JWSS - Journal of Water and Soil Science

In this research, a regression model was introduced to study the mechanisms of the formation of gullies in the Quri Chay watershed, northern Ardebil province (Moghan Plain); this was done through investigating the effective factors of geo-environment and soil characteristics on the gully erosion. For this purpose, 17 gullies were randomly assigned through field surveys. Mapping and recording the morphometric of the selected gullies were performed by GPS positioning after seven rainfall events. The catchment-upper area of each gully was determined and its related physical parameters were calculated in order to investigate the effect of the physical characteristics of the catchment. Soil sampling was also done at the head of each gully at two different depths (30-30 and 60-30 cm) in order to determine the physical and chemical characteristics of the soil. According to measurement of the morphometric characteristics of the gully and soil characteristics through multivariate analysis of the data, a suitable regression model was developed for the longitudinal development of erosion after determining and calculating environmental factors related to the upper catchment of the gullies. The results of the correlation matrix between the longitudinal extension of the gully and the factors investigated indicated that the factors related to the physical characteristics of the beside watershed (area, perimeter, main stream length and average width of the catchment, main stream slope), gully morphometric characteristics (mean of gully cross section, the gully expansion area, and the gully average width) and soil characteristics (geometric mean of the aggregates diameter, lime, organic matter percentage) affected  the formation and expansion of gully erosion in the Quri chay catchment. The results of regression analysis showed that the longitudinal expansion of the gully was mostly influenced by the area around each gully and the percentage of organic matter, which resulted in pressure on the rangeland and the loss of vegetation, which increased runoff and accelerated the lengthwise expansion of the gully. Also, the  increase in the area of the beside catchment the gullies is known as one of the factors influencing the length of the gully, due to the high volume of runoff entering the head cut section; so it is necessary to manage  runoff in the gully with the large beside catchment.

One of the important elements in mechanized irrigation is to know the relation between suction force (matric force) and soil moisture, which is referred to as moisture curve. The shape and coefficients of this curve are influenced by the texture and structure of the soil and can change with soil structure modification.  The most important goals of this study were to evaluate the effect of using zeolite on water holding capacity and coefficients of moisture curve patterns of two sandy and loamy soil texture, the effect of using zeolite on the shape and soil moisture curve coefficients based on various models, some of them so far in Iran, zeolite was added to soils at levels of consumption (2, 5 and 10%). The moisture content of each soil was determined at various points in 12 points using a Dicagon machine.  Soil moisture curve coefficients using software and fittings of six Brooks and Corey models, Kosugi, Durner, Fredlund and Xing,  VanGenuchten and Seki. The results indicate that in all models, the parameter value increases with the use of zeolite and increase the level of use. Water storage capacity also increases with the use of zeolite.  Other results showed that the best model for estimating the moisture curve of laryngeal and sandy soils of the Darren model is weakest and the weakest models in the lush soils of the broccoli model and Kasughi model and in the sandy soil of the Brooksouli model Blindness and model-gnuchten Shand.

Due to the limitation and scarcity of water supplies, it is essential to identify and reuse alternative water sources, particularly in the arid and semi-arid regions according to environmental conditions. Reuse of runoff is an adaptive management philosophy and approach to balance efforts and provide sustainable water services and manage hazards. The present study is aimed to design a suitable model of water resource management with an emphasis on crisis management. In this study, indices and dimensions of the water resources management model were determined via the Delphi method (based on Schmidt, et al.). Delphi panel members were identified and selected in three stages using random sampling. The faculty members of water resources and watershed management university specializing and passive defense experts of water organization were selected as the Delphy panel members. Initially, panel members identified the most important effective items on water resources security, based on their inference of the model. Based on the first evaluation and after eliminating duplicates, 43 items remained. Finally, 36 items remained in the analyses, when the items with low and medium significance coefficients were eliminated. The final model of water resources management was approved by the expert opinion based on the crisis management approach. According to the results, designing rainwater collection and storage systems in different parts of the city and installing tanks for roof rainwater collection in each home were selected as the best approach in the critical condition (with an average grade of 4.94), whereas the installation of the sensors in different parts of water pipe with an average grade of 2.10 was ranked in the 33rd selection. Finally, the items identified by the Delphi panel were classified into four general indices: retrofit, safety, culture, and planning. In general, it is necessary for the officials of urban water resources, as well as crisis management, must prepare for crisis conditions as well as the correct, principled, and scientific use of available water resources to extract and store rainwater and runoff to use it in crises and disrupt the general water supply system.