Harsh weather conditions in North Dakota mean a short construction period for the state's Department of Transportation (NDDOT). So in situations where construction activities would directly impact rivers and streams, NDDOT has taken a practical approach to protecting aquatic life. Instead of avoiding construction during fish spawning and migration (April 15 to June 1), the Department is installing temporary "curtains" or floating turbidity barriers which isolate the work area from the river channel and collect and filter construction-site sediment. Foam on the top of the barrier allows it to float on the water and chain weights on the bottom edge keep it in place. Fish can pass underneath, and sediment from the construction work stays out of the main river channel and eventually settles on the river bottom. The solution minimizes the risk of construction sediment smothering fish eggs and adversely affecting aquatic life downstream, and it has prevented long and costly project delays.
--Apr 2, 2009
|Photo by Photo by NDOT.|
|This floating turbidity barrier protected fish from bridge-construction debris.|