IRAN-WATER RESOURCES RESEARCH
Year:2012 | Volume:8 | Issue:1 (23)|Papers Count:11

The Avan unconfined aquifer is one of the reliable groundwater storages in the west of Khuzestan province. The great Karkheh dam and the irrigation network development resulted in more water injection into the Avan aquifer. The purpose of this investigation is to evaluate uprising of groundwater table, to demarcate zones most affected by the water level and evaporation, and to estimate annual volume of water from the Karkheh dam storage into the Avan aquifer. In order to assess the spatial spreading of the groundwater level in different parts, pre- and post-dam water level maps were prepared. To understand the general trend of water level, unit hydrograph of the plain was also prepared. The collected results indicated that in average the water level risen about 5 meters and the most up coning was about 14 meters in the west and north. Two methods including flow channel and chemical balance was used to compute the flow input from the Karkheh dam into the aquifer. The annual water inflow from the Karkheh dam storage into the aquifer using the average data was 7.3 MCM.

Overexploitation of groundwater resources may result in lowering the groundwater table at a faster rate. In order to balance groundwater exploitation with recharge, the major remedial measures suggested are to strengthen groundwater management, to adopt water demand policies, to raise water use efficiency, and to increase water supply from other sources. The relationship between farmers’ income and the withdrawal was then examined using goal programming with 10, 20 and 30 percent deficit from water consumption target. The needed data were obtained from a random sampling. 112 farmers were chosen in the selected villages. The results at plain level showed that annual groundwater pumping; with optimal control is less than current groundwater pumping at discount rate less than 18 percent. The decrease percentage on benefit was less than that of the withdrawal for all representative farmers, based on the result obtained from goal programming. For example with the equal weight assigned to the water consumption and to the benefit objective, the water consumption target can be fully achieved. In this case products with deficit irrigation strategies and sprinkler irrigation method are used in the crop pattern. This study also revealed that the application of deficit irrigation strategies and sprinkler irrigation method lead to a decrease in extracting groundwater compared to the current status. Finally, the results can help farmers to choose crop pattern, irrigation strategies and irrigation method in such a way that both farmers’ income and withdrawal are simultaneously optimized.

Qazvin’s traditional gardens have had important roles in the history of Qazvin. But today because of two major problems, water shortage and city expansion, these gardens are in an improper situation. In this paper using the Operational Research method, it is tried to develop a management inclusive plan with two fundamental policies: gardens vitalize in a short-term horizon and gardens flourish in a long- term horizon. The action plans are determined for the policy makers in order to achieve sustainable development in the garden complex. According to the results of this study, in the framework of policies mentioned, water distribution and related expenses over the gardens would be fair. Also the irrigation efficiency in the garden complex would be improved from 33% in current situation to 38% in short-term horizon and 59% in long-term horizon.

In the study area Chaleh Monar and Shelar anticlines covered by the Asmari formation (160km2), are heavily affected by tectonic processes. As a result a variety of structural features such as fracture, folding and faulting has been developed. The extensive exposure of carbonate rocks and suitable climatic condition (815 mm annual rainfall) created good conditions for karst phenomena in the Shirin Behar area. The structural study indicated that in addition to large scale faults, local faults have been developed. Besides, the fracture’s longitudinal density is more than the lateral density. The aim of this study was to determine hydrogeological characteristics of the Dreh-e-Anari spring with discharge of 2.8 m3/s in Shirin Bahar area. To assess hydrogeological characteristics of the Dreh-e-Anari spring, spring’s hydrograph was analyzed. Analyses of the Darah-e- Anari recession curve showed that the dominant flow regime was conduit diffuse. The catchment area of the spring was estimated to be about 154 km2.

In this research the level of accuracy for Chow regression and stochastic methods is compared for estimating annual peak flood in central Alborz region. The annual peak flood data in this region were incomplete, and regression method was used for data completion. 23 gauge stations with 20 years common data were selected for the analysis. The observed data at each station was divided into time series of 10, 15 and 20 years preparing 414 time series of annual peak floods for the analysis. Using 7 important frequency distributions including, Normal, 2 parameters Log Normal, 3 parameters Log Normal, 2 parameters Gama, Pearson type 3, Log Pearson type 3, and Gumbel 1the probabilities were accounted for each of these time series. Then the best distribution was chosen and the annual peak floods for 2, 5, 10, 15, 20, 25, 30, 50, 100, 500, and 1000 years return periods were estimated. Peak discharges for these return periods were estimated using chow’s regression and Stochastic methods, and then compared using probability indices such as, MSE and MBE. This research showed that Chow’s regression method gives better results for estimating annual peak flood in the central Alborz region.

Optimal groundwater bioremediation formulation are often complex, nonlinear, and involve intensive computations. Population-based optimization techniques allow solution of more complex nonlinear problems compared to the traditional gradient-based approaches, but computationally they are more intensive. For the first time, this study, proposed ant colony optimization (ACO) algorithm for groundwater bioremediation problems. Performance is compared to the hybrid genetic algorithm and simulated annealing. Rates of injection and extraction pumping and well locations are decision variables. The BIOPLUMEII is used as simulation model. Results showed the phenomenal capability of ACO algorithm in cutting calculation cost, in comparison to Hybrid simulated annealing and genetic algorithm, with a minor calculation error of 1.8%. Optimization results showed that ACO note worthily reduces computational time (56%) compared to the hybrid genetic algorithm and simulated annealing. ACO can be used as an alternative method for solving larger-scale groundwater remediation problems.

Dam break wave is a phenomenon resulting from sudden release of water in a channel. Aiming at a numerical study on such waves, this paper presents a finite volume model based on shallow water equations which utilizes the Weighted Average Flux (WAF) scheme to estimate inter-cell numerical fluxes. The model has a shock capturing feature, and requires no special treatment to handle waves propagating over dry beds. Different stages of wave propagation were analyzed by offering free surface profiles for the cases studied. Furthermore, several computational tests, including comparison with the existing analytical solution as well as experimental data, are provided to confirm the performance of the model in simulating unsteady flow due to the dam break.

Principal components and cluster analysis were used for grouping the monthly precipitation over Iran into some homogeneous regions. Such grouping is considered as an essential and primary step for pre-process in downscaling of the general circulation models outputs. The monthly precipitation data of 42 stations for the period of 1967-2003 (37 years) forming a 42×444 matrix was used as input file of the principal components analysis. Using PCA, this matrix was reduced into a 42×33 matrix that accounted for about 96% of total variance in the observational time series. The reduced matrix was used as the input file of the Cluster analysis. The results regionalized the country into six different regions.

Hyrogeological drought is a natural hazard that develops when groundwater systems are affected by drought., First the groundwater recharge is decreased. Then the groundwater levels and finally, groundwater discharge by rivers and springs are decreased or stopped. This research analysed the effects of artificial recharge of groundwater on temporal and spatial distribution of hydrogeological droughts using Piezometric State Index (PSI) in Garbaygan plain. The results of this study showed that the efficiency of flood spreading systems for reduction of groundwater level drop caused by droughts, limited to the initial years exclusively and severe hydrogeological droughts have gradually been initiating since 1376 to 1387 in the south of the implemented flood spreading project.