Laurel Run (also known as Laurel Run No. 3) is a tributary of the Lackawanna River in Lackawanna County, Pennsylvania, in the United States. It is approximately long and flows through Jefferson Township and Archbald. The watershed of the stream has an area of . The stream is somewhat affected by mine drainage. A reservoir known as the Laurel Run Reservoir is in the watershed and is dammed by the Cawley Dam. Waterfalls, ravines, ledges, and slides occur on some reaches of the stream. Additionally, the stream is a source of flooding in the borough of Archbald. Its drainage basin is designated as a Coldwater Fishery and a Migratory Fishery.
Course
Laurel Run begins on a mountain in Jefferson Township. It flows southwest for a short distance before turning west for a few tenths of a mile. The stream then turns west-northwest for more than a mile, flowing down the mountain and entering Archbald. In Archbald, it turns west-southwest for several tenths of a mile and enters a ravine, where it receives an unnamed tributary from the left and passes through the Laurel Run Reservoir. A short distance further downstream, the stream turns northwest for a few tenths of a mile and crosses US Route 6 before turning west. After a few tenths of a mile, it leaves the ravine and after another few tenths of a mile, it reaches its confluence with the Lackawanna River.
Laurel Run joins the Lackawanna River upriver of its mouth.
Tributaries
Laurel Run has no named tributaries. However, it does have one unnamed tributary, which is known as "Unnamed trib 1". This tributary is long.
Hydrology
Some flow loss occurs in Laurel Run near its culvert under the Robert Casey Highway.
Some mine drainage flows into Laurel Run just downstream of the Laurel Run Reservoir via small seeps. However, iron oxide is only deposited along a few hundred feet of the stream and mine reclamation efforts have been done in the area.
Upstream of its confluence with the Lackawanna River, the peak annual discharge has a 10 percent chance of reaching 423 cubic feet per second. It has a 2 percent chance of reaching 719 cubic feet per second and a 1 percent chance of reaching 867 cubic feet per second. The peak annual discharge has a 0.2 percent chance of reaching 1275 cubic feet per second.
At its confluence with the Lackawanna River, the peak annual discharge has a 10 percent chance of reaching 48 cubic feet per second. It has a 2 percent chance of reaching 110 cubic feet per second and a 1 percent chance of reaching 150 cubic feet per second. The peak annual discharge has a 0.2 percent chance of reaching 300 cubic feet per second.
The borough of Archbald once requested a permit to discharge stormwater into Laurel Run and a number of other streams. In the early 1900s, the stream was clear of culm and other forms of pollution as far downstream as the Olyphant Water Company's dam. Near the dam, two streams of mine water from the Humbert Coal Company discharged into the stream, but this had little effect on its water quality.
Geography and geology
The elevation near the mouth of Laurel Run is above sea level. The elevation of the stream's source is between above sea level.
A morphologic site known as the Laurel Run Sinuosity occurs in the watershed of Laurel Run in Archbald. Additionally, the Francis Cawley Dam is in the steam's watershed. This dam impounds the Laurel Run Reservoir, a former water supply reservoir on the stream. A wetland known as the Laruel Run Marshes occurs in the watershed in Jefferson Township.
From the Cawley Dam downstream to the culvert under the Robert Casey Highway, a 0.3-mile (0.5-kilometer) reach of Laurel Run has a high gradient and its course contains waterfalls, ravines, ledges, and slides. The stream is relatively unimpacted in this reach, despite historic mining nearby.
The headwaters of Laurel Run are in a wetland in the Moosic Mountains. The stream is a mountain stream.
Watershed
The watershed of Laurel Run has an area of . The mouth of the stream is in the United States Geological Survey quadrangle of Olyphant. However, its source is in the quadrangle of Lake Ariel.
Laurel Run is a second-order stream.
Upstream of the Robert Casey Highway, Laurel Run and its riparian area are mostly undisturbed, undeveloped, and on private property. However, downstream of the highway, the stream and its riparian area are impacted by waste mine rock from historical mining operations. There is some development in the upper reaches of the watershed, along Salem Mt. Road. However, the impacts caused by this development are likely to be small.