نشریه پژوهش های حفاظت آب و خاک
سال بیست و یکم شماره 3 (امرداد و شهریور 1393)

Water shortage in arid regions, is a serious issue. Therefore the residents of these areas need to have proper knowledge about water harvesting and its efficient use. Thus water harvesting is considered as an efficient economic target. Information about different systems of water harvesting is a major requirement. The most important step in making use of rainwater harvesting systems is appropriate site selection. Identifying appropriate areas for water harvesting systems results. Furthermore it results in optimal utilization of water resources. The aim of this research is developing a framework for spatial assessment of rain water harvesting potential. To assess the potential for runoff generation and groundwater recharge, a conceptual model of rainfall- runoff has been applied. Integrating this conceptual model and Arc GIS, spatial distribution of runoff potential and groundwater recharge across the study area has been estimated. Then, prioritization of areas and sub watershed for surface water harvesting and groundwater recharge purposes has been carried out based on physical and economic index. The benefit/cost indicator has been used in the economic analysis. The results shows that these economically prioritized sub watershed are those with higher total amount of surface water harvesting and ground water harvesting potential while have lower establishment costs. It is worth to mention that an extensive data set has been used for the spatial assessment purpose, the proposed methodology improve the capability for water resource management in the Golbahar and other similar watersheds. The proposed methodology in this study, has utilized the Geographical Information system as a powerful and useful tool in processing, integrating and extracting required information from various data layer for spatial assessment. Therefore, by identification and allocation of water harvesting system to the most suitable areas, while increasing efficiency of these systems a remarkable saving in the time and cost is gained.

Soil temperature is an important physical parameter that affects energy balance between the atmosphere and earth’s surface. Soil and air temperature which are controlled by surface energy balance, have strong physical relationship. Because of the difference in thermal capacity between air and soil temperature, lag time exists between the occurrence of maximum of soil (Ts) and air (Ta) temperatures. In this research, observed daily soil temperature (6 depths) and screen temperature (170 cm) data were used from 1993 to 2008 for different climates including: Ahvaz (arid), Tabriz (semi-arid), Ilam (Mediterranean), Babolsar (humid) and Rasht (hyperhumid). Since, there are limited studies which have investigated the lag-time between the occurrence of maximum soil temperature (Ts) and screen temperature (Ta), this study aims to investigate the role of the lag-time on annual Ts-Ta regression relations. We constructed various regression equations between maxima of Ts (at 50 and 100 m) and Ta (170 cm). Using correlation method and Fourier series approach, the time lag between Ts (independent variable) and Ta (dependent variable) was also determined for all the study sites. Results from the mentioned methods were compared by RMSE, MAE, MBE and MPE criteria against each other. The differences between the two methods were statistically insignificant. The numbers of lag days (NLD) were found to be nearly the same for either mentioned methods. Regression equations between two statistical pairs (Ts-Ta) were constructed for two different scenarios (with and without lag) and the corresponding coefficients of determination were compared for the above scenarios. Results revealed that inclusion of NLD could significantly improve the Ts-Ta regression equations (at P<0.1 significant level), in particular for 100 cm depth. In addition, the NLD and the relevant equations were found to be different for each climate.

Forecasting hydrological variables are suitable tools for water resources management. For this aim, time series models as efficient methods have been considered by the hydrologists. Also, in this study, time series modeling has been considered and seasonal time series models on the total flow, base flow and run-off data of hydrometric station Arazkuseh with 35-years period have been fitted. Afterwards, condition and accuracy of fitted models in forecasting future discharges were considered using Akaike Information Criterion (AIC), Root Mean Squared Error (RMSE) and other parameters.The results show that, ARIMA(1,0,0)(0,1,1) is the best model for forecasting the total flow and base flow, respectively and ARIMA(1,0,1)(0,1,1) is the best model for forecasting the run-off. for assessing the accuracy of models, 5 years data from 2007 to 2012 were used for estimation of total flow, base flow and run-off. RMSE and R2 for forecasting the total flow is 3.46 and 0.47, for base flow 2.61 and 0.48 and run-off 0.83 and 0.23 were obtained. The results revealed that if the total discharge was obtained by summation of values obtained from base flow and run off time series model, the more accurate results could be obtained.

Groundwater is the most important water resources for agriculture, industry and drinking and therefore qualitative changes in program planning and sustainable management of water resources is necessary. The aim of this study was to evaluate the trend of groundwater quality parameters of some selected stations in Golestan province by using non-parametric Mann-Kendall and Sen̕s Methods. For this purpose, the water quality data were gathered in 8 stations of Zarringol plain during 1996-2011. The quality parameters used in this study were TH, Cl-, K+, Mg2+, Ca2+, Na%, TDS, SAR, Na+, HCO3 -, SO4 2-, EC, pH, the total sum of cation and anion. Before analyzing the data, the effect of significant first order autocorrelation was removed from the data set. The results showed most water quality parameters tends to rise. 41% and 20% of groundwater quality time series show meaningful positive trend during wet and dry season, respectively. Also 20% and 10% of groundwater quality time series show meaningful negative trend during wet and dry season, respectively. Due to the positive slope of the trend line for most quality parameters, water quality in this region tends to decreases. The maximum positive slope of the trend line is belong to EC, where observed in downstream of plain. The loss of groundwater level due to increase of consumption can be one of the main reasons for decreasing the ground water quality and salinity.

Lithology and soil forming conditions play a very important role in controlling the properties of residual soils. To assess the role of these factors on the composition of clay minerals, residual soils developed on three parent materials including peridotite (Pe), tonalite (To) and limestone (Li) were studied in forest ecosystems of Fuman-Masoule region. Parent rock mineralogy, clay mineralogy of saprolite and soil genetic horizons were determined. In Pe pedon, saprolite and soil genetic horizons have different clay mineralogy. Kaolinite and vermiculite are the major clay minerals present in C2 horizon, whereas smectite, illite, illitevermiculite, illite-smectite and kaolinite are present in upper horizons. Smectite and kaolinte might have formed from pyroxene, olivine, biotite and vermiculite via autogenic and transformation pathways. The presence of illite in pedogenic horizons of Pe pedon is in line with the vertical distribution of total K concentration of clay fraction and could be due to accumulation of K and formation of secondary illite in topsoil. In the saprolite of Li pedon, illite and smectite are present in clay fraction. However, illite is replaced by kaolinite in genetic horizons. Pyrite oxidation in parent material seems to enhance the pedogenic formation of smectite and kaolinite. Clay mineral composition of saprolite layers, especially in Pe and Li pedons, is highly influenced by parent materials and is different from genetic horizons. Although the mineralogical composition of genetic horizons developed on different parent materials is not substantially different, the relative content of given clay minerals might be different in various soils.

Image analysis is an advanced method of quantifying soil properties and increasing the accuracy of morphological and micromorphological studies. Microscopic and ultramicroscopic techniques provide invaluable information about the soil genesis and physicochemical, mineralogical and morphological properties of undisturbed natural soil structure. In this study, the physicochemical characteristics of some disturbed and undisturbed samples of eight pedons located at the Rice Research Station of Chaparsar were analyzed. By using image analysis softwares Image J and AnalySIS, the micromorphological characteristics of pores and redox properties in the intact samples were studied. The results showed that changing the land use from paddy to Kiwi orchard increased soil porosity and caused the formation of more crystallized forms of iron due to higher microorganism growth because of saturated conditions. The results of image analysis confirmed the presence of a puddled layer in the paddy soils and higher porosity in Kiwi cultivation. Image analysis of different iron forms also indicated the higher contents of iron in the non-paddy land under Kiwi cultivation than the paddy soils that are due to the improper land use. The differences in the nature and structure of different forms of iron are probably the reasons for the differences in image analysis and chemical results.

In recent years, energy cost has increased more than other expenses of agriculture sectors. Reconsidering the status of agricultural pumping stations, the features of their energy consumption and applying the new design methods, to increase the efficiency, have valuable roles in controlling energy consumption. In these stations constant-speed pumps are used which could have suitable efficiency in a small range of pressure and discharge changes. If the less pressure or discharge is favored according to irrigation program, the unbalanced relation between motor speed and system curve will, cause high energy losses. This problem, especially in systems like pressurized irrigation that frequently confront the demand changing, imposes extra costs. In this study, Harkalleh-Laali irrigation system, with introducing a method as well as analyzing a practical example, the effects of variable-speed pumps displacement were evaluated in comparison with constantspeed pumps in viewpoints of hydraulics of plan, energy consumption and pump efficiency. Results show that with employing variable-speed pumps in this project, pump efficiency could be increased up to 10% and the reduction of energy consumption per year could reach 49%, related to the current plan.

Dam construction on rivers can lead to sedimentation in reservoirs causing a lot of problems. Forecasting the amount and distribution of sedimentation is very important for the designers of the dam. The area reduction method is one of the experimental models to study the sedimentation in reservoirs. The parameters used in area reduction method have been obtained by Borland and Miller according to the study on 30 dams in America. It is necessary to obtain the optimal values of these parameters for the reservoir sedimentation in other areas. In this study, some models has been developed based on harmony search algorithm (HS) and its various improved algorithms such as IHS, GHS and SAHS in combination with area reduction methods for calculating optimal values of area reduction parameters. At first the accuracy of the developed models has been evaluated using standard functions and then Karaj reservoir sediment is estimated using developed model. Statistical comparisons of different improved methods and area reduction method with the actual sediment deposits in Karaj dam indicate high performance of developed models. Among these methods, the rate of error 90 percent has been reduced by combination of SAHS and HIS with area reduction method.

Since information about temporal variation of suspended sediment establishes a basis for watershed and river management, it is crucial to utilize a method for modeling and forecasting suspended sediment that takes all influential factors into account. In this research, the transfer function model is used to study temporal variation of suspended sediment on seven selected stations in Gorganrood river. In order to evaluate the performance of the model in forecasting suspended sediment compared to the sediment rating curve, only flow discharge is considered as a highly effective factor in variation of suspended sediment. Although this comparison reveals that these two variables are mainly related at the same time but to develop into a more precise and accurate set of forecasts, the values of suspended sediment and flow discharge at past time should be taken in the model. Based on the validation criteria, the transfer function model was accurately fitted in both stations. Finally, comparing two models from forecasting point of view revealed that the transfer function model with model efficiency 98 and 97 for Hajighoshan and Voshmgir stations, respectively and with the bias less than 1 for both stations presents more accurate and precise forecasts compared to sediment rating curve.

Agriculture is the largest consumer of water resources in Iran. One of the best options for increasing the irrigation efficiency and better application of precipitation in arid and semi-arid areas is employing superabsorbent polymers to soil. Polymers can absorb rain and irrigation water, decrease deep percolation and increase water use efficiency. In this research we examined the effect of super absorbent on the pattern of water (advance and rollback curve) and calculating the parameters of advance and rollback equation in furrow irrigation based on the existing relationships and also examined the accuracy of these relations in comparison with the real data. The experiment were performed in the educational farm of the Gorgan university of Natural Resources and Agriculture in a no cultivation conditions. In this research four combinations of superabsorbent polymers A200 with soil which were composed of 0, 7, 11, 16, gram of polymers in square at a depth of 25 cm and the electric current of 0.75 liter per second were considered. The experiment was performed four times. The results indicated that by adding polymers to the soil, advance and rollback time were increased. Elliott and Walker equations advance and rollback calculations are accurate enough. A according to the advance curves, in the control furrow, water advance at outset is fast but gradually was reduced to the end of furrow, with increasing polymer advance speed the water movement fluctuations to the end end furrow is less variable. Also these changes were observed in the rollback curve.

Combination of weir and gate as a hydraulic measuring structure has advantages such as passing the float and settling materials (ice, wood, sediments, etc) simultaneously in compression using weir and gate separately. The flow through combined devices may be submerged when the downstream water level affect on discharge coefficient. In this study, the authors describe new experiments of both submerged cylindrical and sharp edge weir-gate to investigate the effects of geometric and hydraulic parameters on flow discharge. The experiments have been done on rectangular and horizontal small laboratory flume with fore cylinder sizes and also same sharp edge sheet for several flow rates and downstream water level. The results demonstrate that the discharge coefficient are affected by ratio of upstream depth to gate opening H/a, the ratio of upstream depth to height of structure H/P and the ratio of downstream water depth to upstream depth. Also, two submergence limits can be defined for combinational model. The first one depends on gate and it occurs when HTW/H=0.55-0.65 and the second one belongs to weir in HTW/H=0.8-0.85. Moreover, in the both sharp- edged and cylindrical combination models with increasing the submergence ratio, the trend of discharge coefficient decreases similarly and in a constant submergence ratio, the relative discharge coefficients of both models are similar.

Alternative sustainable water sources must be identified when water demand is increased. Artificial groundwater recharge for water reuse are supply augmentation methods in water limited areas. Monitoring the present solute transport process is necessary in determining possible threats to drinking water supplies in the future. In this study the groundwater flow is investigated to represent movement and quality transformations for a modeling period of 5 years (Sep. 2002 to Oct. 2007). Total dissolved solids, TDS, concentration as aquifer water quality index was simulated using Modflow and MT3D models in two direct and indirect recharge scenarios. The model has been calibrated under steady state and transient conditions. Hydraulic conductivity and specific yield in flow model and transverse and longitudinal dispersivity and molecular diffusion coefficient in solute transport simulation was calibrated by first four years and was verified with observed data in last year. Seven urban wells were selected as the observation points and the calibrated model was used to evaluate the vulnerability of aquifer on wastewater recharge. The results show that the developed numerical model is capable of simulating the TDS concentration in porous media. Direct and indirect recharge methods increase the average of water table about 4 m and 2 m, respectively. The effect of contaminant transport with concentration of 2000 mg/L is approximately in distance of 200 m. Also, deep percolation of agricultural lands had more effect than advection, dispersion and diffusion terms to groundwater contamination.

Flood routing, as a mathematical method for predicting the changing magnitude and celerity of a flood wave as it propagates down rivers, provides the substantive bases for conducting flood zonation, flood forecasting and design of river structures. The Muskingum technique is one of important and most frequently used techniques of flood routing. In the present research, accuracy of some methods for optimization of Muskingum parameters (K, x and m) including graphical technique, linear programming, genetic algorithm, ant colony algorithm and artificial bee colony algorithm has been evaluated by using statistics of 9 flood hydrographs contemporaneous detected in two hydrometric stations of Mola Sani and Ahwaz in a 63-km reach of Karun River called Mola Sani-Ahwaz. In order to evaluate the different techniques, statistical criteria of the root-mean-square error (RMSE), relative error (RE), mean absolute error (MBE), mean error deviation (MAE), Nash and Sutclife coefficient (NS), coefficient of determination (R2) and also visual comparison by plotting estimated and observed hydrographs were used. The results showed that artificial bee colony and genetic algorithms with RMSE of 79.85 m3/s were found to be superior to graphical technique with RMSE of 88.07 m3/s for estimation of Muskingum model parameters. Comparing peak flow of hydrographs indicate more accurate for graphical technique with mean absolute error (MAE) of 31.2 m3/s than genetic algorithm with MAE of 58.8 m3/s and artificial bee colony algorithm with MAE of 62.18 m3/s.

The study was conducted to investigate the effect of polyvinylacetate on some physical properties and wheat grain germination in a marl soil in the west Zanjan proviue in 2011. Polyvinylacetate (PVAc) solution was sprayed at four levels (0.00, 33.34, 66.67 and 100.00 kg ha-1) with four replications on 16 soil samples. The polymerized soils were put in the boxes with a dimension of 30 cm × 50 cm and 20 cm- height. Wheat grains were planted in 2 cm -depth with an interval of 5 cm each other. The polymerized soils were affected by four rainfall events with an intensity of 40 mm h-1. Soil compaction was determined based on the bulk density and soil surface resistance was measured by a penetrometer. Germination percentage was computed using the ratio of germinated grains to total planted grains. Results showed that the PVAc significantly affected the soil compaction and surface resistance (P<0.001). There was a positive relationship between the soil surface resistance and the soil compaction and affected by the PVAc (R2=0.99). The highest germination rate (95.39%) obtained with application of 100 kg ha-1 polyvinylacetate level which was 7.5% higher than the control treatment (88.2%). By using the PVAc, soil aggregation was remarkably improved and consequently soil compaction and surface resistance considerably deceased. The wheat germination rate significantly enhanced in the polymerized soils due to improvement of the soil physical properties.

The study of sediment quality indicators in the basins of Gorganroud, as one of the most important part of Golestan province, can give us a better understanding of water pollution, sediment contamination and their effects on aquatic organisms. study was conducted to determine the effect of climatic condition on the quality and quantity of sediment and nutrients loss at various points of the catchment. Four dams along the river (Bostan, Golestan, Voshmgir and the Khajeh nafas) were selected and sediment sampling was performed at the depth of 0-30 cm on the location of the input on each dam. The data were analyzed in nesting factorial model in three replications. With respect to the average rainfall of 12 years (1380- 1391), which was 608.8 mm at the Tamar station and 445 mm at the Aghghala station, amount of nutrient loss was various in different parts of the river. The results showed that amount of phosphorus varied between 13.37-42.18 mg/kg along the river and entrances. In addition, significant diference were observed between the amount of lime and organic matter in all four different regions and varied from 16.4 to 30, 0.890 to 1.6% respectively. The cation exchange capacity was in the range of 6.5-37 cmol/kg. Current study shows that the climate could play a crucial role in erosion, sediment regeneration and nutrient loss in different parts of the studied Basin.

Identification and quantification of heavy metals concentrations and water quality parameters in reservoir are important environmental scientific issues. In this study 15 stations were chosen and per station and some water quality parameters (Temperature, Total Dissolved Solids, pH, Electrical conductivity) and concentrations of heavy metals (Cd, Cu, Mn and Fe) were determined in surface and bed water samples of Chahnimeh 1 reservoir. Mean amounts of these quality parameters including Temperature, TDS, pH and EC in surface and bed water samples were 23.02, 20.5 oC and 339.6, 383 mgl-1 and 8.22, 8.02 and 684, 760.7, Mmhos/cm respectively. Mean concentrations of the heavy metals including Cd, Cu, Mn and Fe in surface and bed water samples were 0.0107, 0.0114 and 0.0192, 0.0205 and 0.514, 0.654 mgl-1 and 0.449, 0.512, respectively. According to the results, average of all physical water quality parameters has been seen drinking water quality criteria. The concentrations of heavy metals Cd and Cu met the optimal level of the drinking water and the amount Mn and Fe exceeded the maximum permissible level. According to limitation of water resource in the province and considering the fact that drinking water of this area were supplied from the Chahnimeh1 reservoir determination of pollutants levels in the environment were necessary.