Reclamation Information Sharing Environment (RISE)

Under an Interagency Agreement, the USGS created a risk mapping web application for dreissenid mussels in the Columbia River Basin. Additional analysis was conducted investigating the usefulness of using mean calcium and pH measurements from the Water Quality Portal for estimating establishment risk. Lentic waterbodies are the most likely initial establishment sites. Local lotic data is not a good predicter of lentic risk. Calcium is a more stable and reliable variable that should be used when available. Lentic pH data can be highly variable with daily mean values in all three risk categories for many individual sites. A single mean pH below 7.3 of a full lentic profile can be used as an indicator of calcium levels in the moderate or low risk category when calcium data is not available. If the application is expanded to other geographic areas, an analysis of local pH dynamics should be conducted prior to using it as a risk factor. Overall, this application should be used as a high-level screening tool. A deeper dive into the data should be done before making management decisions based on the risk categories displayed in the application.