as a lowered water table and the destruction of agriculture lands. Constructed In agricultural areas in climates needing irrigation, farmers traditionally relied on small constructed arroyos, acequias, zanjas or aqueduct channels and ditches for the distribution of water. An example of larger constructed arroyos is in Albuquerque, New Mexico. There are several miles of open-air concrete lined drainage channels that drain an area into the main North Diversion Channel, a tributary of the Rio Grande joining upstream of Albuquerque. After the San Juan Project Water Treatment Plant here, the Rio Grande's flow exceeding that needed for the river's silvery minnow habitat is available for municipal water supply diversion. Signs are posted at the constructed arroyos warning to keep out due to danger of flash flooding. The Arroyo Seco and Los Angeles River are more famous examples in Southern California of former natural arroyo seasonal watercourses that became constructed open drainage system arroyos. See also Billabong Draw Wadi Notes External links Fluvial landforms Erosion landforms Dry or seasonal streams Canyons and gorges Valleys