As of 2007, the USACE reported that Tully Lake had prevented an estimated $26 million in flood damages. The dam's capacity is 6.69billion US gallons (25,300,000m3) of water; it can contain 7.72inches of rainfall runoff and has a downstream channel capacity of 850 cubic feet per second (24m3/s). The closest the lake has come to capacity was in 1987, when it rose to 62%.
Recreation
Tully Lake is open to fishing, small boats, hiking, cross country skiing, mountain biking, picnicking, hunting (in season), and swimming.[2] Motor vehicles are not allowed on the property. The USACE maintains a disc golf course, a mountain bike trail, and a picnic area. The Trustees of Reservations, a non-profit conservation organization, operates a 35 site tent-only camping facility on Tully Lake, open seasonally.[3]