نشریه منابع آب و توسعه
سال سوم شماره 1 (پیاپی 9، بهار 1394)

For investigating the effect of drought on Benthic macroinvertebrates communities in Zayande-Roud River, presence and abundance of macroinvertebrates were compared in spring and summer of 2007 and 2013 in 5 stations. To this purpose, 5 stations were selected and monthly sampled when the river was flowing in 2013. Sampling was done in tree replicates by Sourber sampler (area 625 cm2) and PVC tube with 90 mm diameter in 3 iterations. The macroinvertebrates samples were identified and counted in laboratory. After spotting taxonomic composition and investigating some population parameters, the results were compared with the data obtained in 2007. According to the results, 19 families of macroinvertebrates were identified. The results also showed that Corixidae, Hydrobiidae and Haplotaxidae families observed in August and July 2013 were not reported in the same period in 2007. However, Elmidae, Athericidae, Erpobdellidae and Valvatidae families reported in 2007were not observed in 2013. In addition, the results of the Paired-Sample T-Test showed a significant reduction in benthic macroinvertebrate's density in comparison with the results obtained in 2007 (p<0.05). Moreover, in some stations Shannon-Wiener, Brillouin and EPT indices showed a severe reduction in density and frequency which effected by drought.

Evapotranspiration from irrigated land is a useful indicator to evaluate the amount of water use in irrigation. Conventional methods of computing evapotranspiration are based on climate data and can only provide a point estimation. While better regional estimation of evapotranspiration can be obtained from satellite remote sensing and individual pixel to an entire image. One of the most popular remote sensing algorithms in the retrieval of ETa is Sebal. Sebal can calculate surface energy balance for each pixel of a satellite image at each moment. In this study, surface albedo, surface temperature and vegetation status index were calculated by using Sebal algorithm, multi-spectral satellite data and meteorological information such as degree of temperature, hours of sunshine, wind, saturated vapor pressure, soil humidity, etc. In this study, the evapotranspiration of Bilevar plain (located in western Iran) was determined and the evapotranspiration maps were prepared. Moreover, the actual evapotranspiration was computed for wheat using Penman-Montieth method and was compared to Sebal method. The results showed that there was a high correlation (0.83) between the abovementioned methods and that Sebal has a great ability to calculate evapotranspiration.

The damages of floods can be reduced by evacuation if there is an on-time warning. The Fahlian Basin, in the south of Iran, has steep slopes and flash floods, so the location of rainfall-gauges and their distance from basin’s outlet might have a considerable effect on the estimation of the flood-warning lead time. Thus, the main purpose of this research is to assess the effect of the distribution of rainfall-gauges on flood-warning lead time using WMS/HEC-HMS model in this basin. Therefore, after calibration and validation of the model, double, triple and quadruple combinations of rainfall-gauges were examined. After flood simulation by WMS/HEC-HMS for various return periods, the lead times for the different rainfall combination were determined according tolegalistic river bed. The results showed that the lead time increases by increasing rainfall and decreasing the distance of the rainfall gauges from the basin’s outlet. Finally, a method is proposed to determine the lead time based on multivariate analysis which can be used in flood warning systems.

Intakes must be designed in a way to have the best performance in discharge with the minimum sediment transport. Therfore, the selection of the intake site and side angle divergence degree in water transport system are considered important factors to meet the mentioned goals. In this study, the Fluent model was utilized to this purpose. The model was first calibrated and then, testedfor various divergence degrees. The results showed that the best degree was 30, which was consistent with that of lab results. The particle transformation routing method was also used to investigate the transportation of sediment to intake. After evaluating Frude number variations, it was found that there was no major effect on flow conditions.

The relationship between rainfall and runoff plays an important role in the hydrological studies of watershed. In this study, an attempt was made to use the dimensionless hydrograph, which was used in the basins with no statistical data, for a comparative watershed study in Dehbala. These models are as follows: Schneider unit hydrograph models, SCS and triangular model. Due to the unavailability of accurate statistics, a flood event was used in Dehbala. The comparison of three methods of synthetic unit hydrograph with the natural one was indicative of the better coordination of the Schneider procedure for estimation of the observed hydrograph. Moreover, the highest peak of the lowest motion error is related to the SCS method. Among those methods, unit hydrograph needs the least amount of time to reach peak flow error is observed in Schneider method and the maximum error in time is related to the triangular method. The least degree of conformity is observed in the triangular and SCS methods However, Schneider is in good agreement with the observed hydrograph.

One of the most important considerations in quantitative management of groundwater resources is the estimation of groundwater level by using the data collected from observation wells network. The objective of this study is to investigate the effect of the number of observation wells in evaluating Geostatistical methods and comparing three methods of Cokriging, Kriging and Inverse Distance Weighting (IDW) for estimating groundwater level in three important plains of Khuzestan province in southwest of Iran. The results showed that if the number of the observed wells is more and their dispersal is regular, the estimating of water level by geostatistical methods would be more accurate and have suitable evaluating criteria. The results of the fitness of three types of Variogram and Cross Variogram including Spherical, Exponential and Gaussian indicated that in all plains, the Gaussian model had more appropriate evaluating criteria compared to other models. Moreover, in two plains of Dezfool and Ramhormoz the cokriging method and in Zeidoon plain the kriging method were selected as the most appropriate method in estimating the groundwater level.

River banks are generally subject to erosion due to water flow and groynes can be utilized to preserve them and maintain their stability. Accordingly, understanding the characteristics of flow around these types of hydraulic structures for the design and performance optimization usages through experimental or numerical investigations would be inevitable. In this research, the flowpattern around a submerged groyne is analyzed making use of the finite difference code; FLOW-3D. Subsequently, the obtained numerical results for longitudinal velocity and free surface flow are compared to and verified by the respective experimental results. Finally, new numerical simulations were conducted employing identical computational assumptions utilized in the preceding simulation in order to examine the impact of various new groynes structures on the flow pattern. The analysis of the obtained numerical data reveals that among the investigated structures, the T-shaped groyne is more practical and it can effectively reduce the separation zone and therefore, decrease the coastal erosions.

Gharasoo River is one of the major rivers in Kermanshah province that is the source of water for agriculture in this region. The purpose of this study was to assess the river water quality using water quality index for agriculture and drinking utilization. In this study, the parameters of PH, EC, TDS, HCO3 -2, Cl, SO4 -2, Ca, Mg, Na, SAR and % Na were collected from water and wastewater organization of Kermanshah City. Wilcox and Schuler Indicators and Piper diagram were used for the assessment of water quality. Aq.QA-1 software and Ms. Excel were utilized for analyzing the data. The results of trending showed that the concentration of the parameter changes is highest in the dry season and lowest in rainfall season. According to Wilcox index Gharasoo water quality is located in C2-S1 for agricultural usage. The value of %Na and RSC are acceptable and suitable,respectively. Schuler water quality index was indicative of high level of hardness which is classified as inappropriate. Calcium and magnesium were located in the moderate range. Radial diagram presented high values of calcium and magnesium and bicarbonate and Piper diagram of water face showed HCO3-Na + k which is a type of fresh water.

In this study, phosphorous adsorption characteristics of five soil samples from Moghan region in northeastern Iran were studied in the cropping year of 2012-13. For this purpose, adsorption tests of phosphorous at concentrations of 4, 12, 25, 50, and 70 mg/l prepared from diammonium phosphate [(NH4)2HPO4)] were conducted on five soil samples and Linear, Van Huay, Freundlich,and Langmuir adsorption isotherms were fitted to the adsorbed values. The results indicated that the accuracy of soil phosphorous adsorption isotherms decreased slightly from the Linear to the Van Huay, Freundlich, and Langmuir adsorption isotherms, respectively. Moreover, the maximum phosphorous adsorption in the tested soils varied from 166 to 1000 mg/kg, and the average maximum phosphorous adsorption by the soil samples was 483 mg/kg. There was a significant positive correlation between soil clay and organic matter contents and the quantity of phosphorus adsorbed by the soil, so that phosphorous adsorption by the soil increased with increases in soil clay and organic matter contents. Furthermore, there was a significant inverse correlation betweenthe quantity of phosphorus adsorbed by the soil and soil electrical conductivity and calcium carbonate content. However, there was no significant correlation between the amount of adsorbed phosphorus and Olson phosphorous.

This research is in the field of sediment control studies in shrimp culture fields which are constructed close to the coastal lines. If supplying water for shrimp culture fields contains suspended mud, the suspended sediments settle within intake channels and some difficulties can occur in shrimp culturing. This will increase shrimp production costs. The present study was carried out in one of the shrimp culture fields in the bank of Bahmanshir River surrounding Abadan (Choebdeh shrimp culture) in Khuzestan province. The water needed for this shrimp culture field is supplied by Bahmanshir River. Bahmanshir River intake is affected by the tide in Persian Gulf and the river is always muddy. Furthermore, in order to know the flow conditions and other physical characteristics of water, some measurements are performed in one of the intake channel. These measurements include depth, concentration of suspended sediments, velocity and salinity. The results showed that the maximum suspended sediment load happens in the first intake channel. Moreover, the entrance of intake channel is a significant part to prevent suspended sediment, so that the sediment can be settled in the channel.

One of the initial investigations for analyzing the hydrological time series is the investigation of trend using statistical methods. Detecting trend in the hydrological time series might be based on the gradual variations of the climate which is affected by the human activities. In this study, one day and sixty day's drought volume were extracted for the rivers located in the Lake Urmia basin by using the daily flow data, and the trend of annual river flow changes and one day drought volume of rivers were investigated using Mann-Kendall test. The results showed that there was no significant trend in the drought volume of Dizaj, Urmia Band and Tapik stations and except Pole-Ozbak station, the other stations showed a significant positive trend in the one day drought volume data. Moreover, the results indicated that among the nine rivers studied, there was a non-significant upward trend for three important rivers of west Azerbaijan (Nazluchai, Shaharchai and Barandouzchai rivers) and the other rivers showed a downward trend.

Wetlands are strongly influenced by human activities at landscape scale. Choqakhor Wetland is considered to be one of the most important Ramsar sites in Iran and designated as the 23rd Wetland of International Importance in Iran. The main goal of this study was to quantify the change in land use/ cover in Choqakhor Wetland in Chaharmahal and Bakhtiari Province in a period of 6 years (2003–2009) and to evaluate landscape pattern change surrounding the wetland. For quantifying landscape pattern of the study area, various landscape metrics were derived from spatial analysis software FRAGSTATS3.3, including PLAND (Percentage of Landscape), NP (Number of Patches), ED (Edge Density), LPI (Largest Patch Index). Landsat satellite images from 2003 to 2009 were used for analyzing the landscape pattern changes. In the first place, the satellite images were geometrically corrected and classified by ENVI4.8 Software. The analysis showed that the proportion of water decreased by 17.2%, while those of the agricultural area and settlements increased from 2003–2009. The results was indicative of the degradation in the habitat of migratory birds as well as water resources in this ecosystem that is very important for wetlands and birds management.

Over exploitation and improper usage of non-renewable resources and long-term drought cause vegetation cover degradation and desertification in many parts of Iran. Artificial recharge of groundwater by controlling and spreading the floods could be an appropriate solution for most areas. Among the different evaluated parameters, the soil texture and specially clay value affectedthe amount of soil cohesion and erosion threshold. The main purpose of this study was to investigate the effect of clay value on erosion threshold in flood spreading projects. In this study, an open flume with 100 m length was used to simulate an overland flow with a 10 cm depth. Five clay value treatments of 0.06, 0.12, 0.18, 0.24 and 0.30 were examined and in each treatment, three experiments were conducted and in each of them the discharge rate and the depth of flow were directly measured and the flow area as well as flow velocity were calculated. In the next step, the erosion and sedimentation depths were individually measured for each experiment. The results showed that the distance of threshold value increased with the increase in clay percent of soil.Moreover, the threshold values were estimated for different clay value treatments of 56, 60, 65, 75 and 95, respectively. The results also showed that the flow velocities increased with flow length.

Pressurized irrigation methods in Iran is one of the strategies for improving the efficiency of irrigation and agricultural water consumption patterns. In this context, the present article makes an attempt to identify the factors affecting the performance of the pressurized irrigation methods using library resources in three dimensions (structural, economical- social and natural) and thirteen component. Then components priorities were identified using AHP technique. According to the responses to the questionnaire of the three dimensions of research, based on AHP method, priorities were rated as follows: a) natural causes b) socioeconomic factors, and c) structural factors. Among the natural components, scarcity of agricultural land, among the socioeconomic factors, access to credit facilities and among the structural factors, high cost were the top three priorities, respectively.

Estimation of hydrologic components including blue water and green water is vital for a proper management of the watersheds with limited available water resources. This study was conducted with the following 1. determining the hydrologic components of Kohnak watershed (located in Khozestan province) using SWAT model in combination with SUFI-2 designing algorithms for uncertainty analysis and 2: prioritizing the sub-basins for management purposes. The calibration time period was from 2000 to 2009 and the model was validated for time period from 1995 to 1999. Blue and green water parameters were determined for 21 sub-basins. Uncertainty in the simulation results was evaluated using p-factor and r-factor indices. The p-factorand r-factor values were 0.51 and 1.09 for the calibration and 0.51 and 0.72 for the validation steps, respectively, indicating an acceptable simulation accuracy in monthly runoff prediction. The investigation of the simulation results revealed a proper estimation of the blue water and green water components. However, uncertainty in the results was high in some sub-basins which was probably due to the restrictions in the available information for the rainfall, groundwater, and management data. Furthermore, the lowest simulated green water storage and the lowest uncertainty in green water flow estimation were obtained for the northern part of the watershed.

Groundwater is one of the main important sources of irrigation water. Thus, special attention should be paid to these sources to prevent their contamination. Geostatistical techniques reduce the number of the necessary samplers and increase the accuracy of estimates. Therefore, this method could be used as a convenient method for studying groundwater quality. The electrical conductivity is an important method for qualitative estimation of groundwater. Therefore, the present study was carried out to investigate the different approaches and to find a suitable interpolation method in electrical conductivity of groundwater to find land area for farming in Ravansar Sanjabi. Hence, Groundwater samples were taken from 903 wells within the study area. To compare the two statistical methods for interpolation (deterministic and Geostatistic), Arc GIS 9.3 was used. The results showed that among these methods, the radial radiation and ordinary kriging with Five-sided model have the highest accuracy. Moreover, based on the results of the zonation of groundwater, 20 percent of the study area is of high suitability for agriculture, 66 percent of this land is of good suitability and 14 percent of the study area has a high suitability for agriculture.

Collecting and surface water disposal during and after rain is important in flood management. Blockage of water passages, improper steering of surface water flow which contains sand, gravel, mud and debris into the sewage system can cause blocking and much damage to the sewer system. The aim of this study is to evaluate surface water collection system and steer it into the drainage systems and investigate the problems caused by the existence of surface water as a result of heavy rain in University of Shahrekord. After studying the flowing surface water collection and in University of Shahrekord. After studying the collecting systems and surface water disposal, their weaknesses and strengths were investigated using a non-defense approach. Ultimately, some suggestions were proposed to remove the defects. The results were indicative of the ignorance of the principles of non-defense operating in surface water collection in University of Shahrekord.

Groundwater is one of the best sources of fresh water for meeting human’s needs. Population growth and overexploitation of groundwater aquifers and some human activities such as agriculture and industrial activities have imposed urban pollutions on groundwater aquifers. Therefore, it is important to preserve the groundwater quality. In this regard, the first quantitative model of Arsanjan environs (MODFLOW) will be made in this study and after the calibration and verification of hydraulic parameters of the plain, the quality factor of groundwater in this area (Cl-) was simulated by pollution transport models (MT3DMS). The results for the Qadamgah wells 1 and 2 showed that if the origin of the supposed contamination release 5000 mg/l chlorine and the origin is 1655 meters away from wells, the first contact of cloud contamination of this wells would take pace in 151 days and could be reached with an average concentration of 240 mg/l to Qadamgah wells 1 and 2.

Nowadays, in some areas of the world, the damage caused by natural disasters is much greater than what was before. Development of human societies and the increase of human activities in the Northern part of Iran, especially Talar watershed, have led to the destruction of forest lands or their changing into agricultural and range lands. This study, therefore, aimed at investigating the effects of human activities on the land use changes, impervious surface development, and finally the influence of these set of changes on runoff generation and flood hydrograph. To this end, the researchers used aerial photos, topographic maps 1:25000, land use maps, and satellite images. Also, a runoff-rainfall model has been presented using ARC GIS (HEC-GeoHMS extension) and hydrologic model (HEC-HMS). It should be noted that the optimized model is evaluated by the six events of flood. Then, landuse changes and the development of the residential areas and roads have been included in the evaluated hydrologic model; their effects on intensifying runoff generation and flood hazard, during the recent forty years, have been investigated, quantitatively. This study, hence, describes the complex succession of floods, transformation of the forests by human and major land use changes, in the study area.

The present hydro-geochemical study was confined to the Chhatna Block of Bankura district which falls between latitude 23˚20′N- 23˚30′N and longitude 86˚45′E- 86˚55′E. Twenty one groundwater samples were collected and analyzed for various physicochemical parameters like pH, electrical conductivity, total dissolved solids, Na, K, Ca, Mg, Fe, Cl, HCO3, SO4 and F were determined. Sodium Adsorption Ratio (SAR), Soluble Sodium Percentage (SSP), Residual Sodium Carbonate (RSC), Magnesium Adsorption Ratio (MAR), Total Hardness (TH), and Permeability Index (PI) were calculated as derived parameters to investigate the ionic toxicity. Based on the analytical results, groundwater in the area is generally fresh and hard to very hard. The abundance of the major ions is as follows: HCO3>Cl> SO4 and Ca>Mg>Na>K>Fe. The results also showed that bicarbonate ions (HCO3) dominated the other anions (Cl and SO4). According to Gibbs, diagrams samples fall in the rock dominance field and the chemical quality of groundwater is related to the lithology of the area. Assessment of water samples from various methods indicated that groundwater in study area is chemically suitable for drinking and agricultural uses. Fluoride is within the permissible limits for human consumption as per the WHO and Bureau of Indian standards.