vania-janet/multiturn-rag-retrieval-data huggingface dataset:
Meander
As the cut bank is undermined by erosion , it commonly collapses as slumps into the river channel . The slumped sediment , having been broken up by slumping , is readily eroded and carried toward the middle of the channel . The sediment eroded from a cut bank tends to be deposited on the point bar of the next downstream meander , and not on the point bar opposite it . This can be seen in areas where trees grow on the banks of rivers ; on the inside of meanders , trees , such as willows , are often far from the bank , whilst on the outside of the bend , the tree roots are often exposed and undercut , eventually leading the trees to fall into the river .
Fresh water
Changing landscape for the use of agriculture has a great effect on the flow of fresh water . Changes in landscape by the removal of trees and soils changes the flow of fresh water in the local environment and also affects the cycle of fresh water . As a result , more fresh water is stored in the soil which benefits agriculture . However , since agriculture is the human activity that consumes the most fresh water , this can put a severe strain on local freshwater resources resulting in the destruction of local ecosystems .
Anticyclone
Surface anticyclones form due to downward motion through the troposphere , the atmospheric layer where weather occurs . Preferred areas within a synoptic flow pattern in higher levels of the troposphere are beneath the western side of troughs . On weather maps , these areas show converging winds ( isotachs ) , also known as confluence , or converging height lines near or above the level of non-divergence , which is near the 500 hPa pressure surface about midway up the troposphere . Because they weaken with height , these high - pressure systems are cold .
Fresh water
The source of almost all fresh water is precipitation from the atmosphere , in the form of mist , rain and snow . Fresh water falling as mist , rain or snow contains materials dissolved from the atmosphere and material from the sea and land over which the rain bearing clouds have traveled . In industrialized areas rain is typically acidic because of dissolved oxides of sulfur and nitrogen formed from burning of fossil fuels in cars , factories , trains and aircraft and from the atmospheric emissions of industry . In some cases this acid rain results in pollution of lakes and rivers .
Soil erosion
Valley or stream erosion occurs with continued water flow along a linear feature . The erosion is both downward , deepening the valley , and headward , extending the valley into the hillside , creating head cuts and steep banks . In the earliest stage of stream erosion , the erosive activity is dominantly vertical , the valleys have a typical V cross-section and the stream gradient is relatively steep . When some base level is reached , the erosive activity switches to lateral erosion , which widens the valley floor and creates a narrow floodplain . The stream gradient becomes nearly flat , and lateral deposition of sediments becomes important as the stream meanders across the valley floor . In all stages of stream erosion , by far the most erosion occurs during times of flood , when more and faster - moving water is available to carry a larger sediment load . In such processes , it is not the water alone that erodes : suspended abrasive particles , pebbles and boulders can also act erosively as they traverse a surface , in a process known as traction .
Transpiration stream
In plants , the transpiration stream is the uninterrupted stream of water and solutes which is taken up by the roots and transported via the xylem to the leaves where it evaporates into the air / apoplast - interface of the substomatal cavity . It is driven by capillary action and in some plants by root pressure . The main driving factor is the difference in water potential between the soil and the substomatal cavity caused by transpiration .
Timeline of Hurricane Katrina
Sheet piling blocks water flow into the 17th Street Canal , making closure of the breach not relevant to city flooding . Work on closing the breach continues for purposes of pumping .
Soil erosion
Gully erosion occurs when runoff water accumulates and rapidly flows in narrow channels during or immediately after heavy rains or melting snow , removing soil to a considerable depth .
Hurricane Katrina
Katrina 's storm surge led to 53 levee breaches in the federally built levee system protecting metro New Orleans and the failure of the 40 Arpent Canal levee . Nearly every levee in metro New Orleans was breached as Hurricane Katrina passed just east of the city limits . Failures occurred in New Orleans and surrounding communities , especially St. Bernard Parish . The Mississippi River Gulf Outlet ( MR - GO ) breached its levees in approximately 20 places , flooding much of east New Orleans , most of St. Bernard Parish and the East Bank of Plaquemines Parish . The major levee breaches in the city included breaches at the 17th Street Canal levee , the London Avenue Canal , and the wide , navigable Industrial Canal , which left approximately 80 % of the city flooded .
Hurricane Harvey
On August 28 , the U.S. Army Corps of Engineers began controlled water releases from Addicks and Barker Reservoirs in the Buffalo Bayou watershed in an attempt to manage flood levels in the immediate area . According to the local Corps commander , `` It 's going to be better to release the water through the gates directly into Buffalo Bayou as opposed to letting it go around the end and through additional neighborhoods and ultimately into the bayou . '' At the time the releases started , the reservoirs had been rising at more than 6 inches ( 15 cm ) per hour . Many people began evacuating the area , fearing a levee breach . Despite attempts to alleviate the water rise , the Addicks Reservoir reached capacity on the morning of August 29 and began spilling out . The NASA Johnson Space Center was closed to employees and visitors due to the flooding until September 5 . Only the critical mission control staff remain and reside in the control rooms to monitor procedures of the International Space Station . Deep
Hurricane Harvey
The system continued north and then north - northeast , weakening to a tropical depression over central Louisiana around 00 : 00 UTC on August 30 . Associated convection with Harvey became focused north of the center and along a warm front on September 1 , indicating that the system transitioned into a post-tropical cyclone by 15 : 00 UTC that day . However , Harvey 's remnants continued moving northeastward , while slowly weakening . Late on September 2 , the WPC issued its final advisory on Harvey 's remnant low , while it was located over Ohio . Harvey 's remnants continued to drift northward , before being absorbed by another low pressure system north of Lake Erie , late on September 3 .
Soil erosion
If the soil is saturated , or if the rainfall rate is greater than the rate at which water can infiltrate into the soil , surface runoff occurs . If the runoff has sufficient flow energy , it will transport loosened soil particles ( sediment ) down the slope . Sheet erosion is the transport of loosened soil particles by overland flow . A
River Thames
The floods were caused by 4.6 inches ( 120 mm ) of rainfall ( including snow ) ; the peak flow was 61.7 billion litres ( 13.6 billion imperial gallons ) of water per day and the damage cost a total of £ 12 million to repair . War damage to some of the locks made matters worse .
St. Johns River
Florida in the 20th century experienced a massive migration into the state . Undeveloped land sold well and draining to reclaim wetlands has often gone unchecked , and often encouraged by government . The St. Johns headwaters decreased in size from 30 square miles ( 78 km ) to one between 1900 and 1972 . Much of the land was reclaimed for urban use , but agricultural needs took their toll as fertilizers and runoff from cattle ranching washed into the St. Johns . Without wetlands to filter the pollutants , the chemicals stayed in the river and flushed into the Atlantic Ocean . Boaters destroyed the floating islands of muck and weeds in the upper basin with dynamite , causing the lakes to drain completely . A
Chernobyl disaster
Two floors of bubbler pools beneath the reactor served as a large water reservoir for the emergency cooling pumps and as a pressure suppression system capable of condensing steam in case of a small broken steam pipe ; the third floor above them , below the reactor , served as a steam tunnel . The steam released by a broken pipe was supposed to enter the steam tunnel and be led into the pools to bubble through a layer of water . After the disaster , the pools and the basement were flooded because of ruptured cooling water pipes and accumulated firefighting water , and constituted a serious steam explosion risk . Chernobyl
High-voltage direct current
If no metallic return conductor is installed , current flows in the earth ( or water ) between two electrodes . This arrangement is a type of single - wire earth return system .
Kidney
After filtration occurs , the blood moves through a small network of venules that converge into interlobular veins . As with the arteriole distribution , the veins follow the same pattern : the interlobular provide blood to the arcuate veins then back to the interlobar veins , which come to form the renal vein exiting the kidney for transfusion for blood .
Tropical cyclone
Due to surface friction , the inflow only partially conserves angular momentum . Thus , the sea surface lower boundary acts as both a source ( evaporation ) and sink ( friction ) of energy for the system . This fact leads to the existence of a theoretical upper bound on the strongest wind speed that a tropical cyclone can attain . Because evaporation increases linearly with wind speed ( just as climbing out of a pool feels much colder on a windy day ) , there is a positive feedback on energy input into the system known as the Wind - Induced Surface Heat Exchange ( WISHE ) feedback . This feedback is offset when frictional dissipation , which increases with the cube of the wind speed , becomes sufficiently large . This upper bound is called the `` maximum potential intensity '' , v p ( \ displaystyle v_ ( p ) ) , and is given by
Hurricane Harvey
Houston has seen rapid urban development ( urban sprawl ) , with absorbent prairie and wetlands replaced by hard surfaces which rapidly shed storm water , overwhelming the drainage capacity of the rivers and channels . Between 1992 and 2010 , almost 25,000 acres of wetlands were lost , decreasing the detention capacity of the region by four billion gallons . However , Harvey was estimated to have dropped more than fifteen trillion gallons of water in the area .
Waikato River
The removal of the native vegetation throughout the catchment to accommodate the increasing demand for farmland has contributed to the silting - up of the river with loose soils from eroded farmland , although most of the silting is due to the construction of the many hydrodams . In its pre-1930s wild state , the silt was flushed from the river every winter by flood surges . The remnants of these can be seen in the silt channels carved out of what is now St Andrews golf course , adjacent to the river in Hamilton .
Trailing suction hopper dredger
From the side of the ship one or two suction pipes descend to the bottom of the seabed . On the end of the pipe a so - called trailing drag head is connected . This head is comparable to a large vacuum cleaner and is trailed along the seabed . In the head there are nozzles connected to a high pressure water installation that are capable of loosening the material on the seabed . Due to lower pressure in the pipe , the material will be sucked inward and discharged in the hopper .
Hurricane Harvey
Harvey approached Houston over sea - surface waters which were significantly above average temperatures . Warm waters provide the main source of energy for hurricanes , and increased ocean heat can result in storms being larger , more intense and longer lasting , in particular bringing greatly increased rainfall . Sea level rise added to the resulting problems . According to officials from the Harris County Flood Control District , Harvey caused the third ' 500 - year ' flood in three years . The National Climate Assessment states :
River Thames
However , untreated sewage still regularly enters the Thames during wet weather . In the summer of 2004 , storms led to the discharge of a million tonnes of raw sewage into the river , leading to the death of over ten thousand fish .
Environmental impact of irrigation
An irrigation scheme draws water from groundwater , rivers , lakes or overland flow , and distributes it over an area . Hydrological , or direct , effects of doing this include reduction in downstream river flow , increased evaporation in the irrigated area , increased level in the water table as groundwater recharge in the area is increased and flow increased in the irrigated area . Likewise , irrigation has immediate effects on the provision of moisture to the atmosphere , inducing atmospheric instabilities and increasing downwind rainfall , or in other cases modifies the atmospheric circulation , delivering rain to different downwind areas . Increases or decreases in irrigation are a key area of concern in precipitationshed studies , that examine how significant modifications to the delivery of evaporation to the atmosphere can alter downwind rainfall .
Soil erosion
In splash erosion , the impact of a falling raindrop creates a small crater in the soil , ejecting soil particles . The distance these soil particles travel can be as much as 0.6 m ( two feet ) vertically and 1.5 m ( five feet ) horizontally on level ground .
Fresh water
In desert areas , or areas with impoverished or dusty soils , rain - bearing winds can pick up sand and dust and this can be deposited elsewhere in precipitation and causing the freshwater flow to be measurably contaminated both by insoluble solids but also by the soluble components of those soils . Significant quantities of iron may be transported in this way including the well - documented transfer of iron - rich rainfall falling in Brazil derived from sand - storms in the Sahara in north Africa .
River Welland
The bridge at Deeping Gate carries the date 1651 , and is a Grade II * listed stone structure with three round arches . After the remains of Deeping High lock and Deeping Low lock , there is a junction where the old course , the Maxey Cut , the South Drain and the Folly River , also a drain , meet . The river is officially navigable below this point . Through Crowland and Cowbit to the edge of Spalding , the river is laid out with washlands , which were historically used as pasture , because the river was allowed to flood the land when tidal levels prevented the water discharging into the sea . The river is bounded on the north and west by a bank , while the New River , a drainage channel to the south and east of it , is bounded by another bank . The land between the channels forms Crowland High Wash , Crowland Fodder Lots and Cowbit Wash . The southern bank is variously named Corporation Bank , Wash Bank and Barrier Bank . These wash lands were designed to be flooded in extremis , although the building of the Coronation flood relief channel has made this purpose obsolete .
Hurricane Katrina
`` Storm surge pushing across shallow Lake Borgne from the east is constrained by these MRGO levees to the south and , to the north , by the long - standing levees of the Intracoastal Waterway ( GIWW ) . Initially ten or more miles apart , these two channels meet , and when they do , the water building between their levees is squeezed into a single channel -- the Funnel -- only 260 yards wide , constrained by levees 14 feet to 16 feet high .... In concert with the denuded marshes , it could increase the local storm surge hitting the Intracoastal Waterway by 20 percent to 40 percent -- a critical and fundamental flaw . ''
Sinking of the RMS Titanic
Although the watertight bulkheads extended well above the water line , they were not sealed at the top . If too many compartments were flooded , the ship 's bow would settle deeper in the water , and water would spill from one compartment to the next in sequence , rather like water spilling across the top of an ice cube tray . This was what happened to Titanic , which had suffered damage to the forepeak tank , the three forward holds and No. 6 boiler room , a total of five compartments . Titanic was only designed to float with any two compartments flooded , but it could remain afloat with certain combinations of three or even four compartments ( the first four ) open to the ocean . With five compartments , the tops of the bulkheads would be submerged and the ship would continue to flood . Animation
River delta
As the slope of the river channel decreases , it becomes unstable for two reasons . First , gravity makes the water flow in the most direct course down slope . If the river breaches its natural levees ( i.e. , during a flood ) , it spills out onto a new course with a shorter route to the ocean , thereby obtaining a more stable steeper slope . Second , as its slope gets lower , the amount of shear stress on the bed decreases , which results in deposition of sediment within the channel and a rise in the channel bed relative to the floodplain . This makes it easier for the river to breach its levees and cut a new channel that enters the body of standing water at a steeper slope . Often when the channel does this , some of its flow remains in the abandoned channel . When these channel - switching events occur , a mature delta develops a distributary network .
River Welland
Just before Stamford , the Great North Road , now labelled the A1 , crosses the river , and a pumping station on the north bank at Stamford Meadows has pumped large quantities of water to the Rutland Water reservoir since its construction in 1975 . Stamford was the lowest point at which the river could be forded so the Roman Ermine Street crossed the Welland there . The A16 road crosses the river by a three - arched stone bridge designed by Edward Browning in 1845 . Below it , Albert Bridge is made of iron with stone piers , and was erected by Stamford Town Council in July 1881 , to replace an earlier bridge which was washed away in a flood . Beyond Stamford , the river passes the site and ruins of the Benedictine St Leonard 's Priory . Hudd 's Mill marks the point at which the Stamford Canal left the river . The present mill building dates from 1751 and 1771 . The River Gwash , which the canal crossed on the level , joins from the north , and the remains of the canal follow the river on its north bank . Below Uffington , the county border follows the old course of the river , first to the south to Tallington and then to the north , while the main course now flows along the Maxey Cut to Peakirk . The old course consists of two streams , fed by sluices from the Maxey Cut , which meander to The Deepings . The eastern stream supplied power to Lolham and Maxey mills , while the western stream did the same for Tallington Mill , which dates from around 1700 , West Deeping mill , and Molecey 's mill , which still retains its seventeenth - century undershot waterwheel , modified in the 19th century to Poncelet 's improved design , and the only surviving waterwheel of its type in Lincolnshire . At the western edge of Market Deeping the two streams join , and they are also joined by the Greatford Cut , which has carried the diverted waters of the West Glen river since the early 1950s .
Hurricane Katrina
Katrina 's storm surge inundated all parishes surrounding Lake Pontchartrain , including St. Tammany , Tangipahoa , St. John the Baptist , and St. Charles Parishes . St. Tammany Parish received a two - part storm surge . The first surge came as Lake Pontchartrain rose and the storm blew water from the Gulf of Mexico into the lake . The second came as the eye of Katrina passed , westerly winds pushed water into a bottleneck at the Rigolets Pass , forcing it farther inland . The range of surge levels in eastern St. Tammany Parish is estimated at 13 -- 16 feet ( 4.0 -- 4.9 m ) , not including wave action .
St. Johns River
Acidic rainwater erodes the limestone and can form underground caverns . When the overlay of these caverns is particularly thin -- less than 100 feet ( 30 m ) -- sinkholes can form . Where the limestone or sand / clay overlay dissolves over the aquifer and the pressure of the water pushes out , springs form . The upper and middle basins of the St. Johns River are located in a portion of the peninsula where the aquifer system is thinly confined , meaning springs and sinkholes are abundant . Springs are measured in magnitude of how much water is discharged , which is dependent upon season and rainfall . The greatest discharge is from first magnitude springs that emit at least 100 cubic feet ( 2.8 m ) of water per second . There are four first magnitude springs that feed the St. Johns River : Silver Springs in Marion County , emitting between 250 and 1,290 cubic feet ( 7.1 and 36.5 m ) / second ; Silver Glen Spring straddling Marion and Lake Counties , emitting between 38 and 245 cubic feet ( 1.1 and 6.9 m ) / second ; Alexander Springs in Lake County , emitting between 56 and 202 cubic feet ( 1.6 and 5.7 m ) / second ; and Blue Spring in Volusia County , emitting between 87 and 218 cubic feet ( 2.5 and 6.2 m ) / second .
Storm drain
Southeastern Los Angeles County installed thousands of stainless steel , full - capture trash devices on their road drains in 2011 .
Tropical cyclone
Physically , the cyclonic circulation of the storm advects environmental air poleward east of center and equatorial west of center . Because air must conserve its angular momentum , this flow configuration induces a cyclonic gyre equatorward and westward of the storm center and an anticyclonic gyre poleward and eastward of the storm center . The combined flow of these gyres acts to advect the storm slowly poleward and westward . This effect occurs even if there is zero environmental flow .
Timeline of Hurricane Katrina
At approximately 8 : 14 AM CDT ( 1314 UTC ) , the New Orleans office of the National Weather Service issued a Flash Flood Warning for Orleans Parish and St Bernard Parish , citing a levee breach at the Industrial Canal . The National Weather Service predicted three to eight feet of water and advised people in the warning area to `` move to higher ground immediately . ''
Thunderstorm
Flash flooding is the process where a landscape , most notably an urban environment , is subjected to rapid floods . These rapid floods occur more quickly and are more localized than seasonal river flooding or areal flooding and are frequently ( though not always ) associated with intense rainfall . Flash flooding can frequently occur in slow - moving thunderstorms and is usually caused by the heavy liquid precipitation that accompanies it . Flash floods are most common in densely populated urban environments , where few plants and bodies of water are present to absorb and contain the extra water . Flash flooding can be hazardous to small infrastructure , such as bridges , and weakly constructed buildings . Plants and crops in agricultural areas can be destroyed and devastated by the force of raging water . Automobiles parked within affected areas can also be displaced . Soil erosion can occur as well , exposing risks of landslide phenomena .