66-593: The Shenandoah River / ˌ ʃ ɛ n ə n ˈ d oʊ ə / is the principal tributary of the Potomac River , 55.6 miles (89.5 km) long with two forks approximately 100 miles (160 km) long each, in the U.S. states of Virginia and West Virginia . The river and its tributaries drain the central and lower Shenandoah Valley and the Page Valley in the Appalachians on the west side of
132-736: A body of water leads to oxygen depletion as microorganisms use up available oxygen in the process of breaking down organic matter . For example, a 10 miles (16 km) fish kill in September, 2010, in the Sangamon River in Illinois was traced to discharge of animal waste into the river from a large dairy operation. The illegal discharge resulted in a complete kill of fish, frogs, mussels and mudpuppies . Excessive anthropogenic nutrient enrichment of phosphorus and nitrogen allow for rapid growth and multiplication of phytoplankton in
198-469: A fish native to a more tropical region has been introduced to cooler waters, such as the introduction of the tilapia to bodies of water in Florida. Native to Africa's Nile River , the tilapia stop feeding when water temperatures drop below 60 °F (16 °C) and die when it reaches 45 °F (7 °C). Thus, tilapia that have survived and successfully reproduced in Florida are occasionally killed by
264-486: A generally illegal practice known as blast fishing . Underwater explosions may be accidental or planned, such as for construction, seismic testing , mining or blast testing of structures under water. In many places, an assessment of potential effects of underwater explosions on marine life must be completed and preventive measures taken before blasting. Droughts and overstocking can also result in inland fish kills. A drought can lead to lower water volumes so that even if
330-400: A localized mass die-off of fish populations which may also be associated with more generalized mortality of aquatic life. The most common cause is reduced oxygen in the water, which in turn may be due to factors such as drought , harmful algal bloom , overpopulation , or a sustained increase in water temperature. Infectious diseases and parasites can also lead to fish kill. Toxicity is
396-596: A maximum of 8 mg/L of oxygen can dissolve in sea water (35 mg/L salinity ) while a maximum of 9 mg/L of oxygen can dissolve in fresh water. The amount of oxygen that can be dissolved in the water decreases by about 1 mg/L for each 10 °C increase in water temperature above 20 °C. Many cold water fish that live in clean cold waters become stressed when oxygen concentrations fall below 8 mg/L while warm water fish generally need at least 5 ppm (5 mg/L) of dissolved oxygen. Fish can endure short periods of reduced oxygen. Depleted oxygen levels are
462-400: A new river, to be given its own name, perhaps one already known to the people who live upon its banks. Conversely, explorers approaching a new land from the sea encounter its rivers at their mouths, where they name them on their charts, then, following a river upstream, encounter each tributary as a forking of the stream to the right and to the left, which then appear on their charts as such; or
528-452: A normally stable aquatic population. Because of the difficulty and lack of standard protocol to investigate fish kills, many fish kill cases are designated as having an unknown cause. Oxygen enters the water through diffusion . The amount of oxygen that can be dissolved in water depends on the atmospheric pressure , the water temperature and whether the water is salty. For example, at 20 °C (68 °F) and one atmosphere of pressure,
594-399: A real but far less common cause of fish kill, and is often associated with man-made water pollution . Fish kills are often the first visible signs of environmental stress and are usually investigated as a matter of urgency by environmental agencies to determine the cause of the kill. Many fish species have a relatively low tolerance of variations in environmental conditions and their death
660-402: A shuttle named Shenandoah. Tributary A tributary , or an affluent , is a stream or river that flows into a larger stream ( 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 into which they flow, drain the surrounding drainage basin of its surface water and groundwater , leading
726-458: A spilled substance causes direct toxicity or a shift in water temperature or pH that can lead to fish kill. For example, in 1997 a phosphate plant in Mulberry, Florida , accidentally dumped 60 million US gal (0.23 million kl) of acidic process water into Skinned Sapling Creek, reducing the pH from about 8 to less than 4 along 36 miles (58 km) of creek, resulting in
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#1732773322744792-556: A valley across Shenandoah County , along the western side of Massanutten Mountain . It flows past Woodstock and Strasburg . On the north end of the ridge it turns briefly southeast to join the South Fork from the northwest to form the Shenandoah. The American folk song and river and sea chantey titled " Oh Shenandoah " has been adapted to explicitly reference the river or river valley, although earlier versions referred to
858-592: A winter cold front. In January, 2011, a selective fish kill affecting an estimated 2 million juvenile spot fish was attributed to a combination of cold stress and overpopulation after a particularly large spawn. "Hundreds of thousands" of fish were found dead in Texas in June 2023 due to warming water. Underwater explosions can lead to fish kill, and fish with swim bladders are more susceptible. Sometimes underwater explosions are used on purpose to induce fish kills,
924-793: Is a matching pH rhythm as bicarbonate ion is metabolised by plant cells. This can lead to pH stress even when oxygen levels are high. Additional dissolved organic loads are the most common cause of oxygen depletion and such organic loads may come from sewage, farm waste, tip/landfill leachate and many other sources. Fish are subject to various viruses , bacteria and fungi in addition to parasites such as protozoans , flukes and worms, or crustaceans. These are naturally occurring in many bodies of water, and fish that are stressed for other reasons, such as spawning or suboptimal water quality, are more susceptible. Signs of disease include sores, missing scales or lack of slime, strange growths or visible parasites, and abnormal behavior–lazy, erratic, gasping at
990-449: Is defined as the measure of water clarity by how much the suspended material, such as algae and phytoplankton, constrict the passage of sunlight through water. Hence, as phytoplankton begin to multiply more rapidly, turbidity in the river and gulf increases. The increasing turbidity blocks plants from absorbing sunlight. The process of turbidity results in limited photosynthesis production, and sometimes even death from sunlight deprivation of
1056-516: Is evident, and the limestone is honeycombed with caves. Several have been developed as commercial tourist attractions, including Luray Caverns , Shenandoah Caverns , and Skyline Caverns . On the riverbank, a few miles above Harper's Ferry, is said to be a cave with an opening just large enough for a mounted rider to squeeze through. It widened in the interior to a spacious room where hundreds of Col. John Mosby's raiding troops are said to have hidden from pursuing Union cavalry. The Shenandoah River
1122-752: Is in full motion, a dead zone has been created. As a result of the excess nutrient enrichment in the Mississippi River, dead zones appear in the Gulf of Mexico, created from the process of eutrophication. The dead zones in the gulf are mainly created by the nitrogen and phosphorus enrichment of the Lower Mississippi River. Some species of fish exhibit mass simultaneous mortality as part of their natural life cycle. Fish kill due to spawning fatalities can occur when fish are exhausted from spawning activities such as courtship, nest building, and
1188-418: Is often a potent indicator of problems in their environment that may be affecting other animals and plants and may have a direct impact on other uses of the water such as for drinking water production. Pollution events may affect fish species and fish age classes in different ways. If it is a cold-related fish kill, juvenile fish or species that are not cold-tolerant may be selectively affected. If toxicity
1254-496: Is one of the most common natural causes of fish kills. The suffocating event may be brought on by factors such as algae blooms , droughts, high temperatures and thermal pollution . Fish kills may also occur due to the presence of disease, agricultural runoff , sewage discharges, oil or hazardous waste spills, hydraulic fracturing wastewater, sea-quakes , inappropriate re-stocking of fish, poaching with chemicals, underwater explosions , and other catastrophic events that upset
1320-416: Is the appearance of a large amount of algae or scum floating on the surface of a body of water. Algae blooms are a natural occurrence in nutrient-rich lakes and rivers, though sometimes increased nutrient levels leading to algae blooms are due to fertilizer or animal waste runoff . A few species of algae produce toxins , but most fish kills due to algae bloom are a result of decreased oxygen levels. When
1386-485: Is the cause, species are more generally affected and the event may include amphibians and shellfish as well. A reduction in dissolved oxygen may affect larger specimens more than smaller fish as these may be able to access oxygen richer water at the surface, at least for a short time. Fish kills may result from a variety of causes. Of known causes, fish kills are most frequently caused by pollution from agricultural runoff or biotoxins. Ecological hypoxia (oxygen depletion)
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#17327733227441452-708: The Blue Ridge Mountains , in northwestern Virginia and the eastern panhandle of West Virginia . There is a hydroelectric plant along the Shenandoah River constructed in 2014 by Dominion . The Shenandoah River is formed northeast of Front Royal near Riverton, by the confluence of the South Fork and the North Fork . It flows northeast across Warren County , passing underneath Interstate 66 1 mile (1.6 km) from its formation. Beyond
1518-593: The Mississippi River . As phytoplankton continue to rapidly grow under optimal conditions, their biomass is almost doubled every 24 hours. In the water, higher concentrations of organic matter are present because of the high reproductive rate of the phytoplankton over a short period of time. The rapid growth of phytoplankton causes turbidity in the waters of the Mississippi and the Gulf of Mexico . Turbidity
1584-689: The Virginia Department of Health (VDOH) states that it is not safe to consume any species except trout which are caught between Waynesboro and Grottoes, Virginia due to elevated mercury levels. In general, the VDOH states that it is not safe to consume more than two fish per month which are caught on the Shenandoah River in Page , Warren , Augusta , or Rockingham counties. In 2017 DuPont agreed to pay $ 42,069,916.78 to address natural resource damages and to implement restoration projects related to
1650-442: The layers can mix . If the volume of low oxygen water is much greater than the volume in the warm surface layer, this mixing can reduce oxygen levels throughout the water column and lead to fish kill. Fish kills can also result from a dramatic or prolonged drop in air (and thus, water) temperature. This kind of fish kill is selective – usually the dead fish are species that cannot tolerate cold. This has been observed in cases where
1716-501: The 18th century Oneida Chief Shenandoah and the Missouri River , 1,000 miles to the west. The 1971 hit and signature song of John Denver , " Take Me Home, Country Roads ", prominently mentions the Shenandoah River, and was adopted by the state of West Virginia in 2014 as its fourth official state song . An episode of Star Trek: Deep Space Nine , continuing the tradition of naming their runabout vessels after rivers, has
1782-414: The 1950s were due to a pesticide called endrin . Natural instances of toxic conditions can occur, especially in poorly buffered water. Aluminium compounds can cause complete fish kills, sometimes associated with autumn turn-over of lakes leading to complex chemical interactions between pH, calcium ions and complex polymeric salts of aluminium. Human-induced fish kills are unusual, but occasionally
1848-772: The I-66 bridge, the river flows through a set of bends before turning to the northeast again, crossing into Clarke County 11 miles (18 km) below I-66. Five miles (8 km) downriver from the Clarke County border, the Shenandoah passes under U.S. Route 50 and then passes through a triple bend. 14.5 miles (23.3 km) below the Route 50 bridge, the river passes underneath State Route 7 and then continues northeast another 8 miles (13 km) where it crosses into Jefferson County in West Virginia. Once in West Virginia,
1914-490: The United States, particularly in the Gulf of Maine . This type of bloom is caused by another species of dinoflagellate known as Alexandrium fundyense . These blooms are natural phenomena, but the exact combination of factors that result in red tide outbreaks is not fully understood. Just as an algae bloom can lead to oxygen depletion, introduction of a large amount of decaying biological material in general to
1980-655: The adult redbreast sunfish and smallmouth bass, juvenile populations appeared to be unaffected. The following year more-localized fish kills in Clarke County spread to two of the Shenandoah's three species of sucker: the shorthead redhorse and the northern hogsucker – the former suffering from similar lesions witnessed in the previous year's fish kill. Virginia's Department of Environmental Quality received reports of fish kills near Elkton and between Bentonville and Front Royal in late April 2007 and observed fish exhibiting lesions and strange behavior. Various accounts tell
2046-491: The algae die, decomposition uses oxygen in the water that would be available to fish. A fish kill in a lake in Estonia in 2002 was attributed to a combination of algae bloom and high temperatures. When people manage algae blooms in fish ponds , it is recommended that treatments be staggered to avoid too much algae dying at once, which may result in a large drop in oxygen content. Some diseases result in mass die-offs. One of
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2112-850: The available resources, parasites or disease can spread quickly. In channel catfish aquaculture ponds , for example, the "hamburger gill disease" is caused by a protozoan called Aurantiactinomyxon and can kill all the fish in an affected pond. In addition to altered behavior, affected fish have swollen gills that are mottled and have the appearance of ground hamburger meat. Some early warning signs of fish suffering from disease or parasite infections include: Agricultural runoff , sewage , surface runoff , chemical spills and hazardous waste spills can all potentially lead to water toxicity and fish kill. Some algae species also produce toxins. In Florida, these include Aphanizomenon , Anabaena and Microcystis . Some notable fish kills in Louisiana in
2178-534: The dead phytoplankton accumulate, detritus, or organic matter waste, forms at the surface along with other bacteria and algae. As more phytoplankton die, the higher the concentration of organic matter becomes; and with a higher concentration of organic matter, more bacteria will reproduce. Consequently, as more bacteria, phytoplankton, and algae exponentially grow and multiply, the more submerged aquatic vegetation die, because they do not have access to sunlight due to eutrophication. Once this snowball-like course of action
2244-546: The death of about 1.3 million fish. It is often difficult or impossible to determine whether a potential toxin is the direct cause of a fish kill. For example, hundreds of thousands of fish died after an accidental spill of bourbon whiskey into the Kentucky River near Lawrenceburg . However, officials could not determine whether the fish kill was due to the bourbon directly or to oxygen depletion that resulted when aquatic microbes rapidly began to consume and digest
2310-410: The developed world have specific provisions in place to encourage the public to report fish kills so that a proper investigation can take place. Investigation of the cause of a kill requires a multi-disciplinary approach including on-site environmental measurements , investigation of inputs, review of meteorology and past history, toxicology, fish autopsy, invertebrate analysis and a robust knowledge of
2376-694: The east and the Massanutten Mountain range to the west. The North Fork is 105 miles (169 km) long and rises in northern Rockingham County , along the eastern flank of Shenandoah Mountain in the George Washington National Forest . At its formation, the principal feeder on the North Fork is the German River . The North Fork flows initially southeast, down from the mountains, then northeast through
2442-422: The first-order tributary being typically the least in size. For example, a second-order tributary would be the result of two or more first-order tributaries combining to form the second-order tributary. Another method is to list tributaries from mouth to source, in the form of a tree structure , stored as a tree data structure . Fish kill The term fish kill , known also as fish die-off , refers to
2508-403: The fish remain in the area, continuing to provide nourishment, then the zoospores start secreting a neurotoxin . This toxin results in the fish developing bleeding lesions, and their skin flakes off in the water. The dinoflagellates then eat the blood and flakes of tissue while the affected fish die. Fish kills by this dinoflagellate are common, and they may also have been responsible for kills in
2574-451: The handedness is from the point of view of an observer facing upstream. For instance, Steer Creek has a left tributary which is called Right Fork Steer Creek. These naming conventions are reflective of the circumstances of a particular river's identification and charting: people living along the banks of a river, with a name known to them, may then float down the river in exploration, and each tributary joining it as they pass by appears as
2640-517: The impacted resources in the South Fork Shenandoah River watershed. Since 2005, the Shenandoah River has experienced several springtime fish kills that have affected several of its native fish species. In 2005, redbreast sunfish and smallmouth bass along a 100-mile (160 km) stretch of the South Fork Shenandoah River began dying of lesions caused by bacteria and fungi. Although the fish kill eventually wiped out 80% of
2706-424: The joining of tributaries. The opposite to a tributary is a distributary , a river or stream that branches off from and flows away from the main stream. Distributaries are most often found in river deltas . Right tributary , or right-bank tributary , and left tributary , or left-bank tributary , describe the orientation of the tributary relative to the flow of the main stem river. These terms are defined from
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2772-421: The liquor. Cyanide is a particular toxic compound that has been used to poach fish . In cyanide poisoning the gills turn a distinctive cherry red. Chlorine introduced as alkaline hypochlorite solution is also extremely toxic, leaving pale mucilaginous gills and an over-production of mucilage across the whole body. Lime produces similar symptoms but is also often associated with milk eyes. An algae bloom
2838-556: The magnitude of a kill presents a number of problems. Some very large fish kills may never be estimated because of these factors. The discharge of red aluminium sludge from a reservoir in Hungary into the Marcai River is acknowledged as causing environmental devastation, The loss of adult fish also can have long-term impacts on the success of the fishery as the following year's spawning stock may have been lost and recovery of
2904-419: The more bizarre and recently discovered diseases produces huge fish kills in shallow marine waters. It is caused by the ambush predator dinoflagellate Pfiesteria piscicida . When large numbers of fish, like shoaling forage fish , are in confined situations such as shallow bays, the excretions from the fish encourage this dinoflagellate, which is not normally toxic, to produce free-swimming zoospores . If
2970-518: The most common cause of fish kills. Oxygen levels normally fluctuate even over the course of a day and are affected by weather, temperature, the amount of sunlight available, and the amount of living and dead plant and animal matter in the water. In temperate zones oxygen levels in eutrophic rivers in summertime can exhibit very large diurnal fluctuations with many hours of oxygen supersaturation during daylight followed by oxygen depletion at night. Associated with these photosynthetic rhythms there
3036-580: The name was in use when Washington was a child, as evidenced in land grants and correspondence. It is also said to be named after the Senedo people , a little-documented tribe said to have lived on the north fork of the river and destroyed by the Catawba , some time between 1650 and 1700. The Shenandoah River is a very popular river for canoeing , river tubing , and white-water recreation such as rafting and kayaking (class I-III in season, II-III+ during
3102-406: The opposite bank before approaching the confluence. An early tributary is a tributary that joins the main stem river closer to its source than its mouth, that is, before the river's midpoint ; a late tributary joins the main stem further downstream, closer to its mouth than to its source, that is, after the midpoint. In the United States, where tributaries sometimes have the same name as
3168-637: The origin of the name. According to one, General George Washington named the valley (and river) in honor of Skenandoa (or Shenandoah), an Oneida "pine tree chief" based in New York, who led hundreds of Oneida and Tuscarora warriors in support of the American rebels on the frontier during the Revolutionary War. He also sent much needed corn to Washington and his troops during their hard winter at Valley Forge, Pennsylvania in 1777–1778. However,
3234-443: The oxygen concentration available to fish Overstocking of fish (or an unusually large spawn ) can also result in inland fish kills. Fish kill due to insufficient oxygen is really a matter of too much demand and too little supply for whatever reason(s). Recommended stocking densities are available from many sources for bodies of water ranging from a home aquarium or backyard pond to commercial aquaculture facilities. Estimating
3300-460: The past which were thought to have had other causes. Kills like these can be viewed as natural mechanisms for regulating the population of exceptionally abundant fish. The rate at which the kills occur increases as organically polluted land runoff increases. Red tide is the name commonly given to an algal bloom of Karenia brevis , a microscopic marine dinoflagellate which is common in Gulf of Mexico waters. In high concentrations it discolors
3366-476: The perspective of looking downstream, that is, facing the direction the water current of the main stem is going. In a navigational context, if one were floating on a raft or other vessel in the main stream, this would be the side the tributary enters from as one floats past; alternately, if one were floating down the tributary, the main stream meets it on the opposite bank of the tributary. This information may be used to avoid turbulent water by moving towards
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#17327733227443432-632: The potential to hold more oxygen, so a period of sustained high temperatures can lead to decreased dissolved oxygen in a body of water. An August 2010 fish kill in Delaware Bay was attributed to low oxygen as a result of high temperatures. A massive (hundreds of thousands) fish kill at the mouth of the Mississippi River in Louisiana , September, 2010, was attributed to a combination of high temperatures and low tide. Such kills are known to happen in this region in late summer and early fall, but this one
3498-533: The pre-kill population may take years. The loss of food supplies or recreational income may be very significant to the local economy. Fish kills are difficult to predict. Even when conditions that contribute to fish kill are known to exist, prevention is hard because often conditions cannot be improved and fish cannot be safely removed in time. In small ponds, mechanical aeration and/or removal of decaying matter (such as fallen leaves or dead algae) may be reasonable and effective preventive measures. Many countries in
3564-517: The release of eggs or milt (sperm). Fish are generally weaker after spawning and are less resilient than usual to smaller changes in the environment. Examples include the Atlantic salmon and the Sockeye salmon where many of the females routinely die immediately after spawning. A fish kill can occur with rapid fluctuations in temperature or sustained high temperatures. Generally, cooler water has
3630-647: The river completes six large bends before joining the Potomac from the southwest near Harpers Ferry . The confluence is on the West Virginia-Maryland border, and 0.4 miles (0.64 km) from the Virginia-West Virginia border. The Shenandoah Valley is underlaid by limestone . The fertile soil made it a favored place for early settlement. It remains a major agricultural area of Virginia and West Virginia. Some karst topography
3696-666: The river into which they feed, they are called forks . These are typically designated by compass direction. For example, the American River in California receives flow from its North, Middle, and South forks. The Chicago River 's North Branch has the East, West, and Middle Fork; the South Branch has its South Fork, and used to have a West Fork as well (now filled in). Forks are sometimes designated as right or left. Here,
3762-418: The smaller stream designated the little fork, the larger either retaining its name unmodified, or receives the designation big . Tributaries are sometimes listed starting with those nearest to the source of the river and ending with those nearest to the mouth of the river . The Strahler stream order examines the arrangement of tributaries in a hierarchy of first, second, third and higher orders, with
3828-533: The spring run-off), and several commercial outfitters offer a variety of guided trips and rentals. The South Fork is formed at Port Republic in southern Rockingham County , by the confluence of the North River and South River . It flows 98.5 miles (158.5 km) northeast in a tight meandering course, past Elkton and Shenandoah , through Page Valley, with the Blue Ridge Mountains to
3894-432: The streams are seen to diverge by the cardinal direction (north, south, east, or west) in which they proceed upstream, sometimes a third stream entering between two others is designated the middle fork; or the streams are distinguished by the relative height of one to the other, as one stream descending over a cataract into another becomes the upper fork, and the one it descends into, the lower ; or by relative volume:
3960-449: The submerged aquatic vegetation that are affected by the opaque turbid water accumulating at the surface. Furthermore, a significant detrimental outcome caused by eutrophication in the Mississippi River is the increased uptake of dissolved oxygen by bacteria, in response to higher concentrations of organic matter. After eutrophication starts and is in progress, the phytoplankton reach their maximum population density and begin to die. As
4026-442: The water contains a high level of dissolved oxygen, the reduced volume may not be enough for the fish population. Droughts often occur in conjunction with high temperatures so that the oxygen carrying capacity of the water may also be reduced. Low river flows also reduce the available dilution for permitted discharges of treated sewage or industrial waste . The reduced dilution increases the organic demand for oxygen further reducing
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#17327733227444092-466: The water out into an ocean. The Irtysh is a chief tributary of the Ob river and is also the longest tributary river in the world with a length of 4,248 km (2,640 mi). The Madeira River is the largest tributary river by volume in the world with an average discharge of 31,200 m /s (1.1 million cu ft/s). A confluence , where two or more bodies of water meet, usually refers to
4158-498: The water surface or floating head, tail or belly up. For example, since 2004 fish kills have been observed in the Shenandoah River basin in the spring, from the time water temperatures are in the 50s (°F) until they reach the mid-70s. So far, investigators suspect certain bacteria, along with environmental and contaminant factors that may cause immune suppression . In fish farming , where populations are optimized for
4224-425: The water which often appears reddish-brown in color. It produces a toxin which paralyses the central nervous system of fish so they cannot breathe. Dead fish wash up on beaches around Texas and Florida. Humans can also become seriously ill from eating oysters and other shellfish contaminated with the red tide toxin. The term "red tide" is also commonly used to describe harmful algal blooms on the northern east coast of
4290-464: Was contaminated with mercury which was released by a DuPont rayon manufacturing facility located in Waynesboro, Virginia from 1929 to 1950. This mercury is still present in the fish population of the river today; data collected over the last several decades shows that mercury levels remain stable. The fish in many sections of the Shenandoah River are not safe for human consumption. For example,
4356-430: Was unusually large. A short period of hot weather can increase temperatures in the surface layer of water, as the warmer water tends to stay near the surface and be further heated by the air. In this case, the top warmer layer may have more oxygen than the lower, cooler layers because it has constant access to atmospheric oxygen. If a heavy wind or cold rain then occurs (usually during the autumn but sometimes in summer),
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