New Rapid Creek Wetlands Absorb Pollution

Jul 16, 2015

This wetland dug along Rapid Creek is one of the areas Galen Hoogestraat calls a mini water treatment plant.
Credit Charles Michael Ray

You might not think about what happens to the rain water that washes down a city street and into a grate.   
But that water eventually runs into a local waterway and it can often be polluted by oil, or sediment, or even animal waste it picks up from the streets.
In the 1990’s federal laws were enacted to make cities clean storm water runoff before it’s discharged into streams.   
Building a water treatment plant can cost local taxpayers millions, but Rapid City found a cost effective way to clean the water using mother nature.

Rapid Creek is a great place to catch trout and those like Galen Hoogestraat want to keep it that way.  
“Rapid Creek is really valuable for the city of Rapid City and the Black Hills region as a whole,” says Hoogestraat.  “It’s really known as a world class trout fishery, a bit important thing that we need to keep out of the water is just sediments in general.  The trout they like to have clean water.  They don’t want to have dirt and sediments plugging up their gills.”  
Hoogestraat is with the United States Geological Survey.  His office helps monitor water quality in Rapid Creek following the addition of new wetland drainages put in near storm water outlets. 

It's really known as a world class trout fishery -- Galen Hoogestraat, USGS

Basically the drainage pipes that bring water off city streets are discharged into small swampy areas.  The small slow moving wetlands are full of reeds and grasses that help filter water before it hits the creek.
“What a common person might see as oh it’s just more grass or just a wetland it’s actually a mini water treatment plan we’re looking at here,” says Hoogestraat.  “It would be insanely expensive to try and treat the amount of storm water through a conventional water treatment plant,” he adds.
Testing in past years showed Rapid Creek unsafe for swimming during heavy rain events that would wash dirty water off the streets.  But Hoogestraat says tests show the new wetland drainages along the creek are working to reduce pollution and sediment contamination from urban runoff by up to 40 percent.

You can hear an extended interview with Galen Hoogestraat during a walk along Rapid Creek by clicking play below.