Wells and groundwater
Water quality is a key environmental issue facing the agricultural sector. Groundwater provides water for rural domestic use, industrial use, livestock watering, irrigation and aquaculture.
It is important to understand the relationship between groundwater water sources and how water wells are utilized by the agriculture sector.
Aquifers are geologic formations that hold the water below the surface of the ground. As water infiltrates into the ground and begins to seep downward it collects in porous spaces, fractures and voids of sediments and/or rock formations. It can return to the ground surface through springs and streams. This is part of the continuous circulation of water between ocean, atmosphere and land termed the hydrologic cycle.
Contrary to popular belief, groundwater does not exist in underground lakes or rivers, but rather in fractures and pore spaces of rocks and sediments beneath the earth's surface.
When the supply of the underground water is large enough to produce a usable amount when tapped by a well, the deposit is called an aquifer. Aquifers can vary greatly in thickness and area and can occur at virtually any depth.
Groundwater quality is affected by physical, chemical and biological factors. All water must meet the quality requirements for its intended use, whether for livestock, irrigation or drinking water. Some agricultural water requirements demand very high quality water, such as water used in dairy production or food processing. Drinking water must meet certain standards for health-related parameters, and should also be aesthetically acceptable with respect to taste, odour and colour. For other rural uses, non-potable water should be of sufficient quality to ensure it does not negatively affect quality of life, such as staining of fixtures or clothing, and should be acceptable for livestock and crop-spraying purposes.
Deep groundwater supplies typically have high mineral concentrations. Shallow ground water supplies (15 metres deep or less) are generally less mineralized, but are more susceptible to bacteriological contamination from surface sources, and in some cases contaminants, such as nitrates, can accumulate in the groundwater supply overtime.
Water wells are structures constructed in the ground that economically and efficiently withdraw groundwater from a water-bearing formation.
The design and installation of water wells is dependent upon a wide variety of factors, but mainly upon the underground geologic environment in which the water well is completed. Proper well design and construction is essential to ensure aquifers to not become contaminated by surface water sources or nearby land use practices. All wells should be designed and constructed by qualified experienced professionals.
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