T. Sohrabi, U.a. Khoshkhahesh,
Volume 3, Issue 4 (1-2000)
Abstract
The purpose of this research is to determine the application efficiency of rice irrigation plots and to analyze the reasons for low efficiency. The study will also try to determine the effective factors which could increase the application efficiency of rice fields. The selection of rice fields was based on climate, soil characteristics, and farmer management. Water application efficiency was determined by field measurements in three modern irrigation networks named Fouman (F), Rasht (G) and Lahidjan (D). In the meantime, a traditional network was included for comparison. In the study areas, the soil texture was heavy with an infiltration rate of less than 3 mm/day. The study was carried out under two different conditions: (1) without return flow and (2) with return flow. In the first case, the average application efficiencies in Fouman (F), Rasht (G) and Lahidjan (D) were about 51.2, 49.0 and 49.4 percent, respectively and the maximum and minimum values were about ((52.6, 49.7)), ((50.7 , 47.3)), and ((50.7 , 48.0)) percent, respectively. In the second case, the average application efficiencies for the above-mentioned regions increased to 73.4, 73.3 and 72.4 percent, respectively and the maximum and minimum values were about ((74.3, 72.4)), ((74.3, 72.1)), and ((73.0, 71.5)) percent, respectively. Runoff ratios in the above-mentioned regions were 30, 33 and 31 percent, respectively. During growing period (from transplanting to harvesting), the average applied irrigation water was about 1130 mm (11300 m3/ha) and the average evapotranspiration was determined to he about 561mm.
M. J. Monem, M. R. Alirezaee, E. Salehi,
Volume 6, Issue 4 (1-2003)
Abstract
Recent studies have shown poor performance of irrigation systems, which indicates the requirement for special attention to performance improvement. The first step for improving the performance of irrigation systems is evaluation of the present situation. Performance evaluation methodologies presented so far are either qualitative such as DA (Diagnostic Analysis), RA (Rapid Appraisal) and FA (Framework Appraisal), or they are similar to classical methods even if they produce quantitative indicators. They fail to introduce performance standards. In this study, using Data Envelopment Analysis (DEA), which is a quantitative method and produces realistic standards, 8 irrigation systems were evaluated and their performances were determined. With respect to the number of decision-making units, inputs, outputs, and corresponding returns to scale for irrigation systems, a suitable DEA model was selected. Capabilities of DEA allow for separate treatment of performance evaluation of overall irrigation network and its operating company. This feature is implemented using different technical and operational indicators.
The results indicated that Zayandeh Rood irrigation system, among the 8 irrigation systems, has the highest technical efficiency. Minab and Varamin systems have the lowest technical efficiencies. Golestan and Behbahan Networks perform well, although their operating companies are inefficient. Garmsar, Ghazvin, and Moghan systems, although not inefficient, have some improvement potentials. In general, with respect to the capabilities of DEA in performance evaluation of irrigation systems and indicating appropriate standard, it can be concluded that this technique is quite efficient and successful for performance evaluation and improvement of irrigation systems.
