Identifying Changes in Background Water-Quality Conditions, Arkansas River and Fountain Creek, near Pueblo, Colorado

What do the tolerance limit plots of concentration tell me?

Scenario A: Dissolved-solids concentrations (A1) exceed the tolerance limit for a period of time and flow-adjusted dissolved-solids concentrations (A2) exceed the tolerance limit. The results indicate the exceedances are likely attributable to changes in source loadings to the river and less likely due to changes in streamflow.

Scenario B: Dissolved-solids concentrations (B1) and flow-adjusted dissolved-solids concentrations (B2) did not exceed the tolerance limit. The results indicate that there is no change in water quality as indicated by dissolved solids with respect to historic conditions.

Scenario C: Dissolved-solids concentrations (C1) exceed the tolerance limit for a period of time; however, flow-adjusted dissolved-solids concentrations (C2) did not exceed the tolerance limit. The results indicate that the exceedances in concentrations are likely associated with changes in streamflow that may be attributable to changes in water operations. This scenario also indicates that the exceedances are not likely attributable to changes in source loadings.

Estimated dissolved-solids concentrations, milligrams per liter
blue line blue line Tolerance Limit blue line Mean  Current Concentration
Example plots of dissolved solids concentrations.
Estimated Flow-adjusted dissolved-solids concentrations, milligrams per liter
blue line blue line Tolerance Limit blue line Mean  Current Concentration
Example plots of flow-adjusted dissolved-solids concentrations