Rehabilitation of Irrigation Distribution Systems: The Case of Jericho City
Efficiency enhancement in irrigation distribution system (IDS) contributes to substantial water savings. This paper aims to present the methodology and lessons learned from efforts to improve efficiency in the irrigation distribution system of Jericho City. This effort presents a new paradigm in water management in water scarce countries, which focuses on both supply and demand management rather than on supply augmentation. Converting the existing irrigation canal system to a pressurized pipe network carries out rehabilitation of IDS in Jericho City. Analysis of the new IDS is performed through computer simulation. Considerations and constraints for sustainable irrigation management are presented.
Groundwater in the Shallow Aquifer of the Jericho Area, Jordan Valley – Noble Gas Evidence for Different Sources of Salinization
Arid to semi-arid conditions that generally promote water scarcity are common in many regions in the Near East. Moreover, various places in that geographic domain are affected by groundwater salinization. This challenge is also shared by the Jericho area, located on the western side of the lower Jordan Valley, about ten kilometres NW of the Dead Sea. Due to a unique hydrogeological situation in this area, the discrimination of the hydrochemical signatures of the possible sources of salinization are fuzzy. Part of the potentially salt bearing aquifer material was deposited by the high saline Pleistocene precursor of the Dead Sea, the Lake Lisan, and thus resembles the signature of known residual brines of the former lake. Brine occurrences at other locations in the area usually are connected to the western boundary fault, which is a structural element of the Dead Sea Transform system. From the study of the helium and neon noble gas isotope composition of samples from saline wells and springs at the northwestern Dead Sea shore as well as from six Jericho agricultural wells there is evidence that admixing brines are supposedly not the only source of salinization in the study area. Indeed it is shown that the highest helium excess concentrations are related to the vicinity of the border fault, where moderate salinities are already present. Wells not too far in the E of the study area but in close vicinity to Wadi Qilt produce groundwater with a noble gas composition typical for air-equilibrated surface water. This reflects significant volumes of infiltration in the rainy season due to the mountain discharge, that is mainly derived from springs in the upstream area of Wadi Qilt as well as run off. An intermediate position between the first two groups is demonstrated by the most saline groundwaters, which are found remote from the border fault in the E of the study area. This is interpreted as evidence for additional non-brine salinization input probably from the surrounding sediments of the Lisan Formation.
Review of irrigation system performance with respect to initial objectives
This paper presents the results of assessment studies of the performance of gravity irrigation projects, in six countries in different climate and social environments, with respect to their original objectives in terms of water availability, water use efficiencies, equity of water distribution, cropping intensity and crop yields, and project economic rates of return.An important lesson is the need for more realistic assumptions in the adoption of design standards, especially irrigation efficiency which affect the cropping intensity, the overall productivity of the project and its economic viability. This comparative method of performance assessment applied to a variety of projects has also provided some useful insights into the relative value of the different approaches to design of gravity irrigation systems.