Simulation of the Groundwater-Flow System in Pierce, Polk, and St. Croix Counties, Wisconsin

Hydrology and water quality of Shell Lake, Washburn County, Wisconsin, with special emphasis on the effects of diversion and changes in water level on the water quality of a shallow terminal lake

“…These recharge and hydraulic conductivity values are similar to values used in previous GFLOW models developed in nearby areas (Juckem and Hunt, 2007;Juckem and Hunt, 2008;Juckem, 2009;Robertson, Rose, and Juckem, 2009;Hunt and others, 2010). While the GFLOW model was used only as a screening model to test the conceptual model and provide hydraulic boundaries, the model simulated heads and flows reasonably close to measured values.…”

“…Thus, it was assumed for the steady-state groundwater model that evaporation from the lake surface was equal to precipitation. For transient simulations, annual evaporation was estimated from pan evaporation measured at Rainbow Reservoir in Oneida County in northcentral Wisconsin (National Climatic Data Center, 2007-9) during May-October for 1949-96, and from Marshfield, Wis., in Wood County, central Wisconsin during May-September for 1997-2009(National Climatic Data Center, 2007. The annual pan evaporation rates were adjusted by calibrated multipliers (1.28 for Rainbow Reservoir and 0.99 for Marshfield) for the transient simulation to account for differences Table 3.…”

“…Evaporation from each lake and groundwater recharge to the aquifers were adjusted annually for each of the 61 simulated years using adjustment factors estimated with the use of PEST (Doherty, 2008). Annual evaporation for each LAK-package lake was adjusted from pan evaporation data at Rainbow Reservoir (Oneida County;1949-96) and Marshfield (Wood County;1997-2009) using calibrated evaporation adjustment factors of 1.28 for Rainbow Reservoir and 0.99 for Marshfield to account for differences between pan and lake evaporation and climatic gradients from the Shell Lake area to the weather station locations. With these adjustment factors, the long-term average annual evaporation applied to lakes in the model was similar to the long-term average precipitation measured at Spooner.…”

Simulation and assessment of groundwater flow and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2003 through 2013: Chapter B of Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015</i>

“…The development of a conceptual model involves identifying and characterizing the important components of a groundwater-flow system, including (1) aquifers and confining units, (2) water sources and sinks, and (3) hydrologic boundaries. Simplifying model assumptions are necessarily applied to the groundwater-flow system in the process of designing the conceptual model because it is not feasible to include all complexities of a groundwater-flow system into a model (Juckem, 2009); however, enough complexity must be retained in the model such that it represents the general behavior of the natural groundwater-flow system, including groundwater and surface-water exchanges. The conceptual model is based on and informed by existing data and represents how groundwater is thought to move and the relative importance of water sources and sinks.…”

“…The model boundaries to the east, south, and west (fig. 6) were placed on the basis of the following: (1) groundwater levels generated from the MM3 model and other existing groundwater-flow models (Juckem, 2009) and (2) the relative location of major rivers and lakes that are large groundwater sinks ( fig. 6).…”