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36-717: The lake is on Arroyo Valle (Spanish for "creek of the valley") in the Diablo Range , and is formed by Del Valle Dam, completed in 1968 (56 years ago)  ( 1968 ) . The lake and dam are part of the California State Water Project , as part of the South Bay Aqueduct . The lake serves in part as off-stream storage for the South Bay Aqueduct. The capacity of the lake is 77,000 acre-feet (95,000,000 m), however,

72-520: A fishing advisory regarding the mercury levels of fish caught from the body of water. The dam is 230 feet (70 m) high and 880 feet (270 m) long. Its crest elevation is 773 feet (236 m). The dam contains 4,150,000 cubic yards (3,170,000 m) of earth fill. Arroyo Valle Arroyo Valle or Arroyo Del Valle is a 36.4-mile-long (58.6 km) westward-flowing stream that begins in northeastern Santa Clara County, California , and flows northwesterly into Alameda County where it

108-487: A low density on a pasture, so as not to overgraze. Controlled burning of the land can help in the regrowth of plants. Although grazing can be problematic for the ecosystem, well-managed grazing techniques can reverse damage and improve the land. On commons in England and Wales, rights of pasture (grassland grazing) and pannage (forest grazing) for each commoner are tightly defined by number and type of animal, and by

144-449: A rotation of fresh grass after burning with two years of rest. Conservation grazing proposes to use grazing animals to improve the biodiversity of a site. Grazing has existed since the beginning of agriculture ; sheep and goats were domesticated by nomads before the first permanent settlements were constructed around 7000 BC, enabling cattle and pigs to be kept. Livestock grazing contributes to many negative effects on

180-546: A short period of time. Conservation grazing is the use of grazing animals to help improve the biodiversity of a site. Due to their hardy nature, rare and native breeds are often used in conservation grazing. In some cases, to re-establish traditional hay meadows, cattle such as the English Longhorn and Highland are used to provide grazing. A form of rotational grazing using as many small paddocks as fencing allows, said to be more sustainable. Mob grazing

216-482: A system of checks and balances, and allowing higher plant biodiversity. In Europe heathland is a cultural landscape which requires grazing by cattle, sheep or other grazers to be maintained. An author of the Food and Agriculture Organization (FAO) report Livestock's Long Shadow , stated in an interview: Grazing occupies 26 percent of Earth's terrestrial surface   ... feed crop production requires about

252-552: A third of all arable land   ... Expansion of grazing land for livestock is also a leading cause of deforestation, especially in Latin America... In the Amazon basin alone, about 70 percent of previously forested land is used as pasture, while feed crops cover a large part of the remainder. Much grazing land has resulted from a process of clearance or drainage of other habitats such as woodland or wetland . According to

288-492: Is a system, said to be more sustainable, invented in 2002; it uses very large herds on land left fallow longer than usual. Many ecological effects derive from grazing, which may be positive or negative. Negative effects of grazing may include overgrazing , increased soil erosion , compaction and degradation, deforestation , biodiversity loss , and adverse water quality impacts from run-off . Sometimes grazers can have beneficial environmental effects such as improving

324-648: Is allowed access to the same grazing area throughout the year. Seasonal grazing incorporates "grazing animals on a particular area for only part of the year". This allows the land that is not being grazed to rest and allow for new forage to grow. Rotational grazing "involves dividing the range into several pastures and then grazing each in sequence throughout the grazing period". Utilizing rotational grazing can improve livestock distribution while incorporating rest period for new forage. In ley farming, pastures are not permanently planted, but alternated between fodder crops and arable crops. Rest rotation grazing "divides

360-748: Is dammed by the Del Valle Dam, which forms the reservoir Lake Del Valle in southeastern Alameda County . Downstream from the reservoir, Arroyo Valle drains much of the southern portion of the city of Livermore , and it also flows through and drains a considerable fraction of the city of Pleasanton , both in the Livermore Valley . The stream is a tributary to Arroyo de la Laguna , which is in turn tributary to Alameda Creek , which ultimately reaches San Francisco Bay at Fremont, California . Water quality measurements in Arroyo Valle in

396-446: Is dammed to form Lake Del Valle . After that Arroyo Valle is a tributary to Arroyo de la Laguna which in turn flows into Alameda Creek and thence to San Francisco Bay . In the past, the Arroyo Valle had a significant steelhead migration; however, degradation of the stream in the latter half of the 20th century has decimated this anadromous fish population. Arroyo Valle was also once known as Arroyo De Los Taunamines (Stream of

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432-575: Is on the western slope of 3,804 feet (1,159 m) Mount Stakes , west of the Santa Clara- Stanislaus County border, about 32 miles (51 km) southeast of Livermore . San Antonio Creek traverses the San Antonio Valley as it heads west to Arroyo Valle. Arroyo Bayo also has its origin on Mount Stakes southwestern slope and traverses Upper San Antonio Valley as it also heads west to Arroyo Valle. Arroyo Valle

468-640: Is paid each year for each animal 'turned out'. However, if excessive use was made of the common, for example, in overgrazing, a common would be 'stinted'; that is, a limit would be put on the number of animals each commoner was allowed to graze. These regulations were responsive to demographic and economic pressure. Thus, rather than let a common become degraded, access was restricted even further. Ranchers and range science researchers have developed grazing systems to improve sustainable forage production for livestock. These can be contrasted with intensive animal farming on feedlots. With continuous grazing, livestock

504-552: Is the major cause of degraded riparian habitat on federal rangelands". A 2013 FAO report estimated livestock were responsible for 14.5% of anthropogenic greenhouse gas emissions . Grazing is common in New Zealand ; in 2004, methane and nitrous oxide from agriculture made up somewhat less than half of New Zealand's greenhouse gas emissions, of which most is attributable to livestock . A 2008 United States Environmental Protection Agency report on emissions found agriculture

540-416: Is unsuitable for arable farming . Farmers may employ many different strategies of grazing for optimum production : grazing may be continuous, seasonal, or rotational within a grazing period. Longer rotations are found in ley farming , alternating arable and fodder crops; in rest rotation, deferred rotation, and mob grazing, giving grasses a longer time to recover or leaving land fallow. Patch-burn sets up

576-571: The Civil War . The Taylor Grazing Act of 1934 was enacted after the Great Depression to regulate the use of public land for grazing purposes. According to a report by the Food and Agriculture Organization , about 60% of the world's grassland (just less than half of the world's usable surface) is covered by grazing systems. It states that "Grazing systems supply about 9 percent of the world's production of beef and about 30 percent of

612-619: The Arroyo del Valle flows down the moderately sloping hills to enter gravel pits, where extraction (but not processing) has historically been conducted by Lone Star Industries . Historically, Arroyo Valle was connected to Tulare Lake , a lagoon in the Livermore-Amador Valley, and thus to the Alameda Creek watershed. There are historical records of steelhead trout ( Oncorhynchus mykiss ) in Arroyo Valle although now

648-516: The Lake Del Valle Dam is an impassable barrier to spawning runs. Grazing In agriculture , grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to free range (roam around) and consume wild vegetations in order to convert the otherwise indigestible (by human gut ) cellulose within grass and other forages into meat , milk , wool and other animal products , often on land that

684-477: The Livermore Valley indicate a pH level of 7.0, or neutral with respect to acidity ; phosphate levels were not detectable. In the middle reaches of Arroyo Valle south of Livermore, there has been considerable historic grazing use. Depth to groundwater in this reach of the watershed typically ranges from 50 feet (15 m) to 100 feet (30 m) and flows to the west. Subsequent to this reach,

720-587: The Taunamines), for the Costanoan Taunamines people who lived there. In 1853 it was renamed Arroyo del Valle (Stream of the Valley). The Arroyo Valle watershed drains 147 square miles (380 km ). The upper reaches of Arroyo Valle stretch into northeastern Santa Clara County where the mainstem is formed by the confluence of San Antonio Creek and Arroyo Bayo . San Antonio Creek's origin

756-457: The accumulation of litter ( organic matter ) in some seasons and areas, but can also increase it, which may help to combat soil erosion . This acts as nutrition for insects and organisms found within the soil. These organisms "aid in carbon sequestration and water filtration". When grass is grazed, dead grass and litter are reduced which is advantageous for birds such as waterfowl . Grazing can increase biodiversity . Without grazing, many of

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792-401: The bison–fire relationship on a large landscape scale of 30,000 acres (12,000 ha). In the grazed heathland of Devon , the periodic burning is known as swailing. Riparian area grazing is intended to improve wildlife and their habitats. It uses fencing to keep livestock off ranges near streams or water areas until after wildlife or waterfowl periods, or to limit the amount of grazing to

828-594: The environment, including deforestation , extinction of native wildlife, pollution of streams and rivers, overgrazing , soil degradation , ecological disturbance , desertification , and ecosystem stability . Sheep, goats, cattle, and pigs were domesticated early in the history of agriculture . Sheep were domesticated first, soon followed by goats; both species were suitable for nomadic peoples. Cattle and pigs were domesticated somewhat later, around 7000 BC, once people started to live in fixed settlements. In America, livestock were grazed on public land from

864-487: The heavy grazing. This technique results in a diversity of habitats that different prairie plants and birds can utilize—mimicking the effects of the pre-historical relationship between bison and fire, whereby bison heavily graze one area and other areas have opportunity to rest, based on the concept of pyric herbivory . The Tallgrass Prairie Preserve in northeastern Oklahoma has been patch-burn grazed with bison herds for over ten years. These efforts have effectively restored

900-400: The lake has a flood storage of 25,000 to 40,000 acre-feet (31,000,000 to 49,000,000 m). Thus normally stores 37,000 to 52,000 acre-feet (46,000,000 to 64,000,000 m). The lake is a popular destination for hikers, bikers, and boaters. The Hetch Hetchy Aqueduct passes below the lake, but does not connect to it. The California Office of Environmental Health Hazard Assessment issued

936-644: The opinion of the Center for Biological Diversity , extensive grazing of livestock in the arid lands of the southwestern United States has many negative impacts on the local biodiversity there. Cattle destroy native vegetation, damage soils and stream banks, and contaminate waterways with fecal waste. After decades of livestock grazing, once-lush streams and riparian forests have been reduced to flat, dry wastelands; once-rich topsoil has been turned to dust, causing soil erosion, stream sedimentation and wholesale elimination of some aquatic habitats In arid climates such as

972-478: The period when no grazing occurs. Patch-burn grazing burns a third of a pasture each year, no matter the size of the pasture. This burned patch attracts grazers (cattle or bison ) that graze the area heavily because of the fresh grasses that grow as a result. The other patches receive little to no grazing. During the next two years the next two patches are burned consecutively, then the cycle begins anew. In this way, patches receive two years of rest and recovery from

1008-424: The range into at least four pastures. One pasture remains rested throughout the year and grazing is rotated amongst the residual pastures." This grazing system can be especially beneficial when using sensitive grass that requires time for rest and regrowth. Deferred rotation "involves at least two pastures with one not grazed until after seed-set". By using deferred rotation, grasses can achieve maximum growth during

1044-422: The removal of wild grazing animals), or by other human disturbance. Conservation grazing is the use of grazers to manage such habitats, often to replicate the ecological effects of the wild relatives of domestic livestock , or those of other species now absent or extinct. Grazer urine and faeces "recycle nitrogen, phosphorus, potassium and other plant nutrients and return them to the soil". Grazing can reduce

1080-415: The same grasses grow, for example brome and bluegrass , consequently producing a monoculture . The ecosystems of North American tallgrass prairies are controlled to a large extent by nitrogen availability, which is itself controlled by interactions between fires and grazing by large herbivores. Fires in spring enhance growth of certain grasses, and herbivores preferentially graze these grasses, producing

1116-402: The soil with nutrient redistribution and aerating the soil by trampling, and by controlling fire and increasing biodiversity by removing biomass, controlling shrub growth and dispersing seeds. In some habitats, appropriate levels of grazing may be effective in restoring or maintaining native grass and herb diversity in rangeland that has been disturbed by overgrazing, lack of grazing (such as by

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1152-621: The southwestern United States, livestock grazing has severely degraded riparian areas , the wetland environment adjacent to rivers or streams. The Environmental Protection Agency states that agriculture has a greater impact on stream and river contamination than any other nonpoint source . Improper grazing of riparian areas can contribute to nonpoint source pollution of riparian areas. Riparian zones in arid and semiarid environments have been called biodiversity hotspots . The water, higher biomass , favorable microclimate and periodic flood events together produce higher biological diversity than in

1188-709: The surrounding uplands. In 1990, "according to the Arizona state park department, over 90% of the original riparian zones of Arizona and New Mexico are gone". A 1988 report of the Government Accountability Office estimated that 90% of the 5,300 miles of riparian habitat managed by the Bureau of Land Management in Colorado was in an unsatisfactory condition, as was 80% of Idaho 's riparian zones, concluding that "poorly managed livestock grazing

1224-470: The time of year when certain rights can be exercised. For example, the occupier of a particular cottage might be allowed to graze fifteen cattle, four horses , ponies or donkeys , and fifty geese , while the numbers allowed for their neighbours would probably be different. On some commons (such as the New Forest and adjoining commons), the rights are not limited by numbers, and instead a 'marking fee'

1260-406: The world's production of sheep and goat meat . For an estimated 100 million people in arid areas , and probably a similar number in other zones, grazing livestock is the only possible source of livelihood." Grazing management has two overall goals: A proper land use and grazing management technique balances It does this by allowing sufficient recovery periods for regrowth. Producers can keep

1296-464: Was responsible for 6% of total United States greenhouse gas emissions in 2006. This included rice production, enteric fermentation in domestic livestock, livestock manure management, and agricultural soil management , but omitted some things that might be attributable to agriculture. Studies comparing the methane emissions from grazing and feedlot cattle concluded that grass-fed cattle produce much more methane than grain-fed cattle. One study in

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