مجله سامانه های سطوح آبگیر باران
سال چهارم شماره 3 (پیاپی 12، پاییز 1395)

Rainfall is a source of water with the best quality in the nature. Therefore, harvesting and using of the runoff resulted from rainfall, can help better management of water resources in our country. As a considerable part of urbanized areas are building roofs, quantity of water harvested from roof catchments will be considerable and can prepare a part of water required for the residents. In this study, rainfall and runoff events were measured in cities of Mashhad (with arid and semi-arid climatic condition) and Noor (with sub-humid and humid climatic condition). The surfaces selected to collect rainwater were two roof catchments (one in each city) with almost the same conditions. After preparing the rooftops, the required storages and the related equipments were established and the amount of runoff was measured after each rainfall event for whole the rainy seasons of the year. Information of precipitation events was received from the closest meteorological synoptic stations. Using appropriate statistical analysis, the volume of runoff as well as runoff coefficient for different levels of rainfall depth and intensity was determined after each event. The results of this research show that average runoff coefficient for the fall season in Mashhad is 0.66 and is 0.75 in Noor, for the winter it is 0.69 and 0.76 respectively in Mashhad and Noor, and for the spring season, the average runoff coefficient was measured 0.62 in Mashhad and 0.69 in Noor. The threshold values (minimum values) of rainfall for runoff generation 0.3 mm in Noor and 0.7 mm in Mashhad. The total depth of rainfall and runoff for the measured period in Mashhad were 217.5 and 139.9 mm, respectively, and in the Noor they were 496.8 and 356.1 mm. The highest amount of seasonal runoff generated in Mashhad belongs to the spring but in Noor it has been occurred in autumn season.

The water crisis in terms of quantity and quality has become one of the growing concerns in human societies. In other hand, climate changes due to greenhouse gas emissions exacerbate conditions and the complexity of management decisions. So that the wet areas are not exempt from this problem. Accordingly, in this study sodium adsorption ratio trend were investigated in deep wells Gharesoo basin in Golestan province under climate changes conditions. HadCM3 model has been used during 2011-2100 under three scenarios (i.e. A1B, A2 and B1). In the next step 16 deep wells located in this basin were studied on the basis of the average SAR during the base period which divided into four categories and were introduced to the Anfis model. After that the best membership functions and a model has been selected during the months of April and October was run for next years. The results showed the SAR in the fourth group in all periods was increased in comparison to the baseline in both months. The third group was additive in April and just in scenario in A1B was increased in October and in two other scenarios was decreased. The second group was decreased in April and was increased in October. The first group is often decreased in the first thirty years and was increased in the remaining periods. Finally, we can find how future changes of SAR percent will affect to the baseline by an initial value as well as changes in climate parameters.

This study examines the quality of drinking water using Fuzzy-AHP south of Firozabad, in the Darenjan watershed Fars province. The study area to determine water quality parameters such as total hardness, calcium, magnesium, sodium, conductivity, sulfate and total dissolved solids were examined. In this study, using the Kriging (Gaussian models, spherical, circular and exponential) each parameter zoning map was, determined and then, using the fuzzy membership function map of each of the parameters affecting the quality of drinking water was prepared. Then, the weight of each layer was determined by using Analytical Hierarchy Process (AHP), and finally water quality map was prepared in GIS. The results indicated that only 4.38 percent of the area has very good quality, good quality 23.33%, 64.01% and 8.29% percent of the average quality of water has poor quality. On the other hand, to determine the relationship between water quality and topographic features in the study area, landforms map was prepared by using topographical position indicator. It was also found that the highest water quality is available in the river landforms, valleys, ridges and upstream drainage. While the lowest quality of drinking water in the plains and piedmont of the study area is located.

The lack of sufficient and available moisture for the plant is a common problem that resulted in sensitivity of arid and semi-arid environments. In these regions, inappropriate temporal and spatial variation in rainfall is a serious issue. Thus, Showing a series a series of solutions for harvesting of the rainfall is essential. Therefore, the implementation of projects is very important. Based on the noted key matter, this study was carried out to find appropriate places for six method of the rain harvesting. In this research, first, we investigated the conditions of environmental factors(slope, rainfall, soil, vegetation) affecting on of these projects by sampling and using of the related data. Then, current and implications conditions of these factors for each of six projects were compared. Finally, the map of the appropriate places to perform these projects were produced. The results show that among of four factors affecting on implementation, just slope has a significant effect, because other factors (rainfall, soil, vegetation) had a homogeneity condition all over the region. So, the final map(map of the appropriate places to perform projects) obtained only based on the slope map. Generally, as respects to the obtained results and the regional conditions; the implementation of pitting and contour furrowing projects is only possible.

The groundwater recharge is one of the methods of desirable utilization of water resources. These systems are performed with the purpose of storage of excess surface water in groundwater aquifers for the improvement of quantity and quality of water by passing through the soil layers. The Performing groundwater recharge projects with the novel techniques does not have a long history in Isfahan and has been started since 1987. In this period of time, 17 projects are designed and performed in this province by Isfahan regional water company. But these projects are too expensive, so it is important to assess them in order to recognize their positive and negative characteristics. In this research, according to general assessment, 5 important parameters in the operation of these projects are assessed. Based on threse parameters, these projects are located in appropriate locations, but there are some issues in the studies done before the performing of these projects. Most of the projects have good state, according to operation and performance, but it is necessary to pay more attention to their maintenance.

Choosing the appropriate inputs for intelligent models is important. Because it can reduce costs and save time and increase accuracy and efficiency of the models. This work aims at the use of gamma test to select the optimum combination of input variables including delayed records of in time series modeling precipitation. Monthly time series of rainfall for the period 1383 to 1393 was used for Rasht station Rainfall data as with different lags were employed as input to gamma test. Results showed that time series with three delays (lags), provides better results. The simulation was performed using Bayesian network and multivariate linear regression. The performance of models was assessed using three criteria, i.e. coefficient of determination (R2), root mean square error (RMSE), and dispersion index (SI). Bayesian neural network using a three-month delay the coefficient of determination of 0.82, root mean square error of 17.84 and a diffusion index of 0.17 showed better performance as compared with multivariate regression. The results established the significant role of the gamma test integrated with intelligent models in the appropriate selection of input variables..

Water harvesting using runoff is one of the approaches that reduces risk factors in the country and leads to a stability and sustainability in agricultural activities of arid and semi-arid regions. This work aims to assess the potential of rock outcrops (more than 90% of rock fragment) for supplementary irrigation in the Zoshk-Abardeh watershed. Results showed that runoff volume extracted from rock outcrops with an area of 433 ha in only four month (June, July, August, and September) will be around 866000 m3, which would decrease the reliance on watershed groundwater resources and compensate a significant part of water deficiency in dry season. Ecosystem function of rainwater harvesting in the studied watershed was estimated to be 650$/ha, which can establish the economic justification of these techniques.