Journal of Water Resources Engineering
Year:2009 | Volume:1 | Issue:1|Papers Count:8

Surface irrigation is the most common watering technique due to its lower cost of installation and the lower energy requirement as compared with the methods requiring mechanical pressure. Recent advances have upgraded the efficiency of this technology on a par with the pressurized systems, of which the gated pipes (hydro-flumes) have made the most significant contribution, as the flexible polyethylene pipes have replaced the 4th order laterals. Application efficiency (AE) and water use efficiency (WUE) of wheat, based on the net water requirement as recommended by the National Document of Wheat in the Province of Fars (NDWPF), were studied at 5 locations: Darab 1&2, Kavar, Sarvestan, and Qaderabad. When the best management practices, such as laser leveling were implemented, A E was 92, 70, 62, 68, and 64%, and WUE was 1.20, 1.70, 1.23, 1.17, and 0.85 kg m-3 in those locations, respectively. These results indicate that water loss is independent of the installed irrigation system; mismanagement is the root of the problem. As these results are drastically different from those the NDWPF, a revision of this document is highly recommended. 

This study was carried out to investigate the effects of different water application rate (40, 60, 80, 100 and 120 percent of water requirement) on the yield and water use efficiency (WUE) of the Early Urbana tomato. This experiment was performed at the research farm of the College of Agriculture of the Tehran University (a semi-arid area) on a clay–loam soil, using a randomized complete block design with three repetitions. The results indicated that the different treatment had a significant effect (1% level) on yield and WUE of tomato. The maximum yield and WUE obtained at 100% water requirement. Furthermore, it was observed that the reduction of water application rate by 20, 40 and 60 percent reduced the crop yield 24.04, 57.13 and 74.10 percent, respectively.

Spillways and energy dissipators are very important appurtenances of dams, of which faulty design and construction may result in irreparable damage and harm. The primary hydraulic analysis of the ogee spillway, bucket and stilling basin of the Salman Farsi Dam, located in the province of Fars, revealed the faulty design, which required a renewed study. In this laboratory study we constructed a physical – hydraulic model of a section of the ogee spillway and its bucket in a flume and used different flow rates to simulate the flow regime experienced by the actual structures. Our results revealed the faulty design and emphasized the necessity of further studies.

Precipitation maps perform undeniable roles in the hydrological and water resources management studies. The reliability of the data used in preparing these maps determines their usefulness. As the rain gauging stations are relatively few and far apart, interpolation of the rainfall amount and distribution is an important process in drawing reliable maps. Many statistical methods are available through which interpolation of isohyetal maps may be achieved; however, the estimations made by some of these models are not satisfactory. The geostatistical methods developed in recent decades are the most reliable in predicting the local variations with fewer sampling. We employed different interpolation models in the GIS domain in the present study using the GS+ software to prepare the mean annual precipitation map of the Province of Fars. Furthermore, optimization of the interpolation process was achieved through assessing different estimators and determining the error percentage of each model in predicting the most reliable values. 

The optimum management of water resources in order to preserve and/or enhance water quality requires sufficient data of the location and quantity, as well as the spatial distribution of the chemical factors. Selection and accuracy of appropriate methods for zonation and mapping of variations in groundwater quality parameters depend on the regional conditions and data availability, which is an important stage for groundwater management of the region. The purpose of this research was to determine the most suitable interpolation method for the study of the spatial analysis of the pH and TDS of the groundwater in the Arsanjan Plain located in the northwest of the Province of Fars. Different methods of geostatistics, including the ordinary kriging (OK) and the simple kriging (SK), as well as the deterministic methods such as the inverse distance weights (IDW), the radial basis function (RBF), the local polynomial interpolation (LPI), and the global polynomial interpolation (GPI) were used. The results showed that among the deterministic methods, the RBF method, having the highest R and the lowest RMSE is the most appropriate method for mapping the pH and TDS variations in the study area. Also, the results revealed that the SK, with R=0.77 and RMSE=463.5, and the OK, with R=0.27 and RMSE=0.2 had the highest priority among the kriging methods, thus are selected for mapping the pH and TDS variations, respectively. Finally, the results indicated that the SK and the OK methods had a higher priority than the deterministic methods and thus are selected as suitable methods for mapping the pH and TDS variation in the Arsanjan Plain, respectively.

Water hardness shows corrosive effects on stainless steel pipes. The chloride content in water determines the stainless steel resistance to crevice corrosion. It is well-known that the crevice corrosion rarely occurs in the 304/304L stainless pipes if the pH of water ranges 6.6-8.0 and its chloride content is <200 mg/l. Furthermore, corrosion of 316/316L stainless pipes is rare in the same pH range if the chloride content of water is <1000 mg/l. The chloride content of the water of the Soltan Abad Industrial Complex is 386.36 mg/l (198.7ppm). The crevice corrosion rapidly occurred in the Type 304 stainless steel pipes of Daity diary factory, particularly in and around the welded zones. Metallographic investigation of both the welded and heat-affected zones revealed the poor quality of the welding material; there were pores in the welded zones. Moreover, other faults, such as incomplete penetration and a lack of diffusion of the welding material were observed. A few directives for corrosion prevention of such materials complete the paper.

The objectives of this study were to determine the cost and consumption rate of domestic water for house owners (HO) and tenants (T), estimation of domestic demand function, and price elasticity of water in different seasons. The data were collected through questionnaires. The stratified random sampling method was implemented in data collection from 50 households. Water demand function estimated using the Stone-Gery Model. This study was carried out in Marvedasht, the Province Fars. The mean number of occupants of the HO and T groups was 3.0 and 1.8, respectively. The percentage of increase in water consumption for the HO groups in the spring, summer, autumn and winter was 12.0, 9.6, 7.5 and 12.5, respectively, relative to the T group. The water price for the HO and T groups was 394.5 and 387.0 rial/m3, respectively. On average, the HO group had to remit 43,983, 50,274, 46,229, and 41, 285 rials for water above those of the T group for the spring, summer, autumn, and winter, respectively. In applying the Stone-Gery Model, the independent variable could explain the changes of water demand in spring, summer, autumn and winter by 28, 23, 22 and 24 percentages, respectively. The minimum annual and seasonal water demand for each household was 219.9, 55.6, 71.1, 64.8, and 52.9 m3, respectively. Water demand in different seasons was non-elastic related to its price.

A two dimensional mathematical model was developed to determine the local scouring depth around bridge piers. The Navier-Stokes equations were solved using the finite elements method, through which the velocity field was also obtained. This velocity field in a domain between two vertical parallel plates could then be used as the input data in the sediment transport equations. The Galerkin,s Weighted Residual Method was employed to develop the variational formulation of Navier-Stokes and the sediment transport equations. The domain was discretized into a series of 8-nodded rectangular elements. Quadratic and linear shape functions were respectively used to interpolate the velocity and pressure fields. Having solved the sediment transport equations, and taking into consideration the initial and final sediment concentration, scouring depth could be calculated. The finite elements solutions were compared with the experimental data and those obtained by finite differences method. The results were comparably close.