drawing water from Aridlands dalia munenzon
On America's Great Plains, water in all states of wetness shapes both landscape and subterranean strata, bonding and holding down soil and flora. West of the 100th meridian, surface water is limited and annual precipitation on the plains is below 20 inches/ 50cm a year. As groundwater from aquifers is the primary source of life for any territory at the centre of agricultural production, the depletion of the Ogallala – the High Plains Aquifer – through hotter, drier and more unpredictable weather, jeopardises local ecosystems and communities. This invisible relationship between extraction, production, and the flow of natural resources is key to understanding future risks and opportunities for adaptation. Watershed-based readings of the landscape make these processes visible. the High Plains Aquifer Water from the saturated limestone sponge, the geological terminology for the aquifer, contributes to the annual production of $35 billion worth of crops, a quarter of national crop production. This remnant of an ancient ocean stretches from Texas to South Dakota and provides water to 112 million acres/4.6 million ha of farmland and grazing. Despite being deep underground, stationary groundwater and moving surface water are fundamentally intertwined as the aquifer discharges into streams and rivers. A decline in the aquifer's water level directly affects local streams that are drying at the rate of 6 miles per year. 1 Pumping for agriculture, industry, and residential use from the High Plains Aquifer started in the early 1900s, accelerating in the mid-century with technological developments in gas pumps. Since the 1950s, high-volume pumping has led to a water level drop of 325 billion gallons every year, between 9% and 30% of its volume, and is projected to lose 40% by 2070. With 90% of the water drawn being used for agriculture, the sustainability of long-term use is rooted in regional water management and use policies. reading the landscape In 1878, the geologist John Wesley Powell released his study on the farming and settlement capacity of territories west of the 100th meridian. In 'On the Arid Lands of the Western United States' 2 he stated that there is insufficient surface water or precipitation to sustain European farming practices and that any farming will require irrigation. He proposed managing and dividing the territory based on watersheds, creating administrative structures based on the natural formation of the landscape to allow rational water distribution. His proposal was rejected. However, the projected climate changes and the rapid depletion of the High Plains Aquifer points to a concept worth revisiting.
cross-boundary recharging The composition of sand and gravel in the High Plains Aquifer makes recharging complex and lengthy. Climate variability across the Great Plains, land cover changes and rate of water seepage result in recharge rates ranging from less than 1mm/year in parts of Texas to more than 150mm/year in the Nebraska Sandhills. This implies that the aquifer will take 6,000 years to recharge fully. 1 Ralls, Eric. 'The High Plains Aquifer Is in Danger of Drying Up' Earth.com , 15 Nov. 2017, https://www.earth.com/news/high-plains-aquifer-drying/. 2 Powell John Wesley et al. Report on the Lands of the Arid Region of the United States : With a More Detailed Account of the Lands of Utah. Belknap Press of Harvard University Press 1962.
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on site review 42: atlas :: being in place
:: complex systems
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