Waterway: Lower Sweetheart Lake/Sweetheart Creek
License issued: 4/11/2013
License expires: 3/31/2016
The proposed project would consist of:
(1) the existing Lower Sweetheart Lake, raised to a surface elevation of 628 feet above mean sea level, with a surface area of 1,701.5 acres and an active storage capacity of 94,069 acre-feet at the normal maximum water elevation;
(2) a new 275-foot-long, 105-foot-high concrete and rock face dam, including project intake facilities and a 125-foot-wide overflow spillway, constructed at the natural outlet of Lower Sweetheart Lake;
(3) a new 500-foot-long, 10-foot-diameter stream diversion tunnel that would be converted to reservoir outlet works after project construction;
(4) a new 9,595-foot-long, 12-foot-diameter penstock diverting flow from the project intake to the powerhouse;
(5) a new powerhouse containing three new 6.6-megawatt (MW), Francis generating units having a total installed capacity of 19.8 MW;
(6) a tailrace consisting of:
(a) a new 76-foot-wide to 22-foot-wide, 75-foot-long open afterbay;
(b) a new 225-foot-long, 12-foot-diameter tunnel extending from the afterbay to an outlet structure on a tributary to Sweetheart Creek; and
(c) an existing tributary stream channel, modified to a 100-foot-long, 35-foot-wide channel that will flow into Sweetheart Creek;
(7) new marine access facilities including a dual-height marine ramp, floating docks for seaplane and boat access, and a staging area adjacent to the docks;
(8) a new switchyard adjacent to the powerhouse;
(9) a new 8.69-mile-long, 138-kilovolt transmission line consisting of buried, submarine, and overhead segments;
(10) a new 4,400-foot-long access road; and
(11) appurtenant facilities.
The proposed Sweetheart Lake Project would have an average annual generation of 111 gigawatt-hours.
This is the second preliminary permit for the project for which the first preliminary permit expired on November 30, 2011.