Laserfiche WebLink
DATE: February 13, 2015 <br />TO: Twin Cities Metropolitan Area Water Suppliers <br />FROM: Metropolitan Council Water Supply Planning Unit <br />SUBJECT: Water Demand Projection Methodology and Preliminary Results <br />This memorandum provides a summary of the methods used to project water demand for the public <br />water supply systems in the Twin Cities Metropolitan Area. This work is being done in support of the <br />regional Master Water Supply Plan update that is currently in progress. Presented are the data <br />sources used, and assumptions made, in projecting water use through 2040 for each water system in <br />the region. <br />Generally speaking, the method used is a per capita unit use coefficient approach for each of the <br />municipal water utilities in the seven -county metropolitan area. This approach calculates a per capita <br />water use for each community, based on historical water use, population data, and input received from <br />community public water suppliers. Future water demand projections are obtained by multiplying future <br />population projections by the estimated per capita unit use coefficient: <br />(Projected Water Use) = (Projected Population) X (Per Capita Water Use) <br />The discussion that follows describes the method used to calculate initial projections for each <br />community. Input was also received from communities on draft projections that were distributed in <br />October 2014. A second draft was distributed in January 2015, and a second round of comments were <br />incorporated into the version that was used for running the regional groundwater flow model for the <br />draft Master Water Supply Plan. Local forecasts were used in lieu of Metropolitan Council forecasts <br />when they were provided by communities. <br />Historical Water Use Data <br />Water use data for annual use was obtained from the Minnesota Department of Natural <br />Resources (DNR) water use database (SWUDS). The annual use data was taken from data <br />published on the DNR website for each year between 2000 and 2010: <br />http://www.dnr.state.mn.us/waters/watermgmt section/appropriations/wateruse.html <br />Historical Population Data <br />Total Population <br />Total population for each community was obtained from US Census data for 2000 and 2010. <br />Total population was interpolated linearly between 2000 and 2010. Metropolitan Council <br />population estimates were used for 2011 and 2012. <br />METROPOLITAN <br />COUNCIL <br />