turtle river watershed preliminary data

SCAP/RGA Data Map and Sample Data   turtle river watershed

The North Dakota Department of Health prescribes water sampling protocol for non-point source pollution assessment projects (conducted by the GFSCD) such as the Turtle River Watershed Assessment.  Eight stream locations and one lake location were specified for this project.  Field measurements included temperature, dissolved oxygen, stage, and flow for each stream site; temperature gradient, dissolved oxygen, and water clarity for the lake site.  Water samples were analyzed by the Department of Health Chemistry Lab in Bismarck for Phosphorus, Nitrogen, Fecal Coliform, Chlorophyll, Arsenic, Cadmium, Chloride, Selenium, suspended sediment and several other analytes.  Stream site samples were collected and analyzed twice a week from spring thaw through May, then once per week from June through November.  The lake samples were taken weekly during open water season and monthly during ice over.  Click the link to review data gathered from each site.

 

Riparian assessments of stream channel conditions were conducted in September 2007.  75 sites were randomly selected by the Environmental Protection Agency (EPA).  Two types of assessment were performed at each site:  the Stream Visual Assessment Protocol (SVAP), and the Rapid Geomorphic Assessment (RGA).  The SVAP, used  by the NRCS, scores channel condition, hydrologic alteration, riparian zone, bank stability, water appearance, and several other factors using a numeric value, quantitatively describing the rating from poor to excellent.  SVAP ratings are:  Poor <6.0, Fair 6.1 - 7.4, Good 7.5 - 8.9, and Excellent > 9.0.  The RGA, developed by the National Sedimentation Laboratory, evaluates stream stability by assessing primary bed material, degree of channel incision, degree of channel constriction, Simon's Channel Evolution Model, and several other factors.  RGA ratings are:  Stable 0.01 - 10.00, Moderately Stable 10.01 - 15.00, Moderately Unstable 15.01 - 20.00 and Unstable 20.01 - 30.00.  Click on the following links to view the explanation of Simon's Channel Evolution Model and review the data gather from each site.

 

 

Simon's Channel Evolution Diagram

 

 

Image from:   http://www.stormh2o.com/sw_0503_identifying_a.html

 

 

 

The Six Stages of Simon's Channel Evolution Model are as follows:

Stage I:  The waterway is a stable, undisturbed natural channel.

 

Stage II:  The channel is disturbed by some drastic change such as forest clearing, urbanization, dam construction, or channel dredging.

 

Stage III:  Instability sets in with scouring of the bed. 

 

Stage IV:  Destructive bank erosion and channel widening occur by collapse of bank sections.

 

Stage V:  The banks continue to cave into the stream, widening the channel.  The stream also begins to aggrade, or fill in with sediment from eroding channel sections upstream.

 

Stage VI:  Aggradation continues to fill the channel, re-equilibrium occurs and the bank erosion ceases.  Riparian vegetation once again becomes established.

 

From http://www.ars.usda.gov/is/AR/archive/dec03/state1203.htm