By Gazal Begum I. Sayed Arpita M Kulkarni GROUNDWATER
What is GROUNDWATER ?
Groundwater is the water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formations.
Groundwater is underground water that is held in the soil and pervious rocks.
How does water get into the ground? (Reference: USGS site)
AQUIFER (Reference: USGS site)
An AQUIFER is a geologic unit (or layer) of permeable material (like sand, gravel or fractured bedrock) that is capable of providing usable quantities of water to a well.
Confined aquifers Unconfined aquifers
Other Terms related to GROUNDWATER TABLE
How do you get water out of the ground? (Reference: USGS site)
Can we run out of groundwater? (Reference: USGS site)
Water table is the underground surface below which the ground is wholly saturated with water .
Water table during dry period (Reference: USGS site)
GROundWATER flow & effects of pumping
Water is recharged to the ground-water system by percolation of water from precipitation and then flows to the stream through the ground-water system.
Water pumped from the ground-water system causes the water table to lower and alters the direction of ground-water movement. Some water that flowed to the stream no longer does so and some water may be drawn in from the stream into the ground-water system, thereby reducing the amount of stream flow.
Contaminants introduced at the land surface may infiltrate to the water table and flow towards a point of discharge, either the well or the stream. (Also important, is the potential movement of contaminants from the stream into the ground-water system.)
Water-level declines may affect the environment for plants and animals. For example, plants in the riparian zone that grew because of the close proximity of the water table to the land surface may not survive as the depth to water increases. The environment for fish and other aquatic species also may be altered as the stream level drops.
(Reference: USGS site)
Problems caused by lowered GROUNDWATER
Lowering of the water table.
Saltwater intrusion .
Mining water ( Fossil water ).
(Iron oxide staining caused by unconfined aquifer)
Pollutants released to the ground.
Severe contamination of groundwater by naturally occurring arsenic.
REMEDIES FOR GROUNDWATER POLLUTION
USGS- U.S. Geological Survey (http://pubs.usgs.gov)
Wikipedia- The free encyclopedia (http://en.wikipedia.org/wiki/Groundwater)
“ What is Groundwater” – Lyle S. Raymond (www.extension.umn.edu/distribution/natural resources.html)