|Managing Water for Peace in the Middle East: Alternative Strategies (UNU, 1995, 309 pages)|
|4. Hydro-powered reverse-osmosis desalination in water-resources planning in Jordan|
The potential contribution of non-conventional water-resources development, including the proposed co-generation with hydro-powered RO desalination, in a national water master plan for Jordan for the twenty-first century is studied here, taking into account that 95% or more of the national renewable water resources are going to be fully exploited to meet the increasing demand, especially in the population centres, by the year 2000. Non-conventional water-resources development will be increasingly important in such planning.
4.6.1 Development alternatives and priority
A general characteristic of non-conventional water resources is that they are generally more complex to develop and operate than con ventional sources, and they are almost always more expensive. In most cases, non-conventional measures involve considerably more risk than conventional solutions, and no single non-conventional solution is suitable for all watershort areas. At the same time, by providing water to an arid area, nonconventional water resources may offer an opportunity for development previously considered impossible.
In any situation where a conventional source of water can be developed, it will almost always be preferred to a non-conventional source. However, if conventional groundwater or surface water supplies are inadequate, consideration should be given to some of the nonconventional water-resource techniques. Accordingly, non-conventional water resources are considered here in the context of a national water master plan for Jordan.
CONVENTIONAL ALTERNATIVES. Conventional alternatives comprise fresh surface water and fresh renewable and non-renewable groundwater.
The main potential for further surface water utilization in Jordan is through the construction of new water-storage facilities on the Yarmouk River and riftside wadis, including:
>> the Al Wuheda dam on the Yarmouk,
>> development of the northern Ghor side wadis (Karameh, Kifranja, Al-Yabis, and raising the Kafrein dam),
>> development of the southern Ghor side wadis (Wale recharge dam, Nkheila dam, Tannour dam).
The most important of these will be the Al-Wuheda dam, with a gross capacity of 230 million m³. The total gross water storage potential of the proposed projects has been estimated to be 300-350 million m³.
The potential for further development of renewable groundwater resources is small. Current intensive abstraction amounts to 333 million m³ per year, which accounts for more than 90% of the estimated long-term safe yield of 356 million m³. More attention needs to be given not to development but to management of the aquifer system, taking into account the need for sustainable development to avoid over-extraction and deteriorating quality.
The main potential for non-renewable groundwater lies in the fossil aquifer of Disi, Jordan's last major exploitable source of good-quality water after the Al-Wuheda dam. The Disi groundwater scheme will require expensive conveyance over a distance of about 350 km to the population centres of the north-west highlands (Amman). The mining yield potential, which has been evaluated by a series of computer model simulation studies, has been estimated to be 110 million m³ per year for over 100 years. This non-renewable alternative should be regarded as a strategic reserve, guided by careful monitoring of the aquifer and stepwise development over a decade.
The Disi aquifer is part of an extensive inter-state deep sandstone aquifer system in the Arabian peninsula underlying south-eastern Jordan and northwestern Saudi Arabia. In the early 1980s Jordan feared that the hydraulic influence of Saudi Arabia's intensive abstraction might cross the state boundary. However, the rapid increase in Saudi abstraction from the Tabuk wellfield between 1982 and 1985 dropped the pumping levels by more 120 m of water head, and in its Fifth Development Plan (1990-1995) the government of Saudi Arabia decided to cut part of the national water supply by decreasing the abstraction of non-renewable groundwater for the supply of irrigation. From the experience in Saudi Arabia, the economic limit of abstraction from the Disi aquifer will probably be reached much sooner than expected.
NON-CONVENTIONALE ALTERNATIVES. Alternatives for the development of non-conventional water resources available to Jordan include the following:
>> desalination of brackish groundwater and seawater, including cogeneration, groundwater-hydro, and hydro-powered RO desalination,
>> the reclamation and reuse of municipal sewage effluents,
>> weather modification,
>> inter-state water transportation, including the Euphrates-North Jordan transmission scheme and the Peace Pipeline project.
Brackish groundwater reserves are found in most deep aquifer systems, including the Middle to Lower Cretaceous sequences such as the Ajlun and Kurnub formations. In the extensive eastern desert, groundwater generally has a brackish nature, and is even found in shallow aquifer systems, including the Amman-Wadi Sir formation. The salinity of such brackish groundwater is in the range of 2,000-5,000 mg of TDS per litre, which fits within the effective range of reverse-osmosis desalination.
In 1982 Jordan's first RO desalination plant, with an installed capacity of 80,000 US gallons (300 m³) per day, was commissioned at the Zarqa oil refinery, where the supply source of the groundwater had been contaminated with increasing salinity, from a TDS content of 336 mg/l in the 1960s to 1,700 mg/l, in 1980 (Alawin 1983).
The most promising brackish groundwater resources are to be found in the Amman-Wadi Sir (B2/A7) formation in and around the Azraq springs, about 100 km east of Amman/Zarqa. The priority use for brackish-groundwater RO desalination of the Azraq wellfield will be for M&I water supply, since the piezometric head of the B4 aquifer system is being lowered by over-pumping and is suffering from increasing salinity. The Azraq wellfield has the following characteristics:
Brackish groundwater in deep aquifer systems such as the Kurnub formation has a depth to the water table of more than 200-250 m. The storage potential for brackish groundwater in deep aquifer systems is more than that for fresh water reserves in shallow aquifer systems. The hydrological characteristics of brackish groundwater systems, however, range between renewable and non-renewable. Careful assessment and management of the brackish groundwater resources would be required to sustain development by the application of desalination.
Seawater desalination is possible only in the Gulf of Aqaba. Small scale seawater RO desalination has been carried out for boiler water supply at the Aqaba steam-power plant since the mid-1980s. It is quite clear that the cost of desalting seawater is usually three to five times as high as desalting brackish water (see Appendix A). Water for Aqaba is presently being supplied by developing fossil groundwater from the Disi aquifer, and it is recommended in this study that this source should be replaced by the desalination of brackish groundwater in the adjacent Kurnub aquifer by a hybrid hydro-powered RO system, which can be expected to reduce both the cost and the energy requirement and will help to sustain valuable groundwater resources as a longterm policy. A proposal for seawater desalination, to be coordinated with the National Water Carrier of Jordan, which would convey water from the sea to the population centre of Amman, would require lifting water about 1,000 m or more. At present, seawater desalination has no feasibility except to supply water for M&I use in the Aqaba coastal region. There is still the opportunity to desalinate seawater and lift the product water up to a 1,000 m elevation in the future by developing new renewable-energy alternatives, including solarenergy conversion and ocean-thermal-energy conversion in the hot and arid climatic region of the Gulf of Aqaba.
It is proposed that priority should be given to the development of brackish-groundwater desalination for municipal water supply and that feasibility studies might be undertaken of the following two possibil ities:
>> the desalination of brackish groundwater at Azraq to supply water for Amman,
>> hybrid hydro-powered RO desalination of brackish groundwater from the Kurnub aquifer to supply water for Aqaba.
The reclamation and reuse of municipal sewage effluents as an additional water resource continues to increase potential water resources, corresponding to the increases in water demand and supply in Greater Amman, which consumes about 60% of the total water supply in Jordan. Almost all the sewage effluents in the Amman-Zarqa region are discharged into the Zarqa River system, whether treated or not. The Kherbet Samra sewage plant, which collects the effluents from metropolitan Amman and Zarqa, treated 33.2 million m³ in 1989 and discharged it into the Zarqa River to enhance the base flow of the river system. The King Talal dam on the lower reaches of the Zarqa River subsequently harvests all the sewage effluents that flow into the river system. The Zarqa is mainly polluted by the untreated sewage effluents in its upper reaches, while there is some natural purification in both the flowing and impounding processes. The sewage effluents harvested in the King Talal reservoir are reused exclusively for irrigation water supply in the Ghor (Jordan valley). The exceptional topography of the north-west plateau and the escarpment of the Jordan valley permits reuse for irrigation in the valley of the bulk of the return flow of water used in the uplands.
Weather modification, which includes artificially induced precipitation, or cloud seeding, could probably provide an inexpensive source of water under certain meteorological conditions. However, specific verification is necessary in each mountainous region of Jordan. Experiments on the upper Jordan River in Israel provided encouraging results under the particular orogenic and climatological conditions on the southern slopes of the Anti-Lebanon range (Mount Herman), where the ground elevation exceeds 1,500-2,000 m, with an annual rainfall of more than 500-1,000 mm (Kelly 1974). In Jordan, the potential area for cloud seeding is limited to Ajlun mountain. Cloud seeding may not be very promising, however, since the orogenic and climatic conditions of the Ajlun mountain zone are less attractive than those of the upper Jordan River in Israel. Cloud seeding on the southeastern slopes of Mount Hermon in Syria, where the headwaters of the Yarrnouk River originate, may have the same effect as experienced in Israel. In any case, international cooperation is needed to develop a weathermodification program.
Inter-state water transportation alternatives may include the Euphrates transmission scheme to Jordan and the Peace Pipeline scheme. The transport of water by tanker and barge is a more remote alternative for Jordan, since the main demand area is in northern Jordan, where the ground elevation exceeds 800-1,000 m.
A feasibility study of the Euphrates-North Jordan transmission scheme was made in 1983. This would transport water from the Euphrates River in Iraq to north Jordan (Amman) by water pipeline. Al Qaim, situated on the Euphrates where it enters Iraq, at an elevation of 163-165 m, offers the highest abstraction level, thereby minimizing the overall static lift between the river and the delivery point in north Jordan. The scheme was scheduled to abstract up to 160 million m³ of water annually (5 m³/sec) from the Euphrates River. The pipeline system was designed for a 5 m³/sec rated capacity, 605 km in length, 1.5-2.0 m diameter, 830 m static lift, and 1,380 m of total pumping head (NPCJ 1983). Such an inter-state water transport scheme might be technically and economically feasible if the water were to be used for domestic purposes.
Turkey's ambitious Peace Pipeline proposal, which aims to transfer water from the Ceyhan and Seyhan Rivers in Turkey to eight states in the Arabian peninsula, includes an assumed potential water delivery of 600,000 m³ per day (219 million m³ per year) to Jordan.
Both the Euphrates-North Jordan and the Peace Pipeline schemes have been put aside, however, owing to political constraints, including interstate riparian-rights questions on the Euphrates River, where the use of water as a political weapon has been increasing. These interstate water-transportation projects have now been emphatically rejected by all Arab states, who have said that if necessary they will depend on non-conventional waters in their territories, including seawater desalination. Development priority is therefore likely to be given to marginal waters as non-conventional water resources, taking into account not only technical, financial, and economic but also political feasibility.
4.6.2 Desalination development strategy in the national water master plan
Desalination to develop previously unusable brackish groundwater and seawater as sources of potable water, including energy-saving applications of co-generation and hydro-powered RO processes, should be included in the context of a master plan for the development of the water resources of Jordan. In such a plan, the use of this relatively expensive water-treatment process should be entered into with caution, after the possibility of utilizing more conventional and possibly less expensive sources of water has been carefully weighed. The master plan should include measures for the conservation and optimum development and management of all these natural resources. Steps should be taken to ensure the rational use of water and minimize wastage. Water quality should be maintained at acceptable levels, and an appropriate pricing policy should be established, including the diversion of water from irrigation to municipal and industrial use. The use of fossil groundwater in Disi for growing wheat is one particularly questionable application.
Elements that should be included in a water master plan for the next twenty to thirty years may be delineated by decades into short-, medium-, and long-term development stages as follows, with special focus on the inclusion of non-conventional water resources:
>> short-term development strategy (1990-2000)
>> medium-term development strategy (2000-2010)
>> Long-term development strategy (2010-2020)
The most important, and the highest-priority schemes will be the AlWuheda dam and other storage dams on the side-wadis of the East Bank. These storage, flood-retention, or groundwater-recharge dam schemes would reduce the inflow from the river system into the Dead Sea and be linked with the Mediterranean-Dead Sea conduit scheme in the context of an inter-state basin-development master plan which would be beneficial to Jordan, Palestine, and Israel. Further discussion of the water politics of inter-state basin development of the Jordan River system is included in chapter 5.