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44 <br />decline in groundwater levels that results in a change from artesian to water table condition. For <br />unconfined aquifers, Minnesota Rules (chapter 6115) requires that withdrawal from the aquifer system <br />does not exceed long term average recharge to the aquifer system. Also, Minnesota Statues (Chapter <br />103G) protects surface waters from harmful impacts to groundwater withdrawal. <br />The following are indicators of increased risk of significant aquifer water level decline: <br />• DNR observation well data documents a declining trend in aquifer levels, suggesting groundwater <br />withdrawals exceed safe yield amounts, as defined above <br />• Regional groundwater flow modeling highlights areas where the range of projected 2040 water <br />demand may exceed safe yield amounts, as defined above, if current use patterns and water <br />sources are used to meet that demand; this may be considered as a warning threshold to allow <br />time for contingency plans to be in effect if water levels decline <br />Figure 20 is a map of DNR observation wells that monitor aquifer levels. Trends in annual minimum <br />water levels were developed for wells with complete records between 1993 and 2012. Blue circles <br />indicate an upward trend in the annual minimum water level during that time period. Yellow circles <br />show a downward trend, and white circles indicate wells without enough data to evaluate trends. This <br />map does not identify the cause of these trends, which may represent aquifer response to climate <br />variability or groundwater pumping or both. Regardless of the cause, however, groundwater in areas <br />of downward trends should be reviewed regularly and water levels in nearby wells monitored to <br />prepare for any needed management changes. <br />WATER SUPPLY MASTER <br />PLAN- Draft June 2015 <br />