Tocks Island Lake Project

The consequences of not constructing Tocks Island Reservoir from the standpoint of water supply are examined based on the results of a computerized system analysis of the basin. The analysis considered a recurrence of the 1960s drought; legal flow constraints; estimated 1986 and 2020 consumptive water use including power requirements and out-of-basin diversions to New Jersey; storage reservoirs included in the Basin Comprehensive Plan; and restraints on consumptive use when flow to the estuary is less than the estimated 3,000 cfs needed to contain the salt wedge below the Philadelphia water supply intake at Torresdale. Results of the study using 1986 demands indicated a minimum flow below Trenton with all planned reservoirs of 3,450 cfs; with all reservoirs except Tocks Island, 2,410 cfs; and less than 1,750 cfs with no new reservoir. Both the latter flows represent unsafe conditions considering the salt wedge. Based on demands in 2020, conditions would be worse.