The Indian Bend Wash area is a Superfund cleanup site in Scottsdale and Tempe, Arizona . It was declared a Superfund site in 1983 after industrial solvents were discovered to have contaminated the groundwater in an approximately 13-square-mile (34 km) area. It is one of the largest EPA sites in terms of volume of groundwater treated, estimated at 61.3 billion US gallons (232,000,000 m).
11-570: During the 1960s, it was typical for companies to dispose industrial solvents directly into the ground and into dry wells . In 1981, volatile organic compounds (VOC) were detected in Tempe and Scottsdale city wells, including trichloroethylene (TCE), tetrachloroethylene (PCE), and chloroform . The wells were shut down immediately, and the area was declared a Superfund site in 1983.mPotentially responsible parties Motorola , Siemens , GlaxoSmithKline , along with several smaller companies, have paid for
22-635: A groundwater heat pump . It is a gravity-fed , vertical underground system that can capture surface water from impervious surfaces , then store and gradually infiltrate the water into the groundwater aquifer . Such a structure is also called a dead well , absorbing well , or negative well , and in the United Kingdom a soakaway or soakage pit , and in Australia a soakwell or soak pit . Dry wells are excavated pits that may be filled with aggregate or air and are often lined with
33-431: A perforated casing. The casings consist of perforated chambers made out of plastic or concrete and may be lined with geotextile . They provide high stormwater infiltration capacity while also having a relatively small footprint. A dry well receives water from entry pipes at its top. It can be used part of a broader stormwater drainage network or on smaller scales such as collecting stormwater from building roofs . It
44-411: Is mostly filled by stone. A more advanced dry well defines a large interior storage volume by a concrete or plastic chamber with perforated sides and bottom. These dry wells are usually buried completely so that they do not take up any land area. The dry wells for a parking lot's storm drains are usually buried below the same parking lot. A sump in a basement can be built in dry well form, allowing
55-501: Is used in conjunction with pretreatment measures such as bioswales or sediment chambers to prevent groundwater contamination . The depth of the dry well allows the water to penetrate soil layers with poor infiltration such as clays into more permeable layers of the vadose zone such as sand . Simple dry wells consist of a pit filled with gravel , riprap , rubble , or other debris . Such pits resist collapse but do not have much storage capacity because their interior volume
66-444: The sump pump to cycle less frequently (handling only occasional peak demand). A French drain can resemble a horizontal dry well that is not covered. A larger open pit or artificial swale that receives stormwater and dissipates it into the ground is called an infiltration basin or recharge basin. In places where the amount of water to be dispersed is not as large, a rain garden can be used instead. A covered pit that disposes of
77-671: The approximately $ 100 million in cleanup costs. Cleanup has consisted of several stations that pump and treat groundwater. The area consists of two cleanup sites, the North Indian Bend Wash (NIBW) Superfund site located in Scottsdale (approximately 8 square miles), and the South Indian Bend Wash (SIBW) Superfund site located in Tempe. For eight days in October 2007, trichloroethylene tainted water
88-492: The inclusion of plants or vegetation in their construction, specifically. The use of swales has been popularized as a rainwater-harvesting and soil-conservation strategy by Bill Mollison , David Holmgren , and other advocates of permaculture . In this context a swale is usually a water-harvesting ditch on contour, also called a contour bund . Swales as used in permaculture are designed by permaculturalists to slow and capture runoff by spreading it horizontally across
99-541: The landscape (along an elevation contour line ), facilitating runoff infiltration into the soil. This archetypal form of swale is a dug-out, sloped, often grassed or reeded "ditch" or "lull" in the landform. One option involves piling the soil onto a new bank on the still lower slope, in which case a bund or berm is formed, mitigating the natural (and often hardscape-increased ) risks to slopes below and to any linked watercourse from flash flooding . In arid and seasonally dry places, vegetation (existing or planted) in
110-588: The water component of sewage by the same principle as a dry well is called a cesspool . A septic drain field operates on the same slow-drain/large-area principle as an infiltration basin. Swale (landform) A swale is a shady spot, or a sunken or marshy place. In US usage in particular, it is a shallow channel with gently sloping sides. Such a swale may be either natural or human-made. Artificial swales are often infiltration basins , designed to manage water runoff , filter pollutants , and increase rainwater infiltration . Bioswales are swales that involve
121-505: Was released into the water supply of 1500 residents of Scottsdale by the Arizona American Water Company. 33°28′49″N 111°54′42″W / 33.4803°N 111.9118°W / 33.4803; -111.9118 Dry well A dry well or drywell is an underground structure that disposes of unwanted water , most commonly surface runoff and stormwater , in some cases greywater or water used in
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