灌漑・排水システム工学

An analysis was undertaken of a new development of Archimedes screw consisting of a variable-inclination screw suitable for applications in which the downstream level may vary (e.g. sea level). As a result the energy consumption when the downstream level is low is less than that of a conventional, fixed Archimedes screw. In addition, investment costs are lower as a result of less expensive civil work being required. Moreover, this screw can also act as a check gate because it has a float at his downstream end. The flow rate for different rotational speeds was measured and a good fit was obtained with a developed graphical model. This paper analyses the operation of an Archimedes screw prototype pump of variable inclination and models its behavior. Its energy consumption is then measured and compared with that of conventional fixed inclination screw pumps

Floods are among the most devastating natural hazards in the world. Iran and specially Makoran has big rivers and flood planning and management is mainly concentrated on riverine floods occurring during seasonal rains. This research investigate on the Lower Sarbaz and Kajo rivers and used discharge analysis of river channel-gauging time series to assess the regional water supplies and agricultural purposes. This analysis reveals that for all flood conditions especially on the lower Sarbaz river, have systematically risen for monthly maximum discharge volumes over the period of record. The Sarbaz and Kajo rivers have served as important routes for transportation and commerce since the formation. These two rivers need to be re-assessed especially in light of the predicted large increase in rainfall and water in the rivers over the next 25 years or so as predicted by the global climate change models. Iran has big rivers and flood planning and management is mainly concentrated on riverine floods occurring during monsoon. However, flash floods in hilly and mountainous areas are also common with demonstrated damage potential. Flood events in arid areas can be extremely damaging with increasing development, particularly in Garmbeet and Bahowkalat area (Down-stream of Pishin Dam). Flood protection and drainage design are considerable importance. Existing flood risk models are inadequate, and predicted changes in the climate show that there may be much more water in the system in the near future. New models are being built to test how the river-floodplain systems will respond to large increases in the discharge in the future.

Sumbangtimun Village and Kandangan Village, in the lower part of Bengawan Solo River, are regularly flooded almost every year. These flood prone area are situated in the river meander with low natural levee. Losses due to flood damage were estimated to reach 2.5 billion rupiah in the year 2007/2008 with the greatest losses from agricultural sector. These losses were caused by flooding that comes early before the harvest time. Surround dike to prevent flood inundation is recommended by the river authority. Regarding different land uses, i.e., rice fields, tree crops plantation, settlement, with different inundation tolerant, a set of mini polder is proposed to overcome the problem of inundation and its water management. The polder system is attributed by surrounded dike, local drainage system and pond retention with or without pumping system. The mini polder system that is equipped with lateral gate as flood control structure is proposed to solve the problem of inundation in the agriculture and settlement areas. Hydraulic mathematical models (HEC-RAS and Pond Pack) for simulating flow characteristics in the flood prone area are employed to determine the design of an appropriate mini polder system and its operational procedures. In addition of technical aspects, the design is also reviewed for compliance of the non-technical aspects including agricultural, economic and environmental in the local communities. According to the result of frequency analysis, flood discharge in the Bengawan Solo River was 1,500 m 3 /s for 2 year return period (Q2) and 2,525 m3/s for 10 year return period (Q10). Flood water elevation based on 2 year flood return period was obtained at +17.50 m or inundation depth average was around 1 m. The area that inundated at this condition was around 250.48 ha and the inundation duration was in 2 days. Flood water elevation based on 10 year flood return period was at +19.05 m or inundation depth average was around 2.5 m. The area that inundated at this condition was 382.58 ha with the inundation duration was in 3 days. The use of storage area and lateral structures models can describe flood phenomena in the modeled flood prone area more accura.

The aim of this article is to show what M4P is, how it came into being and how it has been used to guide intervention in different context and to weigh the extent to which it can be used to guide the study and interventions aimed at enhancing the sustainability of smallholder irrigation schemes. M4P is a holistic approach to development that offers agencies the route needed to achieve systemic and sustainable change, focusing on the identification and addressing of fundamental constraints that inhibit the beneficial participation of the poor in market systems as either consumers or producers. M4P historically evolved from diverse experiences in business promotion, private- sector policy development, the SL approach and the failure of economic structural adjustment programs and trade liberalizationas development approaches to development and poverty eradication. This diverse background made it holistic and multi-dimensional. The M4P conceptualises market systems as consisting of core markets, supporting functions, and a set of rules. The smallholder farmers, as potential markets for different value chains are not well understood, hence the need to invest into an M4P guided holistic and multi-disciplinary research to identify the factors that prevent markets from working for the smallholder irrigation farmers in Zimbabwe