Stormwater Mapping
In the past several years, No Name Creek and another unnamed creek in Kenai have shown a trend of elevated turbidity levels. So where exactly is all that sediment coming from? To answer that question, KWF employees have been walking the streets of Kenai to establish where water travels during a rainy day.
As one astute observer pointed out, water flows downhill. Indeed, Kenai does not have any pumping stations, so all stormwater travels by gravity to the outlets. However, the stormwater system was implemented in pieces so stormwater sometimes follows more of a hydro-illogical pattern, depending on the construction of roads rather than natural topography.
To find out the path of stormwater and the pollutants it can carry, a GPS is used to determine the coordinates of culverts, manhole covers, storm drain inlets, and outlets. A level and observations on rainy days are utilized to clarify which direction stormwater travels through ditches and gutters that eventually drain into No Name Creek and the unnamed creek.
Once the series of storm drains and gutters was mapped out, this data was used to build a drainage network in a GIS or Geographic Information System. This digital drainage network provides a better understanding of how the different areas of Kenai are linked to No Name Creek and the unnamed creek. Next, monitoring equipment will be placed where the surface water connects to the stream and water samples will also be collected. Using the GIS, monitoring equipment, and water quality collection in unison will help narrow down potential sources of water pollution that are being flushed into two of Kenai’s creeks and harming salmon habitat.
Below: Stormwater mapping showing the direction of surface and subsurface flow.
