GIS mapping is a big part of my job, but I’ll be the first to admit there’s a limit to what you  can learn about a stream without getting your feet wet, or at least dipping a bucket into the water.

I’ve been testing West Indian Creek and Grant Creek at the lovely Jennett Heritage Area, just above their confluence. (With some help from David Stein and Rick Dietz)  West Indian Creek flows through Nevada and drains 28,417 acres at this point.  Grant Creek, also known as Drainage Ditch 5, drains 13,344 acres between Ames and Nevada.

Based on soils and landcover in the watershed, I’d expect Grant Creek to have comparable or slightly worse water quality than West Indian Creek.  There are nutrient loading models available online and in the Story County Watershed Assessment that predict just that.

Instead, I’ve found that water quality is consistently better in Grant Creek.  West Indian Creek has normal nitrate levels but very high phosphorus levels.  At this point, I don’t know why.

Orthophosphate (mg/L) Grant Creek W. Indian Creek
5/14/2019 0 0.6
6/11/2019 0.1 1.0
7/25/2019 0 3.0
9/10/2019 (after rain) 0.6 4.0

 

Nitrate (mg/L) Grant Creek W. Indian Creek
5/14/2019 2 5
6/11/2019 2 5
7/25/2019 2 5
9/10/2019 (after rain) 0 0

I do know there are people in the West Indian Creek watershed working to improve water quality, both on private land and public landIf you own land or farm in the watershed and are thinking about doing more to conserve soil and water, contact our Watershed Coordinator, David Stein, to set up a free consultation.

If you live near Nevada and are want to help solve the mystery of these two creeks through water testing, contact Dan Haug.  Prairie Rivers of Iowa is working with Story County Conservation and the Izaak Walton League to plan for and support volunteer stream monitoring around Story County in 2020.

A final note:  Don’t judge a stream by its name, or lack of a name.  The lower part of Drainage Ditch 5  is a natural creek with buffer vegetation, fish, clean water, and public access.  The map below shows a pre-settlement land survey superimposed over a current topographic map.  Interestingly, West Indian Creek was forested while Grant Creek was prairie.  Thanks to the restoration efforts of Cindy Hildebrand and Roger Maddux, parts of Grant Creek are prairie once again.