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

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Population Forecasts Water demand projections were based in part on population forecasts from Thrive MSP 2040, the Metropolitan Council's updated regional development framework. These forecasts are derived from macroeconomic models, and more details can be found on the Metropolitan Council website: http://metrocouncil. orp/Data-and-Maps/Data/Census, -Forecasts-Estimates. aspx Unless otherwise specified by a community, forecasted population served by municipal water systems was calculated by subtracting the average population not served, as previously described, from the total population forecast for each community. It is assumed by this method that the population currently not served by the public water system in each community will remain unserved through 2040. It is also assumed that future population growth and development will be served by the public water system. In some cases, the unserved portions of a community will become served as a water system expands its service area. This would result in a projected population served that is too low by the current method. In other cases, future population growth and development could occur in areas that are not served by a public water system. This would result in a projected population served that is too high. Therefore, these potential inaccuracies for each community should be taken into account by local planners when utilizing these projections for water system planning purposes, and local knowledge should be used to adjust these projections where possible. Water Demand Projections Unless otherwise specified by a community, the projected population served was multiplied by the historical average per capita water use to calculate the water demand projection for each community. This method assumes that the historical average per capita water use, as estimated for each year between 2003 and 2012, is representative of future per capita water use. Actual per capita water use is likely to fluctuate around an average value, depending primarily on weather, but also on economic factors. Therefore, actual water use could be higher or lower than the average values calculated by the method described in this memorandum. In addition to annual fluctuation in per capita water use, there are also long-term trends in per capita water use that are emerging in some locations and within specific water use categories. For example, the Water Research Foundation and the US Environmental Protection Agency jointly commissioned a study in 2010 to investigate trends in residential water use'. This work found that newer homes tend to use less water indoors, and that older homes are reducing indoor water use over time through the retrofitting of older plumbing fixtures with newer water conserving fixtures. In communities with newer development, the reduction in water use indoors may be offset by other factors such as larger lots and automatic lawn irrigation systems. There appears to be a trend toward lower per capita water use in many communities in the metro area. This is illustrated in Figure 2, which shows the trend in per capita use between 1990 and 2012 for the City of Richfield. Similar trends can be found for many communities in the region. 1 Coomes P, Rockaway T, Rivard J, Kornstein B (Center for Infrastructure Research, University of Louisville, Louisville, KY). North America Residential Water Usage Trends Since 1992. Denver, CO: Water Research Foundation: 2010.