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94-717: The concept of the Tidal Basin originated in the 1870s to serve both as a visual centerpiece and as a means for flushing the Washington Channel, a harbor separated from the Potomac River by landfills where East Potomac Park is now situated. Colonel Peter Conover Hains of the United States Army Corps of Engineers oversaw the Basin's design and construction. The Basin was initially named

188-689: A European spelling of Patawomeck , the Algonquian name of a Native American village on its southern bank. Native Americans had different names for different parts of the river, calling the river above Great Falls Cohongarooton , meaning "honking geese" and "Patawomke" below the Falls, meaning "river of swans". In 1608, Captain John Smith explored the river now known as the Potomac and made drawings of his observations which were later compiled into

282-409: A day. The inlet gates, located on the Potomac side of the Basin, allow water to enter the Basin during high tide. During this time, the outlet gates, on the Washington Channel side, close to store incoming water and block the flow of water and sediment into the channel. As the tide begins to ebb, the general outflow of water from the Basin forces the inlet gates to close. This same force is applied to

376-707: A dock near the eastern end of the Tidal Basin. The activity is popular during the Cherry Blossom Festival, which takes place in April. Sea level rise and land subsidence has caused portions of the paths next to the water to regularly flood at high tide. To address this problem, the Trust for the National Mall brought together in 2020 five design firms to re-imagine the Tidal Basin's future. After completing an environmental assessment that found that

470-491: A false sense of security to property owners and local residents as evident in this situation. Seawalls along the Japanese coast have also been criticized for cutting settlements off from the sea, making beaches unusable, presenting an eyesore, disturbing wildlife, and being unnecessary. After 2012's Hurricane Sandy , New York City Mayor Bill de Blasio invested $ 3,000,000,000 in a hurricane restoration fund, with part of

564-489: A map and published in London in 1612. This detail from that map shows his rendition of the river that the local tribes had told him was called the "Patawomeck". The spelling of the name has taken many forms over the years from " Patawomeck " (as on Captain John Smith 's map) to "Patomake", "Patowmack", and numerous other variations in the 18th century and now "Potomac". The river's name was officially decided upon as "Potomac" by

658-415: A natural barrier against future disasters like the 2004 Indian Ocean earthquake . Studies have found that an offshore tsunami wall could reduce tsunami wave heights by up to 83%. The appropriate seawall design relies on location-specific aspects, including surrounding erosion processes. There are three main types of seawalls: vertical, curved, stepped, and mounds (see table below). A report published by

752-528: A planned project would have no significant impact "on the natural, cultural or human environment" in the area, the National Park Service (NPS) then announced in 2023 that would renovate approximately linear 6,800 feet (2,073 m) of seawall along the Basin and parts of West Potomac Park . The Basin's seawall will become 4.75 feet (1.45 m) taller and will stand on a new foundation to prevent it from sinking further. The NPS will increase

846-541: A problem as it is not easy for people to predict or imagine the strength of hurricane or storm-induced waves compared to normal, expected wave patterns. An extreme event can dissipate hundreds of times more energy than everyday waves, and calculating structures that will stand the force of coastal storms is difficult and, often the outcome can become unaffordable. For example, the Omaha Beach seawall in New Zealand

940-402: A rise of between +16-19.3 cm throughout 1900–1988. Superstorm Sandy of 2012 is an example of the devastating effects rising sea levels can cause when mixed with a perfect storm. Superstorm Sandy sent a storm surge of 4–5 m onto New Jersey's and New York's barrier island and urban shorelines, estimated at $ 70 billion in damage. This problem could be overcome by further modeling and determining

1034-443: A seawall can be from the area's natural water-table , rain percolating into the ground behind the wall and waves overtopping the wall. The water table can also rise during periods of high water ( high tide ). Lack of adequate drainage can cause the seawall to buckle, move, bow, crack, or collapse. Sinkholes may also develop as the escaping water pressure erodes soil through or around the drainage system. Extreme events also pose

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1128-630: A series of large islands while it heads northeast to Moorefield . At Moorefield, the South Branch is joined by the South Fork South Branch Potomac River and runs north to Old Fields where it is fed by Anderson Run and Stony Run. At McNeill , the South Branch flows into the Trough where it is bound to its west by Mill Creek Mountain (2,119 ft) and to its east by Sawmill Ridge (1,644 ft). This area

1222-665: A serpentine path through the eastern Allegheny Mountains. First, it flows northeast by the communities of Bloomington , Luke , and Westernport in Maryland and then on by Keyser , West Virginia to Cumberland , Maryland. At Cumberland, the river turns southeast. 103 miles (166 km) downstream from its source, the North Branch is joined by the South Branch between Green Spring and South Branch Depot , West Virginia from whence it flows past Hancock , Maryland and turns southeast once more on its way toward Washington, D.C. , and

1316-481: A ton, are weathered black and brown. The seawall is inspected every year and whenever gaps appear or the stones sink into the sand, the government adds more boulders to keep it strong. The Union Territory of Pondicherry recorded around 600 deaths from the huge tsunami waves that struck India's coast after the mammoth underwater earthquake (which measured 9.0 on the moment magnitude scale ) off Indonesia, but most of those killed were fishermen who lived in villages beyond

1410-724: A water intake 725 feet (220 m) offshore, citing potential harm to Maryland's interests by an increase in Virginia sprawl caused by the project. After years of failed appeals within the Maryland government's appeal processes, in 2000 Virginia took the case to the Supreme Court of the United States , which exercises original jurisdiction in cases between two states. Maryland claimed Virginia lost its riparian rights by acquiescing to MDE's permit process for 63 years (MDE began its permit process in 1933). A Special Master appointed by

1504-399: Is a form of coastal defense constructed where the sea , and associated coastal processes, impact directly upon the landforms of the coast . The purpose of a seawall is to protect areas of human habitation, conservation, and leisure activities from the action of tides , waves , or tsunamis . As a seawall is a static feature, it will conflict with the dynamic nature of the coast and impede

1598-795: Is a major river in the Mid-Atlantic region of the United States that flows from the Potomac Highlands in West Virginia to the Chesapeake Bay in Maryland . It is 405 miles (652 km) long, with a drainage area of 14,700 square miles (38,000 km ), and is the fourth-largest river along the East Coast of the United States . More than 6 million people live within its watershed . The river forms part of

1692-481: Is a static feature which can conflict with the dynamic nature of the coast and impede the exchange of sediment between land and sea. The table below summarizes some positive and negative effects of seawalls which can be used when comparing their effectiveness with other coastal management options, such as beach nourishment . Generally, seawalls can be a successful way to control coastal erosion, but only if they are constructed well and out of materials that can withstand

1786-545: Is also a major issue with seawalls. In 2013, more than 5,000 feet (1,500 m) of seawall was found to be crumbling in Punta Gorda, Florida . Residents of the area pay hundreds of dollars each year for a seawall repair program. The problem is that most of the seawalls are over a half-century old and are being destroyed by only heavy downpours. If not kept in check, seawalls lose effectiveness and become expensive to repair. Seawall construction has existed since ancient times. In

1880-463: Is at least 3.5 million years old, likely extending back ten to twenty million years before the present when the Atlantic Ocean lowered and exposed coastal sediments along the fall line. This included the area at Great Falls, which eroded into its present form during recent glaciation periods. The stream gradient of the entire river is 0.14%, a drop of 930 m over 652 km. "Potomac" is

1974-613: Is believed to be a 100-meter row of boulders in the Mediterranean Sea off the coast of Israel. Boulders were positioned in an attempt to protect the coastal settlement of Tel Hreiz from sea rise following the last glacial maximum . Tel Hreiz was discovered in 1960 by divers searching for shipwrecks, but the row of boulders was not found until storms cleared a sand cover in 2012. More recently, seawalls were constructed in 1623 in Canvey Island , UK, when great floods of

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2068-819: Is currently re-bounding as a result of the ICPRB 's successful "American Shad Restoration Project" that was begun in 1995. In addition to stocking the river with more than 22 million shad fry, the Project supervised the construction of a fishway that was built to facilitate the passage of adults around the Little Falls Dam on the way to their traditional spawning grounds upstream.   *denotes naturalized species; Sources: Striped mullet Mugil cephalus Spot Leiostomus xanthurus Spotted seatrout Cynoscion nebulosus Atlantic Croaker Micropogonias undulatus Seawall A seawall (or sea wall )

2162-762: Is located on its banks, as is Mount Vernon , the home of "Father of his Country" George Washington . During the American Civil War, the river became the boundary between the Union and the Confederacy , and the Union's largest army, the Army of the Potomac , was named after the river. The Potomac River runs 405 mi (652 km) from Fairfax Stone Historical Monument State Park in West Virginia on

2256-402: Is said that President Abraham Lincoln used to escape to the highlands on summer nights to escape the river's stench. In the 1960s, with dense green algal blooms covering the river's surface, President Lyndon Johnson declared the river "a national disgrace" and set in motion a long-term effort to reduce pollution from sewage and restore the beauty and ecology of this historic river. One of

2350-443: Is the habitat to bald eagles . The Trough passes into Hampshire County and ends at its confluence with Sawmill Run south of Glebe and Sector . The South Branch continues north parallel to South Branch River Road ( County Route 8) toward Romney with a number of historic plantation farms adjoining it. En route to Romney, the river is fed by Buffalo Run, Mill Run , McDowell Run, and Mill Creek at Vanderlip . The South Branch

2444-526: Is traversed by the Northwestern Turnpike ( U.S. Route 50 ) and joined by Sulphur Spring Run where it forms Valley View Island to the west of town. Flowing north of Romney, the river still follows the eastern side of Mill Creek Mountain until it creates a horseshoe bend at Wappocomo 's Hanging Rocks around the George W. Washington plantation, Ridgedale . To the west of Three Churches on

2538-491: The 2004 Indian Ocean earthquake tsunami crashed against India's south-eastern coastline killing thousands. However, the former French colonial enclave of Pondicherry escaped unscathed. This was primarily due to French engineers who had constructed (and maintained) a massive stone seawall during the time when the city was a French colony. This 300-year-old seawall effectively kept Pondicherry's historic center dry even though tsunami waves drove water 24 ft (7.3 m) above

2632-545: The Allegheny Plateau to Point Lookout , Maryland, and drains 14,679 sq mi (38,020 km ). The length of the river from the junction of its North and South Branches to Point Lookout is 302 mi (486 km). The river has two sources. The source of the North Branch is at the Fairfax Stone located at the junction of Grant , Tucker , and Preston counties in West Virginia . The source of

2726-807: The Atlantic coastal plain . Once the Potomac drops from the Piedmont to the Coastal Plain at the Atlantic Seaboard fall line at Little Falls , tides further influence the river as it passes through Washington, D.C., and beyond. Salinity in the Potomac River Estuary increases thereafter with distance downstream. The estuary also widens, reaching 11 statute miles (17 km) wide at its mouth, between Point Lookout, Maryland, and Smith Point , Virginia, before flowing into

2820-522: The Board on Geographic Names in 1931. The similarity of the name to the Ancient Greek word for river, potamos , has been noted for more than two centuries but it appears to be due to chance. The Potomac River brings together a variety of cultures throughout the watershed from the coal miners of upstream West Virginia to the urban residents of the nation's capital and, along the lower Potomac,

2914-516: The Chesapeake Bay . The exact location of the South Branch's source is northwest of Hightown along U.S. Route 250 on the eastern side of Lantz Mountain (3,934 ft) in Highland County. From Hightown, the South Branch is a small meandering stream that flows northeast along Blue Grass Valley Road through the communities of New Hampden and Blue Grass . At Forks of Waters , the South Branch joins with Strait Creek and flows north across

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3008-1545: The Fall Line . This 108-mile (174-km) stretch encompasses the Potomac from a short distance below the Washington, DC - Montgomery County line, just downstream of the Little Falls of the Potomac River , to the Chesapeake Bay . Along the way the following tributaries drain into the Potomac: Pimmit Run , Gulf Branch , Donaldson Run , Windy Run , Spout Run , Maddox Branch , Foundry Branch , Rock Creek , Rocky Run, Tiber Creek , Roaches Run, Washington Channel , Anacostia River , Four Mile Run , Oxon Creek , Hunting Creek , Broad Creek , Henson Creek, Swan Creek, Piscataway Creek , Little Hunting Creek , Dogue Creek , Accotink Creek , Pohick Creek , Pomonkey Creek , Occoquan River , Neabsco Creek , Powell's Creek , Mattawoman Creek , Chicamuxen Creek , Quantico Creek , Little Creek , Chopawamsic Creek , Tank Creek , Aquia Creek , Potomac Creek , Nanjemoy Creek , Chotank Creek , Port Tobacco River , Popes Creek , Gambo Creek , Clifton Creek , Piccowaxen Creek , Upper Machodoc Creek , Wicomico River , Cobb Island , Monroe Creek , Mattox Creek , Popes Creek , Breton Bay, Leonardtown , St. Marys River , Yeocomico River , Coan River , and Hull Creek . The river itself

3102-563: The Interstate Commission on the Potomac River Basin . The compact was amended in 1970 to include coordination of water supply issues and land use issues related to water quality. Beginning in the 19th century, with increasing mining and agriculture upstream and urban sewage and runoff downstream, the water quality of the Potomac River deteriorated. This created conditions of severe eutrophication . It

3196-687: The Tidal Reservoir . It later received the name of Twining Lake to honor Major William Johnson Twining of the Corps of Engineers, who served on the Board of Commissioners of the District of Columbia as its Engineer Commissioner during 1879. In the Commissioners' annual report to Congress for that year, Major Twining proposed to create the tidal reservoir and use its water to help "flush" the Washington Channel. A 1917 map of Washington that

3290-500: The UK , seawall also refers to an earthen bank used to create a polder , or a dike construction . The type of material used for construction is hypothesized to affect the settlement of coastal organisms, although the precise mechanism has yet to be identified. A seawall works by reflecting incident wave energy back into the sea, thus reducing the energy available to cause erosion. Seawalls have two specific weaknesses. Wave reflection from

3384-619: The US Geological Survey and the Fish and Wildlife Service , began to identify fish in the Potomac and tributaries that exhibited "intersex" characteristics, as a result of endocrine disruption caused by some form of pollution. On November 13, 2007, the Potomac Conservancy, an environmental group, issued the river a grade of "D-plus", citing high levels of pollution and the reports of " intersex " fish. Since then,

3478-612: The United Nations Environment Programme (UNEP) suggests that the tsunami of 26 December 2004 caused less damage in the areas where natural barriers were present, such as mangroves , coral reefs or coastal vegetation. A Japanese study of this tsunami in Sri Lanka used satellite imagery modelling to establish the parameters of coastal resistance as a function of different types of trees. Natural barriers, such as coral reefs and mangrove forests, prevent

3572-547: The 1980s, through sewage plant upgrades and restrictions on phosphorus in detergents. By the end of the 20th century, notable success had been achieved, as massive algal blooms vanished and recreational fishing and boating rebounded. Still, the aquatic habitat of the Potomac River and its tributaries remain vulnerable to eutrophication, heavy metals , pesticides and other toxic chemicals, over-fishing, alien species , and pathogens associated with fecal coliform bacteria and shellfish diseases. In 2005 two federal agencies,

3666-702: The Chesapeake Bay. The source of the North Branch Potomac River is at the Fairfax Stone located at the junction of Grant , Tucker and Preston counties in West Virginia. From the Fairfax Stone, the North Branch Potomac River flows 27 mi (43 km) to the man-made Jennings Randolph Lake , an impoundment designed for flood control and emergency water supply. Below the dam, the North Branch cuts

3760-506: The Global Positioning System, GPS) indicate a mean rate of sea level rise of 1.6–1.8 mm/yr over the twentieth century. The Intergovernmental Panel on Climate Change (IPCC) (1997) suggested that sea level rise over the next 50 – 100 years will accelerate with a projected increase in global mean sea level of +18 cm by 2050 AD. This data is reinforced by Hannah (1990) who calculated similar statistics including

3854-754: The Living Seawalls project was announced as a finalist for the international environment award the Earthshot Prize . Since 2022 it has become part of Project Restore, under the auspices of the Sydney Institute of Marine Science . Some further issues include a lack of long-term trend data of seawall effects due to a relatively short duration of data records; modeling limitations and comparisons of different projects and their effects being invalid or unequal due to different beach types; materials; currents; and environments. Lack of maintenance

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3948-437: The Potomac and its North Branch since both states' original colonial charters grant the entire river rather than half of it as is normally the case with boundary rivers. In its first state constitution adopted in 1776, Virginia ceded its claim to the entire river but reserved free use of it, an act disputed by Maryland. Both states acceded to the 1785 Mount Vernon Compact and the 1877 Black-Jenkins Award which granted Maryland

4042-571: The Potomac as its principal source of drinking water with the opening of the Washington Aqueduct in 1864, using a water intake constructed at Great Falls. An average of approximately 486 million US gallons (1,840,000 m ) of water is withdrawn daily from the Potomac in the Washington area for water supply , providing about 78 percent of the region's total water usage, this amount includes approximately 80 percent of

4136-986: The Potomac from just above Harpers Ferry in West Virginia down to Little Falls, Maryland on the border between Maryland and Washington, DC. Along the way the following tributaries drain into the Potomac: Antietam Creek , Shenandoah River , Catoctin Creek (Virginia) , Catoctin Creek (Maryland) , Tuscarora Creek , Monocacy River , Little Monocacy River , Broad Run , Goose Creek , Broad Run , Horsepen Branch, Little Seneca Creek , Tenmile Creek , Great Seneca Creek , Old Sugarland Run, Muddy Branch , Nichols Run, Watts Branch , Limekiln Branch, Carroll Branch, Pond Run, Clarks Branch, Mine Run Branch, Difficult Run , Bullneck Run, Rock Run , Scott Run, Dead Run, Turkey Run, Cabin John Creek , Minnehaha Branch, and Little Falls Branch . The Tidal Potomac River lies below

4230-411: The Potomac, including bass , muskellunge , pike , walleye . The northern snakehead , an invasive species resembling the native bowfin , lamprey , and American eel , was first seen in 2004. Many species of sunfish are also present in the Potomac and its headwaters. Although rare, bull sharks can be found. After having been depressed for many decades, the river's population of American shad

4324-545: The South Branch continues north through the Monongahela National Forest to Upper Tract where it joins with three sizeable streams: Reeds Creek, Mill Run, and Deer Run. Between Big Mountain (2,582 ft) and Cave Mountain (2,821 ft), the South Branch bends around the Eagle Rock (1,483 ft) outcrop and continues its flow northward into Grant County . Into Grant, the South Branch follows

4418-724: The South Branch is located near Hightown in northern Highland County , Virginia. The river's two branches converge just east of Green Spring in Hampshire County , West Virginia, to form the Potomac. As it flows from its headwaters down to the Chesapeake Bay, the Potomac traverses five geological provinces: the Appalachian Plateau , the Ridge and Valley , the Blue Ridge , the Piedmont Plateau , and

4512-514: The Supreme Court to investigate recommended the case be settled in favor of Virginia, citing the language in the 1785 Compact and the 1877 Award. On December 9, 2003, the Court agreed in a 7–2 decision. The original charters are silent as to which branch from the upper Potomac serves as the boundary, but this was settled by the 1785 Compact. When West Virginia seceded from Virginia in 1863,

4606-576: The Thames estuary occurred, prompting the construction of protection for further events in this flood-prone area. Since then, seawall design has become more complex and intricate in response to an improvement in materials, technology, and an understanding of how coastal processes operate. This section will outline some key case studies of seawalls in chronological order and describe how they have performed in response to tsunamis or ongoing natural processes and how effective they were in these situations. Analyzing

4700-473: The Tidal Basin, carrying eastbound Independence Avenue traffic in three lanes. The bridge's name commemorates Brigadier General Charles Willauer Kutz , a Commissioner of Engineering for the District of Columbia during the first half of the 20th century. Architect Paul Philippe Cret designed the multi-span plate girder bridge , which the engineering firm of Alexander and Repass constructed. Construction began in 1941 and reached completion in 1943. The bridge

4794-520: The U.S. Public Buildings Commission prepared shows the Basin with the name "Twining Lake". In August 1918, the Congressionally-funded Tidal Basin Bathing Beach opened in front of the site of the present-day Jefferson Memorial. Although the racially-segregated beach was "a place to see people and be seen", a strictly-enforced rule prohibited women's bathing suits that stopped more than six inches above

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4888-510: The Vancouver Seawall is a prime example of how seawalls can simultaneously provide shoreline protection and a source of recreation which enhances human enjoyment of the coastal environment. It also illustrates that although shoreline erosion is a natural process, human activities, interactions with the coast, and poorly planned shoreline development projects can accelerate natural erosion rates. On December 26, 2004, towering waves of

4982-518: The Virginia side of the river, it was not completed until 1802. Financial troubles led to the closure of the canal in 1830. The Chesapeake and Ohio Canal operated along the banks of the Potomac in Maryland from 1831 to 1924 and also connected Cumberland to Washington, D.C. This allowed freight to be transported around the rapids known as the Great Falls of the Potomac River , as well as many other, smaller rapids. Washington, D.C. began using

5076-432: The Virginia/West Virginia border into Pendleton County . The river then travels on a northeastern course along the western side of Jack Mountain (4,045 ft), followed by Sandy Ridge (2,297 ft) along U.S. Route 220 . North of the confluence of the South Branch with Smith Creek, the river flows along Town Mountain (2,848 ft) around Franklin at the junction of U.S. Route 220 and U.S. Route 33 . After Franklin,

5170-427: The artificial barrier which reinforces the effectiveness of seawalls. At least 43 percent of Japan's 29,751 km (18,486 mi) coastline is lined with concrete seawalls or other structures designed to protect the country against high waves, typhoons, or even tsunamis. During the 2011 Tōhoku earthquake and tsunami , the seawalls in most areas were overwhelmed. In Kamaishi , 4-metre (13 ft) waves surmounted

5264-484: The battles of Antietam (September 17, 1862) and Gettysburg (July 1–3, 1863). Confederate General Jubal Early crossed the river in July 1864 on his attempted raid on the nation's capital. The river not only divided the Union from the Confederacy, but also gave name to the Union's largest army, the Army of the Potomac . The Patowmack Canal was intended by George Washington to connect the Tidewater region near Georgetown with Cumberland , Maryland. Started in 1785 on

5358-473: The borders between Maryland and Washington, D.C. , on the left descending bank, and West Virginia and Virginia on the right descending bank. Except for a small portion of its headwaters in West Virginia, the North Branch Potomac River is considered part of Maryland to the low-water mark on the opposite bank. The South Branch Potomac River lies completely within the state of West Virginia except for its headwaters , which lie in Virginia. All navigable parts of

5452-416: The catching near Fletcher's Boat House of a Striped Bass estimated to weigh 35 lb (16 kg) was seen as a further indicator of the continuing improvement in the health of the river. The average daily flow during the water years 1931–2018 was 11,498 cubic feet (325.6 m ) /s. The highest average daily flow ever recorded on the Potomac at Little Falls, Maryland (near Washington, D.C.),

5546-485: The disruption of sediment movement and transport patterns. Combined with a high construction cost, this has led to increasing use of other soft engineering coastal management options such as beach replenishment . Seawalls are constructed from various materials, most commonly reinforced concrete , boulders, steel, or gabions . Other possible construction materials include vinyl, wood, aluminum, fiberglass composite, and biodegradable sandbags made of jute and coir . In

5640-445: The drinking water consumed by the region's estimated 6.1 million residents. As a result of damaging floods in 1936 and 1937, the Army Corps of Engineers proposed the Potomac River basin reservoir projects , a series of dams that were intended to regulate the river and to provide a more reliable water supply. One dam was to be built at Little Falls, just north of Washington, backing its pool up to Great Falls. Just above Great Falls,

5734-454: The earthquake zone, as the tsunami washed over walls that were supposed to protect the plants. Arguably, the additional defense provided by the seawalls presented an extra margin of time for citizens to evacuate and also stopped some of the full force of energy which would have caused the wave to climb higher in the backs of coastal valleys. In contrast, the seawalls also acted in a negative way to trap water and delay its retreat. The failure of

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5828-408: The exchange of sediment between land and sea. Seawall designs factor in local climate, coastal position, wave regime (determined by wave characteristics and effectors), and value (morphological characteristics) of landform. Seawalls are hard engineering shore-based structures that protect the coast from erosion. Various environmental issues may arise from the construction of a seawall, including

5922-404: The extension of height and reinforcement of current seawalls which needs to occur for safety to be ensured in both situations. Sea level rise also will cause a higher risk of flooding and taller tsunamis. Seawalls, like all retaining walls , must relieve the buildup of water pressure . Water pressure buildup is caused when groundwater is not drained from behind the seawall. Groundwater against

6016-450: The first century BCE, Romans built a seawall or breakwater at Caesarea Maritima creating an artificial harbor (Sebastos Harbor). The construction used Pozzolana concrete which hardens in contact with seawater. Barges were constructed and filled with the concrete. They were floated into position and sunk. The resulting harbor/breakwater/seawall is still in existence today – more than 2000 years later. The oldest known coastal defense

6110-402: The force of ongoing wave energy. Some understanding is needed of the coastal processes and morphodynamics specific to the seawall location. Seawalls can be very helpful; they can offer a more long-term solution than soft engineering options, additionally providing recreation opportunities and protection from extreme events as well as everyday erosion. Extreme natural events expose weaknesses in

6204-415: The knee. By one estimate, the beach attracted up to 20,000 people on a July day in 1920. The beach hosted beauty contests until 1922, when a beach official banned the pageants for being too risqué. Congress had planned to open a separate beach for African-Americans nearby, but southern senators blocked the plan. Rather than integrating the beach, Congress ordered its dismantling in 1925. The Tidal Basin

6298-454: The much larger Seneca Dam was proposed whose reservoir would extend to Harpers Ferry. Several other dams were proposed for the Potomac and its tributaries. Operational Non-Operational Planned, but never built When detailed studies were issued by the Corps in the 1950s, they met sustained opposition, led by U.S. Supreme Court Justice William O. Douglas , resulting in the plans' abandonment. The only dam project that did get built

6392-473: The nation's capital was to be located on the river. The 1859 siege of Harper's Ferry at the river's confluence with the Shenandoah was a precursor to numerous epic battles of the American Civil War in and around the Potomac and its tributaries, such as the 1861 Battle of Ball's Bluff and the 1862 Battle of Shepherdstown . General Robert E. Lee crossed the river, thereby invading the North and threatening Washington, D.C., twice in campaigns climaxing in

6486-418: The nearby Tidal Basin and was rescued. Police stated that both Mills and Foxe were intoxicated and that Mills was bleeding from his nose and scratches on his face. The Tidal Basin covers an area of about 107 acres (43 ha) and is 10 feet (3.0 m) deep. The Army Corps of Engineers designed the Basin to enable it to release 250 million US gallons (950,000 m) of water captured at high tide twice

6580-401: The normal high-tide mark. The barrier was initially completed in 1735 and over the years, the French continued to fortify the wall, piling huge boulders along its 1.25 mi (2 km) coastline to stop erosion from the waves pounding the harbor. At its highest, the barrier running along the water's edge reaches about 27 ft (8.2 m) above sea level. The boulders, some weighing up to

6674-438: The outlet gates, which open into the channel. The force of the water running into the channel sweeps away the Basin's built-up silt The Corps, which maintains the Basin's gates, has restored their functioning. As part of the restoration and redesign of the Lincoln Memorial Reflecting Pool , completed in 2012, water is pumped from the Basin to fill the pool. From mid-March until October, paddle-boats are available for rent at

6768-462: The performance of seawalls, and analyses of these can lead to future improvements and reassessment. Sea level rise creates an issue for seawalls worldwide as it raises both the mean normal water level and the height of waves during extreme weather events, which the current seawall heights may be unable to cope with. The most recent analyses of long, good-quality tide gauge records (corrected for GIA and when possible for other vertical land motions by

6862-478: The question of West Virginia's succession in title to the lands between the branches of the river was raised, as well as title to the river itself. Claims by Maryland to West Virginia land north of the South Branch (all of Mineral and Grant Counties and parts of Hampshire , Hardy , Tucker and Pendleton Counties) and by West Virginia to the Potomac's high-water mark were rejected by the Supreme Court in two separate decisions in 1910. A variety of fish inhabit

6956-677: The river bank-to-bank from the low-water mark on the Virginia side while permitting Virginia full riparian rights short of obstructing navigation. From 1957 to 1996, the Maryland Department of the Environment (MDE) routinely issued permits applied for by Virginia entities concerning the use of the Potomac. However, in 1996 the MDE denied a permit submitted by the Fairfax County Water Authority to build

7050-502: The river has improved with a reduction in nutrient runoff, return of fish populations, and land protection along the river. As a result, the same group issued a grade of "B" for 2017 and 2018. In March 2019, the Potomac Riverkeeper Network launched a laboratory boat dubbed the "Sea Dog", which will be monitoring water quality in the Potomac and providing reports to the public on a weekly basis; in that same month,

7144-625: The river were designated as a National Recreation Trail in 2006, and the National Oceanic and Atmospheric Administration designated an 18-square-mile (47 km ) portion of the river in Charles County , Maryland, as the Mallows Bay–Potomac River National Marine Sanctuary in 2019. The river has significant historical and political significance, as the nation's capital of Washington, D.C.

7238-566: The seafloor. The Living Seawalls project, which was launched in Sydney , Australia, in 2018, aims to help many of the marine species in Sydney Harbour to flourish, thus enhancing its biodiversity , by modifying the design of its seawalls. It entails covering parts of the seawalls with specially-designed tiles that mimic natural microhabitats - with crevices and other features that more closely resemble natural rocks. In September 2021,

7332-481: The seawall began in 1917, and since then this pathway has become one of the most used features of the park by both locals and tourists and now extends 22 km in total. The construction of the seawall also provided employment for relief workers during the Great Depression and seamen from HMCS  Discovery on Deadman's Island who were facing punishment detail in the 1950s (Steele, 1985). Overall,

7426-474: The seawall – the world's largest, erected a few years ago in the city's harbor at a depth of 63 m (207 ft), a length of 2 km (1.2 mi) and a cost of $ 1.5 billion – and eventually submerged the city center. The risks of dependence on seawalls were most evident in the crisis at the Fukushima Dai-ichi and Fukushima Dai-ni nuclear power plants , both located along the coast close to

7520-628: The section of the Potomac River from the confluence of its North and South Branches through Opequon Creek near Shepherdstown, West Virginia . Along the way the following tributaries drain into the Potomac: North Branch Potomac River , South Branch Potomac River , Town Creek , Little Cacapon River , Sideling Hill Creek , Cacapon River , Sir Johns Run , Warm Spring Run , Tonoloway Creek , Fifteenmile Creek , Sleepy Creek , Cherry Run , Back Creek , Conococheague Creek , and Opequon Creek . This section covers

7614-537: The significant pollution control projects at the time was the expansion of the Blue Plains Advanced Wastewater Treatment Plant , which serves Washington and several surrounding communities. Enactment of the 1972 Clean Water Act led to construction or expansion of additional sewage treatment plants in the Potomac watershed. Controls on phosphorus , one of the principal contributors to eutrophication, were implemented in

7708-411: The spread of tsunamis and the flow of coastal waters and mitigated the flood and surge of water. A cost-benefit approach is an effective way to determine whether a seawall is appropriate and whether the benefits are worth the expense. Besides controlling erosion, consideration must be given to the effects of hardening a shoreline on natural coastal ecosystems and human property or activities. A seawall

7802-583: The successes and shortcomings of seawalls during severe natural events allows their weaknesses to be exposed, and areas become visible for future improvement. The Vancouver Seawall is a stone seawall constructed around the perimeter of Stanley Park in Vancouver, British Columbia . The seawall was constructed initially as waves created by ships passing through the First Narrows eroding the area between Prospect Point and Brockton Point. Construction of

7896-549: The wall may result in hydrodynamic scour and subsequent lowering of the sand level of the fronting beach. Seawalls may also accelerate the erosion of adjacent, unprotected coastal areas by affecting the littoral drift process. Different designs of man-made tsunami barriers include building reefs and forests to above-ground and submerged seawalls. Starting just weeks after the disaster, in January 2005, India began planting Casuarina and coconut saplings on its coast as

7990-590: The watermen of Virginia's Northern Neck. Being situated in an area rich in American history and American heritage has led to the Potomac being nicknamed "the Nation's River". George Washington , the first President of the United States , was born in, surveyed, and spent most of his life within, the Potomac basin. All of Washington, D.C., the nation's capital city , also lies within the watershed. The First United States Congress by act of July 16, 1790 stated that

8084-421: The western side of South Branch Mountain , 3,028 feet (923 m), the South Branch creates a series of bends and flows to the northeast by Springfield through Blue's Ford. After two additional horseshoe bends (meanders), the South Branch flows under the old Baltimore and Ohio Railroad mainline between Green Spring and South Branch Depot , and joins the North Branch to form the Potomac. This stretch encompasses

8178-621: The western side of Cave Mountain through the 20-mile (32 km) long Smoke Hole Canyon , until its confluence with the North Fork at Cabins , where it flows east to Petersburg . At Petersburg, the South Branch Valley Railroad begins, which parallels the river until its mouth at Green Spring . In its eastern course from Petersburg into Hardy County , the South Branch becomes more navigable allowing for canoes and smaller river vessels. The river splits and forms

8272-456: The widths of the walkways around the Basin from the existing 8 feet (2.44 m) to a planned 12 feet (3.7 m) by enlarging the area's paved surface and reducing its green space . In August 2023, the NPS awarded a $ 113 million contract to construct the project, which it expected to start in mid-2024 and take three years to reach completion. The Kutz Memorial Bridge crosses the northern lobe of

8366-605: The world's largest seawall, which cost $ 1.5 billion to construct, shows that building stronger seawalls to protect larger areas would have been even less cost-effective. In the case of the ongoing crisis at the nuclear power plants, higher and stronger seawalls should have been built if power plants were to be built at that site. Fundamentally, the devastation in coastal areas and a final death toll predicted to exceed 10,000 could push Japan to redesign its seawalls or consider more effective alternative methods of coastal protection for extreme events. Such hardened coastlines can also provide

8460-478: Was Jennings Randolph Lake on the North Branch. The Corps built a supplementary water intake for the Washington Aqueduct at Little Falls in 1959. In 1940 Congress passed a law authorizing the creation of an interstate compact to coordinate water quality management among states in the Potomac basin. Maryland, West Virginia, Pennsylvania, Virginia, and the District of Columbia agreed to establish

8554-430: Was dedicated after alterations in 1954. The structure is made of concrete and steel on pilings with granite facing. It is 433 ft (132 m) long and 46 ft (14 m) wide. Download coordinates as: [REDACTED]  This article incorporates public domain material from the National Park Service Potomac River The Potomac River ( / p ə ˈ t oʊ m ə k / )

8648-763: Was designed to prevent erosion from everyday waves only, and when a storm in 1976 carved out ten meters behind the existing seawall, the whole structure was destroyed. The addition of seawalls near marine ecosystems can lead to increased shadowing effects in the waters surrounding the seawall. Shadowing reduces the light and visibility within the water, which may disrupt the distribution as well as foraging capabilities of certain species. The sediment surrounding seawalls tends to have less favorable physical properties (Higher calcification levels, less structural organization of crystalline structure, low silicon content, and less macroscale roughness) when compared to natural shorelines, which can present issues for species that reside on

8742-596: Was in March 1936 when it reached 426,000 cubic feet (12,100 m ) /s. The lowest average daily flow ever recorded at the same location was 601.0 cubic feet (17.02 m ) /s in September 1966 The highest crest of the Potomac ever registered at Little Falls was 28.10 ft, on March 19, 1936; however, the most damaging flood to affect Washington, DC and its metropolitan area was that of October 1942. For 400 years Maryland and Virginia have disputed control of

8836-551: Was the scene of an incident involving the Chairman of the United States House Committee on Ways and Means , Democratic Congressman Wilbur Mills . At 2:00 a.m. on October 7, 1974, Park police stopped Mills' speeding car, whose driver, Albert G. Gapacini, had not turned on its headlights. Also in the car was an Argentine stripper known as Fanne Foxe . After the police stopped the car, Foxe jumped into

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