GROUNDWATER LEVEL AND SALINITY
IN THE MOUNTAIN AND COASTAL AQUIFERS
1. SALINITY OF GROUNDWATER IN THE MOUNTAIN
AND COASTAL AQUIFERS
1970–2011
Milligrams of chloride per liter
275
Maximum recommended concentration in drinking water(1)
250
225
200
175
150
125
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
100
Coastal aquifer
Mountain aquifer
(1) Under “The Nation’s Health Regulations (Sanitation Quality of Drinking Water), 1974 [Integrated Version – 2000]”:
Maximum recommended concentration in drinking w ater – 250 milligrams of chloride per liter; maximum permitted
concentration in drinking w ater – 600 milligrams of chloride per liter.
2. GROUNDWATER LEVEL IN THE MOUNTAIN AND COASTAL AQUIFERS
1970–2011
20
15
10
5
0
-5
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Level relative to height of sea level (meters)
25
Coastal aquifer
( 35 )
Mountain aquifer
Description of the indicator
The indicator presents data on chloride concentration and the level of groundwater in the two
main aquifers in Israel. These data are useful for the investigation of groundwater quality.
Relevance of the indicator to sustainable development
An increase in the salinity of groundwater can influence the environment, society, and the
economy in many ways, such as: impairing the quality of drinking water and the quality of
water used for irrigation; salination of soil, which harms agricultural crops; creating a future
need to invest in advanced treatment methods or in desalination; reduction of pumping
capacities; and limiting the ability of the water economy to handle future crises. Groundwater
level and salinity indicators are central to the determination of the quality of drinking water
abstracted from various sources. Groundwater provides about 60% of the annual water
consumption in Israel. In the recent years, the proportion of groundwater out of total water
consumption in Israel might change due to increased usage of desalinated sea water.
Nevertheless, groundwater continues to be an important source of water in Israel. Most of
the groundwater is abstracted from two main aquifers: the Mountain Aquifer and the Coastal
Aquifer. Ongoing monitoring of the quality and availability of groundwater is essential for the
continued existence of these reservoirs as sustainable sources of water.
Selected findings

The average salinity in the Coastal Aquifer continues to rise. In 2011, the average
chloride concentration in drills in the Coastal Aquifer reached 223 mg/l chloride
(milligrams of chloride per 1 liter of water).

In recent years, the chloride concentration in the Coastal Aquifer has increased by an
average of approximately 2.3 mg/l chloride per year.

The increase in salinity of the Coastal Aquifer is affected by over-pumping, which causes
a drop in water levels and ingress of sea water. It is also affected by droughts, irrigation,
recharging of effluents, and recharging of water from the National Water Carrier.

In the hydrological year 2009/10 (from October 2009 to September 2010), 52.2% of the
volume of water pumped from the Coastal Aquifer was of good quality (up to 250 mg/l
chloride and less than 45 mg/l nitrates), 29.3% was of satisfactory quality (up to 400 mg/l
chloride and less than 70 mg/l nitrates), and 8.6% was of poor quality (over 400 mg/l
chloride or at least 70 mg/l nitrates). The quality of the remainder was unclassified.
According to data from the Hydrological Service, approximately 51,000 tons of chloride
were added to the Coastal Aquifer during that year, primarily as a result of human activity
(35% from irrigation and 29% from the Dan Region Reclamation Project).
( 36 )

In 2009, the average chloride concentration in the Mountain Aquifer drillings reached 143
mg/l chloride, similar to the average concentration in previous years. In contrast to the
Coastal Aquifer, the Mountain Aquifer is not exposed to factors that increase salinity such
as ingress of sea water or recharging of water from the National Water Carrier.

According to data from the Hydrological Service, in the hydrological year 2009/10,
approximately 79% of the water pumped from the Mountain Aquifer had a salinity level of
less than 250 mg/l chloride. The multi-annual analysis of the Hydrological Services
reveals that in 87% of the drillings, no trend of change in salinity could be identified. In
11% of the drillings, an increase in chloride concentration was observed, and in 2% of the
drillings a decrease was observed.
( 37 )