Patapsco River
The Patapsco River mainstem is a river in central Maryland which flows into the Chesapeake Bay. The river's tidal portion forms the harbor for the city of Baltimore. With its South Branch, the Patapsco forms the northern border of Howard County, Maryland. The name "Patapsco" is derived from the Algonquian "pota-psk-ut", which translates to "backwater" or "tide covered with froth." History. Captain John Smith was the first European to explore the river noting it on his 1612 map as the Bolus River. The "Red river", was named after the clay color, and is considered the  old Bolus, as other branches were also labeled Bolus on maps. As the river was not navigable beyond Elkridge, it was not a major path of commerce with only one ship listed as serving the northern branch, and four others operating around the mouth in 1723. The Patapsco River is referred to as The River of History as it is regarded as the center of Maryland’s Industrial Revolution beginning in the 1770s. Milling and manufacturing operations abounded along the river throughout the eighteenth and nineteenth centuries, generally relying on water power generated by multiple small dams. The nation’s  first railroad, the Baltimore and Ohio Railroad's original main line was constructed in 1829 and ran west along the Patapsco Valley; and this route remains, though much altered. Many old railroad bridges were constructed in the valley, most notably the Thomas Viaduct, which is still intact, and the Patterson Viaduct, of which ruins remain. Flour mills and the hydropower dam, Bloede Dam, built in 1907, were formerly powered by the river. The valley is prone to periodic flooding. Modern floods include the 1868 flood that washed away 14 houses and killed 39 people around Ellicott City. A 1923 flood  topped bridges while in 1952, an wall of water swept the shops of Ellicott City. A 1956 flood inflicted heavy damage at the Bartigis Brothers plant. In 1972, as a result of rainfall from the remnants of Hurricane Agnes, Ellicott City and the Old Main Line sustained serious damage. The July 2016 Maryland flood ravaged Main Street leaving two dead, followed just two years later by a flash flood on May 27, 2018 that took the life of one rescuer. The mouth of the Patapsco River forms Baltimore harbor, the site of the Battle of Baltimore during the War of  1812. This is where Francis Scott Key, while aboard a British ship, wrote "The Star-Spangled Banner," a poem later set to music as the national anthem of the United States. Today, a red, white, and blue buoy marks the spot where was anchored. Geography. Watershed. The Patapsco has a watershed area (including the water surface) of . Through most of its length, the Patapsco is a minor river, flowing for the most part through a narrow valley. The last , however, form a large tidal estuary inlet of Chesapeake Bay. The inner part of this estuary provides the harbor of Baltimore , composed of the Northwest Harbor and the Middle Branch including Thoms Cove. (See Baltimore Inner Harbor.) The Patapsco estuary is south of the Back River and north of the Magothy River. The Patapsco River forms the harbor as it empties into the Chesapeake Bay. Besides Baltimore, the river also flows through Ellicott City (the county seat of Howard County) and Elkridge. The Patapsco River mainstem begins at the confluence of the North and South Branches, near Marriottsville, approximately west of downtown Baltimore. The South Branch rises further west at Parr's Spring, where Howard County, Carroll, Frederick, and Montgomery counties  meet. The latter begins at elevation on Parr's Ridge, just south of Interstate 70 and east of Ridge Road (Highway 27), south of Mount Airy, Maryland. The South Branch Patapsco River traces the southern boundary of Carroll County and the northern boundary of Howard County. The first land record regarding Parr's Springs dates from 1744, when John Parr laid out a tract he called Parr's Range. During the Civil War, Parr's Spring was a stop for the Army of the Potomac's Brig. Gen. David M. Gregg's cavalry, on June 29, 1863, while en route  to Gettysburg, Pennsylvania. Parr's Spring was dug to form a pond in the 1950s, filled by seven spring heads that form the headwaters of the South Branch of the Patapsco River. The North Branch flows southward from its origins in Carroll County. Liberty Dam and its reservoir, located on the North Branch, is a major component of the Baltimore city water system. Patapsco Valley State Park extends along of the Patapsco and its branches, encompassing a total of in five different areas. The river cuts a gorge 100–200 feet (35–70 m) deep within the park, which features rocky cliffs  and tributary waterfalls. Bloede's Dam, a hydroelectric dam built in 1906, was located on the Patapsco River within the Park. It was a nearly complete barrier to anadromous fish passage. Although a fish ladder was installed in 1992, it blocked five of six native fish species trying to run upstream to spawn. Impetus to remove Bloede's Dam began in the 1980s when nine drowning deaths occurred, and also to restore fish passage to a large portion of the Patapsco River watershed. Dam demolition began on September 12, 2018, opening the fishery and creating a rocky rapid for kayaking . Two dams upstream of Bloede's Dam, Simkins and Union, were removed in 2010. The removal of Bloede's Dam leaves Daniels Dam, upstream, as the last remaining dam along the mainstem Patapsco River. Ecology and Conservation. Removal of Bloede's Dam in September, 2018 opened up of the Patapsco River watershed which will potentially restore spawning runs of at least six species of native anadromous fish: alewife ("Alosa pseudoharengus"), blueback herring ("Alosa aestivalis"), American shad ("Alosa sapidissima"), hickory shad ("Alosa mediocris"), striped bass ("Morone saxatilis"), sea lamprey ("Petromyzon marinus"), as only one species, sea lamprey, were found using the  Bloede's Dam fish ladder in 2012. One catadromous species would likely also benefit, the American eel ("Anguilla rostrata"), a fish species which lives in freshwater and migrates to the ocean to breed. The Bloede's Dam removal project was led by American Rivers and the Maryland Department of Natural Resources. Now that Bloede's Dam has been removed, removal of Daniels Dam upstream on the mainstem Patapsco River would open to anadromous fishes the remaining of Patapsco River mainstem, the entire length of the South Branch Patapsco River, of the North Branch Patapsco River up to the Liberty Dam , and many of these rivers' tributaries. Water quality. The eastern portion of the Patapsco River is in a highly urbanized area and is subject to extensive stormwater runoff and other forms of water pollution. The Maryland Department of the Environment has identified the Lower North Branch as containing high levels of heavy metals (chromium, arsenic, cadmium, copper, mercury, nickel, lead, selenium, and zinc), as well as phosphorus, fecal coliform bacteria, and PCBs. The Piney Run Reservoir on the South Branch of the Patapsco is polluted by excess levels of phosphorus and sediment. Clean-up efforts by the residents of surrounding  communities have been led by environmental nonprofit organizations, such as The Friends of Patapsco Valley & Heritage Greenway, Inc. (PHG). From 2006 to 2012, PHG volunteers participated in 183 stream clean ups, removing 264 tons of trash from the streams of the Patapsco Valley watershed. Recreation. There is recreational swimming in areas of the Patapsco River, sometimes involving rope swings, inner tubing, and wading. The river also serves as a venue for rafting. Crossings. This is a list of all crossings of the main stem of the Patapsco River and selected crossings of its three main tributaries. Listings start downstream and  continue upstream to the sources of the rivers.