Fiaschetti, Aaron, M.S., December 2006 Geology
Assessment of Ground Exchange in Two Steam Channels and Associated Riparian
Zones, Jocko Valley, Western Montana
Chairperson: William W. Woessner
Degraded riparian habitat is a concern throughout the United States. Repairing anthropogenic damage to river channels and wetlands is becoming increasingly popular,though including design features to re-establish ground water and surface water exchange rates and timing are rarely implemented. The goal of this project is to characterize the surface water/ ground water exchange rates of two stream and riparian systems that have been altered by agriculture use. Hydrogeological and hydrological field experiments were performed to better understand the location and magnitude of ground water and surface water exchange throughout each site. These data were compiled into a water balance for
the Sque-que study site. Vertical hydraulic gradients, temperature monitoring and ground
water chemistry were key components used to identify areas of surface water/ground
water exchange.I concluded that surface water/ground water interactions are occurring on
sub-reach scales throughout the Sque-que study site. The riparian water table position
changed little throughout the year and remained within two meters of the land surface. At
the Jocko River site a net gain of ground water along the 1 km reach was not detectable.
Modeling suggests the position of current water table will rise if drainage ditches are
filled at the study sites and that recovery of wetlands is possible.
