Roaring Brook (also known as Roaring Branch Creek or Roaring Creek and historically known as Nay-aug) is a tributary of the Lackawanna River in Lackawanna County, Pennsylvania, in the United States. It is approximately long and flows through Covington Township, Madison Township, Moscow, Roaring Brook Township, Elmhurst Township, Dunmore, and Scranton. The watershed of the stream has an area of . Its named tributaries include Little Roaring Brook, Rock Bottom Creek, White Oak Run, Van Brunt Creek, Bear Brook, and East Branch Roaring Brook. It has a high level of water quality for much of its length. However, it is affected by abandoned mining land, stormwater, and other impacts in its lower reaches. Reservoirs in the watershed include the Hollister Reservoir, the Elmhurst Reservoir, and others. The stream also flows through the Nay Aug Gorge and passes over the Nay Aug Falls, which are on the National Register of Geologic Landmarks. It flows through a concrete channel in its lower reaches. The topography of the watershed contains rolling hills in its upper reaches and the mountainous land of the Moosic Mountains in its lower reaches.
Land uses in the watershed of Roaring Brook include forested land, agricultural land, and developed land such as high-density residential land and downtown commercial land. Abandoned mine land also occurs in the watershed and wetlands occur in some areas. Major roads in the stream's drainage basin include Interstate 380, Interstate 84, Pennsylvania Route 435, Pennsylvania Route 590, and Pennsylvania Route 690. Mills and forges were built along the stream in the late 1700s and early 1800s. During the 19th century, there was a substantial coal and iron industry in the watershed. Several railroads were also built in the stream's vicinity. Numerous bridges, including the Harrison Avenue Bridge (which is on the National Register of Historic Places) have been built across the stream as well. Additionally, sites such as the Scranton Iron Furnaces are in its watershed.
Roaring Brook is designated as a High-Quality Coldwater Fishery and a Migratory Fishery for part of its length and a Coldwater Fishery and a Migratory Fishery for the other part of its length. It is also Class A Wild Trout Waters from the Hollister Dam to the Elmhurst Reservoir. Numerous macroinvertebrate taxa have been observed in the stream and boreal forest trees inhabit wetlands in the watershed. A 12-mile (19-kilometer) rail trail connecting the Lackawanna River Heritage Trail to the Poconos via the Roaring Brook Corridor has been proposed.
Course Roaring Brook begins in a small wetland in Covington Township, a few tenths of a mile from the border between Lackawanna County and Wayne County. It flows west for a few tenths of a mile before turning west-northwest for several tenths of a mile. The stream then turns northwest for several tenths of a mile before receiving Lake Run, its first named tributary, from the left. It then enters the Hollister Reservoir, where it receives the tributary East Branch Roaring Brook from the right. After passing through the reservoir, the stream turns north-northwest. It soon begins flowing along the border between Covington Township and Madison Township and begins to flow alongside Pennsylvania Route 435. The stream enters Moscow and receives the tributary Bear Brook from the right and the tributary Van Brunt Creek from the left. It continues flowing north-northwest and receives the tributary Kellum Creek after several tenths of a mile.
Roaring Brook then enters the Elmhurst Reservoir, where it briefly enters Roaring Brook Township before entering Elmhurst Township and receiving the tributary White Oak Run from the right. The stream continues flowing north-northwest, crossing Pennsylvania Route 435 and reentering Roaring Brook Township several tenths of a mile further downstream. It then crosses Interstate 84 and receives the tributary Rock Bottom Creek from the right as its valley becomes much deeper and narrower. It continues flowing north-northwest for more than a mile alongside Pennsylvania Route 435 before turning south-southwest and briefly entering Dunmore before reentering Roaring Brook Township. After several tenths of a mile, the stream turns northwest for a few miles, crossing Interstate 84 and reentering Dunmore. It passes through the Scranton Water Company Reservoir and receives the tributary Little Roaring Brook from the right before turning south and then west. It then turns northwest and crosses Interstate 81 before turning southwest and passing through the Nay Aug Gorge. The stream turns northwest for several tenths of a mile before turning west-southwest and crossing US Route 11. After a few tenths of a mile, it reaches its confluence with the Lackawanna River.
Roaring Brook is approximately long. It joins the Lackawanna River upriver of its mouth.
Tributaries Roaring Brook has eight named tributaries: Lake Run, East Branch Roaring Brook, Bear Brook, Van Brunt Creek, Kellum Creek, White Oak Run, Rock Bottom Creek, and Little Roaring Brook. Lake Run joins Roaring Brook upstream of its mouth and its watershed has an area of . East Branch Roaring Brook joins Roaring Brook upstream of its mouth and its watershed has an area of . Bear Brook joins Roaring Brook upstream of its mouth and its watershed has an area of . White Oak Run joins Roaring Brook upstream of its mouth and its watershed has an area of . Rock Bottom Creek joins Roaring Brook upstream of its mouth and its watershed has an area of . Little Roaring Brook joins Roaring Brook upstream of its mouth and its watershed has an area of .
Hydrology Roaring Brook has a high level of water quality downstream as far as Cobbs Gap. However, in its lower reaches, it is impacted by urban storm impacts and abandoned mining land. Silt from the DeNaples Auto Parts property washed into the stream in 1991. There are also stormwater impacts and combined sewer overflows in its lower reaches. Most of the stormwater flowing into the stream is associated with a combined sewer system in Scranton and Dunmore. Some highways in the watershed contribute stormwater as well. It is also affected by stormwater from the Daleville Shopping area, the village of Elmhurst, the borough of Moscow, Pennsylvania Route 435, Pennsylvania Route 590, and Pennsylvania Route 690. There are 12 stormwater detention facilities in the watershed's lower reaches.
The concentration of alkalinity in Roaring Brook between its headwaters and the Hollister Dam is 12 milligrams per liter. From the Hollister Dam to the Elmhurst Reservoir, the alkalinity concentration is 15 milligrams per liter. In the early 1900s, the stream was polluted by waste from coal mines upstream of its mouth. The stream experiences measurable flow loss, reaching up to 20 to 30 percent of its total flow in dry weather. In the 1970s, its turbidity ranged from 1 to 35 Jackson Turbidity Units at Scranton.
In the 1960s and 1970s, several measurements of the concentration of manganese in Roaring Brook at Scranton ranged from 0.7 to 21 milligrams per liter and measurements of the calcium concentration ranged from 0.8 to 31.2 milligrams per liter. The concentration of sodium ranged from 6 to 20 milligrams per liter in two measurements and the potassium concentration ranged from 1 to 3.5 milligrams per liter. Two measurements of the concentration of recoverable chromium ranged from less than 20 to 30 micrograms per liter. The concentration of recoverable copper (in unfiltered water only) ranged from 30 to 200 micrograms per liter. The concentration of recoverable iron (in unfiltered water only) ranged from 0 to 444,000 micrograms per liter. The concentration of recoverable lead in the stream's unfiltered waters was found twice to be 50 micrograms per liter. The concentration of recoverable manganese in the stream's unfiltered waters ranged from 20 to 1600 micrograms per liter. The concentration of recoverable zinc in the stream's unfiltered waters ranged from 160 to 380 micrograms per liter. Trace amounts of nickel and silver have been found in the stream. The concentration of recoverable zinc in the stream's unfiltered waters ranged between 100 and 70,000 micrograms per liter. The concentration of recoverable mercury in the stream (with unfiltered water) was once found to be less than 0.5 micrograms per liter.
In the 1960s and 1970s, several measurements of the concentration of dissolved oxygen in Roaring Brook at Scranton ranged from 10.0 to 12.6 milligrams per liter. The concentration of hydrogen ions in the stream had values ranging from 0.00004 to 0.04022 milligrams per liter. The carbon dioxide concentration was found to range from 0.3 to 252 milligrams per liter. Between 1928 and 1968, the bicarbonate concentration ranged from 22 to 141 milligrams per liter during three measurements. Between 1928 and the 1970s, the concentration of ammonia was found to range from 0 to 43.1 milligrams per liter and the nitrate concentration ranged from 0.1 to 18 milligrams per liter in three measurements in 1928 and 1968. The phosphorus concentration ranged from 0.040 to 13.6 milligrams per liter in the 1970s and the phosphate concentration ranged between 0 and 0.644 milligrams per liter.
The concentration of fluoride in Roaring Brook at Scranton was once measured to be 0.2 milligrams per liter (in unfiltered water only). The chloride concentration ranged from 2 to 214 milligrams per liter during several measurements in the 20th century. The sulfate concentration ranged from 8 to 4700 milligrams per liter. During two measurements, the silica concentration ranged from 5.20 to 8.30 milligrams per liter.
In two measurements in 1968, the specific conductance of Roaring Brook at Scranton ranged from 199 to 288 micro-siemens per centimeter at . The pH was measured to range from 4.4 to 8.8 and the acidity concentration ranged from 0 to 260 milligrams per liter in the 1960s and 1970s. The concentration of suspended solids ranged from 0 to 250 milligrams per liter and the concentration of settleable solids ranged between 0 and 4 milligrams per liter. The concentration of water hardness ranged from 12 to 160 milligrams per liter.
The peak annual discharge at the mouth of Roaring Brook has a 10 percent chance of reaching 5260 cubic feet per second. It has a 2 percent chance of reaching 10,500 cubic feet per second and a 1 percent chance of reaching 13,800 cubic feet per second. The peak annual discharge has a 0.2 percent chance of reaching 26,000 cubic feet per second.
Upstream of the tributary Little Roaring Brook, the peak annual discharge of Roaring Brook has a 10 percent chance of reaching 4520 cubic feet per second. It has a 2 percent chance of reaching 9100 cubic feet per second and a 1 percent chance of reaching 12,000 cubic feet per second. The peak annual discharge has a 0.2 percent chance of reaching 23,000 cubic feet per second.
Geography, geology, and climate
The elevation near the mouth of Roaring Brook is above sea level. The elevation of the stream's source is between above sea level. In its lower , the stream's gradient is per mile. Horace Hollister's 1885 History of the Lackawanna Valley noted that the stream was shallow at that time. According to Hollister, the stream appears to have been much larger in ancient times. His book also described Roaring Brook as being "the noisiest tributary of the Lackawanna".