JOURNAL OF ENVIRONMENT AND WATER ENGINEERING
Year:2019 | Volume:5 | Issue:3 |Papers Count:8

Due to its particular physical and chemical conditions, river estuary can affect the structure and concentration of heavy metals present in river water at the time of mixing freshwater and seawater. The mixing of saline and fresh water plays an essential role in autopurification and sedimentation of heavy metals. In the present study, the autopurification of Cd, Co, Ni, Cr and Pb elements was assessed during mixing of Caspian Sea and Shafarood River freshwater in its estuary under laboratory conditions and through controlled potential reduction, pH, DO, and salinity. The rate of heavy metal flocculation at the estuary was Cd (62. 2%)

Water supply is considered as water democracy. Sustainable water resources management has been manifested in response to growing pressures from population growth, socio-economic development, climate change, and ecological degradation. Despite the long history of water structure engineering in Iran, there is always a lack of sustainable water resources management framework, and recreation of hidden values of historic hydraulic structures. The purpose of this study was to compare the characteristics of the historic hydraulic structures of desert cities with water resources’ sustainable management criteria and the importance of restoration, protection and recreation of this historical heritage. This is an inferentialcomparative study. Information gathering tools were library studies, review of written literature, and documents. Study of the structure, performance and management system of the historical hydraulic structures of Yazd Desert City indicated that despite the weaknesses of traditional systems, these structures have been in great harmony with the sustainable management framework for water resources. Therefore, modeling and recreating the values and systems governing the structure and functioning of these structures as the most fundamental factors in explaining the thought and practice of social and ecological life can provide the basis for sustainability in all its dimensions.

As groundwaters make an important part of the permanent rivers flow, their role in maintaining the life of rivers and creating ecological balance in watershed can be determined by knowing the base flow contribution. Moreover, identification of runoff production processes is crucial for assessing the effects of climate change and landuse on the hydrologic response of the watershed. In the current study, the base water separation in Doroud watershed located in Lorestan province with 6 study areas was performed during a period from 1982 to 2011 using PART, one parameter recursive digital filter (Lyne-Hollick) and two parameters recursive digital filter (Eckhart) with filters value of 0. 925, 0. 95, 0. 975, and 0. 99. Then the results obtained by these methods were compared with those of BFI method. The comparison showed that Lyne-Hollick method with filter value of 0. 975 was the best method to separate base water from direct runoff in Doroud watershed. In Bayatan watershed, Silakhor sub-watershed, Ab Sardeh sub-watershed, Sarab Sefid sub-watershed, and Gale Rood sub-watershed, the Eckhart's method with filter value of 0. 975, Lyne-Hollick method with filter value of 0. 975, PART and Lyne-Hollick method with filter value of 0. 975, Lyne-Hollick method with filter value of 0. 95, and Lyne-Hollick method with filter value of 0. 925 were the suitable methods for hydrograph decomposition, respectively. Considering the results obtained by this study and having statistics of this watershed flow rate on a daily basis, the abovementioned methods can be used in future years for hydrograph decomposition.

Rivers accumulate huge amounts of floating debris including the trunk, branches and leaves during the floods, leading to increase the depth of local scour around bridge piers. A large number of the laboratorial and field studies have been performed to understand the mechanism of scouring phenomenon under floating debris. Over two past decades, different types of the artificial intelligence methods have been used to estimate the maximum scour depth around bridges piers. In this study, the Neuro-Fuzzy model based on group method data handling (NF-GMDH) was used to estimate the scour under effect of debris accumulations. The NF-GMDH network was developed using evolutional algorithms: genetic algorithm (GA), particle swarm optimization (PSO), and gravitational search algorithm (GSA). Parameters effective on the maximum scour depth included average velocity of upstream flow of the bridge pier, critical velocity of river bed sediments, depth of flow in section without debris, thickness of submerged debris, debris diameter, average particle size, pier diameter, and channel width. After training and experiencing each NFGMDH models, the performances of each one was evaluated through statistical parameters. The results showed that the models proposed had better performance compared with emperical relationships. NFGMDH-PSO (R=0. 8413 and RMSE=0. 37) and NF-GMDH-GA (R=0. 8407 and RMSE=0. 3640) had relatively similar performance. Finally, sensitivity analysis indicated that the ratio of pile diameter (D) to mean diameter of bed sediments (d50) has the most influence on determination of maximum scour depth.

Berm breakwaters are reshaping rubble mound breakwaters, which as a result of impact with wave attacks, the seaside profile of these breakwaters reach a stable condition after erosion and reshaping. Berm recession (Rec) is one of the most important parameters that should be controlled for designing a stable berm breakwater. Failure of a berm breakwater is typically defined when the berm recession exceeds the initial berm width. Based on experimental tests, the effect of sea state and structural parameters on berm recession was investigated in this study. The berm recession was recorded under different number of waves through performing 34 experiments. The results showed that a berm breakwater experiences more than appproximately 90% of its final recession during exposing to the first 3000 waves. In addition, rising the berm elevation had less effect on reducing the berm recession in comparison with both increasing the berm width and decreasing the water depth. On the other hand, increasing the berm width was the most effective parameter in controlling the berm recession. So that, 20% increase in the berm width had a greater effect on decreasing the berm recession, than 45% increase in the berm elevation. By the way, especially in the absence of suitable stone materials, increasing the berm elevation can be yet a good alternative in order to design a stable structure with simple construction activities.

In irrigation management, the amount and quality of irrigation water is very important. Inappropriate water and soil quality will cause the plant to grow, destroy the soil structure and eventually reduce crop yield. In this study, according to the field measurement, the boundaries of the system were investigated, a conceptual model was developed to determine causal relationships, structural test, and the extent test used for the system dynamics method. Scenarios including water supply from Karkheh Dam and wells of the region as well as crop pattern were evaluated and selected. The conceptual model was based on five submodels: water demand, water supply, environmental stresses, water economy and environment. The results showed that the use of Karkheh Dam water of 160 million cubic meters and the extraction of 90 million cubic meters of the plain aquifer will keep the groundwater level at a distance of 10 meters from the soil surface and will supress the problem of rising groundwater level. In crop pattern scenarios, the model results were the use of crop pattern with emphasis on increasing forage and beet levels to prevent drainage.

Soil characteristics have spatial variations. Understanding spatial variations of soil characteristics is among the effective factors in sustainable land management. A better understanding the effects of management factors on soil characteristics need to quantify their heterogeneity and variability. This research was conducted with the aim of investigating spatial variations of some soil characteristics such as soil texture (clay, silt and sand), calcium carbonate (CaCo3), soil acidity (pH), and soil salinity using geostatistic methods. For this purpose, 252 soil samples (from 0 to 20 cm depth) were prepared from the study area and physical and chemical properties of soil were measured. After normalizing the data, the half-shift of each of the studied characteristics was calculated and the best model was fitted to them. Then, the characteristics of the study were estimated through different methods of conventional Kriging, simple Kriging, discrete Kriging and Inverse Distance Weighted (IDW) using ArcGIS software. The accuracy of the estimation was evaluated using the mean absolute error (MAE), the mean bias error (MBE), and the root mean square error (RMSE). The results showed that the best model for the acidity was the spherical model and for the other measured variables was the exponential model. Moreover, the conventional CoKriging method for clay, calcium carbonate and acidity (pH), IDW method for silt and soil salinity, and conventional Kriging method for sand were better than other methods used and provided more accurate estimates.

Sustainable agriculture requires identification and development of scientific methods that have an important role in optimizing water use, employment and income, community health, and non-oil exports. Significant economical and therapeutic value, market demand and high processing level of medical plants have caused the daily increasing growth of these plants around the world. Considering the climatic and geographical conditions in Iran, the development of these crops, especially in arid areas and semi-arid has doubled. Therefore, in the present study, climatic, topographic and socioeconomic criteria were selected as effective measures in the cultivation of Rosa Damascena and were weighed using the network analysis process and then the ArcGIS was used to digitize and combine the layers. After the formation of the regional spatial database, descriptive information of the maps was added, weighted overlapping in the GIS environment, and finally zoning the areas susceptible to cultivating Rosa Damascena. The results showed that three factors including annual rainfall, altitude, and mean annual temperature had maximum impact and slope parameter had the least impact on the quality and quantity of Rosa Damascena. Moreover, the zoning map showed that 38 percent of northern parts, 15. 6 percent of central pats and 11 percent of western parts of the province, have the most suitable sites for Rosa Damascena cultivation.