Otter Creek is approximately 100 miles long and flows northeasterly from the headwaters of Emerald Lake to its confluence with Lake Champlain. The Otter Creek watershed drains an area of 1,106 square miles and is located in the Champlain Valley, which is a sub-unit of the larger Lake Champlain Basin.
The Eel Weir Project is located at the outlet of Sebago Lake near the cities of Standish and Windham, in Cumberland County, about 14 miles northwest of Portland, Maine. The Presumpscot River originates at the outlet of Sebago Lake and flows in a southeasterly direction for about 25 miles before emptying into the Atlantic Ocean at Casco Bay.
The Green Island Project is located at the west end of the U.S. Army Corps of Engineers (Corps) Green Island-Troy Lock and Dam on the Hudson River in Albany County, New York. The Troy Lock and Dam are located at about river mile 154 on the Hudson River. A forebay is located at the west end of the dam leading to the Green Island powerhouse.