Monitoring Data for Willow Creek Lake, Nebraska, 2012–14—Water Balance

Flow interaction between Willow Creek Lake and groundwater was calculated from a lake water balance (Healy and others, 2007) in which all of the other flow components were either measured or estimated between 2012 and 2014 (as described in Rus and others, 2018) and the interaction was the residual term. Inflow terms consisted of streamflow at three sites (Foster, NT, and ST) as well as the direct precipitation onto the lake. Measured outflow terms consisted of the streamflow at the outflow site and the direct evaporation from the lake. Increases in lake storage had the same effect on the water balance as an outflow. All components of the water balance were tabulated on a daily basis and converted to units of acre-feet per day. As written, this water balance considers groundwater interaction as an outflow, but this interaction can actually occur as an inflow or an outflow. Positive values of groundwater represent flow into the groundwater away from the lake, and negative values represents a gain of water to the lake from groundwater.