Spatio-temporal changes of water quality variables in a highly disturbed river

Quality of river varies widely depending on the land use in the catchment and environmental factors. Many rivers in developing countries are unhealthy because they contain harmful physical, chemical and biological agents. Zanjanrud River, located in Zanjan Province, Iran, where recently faced human intervention needs a regular monitoring from upstream to downstream for sustainable management. Hence, the current study aimed to assess spatial and temporal variations of pollutant in Zanjanrud River in different stations from headstream to tail of the river. To achieve this goal, semi-monthly samples were collected from October 2015 to Jun 2016 at 5 stations along the river. The physicochemical variables were monitored and analysed using two-way analysis of variance. The results showed the highest values of suspended and dissolved solids and total solids (220.13±5.57, 641.6±39.63 and 793.6±34.5mg/L respectively) were at the tail site in low-flow period. Nitrate-nitrogen and nitrate were also highest (5.39±02.44 and 23.90±10.85 mg/L) at the middle of the river where was vicinity to farm lands. The values of pH and dissolved oxygen ranged from 6 to 8.15 and 0.5 to 4mg/L respectively with the highest values in high-flow period at most of the study sites. The maximum and minimum values of electrical conductivity (1439 and 256µs/cm) were recorded at tail site and headstream site respectively. Hardness had an increasing trend from upstream to downstream (189.60±53.53 to 515.83±64.77mg/L). Phosphorus was also lowest (0.09±0.04mg/L) at upstream. Results illustrated the high degree of pollutant in studied river. So, an effective management of erosion, domestic waste and agricultural activities in watershed is highly recommended

Effects of Polyacrylamide in Controlling of Splash Erosion from a Soil induced Freeze-Thaw Cycle

Introduction: The capability of a soil to resist erosion depends on soil-particle size and distribution, soil structure and structural stability, soil permeability, water content, organic matter content, and mineral and chemical constituents. Among many affecting factors on aforesaid characteristics, the freezing-thawing processes may considerably affects. Freeze–thaw fluctuation is a natural phenomenon that is frequently encountered by soils in the higher latitude and altitude regions in late autumn and early spring. Effects of freezing and freezing-thawing phenomena on soil erosion and sediment yield are important. Nevertheless, soil conservation under these phenomena by using different methods as well as soil amendments has not been yet considered. Surface application of anionic polyacrylamide (PAM) in solution has been found to be very effective in decreasing seal formation, runoff, and erosion.PAM stabilizes soil structure due to the ability of the polymer chains to adsorb onto clay particles and bridge them together forming stable domains. This adsorption can be a result of interactions between the negatively-charged functional groups of the PAM molecules and the positively-charged edges of clay minerals, orexchangeable polycations (mainly Ca2+) acting as ‘bridges’ between the negative charges of the PAM's functional groups and the negatively- charged planar surfaces of the clay. The PAM is adsorbed on the external surfaces of the aggregates and binds soil particles far apart together, thereby were shorter and evidently less effective in enhancing increasing their resistance to splash by raindrop impact and detachment by runoff. A lot of research work focused on freezing effects in soils on aggregation or increase aggregate stability and emphasis corresponding effects. But the effects of application of soil amendments on soil induced freeze and thaw cycle have not been studied yet. Materials and Methods: The present study evaluated the performance of PAM in controlling freeze-thaw cycle effects on splash erosion from a silty loam soil. A freeze-thaw cycle was simulated in Soil Erosion and Rainfall Simulation Laboratory of TarbiatModares University. The present study was conducted under controlled laboratory conditions with a simulated rainfall. The maximum efforts were made to mimic natural conditions to get access to results with high level of fidelity. Towards this attempt, air and different soil depth temperatures were analyzed in natural condition and 10 cm soil depth was targeted for the soil laboratory experiments. The rainfall storm with 72 mm h-1 and 30 min duration was simulated and conducted for the study treatments. The soil was poured in small erosion box with 0.25 m2 surface area in three replicates. A thick filter, draining the lower 20 cm of the soil profile was generated using mineral pumices.The prepared soil sample was evenly packed into the soil plots at a bulk density of 1.3 Mg m−3 similar to that measured under natural conditions. The plots were then placed in saturated pool for 24 h and then left to be drained to achieve an average moisture content of 35% similar to that recorded for the realities in the study area. So, splash erosion rates were measured using splash cups in two control treatments without PAM subjected to freezing and freezing-thawing processes, and two other plots treated by freezing and freezing-thawing processesplus application of 20 kg ha-1 of PAM. After securing thenormality ofdata, the average net splash erosionand the average upward and downward rates of splash erosion in allexperimental treatmentswere comparedby paired sampled T-test. Results and Discussion: According to the results of statistical analyses, the PAM application had a significant effect (

Efektywnosc metody TAM [Time-Area Method] w symulacji zmiennosci czasowej wydatku rumowiska ze zlewni Chehelgazi, Iran

The proper prediction of temporal and spatial variation of sediment yield from the watershed is a need for sediment control, river engineering and soil and water conservation studies. The present study was therefore planned to simulate the sediment graphs for Chehelgazi watershed in Gheshlagh dam upstream in Kurdistan Province, Iran, by using Time-Area Method. Towards this attempt, the study watershed was divided into 7 time-area segments based on the time of concentration. The soil erosion in each segment was estimated using the USLE and then routed to the main outlet using sediment delivery ratio as a function of land slope in two adjacent time-areas. The temporal variation of sediment was ultimately predicted with the help of lag time of sediment arrival to the outlet and the concept of superposition for 11 storm events, which occurred during winter 2006 and spring 2007. The comparison between estimated sediment graphs with corresponding observed ones verifi ed the weak capability of the model in simulation of sediment graphs under consideration. The results also verifi ed the calibration necessity of the model to achieve appropriate estimation for important components of the sediment graphs. The results of the calibration fi nally proved the considerable capability of the model in predicting of total volume of sediment yield with respective estimation and verifi cation errors of 30.93 and 33.40%.W artykule przedstawiono zastosowanie metody TAM do symulacji zmienności czasowej wydatku rumowiska ze zlewni Chehelgazi, położonej w prowincji Kurdystan w Iranie. Zlewnię Chehelgazi podzielono na 7 zlewni cząstkowych, biorąc za podstawę czas koncentracji odpływu rumowiska. Do wyznaczenia masy rumowiska transportowanego w czasie wezbrania opadowego wykorzystano uniwersalne równanie strat glebowych USLE. Na podstawie sedymentogramów 11 zarejestrowanych wezbrań opadowych przeprowadzono weryfikację i kalibrację metody TAM. Błąd estymacji i weryfikacji całkowitej objętości wydatku rumowiska ze zlewni wyniósł odpowiednio 30.9 i 33.4%

A novel time, cost, quality and risk tradeoff model with a knowledge-based hesitant fuzzy in-formation: An R&D project application

This paper proposes a novel approach for identifying the best implementation situation for each activity in a project by optimizing and balancing time, cost, quality, and risk criteria under uncertain circumstances. A hesitant fuzzy linguistic term sets (HFLTs) approach is proposed to determine the status of project activities in the presence of quality and risk criteria alongside their time and cost. Afterwards, a multi-objective linear programming (MOLP) model is formulated for a time, cost, quality, and risk tradeoff (TCQRT). To validate the model, a research and development project in the food industry was investigated. The results indicate that the project’s time compared to the deterministic approach was reduced by 20%. Completing the R&D project earlier than other competitors bring higher profit than tradeoff expenses, even without considering the quality and risk tradeoff benefits of the proposed approach. Considering uncertainty in risk and quality of activities via HFLTs and also optimizing all four elements of time, cost, quality, and risk simultaneously in a project are the main values of this research. The proposed approach can be employed by managers to adopt and optimize project planning and scheduling while trading off TCQR in uncertain circumstances.N/

Spatial Soil Erosion Risk at the Brimvand Watershed in Kermanshah Province, Iran

Introduction Soil erosion is considered as one of the critical threats to the conservation of water and soil resources. However, until now, its various components, including its spatial changes, have yet to be given due attention. In order to implement soil erosion control and conservation programs in the watershed, it is essential to have basic information leading to know and accurately identify the factors affecting the degradation of soil and water resources. Meanwhile, the CORINE model has been considered as one of the practical models for estimating soil erosion and displaying the spatial distribution of soil erosion with easy and accessible inputs. The CORINE model developed based on the Universal Soil Loss Equation (USLE) was therefore employed in the present study in the GIS environment to determine the potential and actual erosion risks of the Brimvand Watershed in Kermanshah Province, Iran.   Materials and Methods The main associated factors of soil erosion, viz. soil erodibility and erosivity, such as slope, vegetation, depth, texture, and percentage of gravel, were collected, compiled, and ultimately classified in the ArcGIS software. The Fournier index (FI) and FAO-UNEP drought index (DI) were used to prepare the input maps. The Fournier index reflects the performance of the soil erosive agent. In other words, it shows the role of rainfall on soil erosion. The FAO-UNEP drought index shows the simultaneous performance of evaporation and precipitation on soil erosion of a region. The potential soil erosion risk was obtained by combining slope, erodibility, and erosivity layers. In addition, the actual soil erosion risk map was determined by combining the vegetation map and potential soil erosion risk.   Results and Discussion Based on the results of the vegetation distribution in the region, the use of rainfed and abandoned lands had the largest area in the watershed, with an occupation percentage of 65.48%. Furthermore, the rangeland and forest areas, with respective coverage of 29.65 and 4.87%, stood in the second and third priority from the viewpoint of the area. The region has varying slopes, but more importantly, it has a low slope. Soil texture, depth, and gravel content significantly affect the area's erosion. The soil depth in a large part of the watershed, especiallywith a slope of less than 4% is more than 65 cm where it is mainly covered by abandoned and rainfed lands. In the studied area, the depth of the soil decreases with height increase, which indicates that the high slopes of the area are dominantly outcrops. Most of the area has gravel contents between 10 and 40%. The erosion potential of the region is not that much high because of the desired features of the affecting factors. According to the potential soil erosion risk, it was determined that about 65.57, 23.62, and 10.81% of the area were classified as intermediate, low, and high erosion potential, respectively. Further, the actual soil erosion risk was categorized as low, intermediate, and high with respective areal coverage of 53.83, 15.53, and 30.64%. It is therefore implied that the amount of erosion and sediment transfer will increase if the land cover in the watershed is declined.  This indicates that the erosion rate was highest in hilly areas due to lack of vegetation and soil with loamy texture. Accordingly, to curb soil erosion and prevent its associated adverse effects in the Brimvand watershed, it is strongly suggested to use lands based on their capability and potential, maintain the present cover status, and carry out management plans to restore vegetation.   Conclusion Soil erosion remains one of the most critical challenges in watersheds, and its neglect can lead to various problems for the beneficiaries. In light of this, the present study aimed to address this issue by employing the CORINE model to assess potential and actual soil erosion in the Brimvand Watershed of Kermanshah Province, Iran. The research findings reveal the pivotal role of vegetation in mitigating soil erosion. Notably, areas with gentle slopes, which are inherently susceptible to erosion, benefit significantly from vegetation cover, leading to a noticeable reduction in erosion. However, the loss of this protective cover can trigger a rapid increase in soil erosion and subsequent loss of valuable soil resources. By shedding light on the spatial distribution of soil erosion, this study emphasizes the importance of preserving and promoting vegetation in the watershed to ensure its long-term sustainability and safeguard the well-being of those who depend on it. Therefore, land utilization should be planned based on capacity and potential of the land to curb erosion and avoid its detrimental impacts in the Brimvand Watershed. In addition, not only the current cover situation has to be maintained but also the vegetation conditions have to be improved through the implementation of managerial and reclamation plans leading to managing soil erosion