The Coastal Aquifer
Under conditions of water scarcity, on the one hand, and intensive development, on the other hand, the degradation of water quality becomes a critical problem. Curbing the process of water quality deterioration is one of the central challenges confronting the environmental administration in Israel.
About one-third of Israel’s population and a major portion of its industry and agriculture are concentrated in the region overlying the coastal aquifer. Chemical and microbial pollutants, salination, nitrates, heavy metals, fuels and toxic organic compounds all threaten to contaminate the aquifer.
Salination and chloride accumulation: Salination of the coastal aquifer has resulted from the intrusion of sea water and from the slow accumulation of dissolved salts from irrigation water and other sources. Overpumping has exacerbated the problem since lowered groundwater levels prevent the flushing of pollutants and salts into the sea. Other causes of salination include the import of water from the National Water Carrier and other groundwater basins, irrigation by effluents and groundwater recharge.
A practical model has been developed in Israel to calculate and predict the displacement of the saltwater-freshwater interface in the layered coastal aquifer. The model should help in decision making related to the exploitation of this freshwater resource.
Over the past 25 years, average chloride concentrations in the coastal aquifer have increased from 110 mg/liter to 150 mg/liter. The average increase today is about 1 mg/liter a year. While growing awareness has led to better management and a decrease in overpumping, the prognosis for this aquifer remains bleak. According to estimates of the Hydrological Service, 10% of the wells have already reached a salinity level exceeding 250 mg/liter, a concentration unsuitable for unrestricted agricultural irrigation. Within twenty-five years, over half of the wells will exceed permitted salinity levels.
Nitrate accumulation: Nitrate concentrations in the coastal aquifer have increased considerably due to intensive use of fertilizers in agriculture and the use of treated effluents for irrigation. Since 1950, nitrate concentrations have increased from 30 mg/liter to an average of 40-50 mg/liter today, with an annual rate of increase of close to 1 mg/liter. Some 17% of current groundwater production exceeds levels of 70 mg/l, and nearly 60% exceed recommended levels of 45 mg/l. Within twenty-five years, 26% of the wells are expected to exceed nitrate levels of 70 mg/l and 67% will exceed 45 mg/l levels.
Heavy metals: Contamination by heavy metals is minimal and is confined to sites in the environs of specific industrial zones. Due to the slow transit rate of heavy metals through the ground, the problem may become more evident in future years. Regulations enforced by the Ministry of the Environment prohibit the discharge of industrial wastes, including heavy metals, into the municipal sewage system and strictly limit the concentrations and amounts of heavy metals discharged to municipal wastewater plants. This is of special importance since nearly 70% of Israel’s wastewater is reused for irrigation.
Stricter legislation and enforcement of hazardous substances laws and regulations is expected to make a significant contribution to the prevention of pollution by heavy metals. In addition, Licensing of Businesses Regulations, in force since 1990, require all hazardous waste from industrial plants to be disposed at the national hazardous waste site at Ramat Hovav. The recent government decision on closing some 400 illegal garbage dumps and replacing them with a handful of state-of-the-art sanitary landfills should further decrease water contamination.
Fuel contamination: Contamination of groundwater by fuel, at a scope of some 2,510 cubic meters, was discovered at 11 sites during the period spanning January 1992 to April 1994. Out of this total, some 1,000 cubic meters of fuel were attributed to a leak from the Ashdod oil refineries in March 1992 and about 1,200 cubic meters to a leak from the Israel Electric Corporation facilities in Ramat Hovav in January 1994. Major leaks are generally the result of human error and neglect; smaller-scale leaks are attributed to damage to pipelines by mechanical equipment and to corrosion of old pipelines, especially near the Haifa oil refineries. Over the past few years, microbial remediation methods have been successfully used to treat and rehabilitate sites contaminated by fuel.
To prevent soil and groundwater pollution from fuel leaks, new gasoline stations are required to install secondary containment equipment around their underground gas tanks. Such containment pools must be sealed by cement or high-density polyethylene sheets. In addition, observation wells must be installed between the fuel tank and the pool wall, and gas stations must be equipped with oil-water separators. To assess the scope of the problem in older gas stations, the Ministry of the Environment will carry out surveys, utilizing observation wells near underground fuel tanks, and will follow up on the condition of old fuel tanks at the time of their replacement by new tanks.
A joint team headed by the Water Commissioner and the Ministry of the Environment has completed draft regulations designed to prevent pollution resulting from contamination of groundwater by fuel.
Organic micro-pollutants: Data on organic micro-pollutants in water sources have only begun to accumulate in recent years. In the wake of the discovery of relatively high pesticide concentrations in some wells of the coastal aquifer, two developments have taken place: an advisory committee was appointed to review Israel’s water quality standards in order to adapt them to stricter standards worldwide, and a survey to assess the degree of pollution by organic micro-pollutants in well water was initiated by the central laboratory of the Mekorot Water Company.
The survey, which was initiated in 1991, is monitoring 18 micro-pollutant compounds derived from industrial sources, nine pesticides and four trihalomethanes. Of the 468 wells tested so far throughout the country, 108 wells (23%) showed traces of micro-pollutant concentrations and 13 (2.8%) revealed at least one substance which exceeded the standard in at least one test. The most prevalent micro-pollutant discovered (over 60%) was trichloroethylene. All of the contaminated wells, most of them situated in the highly-industrialized Haifa Bay and Holon areas (near Tel Aviv), were known to be polluted previously and have been taken out of service for drinking water purposes. Data accumulated will serve as a baseline for future changes in water quality.
While the results showed that widespread pollution does not exist, the data should expedite the adoption of a new drinking water standard by the Ministry of Health. A draft regulation has already been submitted which relates to a much wider group of contaminants, including organic solvents and pesticides.
Microbial pollution: Bacteriological standards for drinking water, tightened in 1989, state that water is unfit for drinking if routine microbiological tests reveal more than 3 coliform microbes and/or 1 fecal coliform in a water sample of 100 milliliters. Tens of thousands of tests on the microbiological quality of drinking water are conducted each year by the Mekorot Water Company and by local authorities, under the supervision of the Ministry of Health. Mekorot tests water sources and supply lines before connection with consumers while the Ministry of Health tests the microbiological quality of drinking water at water sources and supply lines within local authorities.
In both cases, only a small percentage of tests (about 4%) shows excess contaminants, most due to antiquated and leaking sewage pipes, especially in the northern part of the country. Results show a steady decline in substandard results in recent years (half the violations since 1989).
To solve remaining problems, several measures have been adopted, including separation of wells from pollution sources, obligatory chlorination or other disinfection means, and installation of treatment systems. Major reduction in microbial pollution is expected in the near future as a result of the active advancement of wastewater treatment systems throughout the country.
The Yarkon-Taninim (Mountain) Aquifer
Because of the deterioration in both quantity and quality of the water in the coastal aquifer, the mountain aquifer is becoming the main supplier of drinking water in the country. However, this deep limestone aquifer is especially prone to contamination due to its karstic nature and the quick transit of pollutants through it. While salinity does not constitute a problem today, overexploitation can lead to a rapid rate of saline water infiltration into the aquifer from surrounding saline water sources. Since the replenishment region of the aquifer is found in the administered territories, future agreements between Israel and the Palestinians on use of the shared mountain aquifer must include stringent requirements with regard to monitoring and control of urban pollution, wastewater, and hazardous agricultural and industrial wastes in order to prevent the contamination of this highly-susceptible aquifer.
During the past 50 years, several changes made in the catchment basin of the Lake Kinneret have modified the balance of the lake’s ecosystem. Draining of the Hula wetlands in the 1950s caused sediments and nutrients to flow directly into the lake while increased population and agricultural activity in the lake’s watershed area have led to contamination by several different pollutants, especially pesticides, fertilizers and cowshed wastes.
The need to manage environmental quality in the lake and its watershed and to protect them from nutrient overload, agriculture, grazing, sewage and even tourists has led to the organization of an effective management system, coordinating research with practical administration and long-range planning. As a result, marked decreases have been noted in bacterial and dissolved nitrogen concentrations and in the number of incidents of pesticide contamination. On the other hand, a gradual rise in total nitrogen concentrations, a clear decrease in zooplankton growth and an increase in algal biomass have been noted.
Recent studies of Kinneret water quality undertaken at the Yigal Allon Kinneret Limnological Laboratory have shown that overall water quality in the lake has not deteriorated and eutrophication has not taken place during the past twenty years. An analysis of primary production and chlorophyll has revealed no significant rise in these parameters between 1972 and 1993. Improvement in water quality in the lake in recent years is expressed in a reduction in water salinity (up to 215 chlorides mg/liter in the epilimnion in the fall of 1993) and a rise in the concentration of dissolved oxygen and pH of the epilimnion. Microbial water quality in pumping sites was good during 1993. Monitoring of bacterial indicators for fecal pollution indicated that most bacterial pollution reaches the lake in the winter with flooding.
Water from Lake Kinneret will meet new, stricter drinking water standards of no more than one turbidity unit when filtered. An advisory committee of the Water Commissioner has advocated centralized filtration of all water pumped from Lake Kinneret and supplied by the National Water Carrier. The recommendation, carrying a $100 million price tag, is under economic evaluation. The alternative is to meet new standards by building dispersed filtration plants at the point of entry of the water to the municipal distribution systems. It is expected that the filtration system will be completed by 1997.
Improvement of water quality should also result from the reflooding and rehabilitation of agricultural areas in the Hula Valley, part of the Kinneret watershed. Drainage of the Hula lake and the surrounding wetland, begun in 1951, rid the area of the malaria-infested swamps and reclaimed 4,000 hectares for agricultural use. However, it exposed land rich in minerals and nutrients to the atmosphere, triggering the production of nitrates which poured into Lake Kinneret during the winter rains. Research conducted in the 1960s and 1970s estimated that the nitrogen outflow from the drained area amounted to nearly 50 percent of the nitrogen input into the Kinneret. The $25 million reflooding and rehabilitation project, meant to help rectify the ecological and economic damage caused by drainage of the Hula thirty years ago, will result in the creation of a wetland wildlife park that will include a lake and islands surrounded by marshes and boating canals for visitors. Within the framework of the four-year project, some 800 hectares will be rehabilitated and 100 hectares reflooded.
The case of the Kinneret serves as an excellent example of what effective basin management can achieve in preventing pollution and enhancing environmental quality. The cooperative efforts of the Kinneret Authority, the Kinneret Limnological Laboratory and the Ministry of the Environment have proven invaluable in preserving the well-being of the lake.
With the exception of the upper part of the Jordan River and its tributaries, nearly all rivers in Israel share a common characteristic: pollution. The reason in most cases can be traced back to the scarcity of water in Israel. Water is all too frequently trapped at its source to supply urban and agricultural demand. The situation is aggravated by the discharge of urban effluentsand at times industrial and agricultural effluents as wellwhich prevents fauna and flora from surviving while fostering the growth of mosquitoes and algae.
The situation, however, is changing. In November 1993, a National River Administration was established to oversee the restoration of the country’s rivers. The administration, consisting of representatives of a number of government ministries and green organizations, is charged with coordinating the efforts of the various bodies working to clean up the rivers, restore landscapes and rehabilitate ecosystems, flora and fauna for purposes of recreation, tourism, education and research.
Yarkon River: Since rivers are usually located under the jurisdiction of several local authorities, river authorities are being established in Israel to deal with the problem of polluted rivers. A prominent example of the restoration of a badly polluted river is the Yarkon, the longest of the coastal rivers. The 27-kilometer long river, originally fed by springs which were diverted through pipes to the Tel Aviv area and the Negev, flows through Israel’s most densely-populated area. Before its waters were diverted in 1956, some 220 MCM of fresh water flowed in the Yarkon, supporting fishing and a rich water vegetation. Following diversion, sewage was introduced, and the natural habitat of plants and animals was destroyed.
In an effort to improve the state of the river, a Yarkon River Authority was set up in 1988. The authority, consisting of representatives of 19 organizations and local authorities, is responsible for cleanup, restoration and development of the river, making it suitable for leisure and recreation. Extensive efforts are being made to remove accumulated trash and debris from the river and to clean the river banks. Administrative and legislative measures are being taken to ensure that sewage is not discharged into the river, and monitoring is carried out to ascertain that vegetation and fish are not damaged.
The success of the rehabilitation program is already evident in the return of flora and fauna to a restored seven-kilometer stretch, in the development of boating and fishing areas and in the eradication of mosquitoes using biological control. A few kilometers upstream, near Petah Tikvah, the National Parks Authority officially inaugurated the Mekorot Hayarkon
(Sources of the Yarkon) National Park in October 1993. The park includes historic sites, a pastoral atmosphere and riverbank vegetation with public access.
With respect to the as yet uncleaned parts of the river, first priority is being accorded to stopping the discharge of sewage. Current efforts are focused on upgrading the treatment plant serving Ramat Hasharon, Kfar Sava and Hod Hasharon which discharges 25,000 cubic meters of effluent a day.
Lachish River: Sewage and waste in the Lachish River, which flows in the northern part of Ashdod, have plagued the city’s residents for years; but this source of dismay will soon be transformed into a source of pleasure. As a result of an intensive restoration project, initiated in 1991 by a number of organizations, the Lachish River Park was inaugurated in October of 1993. The restoration of a three-kilometer stretch of the river will serve as an aesthetic buffer separating Ashdod’s residential area from its heavily industrialized zone.
The first stage of the Lachish restoration program is scheduled for completion next year once sewage treatment and cleanup of the river, riverbanks and adjacent areas are completed. Following years will see the preparation of an infrastructure for sailing, recreation, sport and leisure activities, and the development of commercial tourism projects.
Kishon River: In Haifa, the creation of a Kishon River Authority was approved in May 1994. The Kishon River, which starts in the Jezreel Valley and empties into the sea at Haifa, is one of the most polluted of Israel’s rivers. Sewage, pesticide runoff and industrial wastewater from some of the country’s biggest chemical plants ends up in the river. Analyses carried out on sediments in the river found high concentrations of heavy metals, originating in the industrial effluents which have been discharged into the river for dozens of years. To begin dealing with the tens of thousands of tons of sludge which have entered the river, shallow tunnels were dug along the riverbanks and covered with sealed polyethylene sheets; they are used to store the sludge as a temporary measure until a disposal solution is found. Upgrading of the existing Haifa wastewater treatment plant, at a cost of $27 million, will considerably improve water quality in the Kishon.
Plans are on the drawing board for transforming the river into a tourist attraction, replete with small harbor and fishing boats. Meanwhile, however, a three-kilometer section of the river upstream, in the Kiryat Tivon area
(between the Jezreel and Zevulun Valleys) has been prepared to serve as a park.
Due to the complexity of the ecological system of the Kishon River and Haifa Bay, the European Investment Bank will finance a research study on the carrying capacity of Haifa Bay and on the rehabilitation of the Kishon River. While information on the quantities and quality of the sewage discharged into the Kishon exists, little is known concerning the fate of these pollutants in the marine environment. The study will help develop an integrated approach, based on the processes occurring in Haifa Bay, which will make it possible to develop new standards for sewage and effluent discharge into the Bay.
The Alexander River: The Alexander River, polluted by wastewater discharged by the municipality of Netanya, is due for major cleanup once a new sewage treatment plant, scheduled for operation next year, is established. The area has also been selected as the site for a Technion – Israel Institute of Technology study on the applicability of wetlands technologies to Israeli conditions using effluents from the sewage plant.
The Ministry of the Environment has supported the establishment of a pilot plant for the treatment of Netanya’s effluents using the wetlands method. A large wetted area will be covered with water vegetation to facilitate biological treatment, and the water will then be discharged to the river. The area will serve as a nesting site for birds, reed vegetation, birdwatching and walking paths.
The Ayalon River: The Ayalon River near Lod once served as a sewage conduit and garbage dump, home to discarded refrigerators and building debris. Today, the river and its banks have been cleaned, the riverbank is being transformed into a municipal park, and, following a legal suit, the sewage of Lod and Ramle is being transported via pipeline to the Nesher reservoir for agricultural irrigation. A regional wastewater treatment plant is now being planned to treat the sewage discharged by some 500,000 residents of Ramle, Lod, Shoham, Modi’in and nearby communities.