Evaluation of Hydroulic Performance of Major Canals in the Rahad Agricultural Scheme–sudan

Diagnosis and evaluation of irrigation projects is complex and often neglected subject, in spite of its important role which plays if the declining output of the large scale irrigated projects in Sudan is to be improved. A package of goaloriented performance indicators (quality of irrigation services, water scheduling and area utilization) was used to quantify the hydraulic performance of the main canal water delivery system in Rahad irrigated scheme. As a result, an overall evaluation index is formulated to reflect the irrigation system multiple objectives. Stratified sampling procedure adopted to extensively monitor and quantify water flows at four control points and six Minor canals of Major (No.2). Secondary data was obtained from the various canal operating agencies. The results generally reveal considerable seasonal variability in the performance of the indicators used and maloperation of canal structures. They indicate that water delivery performance in the Minor canal is decreased towards the tail end. Therefore, new operational methodologies are needed to solve these problems. لا صخلم : قتو صيخشت و يف اًيويح اًرود بعلي هنكلو لمهمو دقعم عوضوم ةيورملا عيراشملا مي عيراشملا يف ةيندتملا ةيجاتنلإا نيسحت ةيورملا دوسلاب ىربكلا نا . فادهلأا قيقحت وحن ةهجوملا ءادلأا تارشؤم نم ةمزح مادختسا مت ) يرلا تامدخ ةدوج و يضارلأا للاغتساو هايملا ةجمرب ( ةانق ةكبشل يكيلوردياهلا ءادلأل يمكلا ديدحتلا ضارغلأ يعارزلا دهرلا عورشم يف هايملا عيزوتل ةيسيئر . قت رشؤم ءانب مت هيلع ءانبو و سكعيل يلآ مي فادهلأا يرلا ماظنل ةددعتملا . ةعباتملا ضارغلأ تاقبطلا ساسأ ىلع تانيعلا ةقيرط تمدختسا ةرمن ةيسيئرلا ةانقلا يف ةيوناث تاونق تسو مكحت طاقن عبرأ يف هايملا تافرصتل ةفثكملا ) 2 ( مت ةانقلا ليغشت يف ةلماعلا تائيهلا فلتخم نم ةيوناثلا تانايبلا ىلع لصحتلا . مومع جئاتنلا تحضوأ مادختساو ةمدختسملا ءادلأا تارشؤم ميق يف ةيمسوم تافلاتخا اً ةانقلا تآشنمل ئطاخ . ةياهن وحن صقانتي تاونقلا يف هايملا عيزوت رشؤم نأ جئاتنلا تحضوأ امآ ةانقلا . ةلكشملا هذه لحل ةديدج ليغشت قرط مادختسلا جايتحا كانه اذهلو . INTRODUCTION The major constraint to produce more food to meet the increasing world population demand is water security. One possible approach to conserve this scarce resource may be through improving the performance of the existing large-scale irrigation projects and improving its management and utilization level. A key factor in better management is the performance of human factor. As such development of performance indicators and rigorous evaluation methodology is needed to help managers to improve their system. Evaluation exercise is useful tool to aid scheme manager to compare and the efficiency of alternative system and operating procedures to improve existing projects (to employ intervention or rehabilitation programmed or not, and to compare performance of different sections within a project or different projects). However, performance was conceptually approached by two models. The goaloriented model (Scoatt, 1979; and Seashore, 1983) and system or contingency theory model (Murray-Rust and Snellen, 1993). A field multiobjective evaluation of performance of irrigation systems is limited. Due to this inadequate understanding of field conditions, causes and magnitudes of priority problems were not fully identified especially in less developed countries. Most studies and reports are either based on rapid appraisals or concentrating on one part of the system (Mohamed, 1992). Rahad irrigation scheme is selected as a case study for the purpose of evaluating the performance of multi-objective irrigation project for rural development. Rahad case study may serve as a model to evaluate large agricultural projects in the Central Clay Plains of the Sudan. As reported by (Elawad and Hamid, 1993) development of an index system of evaluating performance of irrigated project can be used as a tool to resolve conflict and measure the service rendered by the operating agencies. Hence, the objective of this study is to develop a systematic and comprehensive procedure for evaluating seasonal performance of irrigated projects and also to propose and test a set of quantitative performance indicators for water delivery at Major level. MATERIALS AND METHODS Development of Index System of Evaluation: On basis of goal oriented model the following sets of indicators are chosen to express the actual and planned values (in terms of ratio) to reflect the quality of irrigation service, water scheduling, agricultural indicators and over all system performance indexes(Bos et al., 1993). Quality of irrigation service conceptually addresses physical system capability and operation to deliver water per schedule and design. As given by (Molden and Snellan, 1993) twelve performance measures are defined relative to four objectives of water delivery system (adequacy, efficiency, dependability, and equity). The suggested performance indicators are depicted in (Table 1) and their respective scale to judge their attainment is given in (Table 2). Water delivery performance (WDP) that reflects the scheduling process through time and space is measured according to (Bailey and Lenton, 1984, Mohammed 1992 and Rao, 1993). It varies from 0.0 to 1.0 where 1.0 is good and 0.0 is worst. It can be defined as: