| Trend analysis of water quality indicators is important in assessing the impact of changes in the landscape and land usage as well as the impact of precipitation within watersheds. I perform a statistical evaluation of trends in dissolved ion concentrations namely: calcium, sodium, potassium, magnesium, chloride as well as trends in total dissolved solids and specific conductance for the Red River within Manitoba over a 45-year period ranging from 1960 until 2007. The analysis is done using two different methods, a nonparametric method namely the Mann-Kendall test for trend, and a parametric flow-weighted method (developed by Aldo Vecchia, USGS). Both methods were used to analyze the water quality constituents and yielded fairly similar conclusions. While the parametric method adjusts for streamflow, there are still significant increasing trends in both methods, it can be concluded that some part of the increasing trends may be due to factors other than flow. |
