Content area
Full text
Hydrogeology of the Kabul Basin (Afghanistan), part I: aquifers and hydrology
Georg Houben & Nadege Niard & Torge Tnnermeier &
Thomas Himmelsbach
Abstract Shallow groundwater represents the main source for water supply in Kabul, Afghanistan. Detailed information on the hydrogeology of the Kabul Basin is therefore needed to improve the current supply situation and to develop a sustainable framework for future groundwater use. The basin is situated at the intersection of three major fault systems of partially translational and extensional character. It comprises three interconnected aquifers, 2070m thick, consisting of coarse sandy to gravely detritus originating from the surrounding mountains. The aquifers were deposited by three rivers owing through the basin. The coarse aquifer material implies a high permeability. Deeper parts are affected by cementation of pore spaces, resulting in formation of semi-diagenetic conglomerates, causing decreased well yields. Usually the aquifers are covered by low-permeability loess which acts as an important protection layer. The main groundwater recharge occurs after the snowmelt from direct inltration from the rivers. The steadily rising population is estimated to consume 3040 million m3 groundwater per year which is contrasted by an estimated recharge of 2045 million m3/a
in wet years. The 20002005 drought has prevented signicant recharge resulting in intense overexploitation indicated by falling groundwater levels.
Keywords Afghanistan . Urban groundwater . Arid regions . Over-abstraction . Unconsolidated sediments
Introduction
Afghanistan was affected by a long period of wars from 1979 to 2002. As a result, much of the countrys
infrastructure, including the water supply in Kabul, has been destroyed. The population sharply increased from1.8 million in 2002 to an estimated 3.0 million in 2004 due to a vast immigration of former refugees. A severe drought lasting from 1998 to 2004 further complicated Kabuls water problems. Groundwater is the major source for drinking water in the Kabul Basin. Only 20% of the population have access to tap water. The rest depends on shallow wells equipped with hand pumps.
The emerging mega city Kabul desperately needs an adapted water supply concept and water resources management. Reliable hydrogeologic data are an indispensable prerequisite for this. On behalf of the Federal Foreign Ofce of Germany, the Federal Institute for Geosciences and Natural Resources (BGR) resumed its work in Afghanistan in 2003. Together with...