Sack Dam

A small dam backs up the river, allowing diversion of most of the flow into the Arroyo Canal on the left.

Sack Dam  Sack Dam is 5-foot-high low-head structure used to divert water from the San Joaquin River into Arroyo Canal. Diversions to Arroyo canal are usually limited to 600 cfs, but range from 0 to 800 cfs (Reclamation 2009b). Recently, changes in groundwater use are causing subsidence between the Eastside Bypass and the San Joaquin River. The San Luis Canal Company (SLCC) reports recent subsidence of Sack Dam at rates exceeding 0.5 foot per year (SLCC 2013)