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18 Cards in this Set
- Front
- Back
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Definition of Ground Water |
Subsurface water that occurs beneath the water table in geological sediments and formations that are fully saturated. Saturated zone = phreatic zone Unsatrated zone = vadose zone or partially saturdated zone |
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Water table is |
A capillary zone, so ground water is not necesarily also below the water table |
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Meteoric water |
Derives from surface sources like water |
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Magmatic |
Juvenile water formed as a result of magmatic processes. Juvenile water has not contracted the atmosphere. |
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Connate |
Born together water has remained trapped in sedimentary rock since ages ago. Old and saline. |
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Aquiclude |
Saturated and impermeable |
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Aquitard |
Saturates and low permeability |
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Aquifuge |
Impermeable and not containing nor transmiting water. |
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Aquifer dynamics |
Rainwarer infiltrares porous soil and rock and flows through the underground toward lakes and other water bodies. During wet periods, water table is high and natural springs can occur. During dry peroiods, evapouration discharges underground water in soils. Water tables fall and shallow wells dry up. Water from streams and lake infiltrates and recharges the surfaes sol and rock. |
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Aquifer specific yield is |
Volume of water drained from saturated unit volume by lowering water table by i unit |
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Aquifer specific storage is |
volume of water remaining in satruated unit volume after gravity drainage. |
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Refer to storage calculations |
blah |
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Issue with well pumping |
Withdrawl of gw causes -Subsidence -ground collapse -salt water intrusion |
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Predicition and prevention |
Gravity and pressure drive flow, low permeabitlyt and lack of recharge resist flow. |
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Unconfined well pumpin g |
Rate of flow is directly proportional to the drop in the water table, Greater drop means higher flow. |
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COnfined well pumping |
Use dupit assumption and apply darcys law. |
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Types of aquifer well testing |
Well performance -Simple and effective -Does not describe aquifer Well and Observation wells -Measures aquifer performance -Can be used to predict effects on neighbouring wells |
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Aquifer test design |
Measure pumping rate Water depths Time and compare on two graphs :) Mind the -Rain -Change in ATm pressure -Stream flow |
