Fourmile Creek is a

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drai ...

Lake Erie Lake Erie ( "eerie") is the fourth largest lake by surface area of the five Great Lakes in North America and the eleventh-largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also h ...

in Erie County, Pennsylvania, United States. It is approximately in length. It has a

drainage basin A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...

of and is a part of the

Lake Erie Watershed A lake is an area filled with water, localized in a Depression (geology), basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the World Ocean, oce ...

Course

Fourmile Creek starts in Greene Township, immediately north of

Pennsylvania Route 8 Pennsylvania Route 8 (PA 8) is a major state route in western Pennsylvania. Officially, PA 8 is named the William Flinn Highway. Its southern terminus is at Interstate 376 (I-376)/U.S. Route 22 (US 22)/ US 30 in Pittsburgh. Its northern terminu ...

. It flows northwest, with its valley getting deeper as it flows onwards. After several miles, it crosses under Interstate 90 and exits Greene Township, entering Harborcreek Township. At this point, the creek turns northwards and its valley continues to get deeper. After some distance, the valley gets shallower and the creek flows under Pennsylvania Route 290. It turns northwest and heads along the border between Harborcreek Township and

Erie Erie (; ) is a city on the south shore of Lake Erie and the county seat of Erie County, Pennsylvania, United States. Erie is the fifth largest city in Pennsylvania and the largest city in Northwestern Pennsylvania with a population of 94,831 a ...

, eventually entering Erie. Upon entering Erie, it continues northwest, passing through the Lawrence Park Golf Club and entering Lake Erie.

Hydrology

The pH of Fourmile Creek ranges between 6 and 9. The salinity ranges from 0.1 parts per trillion to 0.3 parts per trillion. The total concentration of

dissolved solids In chemistry, a solution is a special type of homogeneous mixture composed of two or more substances. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent. If the attractive forces between the solvent ...

ranges from 180 to 500 parts per million. In 1982, the concentration of

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

in the creek ranged from 2.91 to 40.8 milligrams per liter at two sites. In the same year, the concentration of

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

ranged from 2.9 to 14.2 milligrams per liter at two sites. The

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

concentration ranged from 29.3 to 134.5 milligrams per liter at two sites. The concentration of

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...

s ranged from 0 to 0.55 milligrams per liter at two sites. During times of flooding, the velocity of the waters of Fourmile Creek is per second. During

drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...

s, the velocity is per second. The discharge ranges from 1400 cubic centimeters per second in times of drought to 91,000 cubic centimeters per second during floods. The

conductivity Conductivity may refer to: *Electrical conductivity, a measure of a material's ability to conduct an electric current **Conductivity (electrolytic), the electrical conductivity of an electrolyte in solution ** Ionic conductivity (solid state), ele ...

of the creek ranges from 274 micro-siemens to 747 micro-siemens. Between late summer and spring, the water temperature ranges from to . In a list of 22 tributaries of Lake Erie compiled in a Strategic Action Plan, Fourmile Creek was ranked as the fourth-lowest in water quality. There are few cases of nonpoint source pollution in the upper reaches of the creek. There are two

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

s on Fourmile Creek. One is located in the Lawrence Park Golf Course and the other is located south of Station Road. There is also a block of

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...

in the stream that functions as a third dam. A stream in the watershed of Fourmile Creek received sewage discharges for at least 20 years in the 1900s.

Geology and Geography

There is one

waterfall A waterfall is a point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in severa ...

on Fourmile Creek. It is high and located between Cooper Road and Interstate 90. There are

granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies under ...

formations along the upper reaches of Fourmile Creek. Sheets of porphyry are mixed in with the granite. The shale-containing Belt formation occupies parts of the creek's watershed. There is a large mass of rhyolite located near the creek. It is approximately thick and is the largest such mass in Pennsylvania. Another mass of rhyolite in the watershed is thick. In its upper reaches, Fourmile Creek flows through a relatively narrow valley that is deep. There is slide rock in the valley. Fourmile Creek has an elevation of above sea level.

History

Since 2007, improvements have been undertaken to improve

steelhead Steelhead, or occasionally steelhead trout, is the common name of the anadromous form of the coastal rainbow trout or redband trout (O. m. gairdneri). Steelhead are native to cold-water tributaries of the Pacific basin in Northeast Asia and ...

spawning in Fourmile Creek and provide better fishing access. As of 2011, two aluminum

fishway A fish ladder, also known as a fishway, fish pass, fish steps, or fish cannon is a structure on or around artificial and natural barriers (such as dams, locks and waterfalls) to facilitate diadromous fishes' natural migration as well as move ...

s have been added to allow steelhead trout to bypass river obstacles and improve access to their spawning grounds. In 2012, a golf course adjacent to these improvements finalized legal

easement An easement is a nonpossessory right to use and/or enter onto the real property of another without possessing it. It is "best typified in the right of way which one landowner, A, may enjoy over the land of another, B". An easement is a propert ...

s granting public access to the fishways via their private property.

Biology

The pathogenic '' Aeromonas veronii''

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

has been observed in Fourmile Creek. Benthic

macroinvertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s live in the upper reaches of the creek. Six species of

mayflies Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States, as Canadian soldiers in the American Great Lakes region, and as up-winged flies in the United Kingdom) are aquatic insects belonging to the order ...

were observed on the creek in the late 1970s and early 1980s. They are ''

Paraleptophlebia strigula ''Paraleptophlebia strigula'' is a species of pronggilled mayfly in the family Leptophlebiidae Leptophlebiidae is a family belonging to the Ephemeropterans that are commonly known as the prong-gilled mayflies or leptophlebiids. It is the onl ...

'', '' Paraleptophlebia debilis'', '' Habrophlebiodes americana'', '' Baetis tricaudatus'', '' Baetus flavistriga'', and '' Ameletus ludens''.

Pine tree A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden ac ...

s grow densely in the valley in the upper reaches of Fourmile Creek.

References