Aquifers drying up and less water worldwide
I've had a question from a speaker, Anne Lawson, about there being less water worldwide and about aquifers drying up.
How does this affect our work? Is the response that we use whatever is the best technology in that area? Eg we would use a rainwater harvesting tank or gravity flow system, if there is no aquifer in the area?
Unfortunately this problem is becoming more common around the world due to increases in demand for water from rapidly increasing populations, drier weather patterns and the increased use of water as poorer nations develop. Underground water resources are found in water bearing rocks known as aquifers that have taken many hundreds or even thousands of years to accumulate, so once they have become depleted due to over-abstraction they will not recover unless the demand is reduced to a level that is below the natural recharge rate from rainfall, lakes and rivers on the surface. In coastal areas over-abstraction of fresh groundwater can result in salty (saline) sea water being drawn into the aquifers that renders them unusable for human consumption, without expensive treatment.
Our response can be as you state using alternative appropriate technologies from surface resources. Groundwater levels will only recover if the demand from boreholes and wells is reduced to below the recovery rate of the aquifer. This will have an impact on the communities using the boreholes and wells, so they must find alternative sources of water either from lakes, rivers and streams or by rainwater harvesting. It is also possible in some areas to increase the rate of aquifer recovery by a process known as ‘groundwater recharge’. This can be achieved in conjunction with a rainwater harvesting system and we have produced a paper on this work that can be downloaded from our website by following this link:- http://www.wateraid.org/uk/~/media/Publications/rainwater-harvesting-recharging-shallow-groundwater.pdf.
Regards, Frank Lawson (no relation to Anne!) Engineering Adviser, WaterAid
Most of the depletion of aquifers is due to the heavy use by agriculture and in towns, by industry. Adapting technology due to the depleted aquifer is a coping mechanism. Making sure that the water is better managed is a much more sustainable measure. This involves discussions with Integrated Water Management and or a District wide approach where we lobby that WASH is an absolute priority for water allocation, and that the poor need to have a rightful share into this as well.
This is quite a large discussion and Wateraid cannot yet engage everywhere into this. Water Security plans are being developed in India in a number or areas and Bangladesh is looking to start an Integrated Water Management Project. Such experiences will enable us to advocate properly to plan long term water abstraction for WASH.
Deeper water tables typically affect the water supply for the poor, as they are not available to either drill deeper wells, or pay for higher fees (due to more intense pumping). Cheap energy for pumping for irrigation, such as custom in India has clear consequences for water provision for households.
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