CONSUMPTIVE USE OF PUBLIC WATER SUPPLY CALCULATED FOR SIX CITIES IN NEBRASKA

With growing concerns about climate change, global warming, droughts, population growth, and subsequent water shortages, it is important to understand and quantify the consumptive use of public water supply systems. Consumptive use of public water supply can be important data when used as input for groundwater-flow models or as stand-alone data to help make facilities more efficient. Water use commonly is reported as the total volume of water that is extracted. However, the amount extracted does not reflect the actual volume of water that is permanently removed from the hydrologic system. In public water systems, some of the pumped water is returned to the system via effluent from treatment plants, main breaks, or hydrant and main flushing. Some municipalities do not consider effluent return flow in their consumptive use calculations. This study calculates consumptive use for six municipalities in Nebraska with populations of 2,000 to 500,000. Consumptive use is calculated via subtraction of storm water runoff, treated effluent, estimates for water main breaks and hydrant and main flushing from total water pumped. Secondarily, this study compares total per capita water usage in large cities and small towns in Nebraska. Consumptive use amounts have a range of 20 to 218 gallons per person per day with the largest cities generally consuming less water than smaller cities.