Agenda - Council - 07/28/2015 - Laserfiche WebLink

Home

Population Served In many communities, there is a difference between total population and population served by the public water system. Data on population served by the public water system in each community were obtained from Water Supply Plans submitted to the DNR by each community. Those plans require public water suppliers to report estimates for total population of the community and population served by the water system for each of the ten years prior to plan submittal. For each year with complete data in the Water Supply Plan for each community, the population not served by the water system was calculated as the difference between the reported total population and population served. This unserved population was averaged over the number of years with complete data. Figure 1. Example of Population Reporting from Local Water Supply Plan 1999 2000 2001 2002 2003 2004 2005 2006 .2.588 3.513 4.295 4.935 5.505 5.685 6.64 2 6.683 6.901 Following the calculations of average unserved population, the data were manually reviewed for inconsistencies and outliers. Adjustments were also made based on local input. The average unserved population was used to calculate an estimated population served for each year between 2003 and 2012. The estimated population served was set equal to the interpolated census total population minus the average unserved population for each community. In this way, the estimated population served is tied to the recorded census population for each community. (Population Served) = (Interpolated Census Population) — (Average Unserved Population) Per Capita Water Use Calculation Total per capita water use for each community was calculated for each year between 2003 and 2012 by dividing the reported water use by the estimated population served. The per capita water use was then averaged over this ten-year period. The average per capita water use based on population served is reported in this way for each community. (Water Use Per Person) = (Total Water Use) / (Population Served) This value represents the total water use per capita for each community. This includes all water use in the community, including commercial, industrial, institutional, and other uses. Therefore, it is not necessarily indicative of the amount of water used in each household. This is an important distinction since a community may have a large amount of water -intensive industry that drives up the total water use per capita. Therefore, the total per capita use by itself may not be an accurate indicator of the effectiveness of conservation programs for example.