Abstract: The improvement of irrigation systems in the Nile
Delta is one of the most important attempts in Egypt to implement
more effective irrigation technology by improving the existing
irrigation networks. Demand delivery system in the existing irrigation
network is using of mechanical gates structures to automatically
divert water from one portion of an agricultural field to another in the
desired amount and sequence. This paper discusses evaluating main
irrigation networks system under the government managed before
and after improvement systems in the Nile Delta. The overall results
indicate that policy of using the demand delivery concept through
irrigation networks is successful by improving water delivery
performance among them than the rotation delivery concept that used
before. It is provided fair share of water delivery among irrigation
districts and available water in the end of irrigation network,
although this system located in an end of irrigation networks in the
Nile Delta.
Abstract: In Algeria, liberalization reforms undertaken since the 1990s have resulted in negative effects on the development and management of irrigation schemes, as well as on the conditions of farmers. Reforms have been undertaken to improve the performance of irrigation schemes, such as the national plan of agricultural development (PNDA) in 2000 and the water pricing policy of 2005. However, after implementation of these policies, questions have arisen with regard to irrigation performance and its suitability for agricultural development. Hence, the aim of this paper is to provide insight into the profitability of irrigation during the transition period under current irrigation agricultural policies in Algeria. By using the method of farm crop budget analysis in the East Mitidja irrigation scheme, the returns from using surface water resources based on farm typology were found to vary among crops and farmers- groups within the scheme. Irrigation under the current situation is profitable for all farmers, including both those who benefit from subsidies and those who do not. However, the returns to water were found to be very sensitive to crop price fluctuations, particularly for non-subsidized groups and less so for those whose farming is based on orchards. Moreover, the socio-economic environment of the farmers contributed to less significant impacts of the PNDA policy. In fact, the limiting factor is not only the water, but also the lack of land ownership title. Market access constraints led to less agricultural investment and therefore to low intensification and low water productivity. It is financially feasible to recover the annual O&M costs in the irrigation scheme. By comparing the irrigation water price, returns to water, and O&M costs of water delivery, it is clear that irrigation can be profitable in the future. However, water productivity must be improved by enhancing farmers- income through farming investment, improving assets access, and the allocation of activities and crops which bring high returns to water; this could allow the farmers to pay more for water and allow cost recovery for water systems.
Abstract: Renewable water resources are crucial production
variables in arid and semi-arid regions where intensive agriculture is
practiced to meet ever-increasing demand for food and fiber. This is
crucial for the Dez and Moghan command areas where water delivery
problems and adverse environmental issues are widespread. This
paper aims to identify major problems areas using on-farm surveys of
200 farmers, agricultural extensionists and water suppliers which was
complemented by secondary data and field observations during 2010-
2011 cultivating season. The SPSS package was used to analyze and
synthesis data. Results indicated inappropriate canal operations in
both schemes, though there was no unanimity about the underlying
causes. Inequitable and inflexible distribution was found to be rooted
in deficient hydraulic structures particularly in the main and
secondary canals. The inadequacy and inflexibility of water
scheduling regime was the underlying causes of recurring pest and
disease spread which often led to the decline of crop yield and
quality, although these were not disputed, the water suppliers were
not prepared to link with the deficiencies in the operation of the main
and secondary canals. They rather attributed these to the prevailing
salinity; alkalinity, water table fluctuations and leaching of the
valuable agro-chemical inputs from the plants- route zone with farreaching
consequences. Examples of these include the pollution of
ground and surface resources due to over-irrigation at the farm level
which falls under the growers- own responsibility. Poor irrigation
efficiency and adverse environmental problems were attributed to
deficient and outdated farming practices that were in turn rooted in
poor extension programs and irrational water charges.
Abstract: Sediment formation and its transport along the river course is considered as important hydraulic consideration in river engineering. Their impact on the morphology of rivers on one hand and important considerations of which in the design and construction of the hydraulic structures on the other has attracted the attention of experts in arid and semi-arid regions. Under certain conditions where the momentum energy of the flow stream reaches a specific rate, the sediment materials start to be transported with the flow. This can usually be analyzed in two different categories of suspended and bed load materials. Sedimentation phenomenon along the waterways and the conveyance of vast volume of materials into the canal networks can potentially influence water abstraction in the intake structures. This can pose a serious threat to operational sustainability and water delivery performance in the canal networks. The situation is serious where ineffective watershed management (poor vegetation cover in the water basin) is the underlying cause of soil erosion which feeds the materials into the waterways that intern would necessitate comprehensive study. The present paper aims to present an analytical investigation of the sediment process in the waterways on one hand and estimation of the sediment load transport into the lined canals using the SHARC software on the other. For this reason, the paper focuses on the comparative analysis of the hydraulic behaviors of the Sabilli main canal that feeds the pumping station with that of the Western canal in the Greater Dezful region to identify effective factors in sedimentation and ways of mitigating their impact on water abstraction in the canal systems. The method involved use of observational data available in the Dezful Dastmashoon hydrometric station along a 6 km waterway of the Sabilli main canal using the SHARC software to estimate the suspended load concentration and bed load materials. Results showed the transport of a significant volume of sediment loads from the waterways into the canal system which is assumed to have arisen from the absence of stilling basin on one hand and the gravity flow on the other has caused serious challenges. This is contrary to what occurs in the Sabilli canal, where the design feature which incorporates a settling basin just before the pumping station is the major cause of reduced sediment load transport into the canal system.Results showed that modification of the present design features by constructing a settling basin just upstream of the western intake structure can considerably reduce the entry of sediment materials into the canal system. Not only this can result in the sustainability of the hydraulic structures but can also improve operational performance of water conveyance and distribution system, all of which are the pre-requisite to secure reliable and equitable water delivery regime for the command area.