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The dam monitoring system checks the level of the water because this creates different pressures on the dam, also in relation to the air and water temperature. All these parameters are controlled and compared with the deformation and stress applied on the structure of the dam, measured with extensimeter, pendulum, reverse pendulum, piezometer, etc.
Land subsidence is a global issue and has different causes. Some are natural, like earthquakes , and some are caused by humans. In the United States, land subsidence from over pumping has affected 45 states and accounts for changes in over 17,000 square miles of land which is an area almost 10 times the size of Glacier National Park in Montana ...
Subsidence frequently causes major problems in karst terrains, where dissolution of limestone by fluid flow in the subsurface creates voids (i.e., caves).If the roof of a void becomes too weak, it can collapse and the overlying rock and earth will fall into the space, causing subsidence at the surface.
These sensors work by sending in small electromagnetic waves into the subsurface level, and receiving information as these waves are returned. [12] Key components of studying land subsidence in the Central Valley include large and small scale monitoring, studying topography in relation to groundwater, and a multi-agency approach.
A more complete analysis uses decompaction of the remaining sequence following each stage of the back-stripping. This takes into account the amount of compaction caused by the loading of the later layers and allows a better estimation of the depositional thickness of the remaining layers and the variation of water depth with time.
Second, the various monitoring zones can be developed using standard well development equipment and procedures before the multilevel monitoring systems are installed in the wells. Finally, installing multilevel systems inside multi-screened wells may simplify the task of decommissioning the wells once they are no longer needed.
"Land Subsidence" was included in the UNESCO programme of the International Hydrological Decade (IHD), 1965–1974 and an ad hoc working group on land subsidence was formed. In 1975 subsidence was maintained under the framework of the UNESCO IHP (subproject 8.4: "Investigation of Land Subsidence due to Groundwater Exploitation") and UNESCO IHP ...
Tectonic subsidence is the sinking of the Earth's crust on a large scale, relative to crustal-scale features or the geoid. [1] The movement of crustal plates and accommodation spaces produced by faulting [2] brought about subsidence on a large scale in a variety of environments, including passive margins, aulacogens, fore-arc basins, foreland basins, intercontinental basins and pull-apart basins.