page_title: Roaring Brook (Lackawanna River tributary)
section_title: Geography, geology, and climate
hierarchical_section_title: Roaring Brook (Lackawanna River tributary) / Geography, geology, and climate
caption_attribution_description: English: 19th-century depiction of the Nay Aug Falls on Roaring Brook
context_page_description: Roaring Brook is a tributary of the Lackawanna River in Lackawanna County, Pennsylvania, in the United States. It is approximately 21 miles 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 56.3 square miles. 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.
context_section_description: The elevation near the mouth of Roaring Brook is 659 feet (201 m) above sea level. The elevation of the stream's source is between 1,940 and 1,960 feet (590 and 600 m) above sea level. In its lower 15 miles (24 km), the stream's gradient is 62.8 feet (19.1 m) 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".
  Roaring Brook begins on the Pocono Plateau. It flows through a water gap known as Cobbs Gap in the Moosic Mountains and there are numerous waterfalls and rapids along it. A waterfall known as the Nay Aug Falls is on Roaring Brook and the stream flows through the a gorge or canyon Nay Aug Gorge, which is listed on the National Register of Geologic Landmarks. The waterfall is a cascade with a height of 22 feet (6.7 m) and cuts through a soft siltstone formation and flows over conglomerate. A spring known as Chico's Spring is in the stream's watershed in Dunmore, as is a feature known as Barneys Ledge. The Madisonville Cliffs and Glen are located in the watershed in Madison Township and Covington Township. Additionally, numerous ponds, reservoirs, and water works are in the watershed.
  The upper reaches of the watershed of Roaring Brook contain rolling hills. However, the lower reaches are mountainous, with steep, high hills and a narrow valley from Elmhurst downstream to Dunmore. The stream's channel is sinuous, but has retaining walls in its lower reaches. The stream flows past rock formations consisting of sandstone, shale, and conglomerate, along with some coal. However, all of its tributaries begin outside of the coal measures. In the Nay Aug Gorge, the stream flows through conglomerate of the Pocono Formation and sandstone of the Llwellyn Formation. A hard white conglomerate known as the Pottsville or Pocono Conglomerate occurs along the stream near the Nay Aug Falls. Erosion by the stream in the Nay Aug Gorge has caused some areas to be undercut. There are also cliffs in the gorge, some over 100 feet (30 m) high.
  Roaring Brook flows through a concrete U-channel from Cedar Avenue to its mouth. Both the manmade and the natural parts of the channel have steep banks, with heights on the order of 10 feet (3.0 m). An abandoned water power dam known as Step Falls is located on the stream in the Nay Aug Gorge. Much of the stream's channel and riparian area have been developed for flood control purposes. The stream is dammed by the Elmhurst Dam, which is in good condition as of May 1978.
  Upstream of Nay Aug, the channel of Roaring Brook is mainly natural and ranges in width from 40 to 60 feet (12 to 18 m). It flows past some steep slopes and rock ledges in this reach. In its lower reaches, the stream flows through 30 pipes with diameters ranging from 6 to 48 inches (15 to 122 cm). A wide gravel and sand bar and some dumped trash occurs along the stream.
  The average annual rate of precipitation in the watershed of Roaring Brook ranges from 35 to 45 inches (89 to 114 cm). In the 1960s and 1970s, several measurements of the water temperature of the stream ranged from 0.0 to 25.0 °C (32.0 to 77.0 °F). The temperature near the stream during several measurements in May 2013 ranged from 74 to 89 °F (23 to 32 °C).
caption: Nay Aug Falls
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