The paper presents the results of a 1998 study of the solid waste generation within the greater Muscat City area. The recent data were compared with the available data from the last 10 years to assess the solid waste problems within the area. Five operating landfills were used as the data collection points. It appeared that through the last decade, the solid waste generation rate has increased sharply. However, the rate of waste production stabilized to 750 – 800 ton/day during the last three years of the 1990s. The rate amounts to 1.5 kg/person/day. Overall municipal waste volume decreased through the years while the amounts generated from private sources such as industries and commercial centers increased during the same period. This is due to the fact that the Sultanate of Oman is developing very fast with increasing industrial, commercial and residential activities. About 80 % of the solid wastes is organic materials. This amount is high when compared to figures found in western countries. The data indicate that about 40 percent of the solid wastes are composed of recoverable materials. The concerned authorities should encourage the growth of industries to be involved in recycling business. Such activities will reduce the solid waste discharge in landfills and increase nearly 1.6 folds the expected life of existing landfills. A survey of the operating landfills indicate that the operational efficiency may be substantially improved by incorporating measures that deal with problems of gas production and leachate movements. The paper includes a detailed discussion of the problem and makes recommendations for possible future actions.

‫الملخص‬ ‫معقدة‬ ‫قرار‬ ‫اتخاذ‬ ‫عملية‬ ‫هو‬ ‫المياه‬ ‫حصاد‬ ‫سدود‬ ‫مواقع‬ ‫إختيار‬ . ‫حيث‬ ‫إ‬ ‫المعايير‬ ‫تقنية‬ ‫دمج‬ ‫يتطلب‬ ‫األفضل‬ ‫الموقع‬ ‫إيجاد‬ ‫ن‬ ‫الجغرافية‬ ‫المعلومات‬ ‫نظم‬ ‫مع‬ ‫المتعددة‬ . ‫على‬ ‫باالعتماد‬ ‫الجغرافية‬ ‫المعلومات‬ ‫نظم‬ ‫استخدام‬ ‫تم‬ ‫البحث‬ ‫هذا‬ ‫في‬ ‫تقنية‬ AHP-OWA ‫السعودية‬ ‫في‬ ‫القصيم‬ ‫منطقة‬ ‫في‬ ‫السدود‬ ‫لبناء‬ ‫مواقع‬ ‫أفضل‬ ‫اليجاد‬ . ‫استخدامات‬ ‫الحوض،‬ ‫انحدار‬ ‫اعتماد‬ ‫تم‬ ‫التخاذ‬ ‫كمعايير‬ ‫المخدمة‬ ‫للمناطق‬ ‫والمسافة‬ ‫الطرق،‬ ‫إلى‬ ‫المسافة‬ ‫األمطار،‬ ‫توزع‬ ‫السطح،‬ ‫جيولوجية‬ ‫التربة،‬ ‫نوع‬ ‫األراضي،‬ ‫القرار‬ . ‫أن‬ ‫القرار‬ ‫لمتخذ‬ ‫السماح‬ ‫مع‬ ‫المياه،‬ ‫حصاد‬ ‫سدود‬ ‫لبناء‬ ‫مواقع‬ ‫أفضل‬ ‫إيجاد‬ ‫في‬ ‫الطريقة‬ ‫هذه‬ ‫أهمية‬ ‫النتائج‬ ‫أظهرت‬ ‫والمتشائمة‬ ‫المتفائلة‬ ‫بين‬ ‫مختلفة‬ ‫سيناريوهات‬ ‫االعتبار‬ ‫في‬ ‫يأخذ‬ . ABSTRACTSelection of a water harvesting dam site involves a complex array of decision criteria that may have conflicting values. Finding the optimum location requires integration of the capacities of Geographic Information Systems (GIS) and Multi-criteria Decision-Making (MCDM). In this paper, a GIS-based multi-criteria decision analysis approach is used to solve this problem. The approach is based on the extension of Analytical Hierarchy Process using fuzzy quantifiers-guided Ordered Weighted Averaging operators (GIS-based AHP-OWA). This approach is applied to determine the optimal site of a water harvest dam in Qassim region, Saudi Arabia. Several factors affect the selection of the best location of the target water harvesting dam such as: slope, landuse, soil type, geology, rainfall, drainage network, distance from the road, and distance from the cities, are used. The results showed that using a combination of GIS-based AHP-OWA is proper approach for optimal water harvesting site selection, where this approach provides a generic powerful decision-making tool that allows decision-makers to define a decision strategy on a continuum between pessimistic (riskaverse) and optimistic (risk-taking) strategies.

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Formatted: Centered Formatted: Font: 8 pt, Complex Script Font: 8 pt environmental and economical settings on the study area. Furthermore, by changing the linguistic quantifiers, the GIS-based AHP-OWA can generate a wide range of decision strategies.

Nile basin countries are experiencing water scarcity due to rapid growth in population and climate change. This scarcity drew attention to the vast amount of water lost in the swamp areas of the Nile basin. Preventing this water loss is essential for reducing the food gap and promoting development in all Nile countries. Jonglei Canal is an important project that was proposed to reduce the vast water losses in the Sudd region in Southern Sudan. The Jonglei Canal project was launched and stopped in the 1980s due to civil war in Sudan. Recently Upper Nile riparian countries have published their plans for possible development projects which might significantly reduce flow to the Sudd region and hence reduce the potential water savings from Jonglei Canal. In addition, environmental concerns about the Jonglei Canal project have been raised by local tribes, that the project may reduce the size of swamps and adversely affect their grazing activities. This paper investigates the impact on the feasibility of the Jonglei Canal project of the proposed development projects in the upstream countries. The projected size of the swamp area is quantified under different scenarios of upstream development and Jonglei Canal operation. The Nile decision support tool (Nile DST model) and a HEC-RAS model were used for hydrologic and hydraulic simulations of the White Nile system. It was found that the ambitious expansion of irrigation projects may affect the benefits of the Jonglei Canal project. The hydraulic simulations indicated that the reduction in the swamp area due to Jonglei Canal would be of the order of only 7%, which could increase to 16% given the upstream developments.