ROCHESTER, MINNESOTA WATER SOURCE SUSTAINABILITY STUDY

Rochester Public Utilities (RPU) provides water to the residents of Rochester via pumping from 32 wells pumping from a total of five aquifers. Current development plans associated with the Mayo Clinic Destination Medical Center (DMC) project a significant increase in population in the Rochester area.

Based on the projected population increase, RPU anticipates installing as many as 18 new wells to meet future water needs. This is a significant increase to the total volume of groundwater being appropriated in the Rochester area. RPU, with assistance from Barr Engineering Co., is performing an evaluation of the sustainability of pumping groundwater to meet the projected increased water demands resulting from DMC-fueled growth. The evaluation is being performed in a phased manner to evaluate if proposed future pumping will be sustainable. The evaluation takes into account potential impacts to the base flow of groundwater fed streams, calcareous fens, and other surface water bodies. The standard by which sustainability is being measured is Minnesota Statute 103G.287 Subd. 5.

To determine if Rochester’s future water demand will meet the four pillars of sustainability outlined in the statute, a groundwater model was used to compare the impacts of additional future withdrawals on the aquifer system as compared to existing conditions. The effects of focused recharge along the Decorah Edge are incorporated into the groundwater model. The groundwater model was used to make preliminary predictions of drawdown and potential impacts on surface water features of value associated with proposed future pumping and to identify data gaps that contribute to predictive uncertainty. Additional field data was collected to address these gaps and the groundwater model updated based on the new data. The revised groundwater model is being used to make updated predictions of potential future pumping impacts and to guide future data collection efforts.