Journal of Water Resources Engineering
Year:2016 | Volume:9 | Issue:29|Papers Count:9

In sustainable development of urban water systems not only different economic, social, environmental and technical aspects should be taken into account, but also the priorities and preferences of all stakeholders and shareholders, including water users, service providers and other involved organizations should be considered. The complexity and multiplicity of variables that exist in a decision-making problem related to urban water systems calls for employing systematic and efficient methods, which can incorporate all criteria into a decision-making process as well as being capable of modeling uncertainties and ambiguities that lie in the problem. Fuzzy group decision-making (FGDM) methods are system analysis tools widely used for solving water resources and environmental planning and management problems. In this paper, an application of fuzzy analytic hierarchy process (FAHP) method in planning for sustainable development of urban water systems is demonstrated in terms of a case study. The objective of the implemented case study is to select a sustainable development scenario for the urban water system of a hypothetical region in Tehran called “Shahrak”. Four sustainable development criteria and eleven indicators were adopted to rank six development scenarios for Shahrak’s urban water system based on expert judgments elicited from questionnaires. The final results verified by some major decision-makers show that FAHP may facilitate the decision-making process for urban water managers and decision-makers and assist achieving the objectives of sustainable development in an urban water management sector.

The impact of global warming on climate change due to an increase in the greenhouse gases in the atmosphere has been proven in many natural systems. All of the general circulation models (GCM)of the atmosphere predict a warmer future for the planet Earth. Hydrological processes such as rainfall and river flows as main sources of water supply will be affected under such circumstances. Due to the low spatial resolution or simplification of some micro-scale phenomena in atmospheric GCMs, they cannot be employed for an accurate approximation of the climate of a certain area, therefore, their output must be downscaled to the specified meteorological station’s domain. Therefore, the data generated by the Had CM3-GCM were downscaled applying the LARS-WG model under two scenarios A2 and A1B, and the parameters of daily rainfall, and the minimum and maximum temperature of the Sufi-Chi basin generated for three periods (2011-203, 2046-2065-, 2080-2099). The artificial neural networks and genetic programming of intelligent model were used to assess the climate change’s effects on runoff generation of the Sufi-chai Basin. The results indicate that rainfall will increase in the 2011-2030 period and will decrease thereafter. Furthermore, the maximum and minimum temperatures will generally increase in the three mentioned periods, however, the runoff volume will decrease in the future relative to the present time.

An adequate quantity and an acceptable quality are cornerstones of achieving sustainable development for a human settlement. These are double important in regard to groundwater, which has been utilized through the ages due to its accessibility and acceptable quality relative to the surface waters. To assess the Qorveh plain’s groundwater quality, 1816 water quality data obtained from 45 production wells during the 1984 to 2012 period by the province of kurdistan Regional Water Company were analyzed using the AqQA software and evaluated by the Piper, Schuler, Wilcox, Gibbs stiff and Durou diagrams.

Recently, water resources development projects and their selectivity have received much attention due to the accelerating population growth and their water requirements. The aim of this research is an application of the multi criteria decision making (MCDM) models in the proper selection and prioritization of dam construction projects. Application of three groups of MCDMs including SAW (simple additive weighing), AHP (analytic hierarchy process) and TOPSIS (techniques for order preference by similarity to ideal solution) have been discussed to select the best site and type of reservoir considering the important decision making criteria. To explain the effectiveness of the mentioned models, a case study is presented on the site selection of the Khersan-1 Dam and hydropower Plant in the province of Chaharmahal & Bakhtiari benefiting from opinions given by some experts and decision makers. The results of an application of these three methods have been analyzed using the Borda method and the best alternative has been selected. To this end, the screening has been Performed for 6 primary axes A to F, and three different alternatives: an arch concrete dam located on the D axis, a gravel dam located on the D axis, and an arch concrete dam located on the F axis were compared with respect to 8 quantitative and qualitative economic and technical criteria. The results confirmed that an arch concrete dam located on the D axis was the best alternative. This research can help the water industry for accurate management of dam construction projects using the novel decision making models combined with expert opinion.

Cavitation is the most important problem in the bottom outlets of dams because of high flow velocities. Due to flow velocities up to 30 m/s and negative pressures, remarkable damages occurred on the lining of these tunnels. In this paper, a numerical model based on the finite volume method for fully three-dimensional (3D) using VOF model in two-phase including air and water is applied. Validation of the work has been obtained by comparison with measurements of a laboratory model, i.e., the pressure and velocity magnitudes are computed along the tunnel with error up to 20 percent. Cavitation index in flow direction have been estimated under different conditions of gate opening and shown critical situation (less than 0.25) at the downstream the gate. For aerated flow, the cavitation index were increased up to 6-7 times greater than the non-aerated flow and improved the flow conditions for cavitation occurrences.

 In contrast with conventional impermeable weirs, Solid objects and dissolves substances can pass through gabion weirs. Thus, due to its minimal negative attributes, gabion weirs are considered environmentally friendly structures. This study aimed to assess the effect of upstream and downstream side slopes of the crump gabion weirs on the discharge coefficient for free flow conditions and compare it with those of impermeable weirs. To achieve this objective, a general non dimensional relationship was developed. Eight different Gabion weir models and 3 impermeable weir models were examined in a horizontal flume, 15.0m long, 0.3m wide, and 0.5m deep, respectively. Multiple, methodical experiments were performed using various discharge rates including: discharge, upstream and downstream depths, material size, and upstream and downstream slopes. It was observed that under the free flow conditions, a decrease in the upstream and downstream slopes led to an increase in the weir and a decrease in the discharge coefficient. Furthermore, an increase in the material size caused a decrease in the head on the weir and an increase in the coefficient development of a relationship to predict the gabion crump weirs’ discharge coefficient (R2=0.97) was achieved through dimensional analysis.

The main purpose of this study was to simulate rainfall - runoff processes to assess the effects of land use changes on the runoff generation using the hydrological WetSpa model, and also to evaluate the accuracy of predicted daily discharge at the Gol Gol Catchment outlet, in Iran. The Nash Sutcliffe efficiency criterion was 0.603 for the daily discharge during the 2003 to 2009 period and the land use map of 2007. The results Further indicated that the land use have changed from 1988 to 2013, as forests and irrigated – gardens have decreased by 3322.502 and 3934.386 hectares (ha), respectively, while rangeland and rain-fed areas have increased by 3942.99 and 3313.9 ha, respectively. For assessing the effects of land use changes on the discharge, the simulated daily discharges generated by the model for the following years,1988, 2003, 2007 and 2013 were compared using the paired t-test. Results showed that there were significant differences at the 99% confidence level between the simulated discharges of 2003 and 2013 land use maps. The average annual discharge has increased from 1.118 m3/s in 2003 to 1.134 m3/s in 2013 due to this land use changes. Moreover, the mean daily discharge was increased by 15 l/s from the beginning to the end of the study period. In addition, there was a general increasing trend in the runoff volume

Elevation is one of the main sources of information required for the determination of physiographic characteristics of a basin. Digital Elevation model (DEM) is one of the products derived from the Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) sensor satellite images. The objective of this study is the determination of physiographic characteristics of basins using ASTER DEM. Thus, The KabudRahang Plain KRP was selected as the study area, which is a part of 3448 km2 of Gharechai Catchment Basin in the northern part of The Province of Hamedan. In order to evaluate the outputs, comparison was made with values provided by the Office of Regional Water Studies of Hamedan, which were extracted from an aerial imagery of National Cartographic Center, and the digital elevation model derived from the SRTM sensor images and the Geographic Information System methods. To achieve the study objectives, Firstly, the channel network, including flow and cumulative flow direction was determined, using the ASTER derived DEM. Then The KPR Basin was studied and the rivers were ranked. Finally, the physiographic characteristics of the basin were extracted. The results show that the basin area, perimeter, and length were 3410.43 km2, 406.34 km, and 112.82 km, with a relative error of 1.09, 5.82, and 8.28 percent, respectively.  Furthermore, the basin shape factor was calculated using the Horton, Gravelius, Miller and Schumm methods, which resulted in 0.267, 1.94, 0.259 and 0.584 values, respectively. The time of concentration values were 13.33, 4.86, 6.91, 46.53 and 148.57 hours calculated using the Kirpich, Kerby- Hathaway, Bransby Williams, Carter, and Ventura methods, respectively.

Weirs have widely been used for the flood flow, flow measurement, flow diversion and control of water levels in dams, rivers and open channels. This study was curried out to investigate the hydraulic characteristics of flow over the sharp-crested triangular plan form weirs for different apex angles. Three-dimensional flow field over the weirs 30, 60, 150 and 180 degrees was numerically simulated based on the RNG turbulence model using the software Flow-3D version 10.0.1. The results showed as the apex angle increases, the interference of the longitudinal and lateral falling flows decreases and in turn leads to less disturbance and vortex flow. Also, in downstream, the flow surface knob of the longitudinal profile and height difference between the transverse cross-section profile becomes less and velocity and Froude number increase, whereas the pressure on downstream bottom decreases. The results show that the RNG turbulence model for determining water surface profiles along the channel downstream of the weir of appropriate accuracy.