The East Branch Lackawanna River is a tributary of the Lackawanna River in Wayne County and Susquehanna County, in Pennsylvania, in the United States. It is approximately long and flows through Preston Township in Wayne County and Ararat Township, Herrick Township, Union Dale, and Clifford Township. The watershed of the river has an area of . The river is not designated as impaired and has a relatively high level of water quality. A portion of the Moosic Mountains (specifically Ararat Mountain and Sugar Loaf Mountain) are in its vicinity. Source ponds in the river's watershed include Bone Pond, Dunns Pond, Independent Lake, Lake Lorain, Mud Pond, and Orson Pond. There are a number of wetlands and swamps in the watershed, but agricultural and forested land is present as well.
The New York, Ontario and Western Railway historically passed through the watershed of the East Branch Lackawanna River. Additionally, a number of bridges have been constructed across the river and there are three major road crossings. The river is designated as a High Quality Coldwater Fishery (a designation which it received in 1991) and a Migratory Fishery. Both brook trout and brown trout are present within it. However, the river has a slightly impaired macroinvertebrate population. It has been described as an "excellent wild trout fishery".
Course
The East Branch Lackawanna River begins in a small lake in Preston Township, Wayne County. It flows southwest through a valley for a few miles, receiving two unnamed tributaries from the left. Its valley broadens and it briefly turns west before turning south-southwest and receiving two unnamed tributaries from the right. After meandering south-southwest for several tenths of a mile, the river exits Preston Township and Wayne County. It then enters Ararat Township, Susquehanna County and flows south alongside the county line for a few tenths of a mile. The river then passes through Mud Pond and turns west for a short distance before turning south-southeast. After several tenths of a mile, it reenters Preston Township, Wayne County, crosses Pennsylvania Route 370, and receives two more unnamed tributaries from the left before turning west-southwest and reentering Ararat Township, Susquehanna County. The river then turns south and slightly west for several miles, entering Herrick Township and receiving several more unnamed tributaries from both sides. It eventually crosses Pennsylvania Route 371 and enters Union Dale, where it turns south-southeast for a few tenths of a mile and then begins flowing south again. After more than a mile, the river enters Clifford Township and turns west, almost immediately entering Stillwater Lake and reaching its confluence with the Lackawanna River.
The East Branch Lackawanna River joins the Lackawanna River upriver of its mouth.
Tributaries
The East Branch Lackawanna River has no named tributaries. However, it does have a number of unnamed tributaries. These include "Orson/Lorain Tributary", "Dunns Tributary", "Bone Tributary", "Independent Tributary", and "Unnamed trib 1". Their lengths are , , , , and .
Hydrology and climate
The East Branch Lackawanna River is not designated as an impaired stream. The water quality of the river ranges from good to excellent. The waters throughout most of the river's length were described as "clear and inviting" in a 2002 report. However, two stream segments were found to be impacted. The Preserve at Dunn Lake has received a permit from the Pennsylvania Department of Environmental Protection to discharge 19,000 gallons of treated sewage per day into the river.
The discharge of the East Branch Lackawanna River was measured in 1970. On May 13, it was 26 cubic feet per second and on September 17, it was 4.5 cubic feet per second. Between 1950 and 1991, 24 measurements of the stream's discharge at Union Dale ranged from 0.83 cubic feet per second to 78.3 cubic feet per second, with an average of approximately 15.47 cubic feet per second. The gauge height ranged from . In the 1970s, the water temperature of the river at Uniondale was found to range from during several measurements. The specific conductance ranged from 50 to 97 micro-siemens per centimeter at . The turbidity was measured to be less than 5 Jackson Turbidity Units on November 4, 1975. The concentration of dissolved solids was 56 milligrams per liter. The level of water hardness ranged from 21 to 34 milligrams per liter.