Selected water-quality data from the Cedar River and Cedar Rapids well fields, Cedar Rapids, Iowa, 2008–17

The Cedar River alluvial aquifer is the primary source of municipal water in Cedar Rapids, Iowa. Municipal wells are completed in the alluvial aquifer about 40 to 80 feet below land surface. The City of Cedar Rapids and the U.S. Geological Survey have led a cooperative study of the groundwater-flow system and water quality of the aquifer since 1992. Cooperative reports between the City of Cedar Rapids and the U.S. Geological Survey have documented hydrologic and water-quality data, geochemistry, and groundwater models. Water-quality samples were collected for studies involving well field monitoring, trends, source-water protection, groundwater geochemistry, surface-water–groundwater interaction, and pesticides in groundwater and surface water. Water-quality analyses were completed for major ions (boron, bromide, calcium, chloride, fluoride, iron, magnesium, manganese, potassium, silica, sodium, and sulfate), nutrients (ammonia as nitrogen, ammonia plus organic nitrogen as nitrogen, nitrite plus nitrate as nitrogen, nitrite as nitrogen, orthophosphate as phosphorus, and phosphorus), dissolved organic carbon, selected pesticides, bacteria, and viral pathogens. Physical characteristics (alkalinity, dissolved oxygen, pH, specific conductance, and water temperature) were measured onsite and recorded for each water sample collected. This report presents the results of routine water-quality data-collection activities from water years 2010 through 2017, and additional viral pathogen data from May 2008 to August 2017. A water year is the period from October 1 to September 30 and is designated by the year in which it ends; for example, water year 2015 was from October 1, 2014, to September 30, 2015. Methods of data collection, quality assurance, water-quality analyses, and statistical procedures are presented. Data include the results of water-quality analyses from quarterly sampling from monitoring wells, municipal wells, two water treatment plants, and the Cedar River, as well as monthly nutrient sampling from the Cedar River.