First a water source needs to be found and then it can be extracted through countless mechanisms. This can be at small or large scales even with the same techniques such as accessing aquifers through wells and pumps by individual households in Jakarta or the Mexico City Water System Wells (SACM). In general this is in order to access drinking water although it can be done for irrigation uses.
Springs are readily accessible sources of water, but Water Mains are established when the source is not yet flowing or flowing in another direction. In the case of Mexico City, the drinkable water of the Endorheic Basin there largely begins at the Sierra Chichinautzin due to the large amount of basalt rock that allows for the water to enter the ground and begin its filtration process. At the other end the Xochimilco springs is an important site for the basin and many of the most productive wells are located here. Some of these make up the 549 wells in the SACM which are also supplemented by the Lerma System wells that bring in water from past the Sierra Madre Occidental from other valleys.
Even further than that the Cutzamala System, taps the Cutzamala River that is part of the Balsas Basin and moves it 60-154km horizontally and over 1000m vertically to bring it to the Valley of Mexico while tapping numerous other sources on the way. The system was initially developed in 1930 as a hydropower project called the Miguel Aleman Hydroelectric System but then it was adapted to the Cutzamala System and 102 pumping stations, 17 tunnels, and 7.5km of canals were planned. Due to the massive scale of this project it was executed in three stages. Now it has eight main reservoirs, six main pumping plants, 322km of canals and tunnels, a water treatment plant, and eight dams. This massively expensive and energy-intensive project has reduced the burden of providing drinking water from the Mexico and Lerma Valley Aquifers and still is the primary focus in infrastructural investments. In 1997, the fourth stage of the project called the Temascaltepec project was to be initiated and was stopped as of now due to the local populations worries about the effects of a tunnel on the springs in the region.
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Aquifer recharged and accessed by different types of wells
Sources: https://cnx.org/resources/91be4f9a9a78064d99ab3028c8c0be2806433e3f/graphics12.jpg
Sources: https://cnx.org/resources/91be4f9a9a78064d99ab3028c8c0be2806433e3f/graphics12.jpg
- National Research Council. 1995. Mexico City's Water Supply: Improving the Outlook for Sustainability. Washington, DC: The National Academies Press. https://doi.org/10.17226/4937.
- Martinez, S., Escolero, O. & Perevochtchikova, M. A comprehensive approach for the assessment of shared aquifers: the case of Mexico City. Sustain. Water Resour. Manag. 1, 111–123 (2015). https://doi.org/10.1007/s40899-015-0010
Wetlands refers to a broad category of landscapes and they are created through a variety of mechanisms. Dependings on the rate of water flow, the salinity, and the quantity of decomposing plants they may be swamps, bogs, marshes or fens.
Wetlands are one of the few wildernesses left in many countries. Due to their definition by local ground condition, rather than climate or remoteness, they are often near to human occupation. As a result they have often been used as places to hide, in the USA’s Great Dismal Swamp populations of escaped slaves called Maroons formed communities, independent of the American state that sought their capture. In Iraq, the Mesopotamian Marshes served as a base for an insurrection against the Hussein regime. Today the marshes of Iraq and the swamps of America are still considered places distant from the reach of the central government.
There have been many attempts to bring the wetlands under control, trying to make them habitable or to exploit their resources. Bogs and marshes are defined by their peat soil, a common fuel in contemporary and historically less developed societies. Swamps are often rich sources of timber, George Washington made much of his money through the exploitation of the Great Dismal Swamp for the timber trade. The key components of the wetlands, that is the wet -water-, and the land, are also of value. The water useful for agricultural irrigation in drier climates with estuary marshes, and the land valuable for real estate. Washington’s original business plan before settling on the timber trade was to produce land for sale.
Through draining the wetlands, the state can also attempt to control its residents. Hussein infamously attempted to drain the marsh in response to the insurgency, and the Great Dismal Swamp is much reduced from its original size. Once a wetland is drained, its land can be indistinguishable from other land. The process of converting wetlands into real estate is called poldering. The process is simply one of draining water from the wetlands quicker than it enters. First drainage is improved through the digging of ditches, if this is not enough dijks can be added to prevent water from entering the area, and water can be pumped outside the polder. Much of the Netherlands is made from reclaimed wetlands. However this system must be carefully maintained, its failure will result in catastrophe. Both the great North Sea flood of 1953, and the flooding of New Orleans during Hurricane Katrina in 2005 demonstrate the enormous destruction that will occur when control is lost and the wetland’s drainage fails.
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An admirable view of the desolation which surrounds the[ir] homes ... and the heartiness and energy with which they make their way to freedom upon the slightest opportunity
Sources: Harper’s Weekly, April 9th, 1864
Subsidence is the sudden sinking or gradual downward settling of the ground's surface with little or no horizontal motion. It may be caused by natural processes or by human activities. The former includes aquifer-system compaction, drainage of organic soils, underground mining, hydro compaction, natural compaction, sinkholes, and thawing permafrost. Human activities include sub-surface mining or extraction of underground fluids, e. g. petroleum, natural gas, or groundwater.
Land subsidence is a global problem. Most cases are driven by the exploitation of groundwater by human activities to provide water for agriculture, industries, and daily water consumption in a city. There are profound problems that associated with the exploitation of groundwater such as, land subsidence, an increase of energy required to pump deeper well, a higher concentration of natural and manmade pollutants in the aquifers, saltwater intrusion, disrupted water ecosystem habitat, severe weather condition from the increase of precipitation, and to some extend impacting the local climate.
Mexico City was initially surrounded by Lake Texcoco and at the end of the 19th century, the city successfully drained the lake basin through the Grand drainage canal to the city of Tequixquiac. This effort of flood protection collectively sends surface water out of the city while extracting groundwater causes not enough natural water left to recharge the aquifer and resulted in the occurrence of land subsidence. Subsidence not only exposes new areas to flooding but also diminished the capacity of the Grand canal until it could no longer drain using gravity alone and later need to develop pump systems and deep drainage system.
In 2017, a woman named Maria Teresa has her apartment sink into the ground during an earthquake in Mexico City. The problem arises when insurance companies look for the cause of this collapse either it's by the earthquake or groundwater extraction. The answer could determine whether or not Maria Teresa and others like her will become homeless because subsidence-related damage is uninsurable in Mexico City while there is a robust insurance plan for earthquake-related disasters. The city has no plan to stop groundwater extraction, therefore subsidence is inevitable. From an insurance perspective, subsidence is not a disaster but a plan. Mexico City's failure to manage the surface water as a resource and aquifer overdraft now resulted in the city problem of flooding, scarcity of clean water for consumption, and other cases like Maria Teresa.
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Land subsidence is a global problem. Most cases are driven by the exploitation of groundwater by human activities to provide water for agriculture, industries, and daily water consumption in a city. There are profound problems that associated with the exploitation of groundwater such as, land subsidence, an increase of energy required to pump deeper well, a higher concentration of natural and manmade pollutants in the aquifers, saltwater intrusion, disrupted water ecosystem habitat, severe weather condition from the increase of precipitation, and to some extend impacting the local climate.
Mexico City was initially surrounded by Lake Texcoco and at the end of the 19th century, the city successfully drained the lake basin through the Grand drainage canal to the city of Tequixquiac. This effort of flood protection collectively sends surface water out of the city while extracting groundwater causes not enough natural water left to recharge the aquifer and resulted in the occurrence of land subsidence. Subsidence not only exposes new areas to flooding but also diminished the capacity of the Grand canal until it could no longer drain using gravity alone and later need to develop pump systems and deep drainage system.
In 2017, a woman named Maria Teresa has her apartment sink into the ground during an earthquake in Mexico City. The problem arises when insurance companies look for the cause of this collapse either it's by the earthquake or groundwater extraction. The answer could determine whether or not Maria Teresa and others like her will become homeless because subsidence-related damage is uninsurable in Mexico City while there is a robust insurance plan for earthquake-related disasters. The city has no plan to stop groundwater extraction, therefore subsidence is inevitable. From an insurance perspective, subsidence is not a disaster but a plan. Mexico City's failure to manage the surface water as a resource and aquifer overdraft now resulted in the city problem of flooding, scarcity of clean water for consumption, and other cases like Maria Teresa.
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Mexico City drinking itself to the ground
Sources: “Why Is Mexico City Sinking?” Mexican Routes Visit and Explore Mexico, August 15, 2020. https://mexicanroutes.com/why-is-mexico-city-sinking/.
Sources: “Why Is Mexico City Sinking?” Mexican Routes Visit and Explore Mexico, August 15, 2020. https://mexicanroutes.com/why-is-mexico-city-sinking/.
- Kiley Fellow Lecture: Seth Denizen, "Thinking Through Soil: Case Study from the Mezquital Valley", YouTube Video, 1:14:58, “Harvard GSD,” September 22, 2020, https://www.youtube.com/watch?v=klJb9M-_3cg.
- Moran, Tara, Janny Choy, and Carolina Sanchez. “Understanding California's Groundwater.” Water in the West. Stanford University. Accessed May 2, 2021. https://waterinthewest.stanford.edu/groundwater/overdraft/.
- Lewis, Alan Christopher & Torres, Janet. (2013). “The Ghosts of Lake Texcoco Still Haunting Mexico City.” The Drop, Water Management and Hydrological Science Program, Texas A&M University, Volume 5, Fall 2013.