Global warming and climatic changes compel Israel to address the continuous decrease in the amount and dispersion of its winter precipitation, limited precipitation, and marked rainfall fluctuations between drought years and rainy years. Irregular precipitation cycles cause significant changes in the natural aquifer recharge rates , thus creating water-consumption demand that exceeds natural replenishment in certain years, with pumping being carried out at the expense of depleting the water reserves in groundwater reservoirs.
Despite the considerable addition of "artificial" water (through desalination of sea and brackish water), "natural" water (ground and surface water) still provide the main answer to Israel's water needs. It is therefore important to preserve and develop Israel's natural water sources alongside other means of water production. By supplementing the national water system with water from other resources, water-resource management in Israel is undergoing a significant change. This change is reflected in the demand for large quantities of "natural" water from aquifers and from the Sea of Galilee over short intervals, meaning that local pumping is increased for short periods of time, and hydrology management has to contend with the hydrological implications of such production (local water-level reduction, temporary local salinization , etc.)
Mekorot has vast experience in pumping water from both shallow and deep layers and from all different types of aquifer, composed of sand, sandstone, limestone, dolomite, basalt, alluvium and conglomerates. The company operates over a thousand active wells – the deepest of which reach the depth of 1,500 meters. Mekorot is the only company in the world to pump water up from such depths. Pumps are installed 500-meter deep in some wells!
Rehabilitation of Wells
Some wells are 50-60 years old. Systematic rehabilitation of old wells is needed to maintain the pumping capacity from natural water resources. The rehabilitation includes mechanical and chemical cleaning of the shaft, and sometimes involves inserting a new pipe column into the well. It is usually cheaper to rehabilitate an old well than to drill a new well. In the Arava, the standard of water in the aquifers causes filter blockage (carbonate and sulfide blockage) within several years. Most wells require regular maintenance to ensure their full production capacity. Maintenance work includes the use of chemicals and other physical measures, most of which are adopted from the oil-drilling sector. This enables restoration of disused wells and maintains the overall national pumping capacity.
In recent years, the field of artificial groundwater recharge has become an important and central field in water-resource management systems in Israel and worldwide. Mekorot's Hydrology Department has gained extensive experience in this field. The main objectives of groundwater recharge are: to increase replenishment, improve water quality, restore natural reservoirs, and use aquifers to store excess water reserves for use during periods of high consumption.
Mekorot is promoting a program for drilling dozens of injection wells in the coastal aquifer for the insertion of excess desalinated water in periods when there is a surplus of such water in the system. The company is examining options for planning and building injection wells using new and advanced drilling technologies, including pipes of types never before used in Israel (such as fiberglass pipes).
Mekorot's Hydrology Department has been involved for many years in international research, in cooperation with many European universities. One of these projects was a joint German-Israeli-Jordanian-Palestinian program called SMART. The research objective was to develop innovative technologies for managing and integrating available and sustainable water resources in groundwater basins draining into the lower Jordan Valley and the northern part of the Dead Sea.
"Dewatering" Hydrology Operations in Israel
In recent years, the Hydrology Department has been involved in a number of large engineering projects requiring a planned process of lowering water-table levels ("dewatering"). One of these projects planning groundwater lowering for the construction of an emergency underground hospital at Rambam Hospital (Haifa). The hydrological conditions (proximity to the sea, and broken and cracked bedrock) created a hydrological challenge for planning the pumping and lowering of the water level, and culminating in the largest dewatering engineering project ever undertaken in Israel. From the hydrological aspect, the project was an overwhelming success.
Hydrology Operations Abroad
In recent years Mekorot has begun implementing programs in a number of foreign countries. The hydrological aspect is crucial for most of these programs. Hydrology Department staff have therefore been conducting research projects over recent years in a number of countries, including Argentina, Peru, India, Guinea and Azerbaijan. The department’s operations abroad are expected to increase. Alongside the company's growing involvement in various projects abroad, Hydrology Department staff also present papers and lecture on the results of their work at international conferences.