Using Geophysics to Site “Forebay-Type” Managed Aquifer Recharge Systems in the Wasatch Front of Utah
Geophysical surveys, consisting of electrical resistivity and seismic refraction tomography, were run in three adjacent canyons for the City of Provo, Utah. An initial set of surveys were run during low flow periods to;
- Map locations where the valley aquifers are in connection in the mountain front recharge zones,
- Map the location of the Wasatch Fault zone
- Map the shape of the bedrock valley aquifers that may be controlling gaining and losing stretches of the stream, and
- Map the volume of unsaturated sediment.
The resistivity surveys were repeated during spring snow runoff high flow conditions to map the change in the unsaturated zone. Data from stream gauges and mass balance calculations were used to estimate the recharge rates during the spring runoff event. The data will be used to design a groundwater model to design recharge systems for up to 32,000 af in one or more of the canyons. The geophysical surveys helped find the optimal locations and methods to recharge the water and helped determine how much water can be recharged in the winter without increasing flood risks in the spring and summer.