Page 157 - Life & Land Use on the Bahrain Islands (Curtis E Larsen)

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Artesian Water: A More Complete View
The general importance of artesian water flow to land abandonment for modern
Bahrain was presented in Chapter n. This discussion noted a distinct gradient in
static water levels for Bahrain, with the northwest corner of the island showing the
greatest hydrostatic pressure and the lowest salinity. The po tent io me trie surface
was distributed diagonally across the main island, with an anomalous zone of high
hydrostatic pressure located above the normal fault complex just described. This
anomaly shows interconnection between the Alat and Khobar aquifers and the
underlying Umm er-Radhuma formation, the Zone C aquifer.
In modern times, the static water levels in these three aquifers have
steadily dropped. As they near sea level, reverse flow occurs through offshore
springs and fractures, allowing contamination by marine water. Thus, the drop in
water level is accompanied by progressive salinization of groundwater resources.
These decreasing water levels were influenced by past climatic conditions. For
example, the east Arabian aquifers were charged by Late Pleistocene rainfall in
central Arabia. Some recharge of these aquifers may have taken place during a
subsequent "Neolithic wet phase," but the moisture conditions of the past 6000
years have not been sufficient to add major new volumes of water to the system.
At least one writer, Wright (1967), claimed an increase in the rate of
water level decline as a direct result of increased extraction of water related, in
turn, to an increase in the number of drilled water wells. The polar view taken by
Italconsult (1971) asserted that there had been a constant linear decrease in water
level directly attributable to a lack of recharge. No increase in water extraction
due to increased drilling was recognized. While each of these arguments is
important in the modern sense, only the era prior to the drilled water well is of
value here. Both researchers agree that replenishment of the three major aquifers
has been minimal over the past several thousand years. Thus, long-term decrease
in static water levels can be expected to have occurred in both Bahrain and eastern
Arabia since the end of the Wlfcm glaciation. The long-term rate of decrease has
not been determined. Were this available, it would prove beneficial to both