Determining Discharge from the Fallasburg Dam and the Hydrology of the Flat River Bypass Channel, Lowell, Michigan

River channel discharge is determined by surface flow and groundwater interaction.  Flow meter readings taken repeatedly over months at a transect 0.5 mile downstream from the Fallasburg Dam show that the Flat River Bypass Channel in Lowell, Michigan, is receiving less than the required dam release of 110 cfs.  Monitoring wells and a minipiezometer were used to determine whether the river was gaining or losing between the dam and the transect location.  Four monitoring wells installed along the river provided groundwater levels and the groundwater gradient.  Minipiezometer readings in the streambed point to a losing river.  Flow meter readings taken at the dam and 0.5 mile downstream on the same afternoon reveal losing conditions.  River level data combined with discharge data indicate that the river shifts seasonally from gaining to losing conditions. The river valley topography and local climate suggest gaining conditions, but results show that the hydrology of the river is complicated.  More work is underway to understand the interactions between surface water and groundwater.