A Primer on Low Head Dams

Image of paddlers on a river
Water Trails are liquid highways to adventure! All kinds of adventures - from solitude and wildlife viewing, to multi-day wilderness camping trips, to whitewater exhilaration - are experiences that can be had on Iowa water trails. They improve local knowledge of rivers and quality of life.
Image of Center Street Dam in Des Moines
Low Head Dams, essentially concrete walls across rivers, sometimes exist for good reasons. They may back up water for water supplies or create a pool for rowing or power boating.
Image of Center Street Dam in Des Moines
Side-effects of Low Head Dams include:
  • Extremely dangerous re-circulating currents below dams, which have drowned dozens of victims in Iowa
  • Blocked game fish passage for some or all of the season
  • Blocked passage for endangered young mussels that hitch rides on gills of fish
  • Disconnected rivers
Image of Center Street Dam in Des Moines
Alternative Dams

Other types of dams made of rock can be just as durable. They are usually inherently safer. Fish can move upstream. They appear more natural. Essentially, a ramp rock serves the same function as a natural river. Depending on the availability of rock locally, they can be more expensive than low-head dams.

A kind of dam called a "step dam" eliminates the re-circulating currents below the dam, but only allows better fish passage if coupled with a lower-angle side channel, or fish ladder, which can double as a "boat chute" for adventurous canoeists and kayakers. This type of dam is a possible safety improvement where flooding concerns are highest.

Alternatively good portage trail can reduce the temptation people sometimes have to "shoot" low-head dams.

Image of Center Street Dam in Des Moines
Whitewater means Economic Development

Families can take exhilarating raft rides, and professional kayakers can converge for slalom and freestyle competitions. The whole atmosphere changes. Downtown living, and retail, become more attractive. Quality of life is enhanced for the surrounding area.