DNR Hydrography - Groundwater Dominated Lakes

The Groundwater Dominated Lakes feature class is derived from the DNR Lakes and Open Water and DNR Level 09 Autocatchment datasets. It represents lakes that have watershed area to lake area ratios of 10 or less and are larger than 10 acres. Lakes larger than 100,000 acres are excluded because they may behave differently from smaller lakes . Because of their relatively small watersheds, these lakes are likely to have a significant groundwater component relative to surface water. The watershed to lake area ratio is a screening tool that indicates the relative importance of groundwater flow to the water balance of a lake. However, the ultimate determination of whether a particular lake is dominated by groundwater flow requires more site specific information.<br/><br/>A best first characterization of lakes into groundwater dominated or surface water dominated can be made by watershed area to lake area ratio. Lakes with a ratio of greater than 10 are likely surface water dominated. Lakes with a ratio of between 5 and 10 may be groundwater dominated, especially if the sediment around the lake is predominantly sandy. Lakes with a watershed to lake area of less than 5 are very likely groundwater dominated, either through relatively large groundwater inflow, outflow, or both. But if the sediment surrounding the lake is clayey there may be little interaction between the lake water and groundwater.<br/>