2015-02-11 CC Packet - Laserfiche WebLink

Home Browse Search

Draft North & East Metro Groundwater Management Area Plan 4-10 sensitive water courses such as trout streams.Therefore, additional evaluation is required to identify impacts of groundwater appropriations on trout streams and other water cou rses within the GWMA. In general, quantitative assessment of groundwater pumping impacts on surface waters is more demanding than assessing compliance with safe yield. Many surface waters and connected ecosystems are sensitive to relatively small hydrologic changes, and evaluating groundwater-surface water interactions is more complex than evaluating aquifer levels. Monitoring data are the foundation for impacts assessment.There is a relatively dense network of precipitation gauges, observation wells, lake gauges, and stream gauges in the North &East Metro GWMA. Nevertheless, monitoring gaps are likely to be identified as improved impacts assessment methods are implemented.The planned data system should also allow for more efficient assessment and use of monitoring data.There is also an opportunity for the DNR to partner with other entities such as watershed districts and other local units of government on data collection and management. A particular area of high uncertainty is lake evaporation.The DNR is working with other organizations to develop improved monitoring of lake evaporation on White Bear Lake and plans to extend what is learned to other lakes in the GWMA. Groundwater recharge is another area of uncertainty. Recharge cannot be directly measured, but recharge can be estimated using land use, climate, soils, and groundwater data.A comprehensive climate and water monitoring plan is under development for the North & East Metro GWMA. Pumping impacts to surface waters cannot be directly measured but must be interpreted from models developed using appropriate field data.To assess current or existing impacts, one must interpret or extrapolate conditions that would have occurred without groundwater pumping. Projections of future conditions are needed to assess the future effects of existing appropriations and the potential effects of proposed appropriations. Improved modeling analysis is needed to quantify the impacts.At the same time, ongoing monitoring will be needed to evaluate and update model projections. Metro Model 3 may serve as a valuable starting point for improved assessments of the risk to lakes from groundwater appropriations. It is a coarse, regional scale model and was not designed to be directly used for assessing pumping impacts on individual water bodies.The Metropolitan Council and U.S. Geological Survey (USGS) are in the process of developing a refined, subregional model of the northeastern Metro to be completed in 2016.This project also includes developing information regarding groundwater-lake interactions, including a collection of related data and information describing characteristics that affect them. 68