed nutrients and allow normal water temperatures to return.
• Removing dams allows sediment to be deposited naturally throughout the river, reduces siltation of important spawning and feeding habitat, and allows debris and small rocks to flow down the river as they would in a natural, healthy stream.
• Dam removal unleashes miles of habitat to aquatic species that rely on free-flowing water to live and reproduce.
• In many cases, removing dams can lessen the chances of flooding since flow is no longer disrupted. Not to mention dam failure would be eliminated, which can cause severe flooding.
• Dam removal will improve conditions for those who use rivers for recreation. The safety of the river will be better and kayakers can enjoy unobstructed passage.