Ariyan Matboo; Vahedberdi Sheikh; Ali Mohammadian Behbahani; Arash Zare Garizi
Abstract
Introduction
The hills surrounding the international wetlands of Almagol and Ajigol in the Golestan Province are exposed to severe erosion and every year a large amount of sediments from these hillslopes discharge into these wetlands. Whilst a large extent of these surrounding hills, covered with Biological ...
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Introduction
The hills surrounding the international wetlands of Almagol and Ajigol in the Golestan Province are exposed to severe erosion and every year a large amount of sediments from these hillslopes discharge into these wetlands. Whilst a large extent of these surrounding hills, covered with Biological Soil Crusts (BSC), has been destroyed due to lack of awareness of their values, sensitivity and ecological functions. Improving soil properties, preventing direct contact of raindrops with the soil surface, all indicate the important role of BSC in hydrological processes and soil loss control.
Materials and methods
In this study, the role of BSC in the hydrological processes of dry areas was investigated using a rain simulator. After a field survey and evaluation of the area, different treatments including biological crust with a dominant lichen cover, biological crust with a dominant moss cover, an area covered with vascular plants, an area without cover and areas covered with a combination of moss and lichen were selected to perform rain simulation and compare their effects on the hydrological processes of the selected region. Rain simulation was done in 2×1 meter plots for 30 minutes and intensity of 82 mm per hour. The start time of runoff and the volume of produced runoff at the outlet of the plot were measured and recorded. Also, at five-minute intervals from the beginning of the simulation process, 500 ml runoff samples were collected and transferred to the laboratory for testing in order to estimate the sediment concentration and mass. In addition, the depth of the wetting front caused by the infiltration of rain was measured at the beginning, middle and end sections of the plots.
Results and discussion
The results of rainfall-runoff simulations at a 2×1 m2 plot scale with a rainfall intensity of 82 mm.h-1 and a duration of 30 minutes plots, showed that the average mass of sediments from plots with the dominant cover of moss (104 g), lichen (91 g), lichen-moss combination (176 g) and bush (99 g) was significantly higher than bare soil (1133 grams). Therefore, in case of destruction of the existing BSC and the formation of bare lands, the sedimentation rate will increase by more than 5 times. A significant decrease in water infiltration into BSC causes a significant increase of 30-40% in runoff generation compared to the treatment covered with bushes and a significant increase of 8-18% compared to the bare soil treatment.
Conclusions
by reducing soil loss and sediment concentration, BSC cause the production and transfer of high-quality runoff to the wetlands and as a result maintain the ecological function and health of the region’s wetlands. The results of this research show the positive influence of BSC on the hydrological and ecological performance of arid areas in the north of Gorgan Plain and protection of Ramsar-listed wetlands in the region.
Maryam Sanjari Banestani; Vahedberdi Sheikh; Arash Zare Garizi; Amaneh Avarand
Abstract
The aim of this study is to assess the feasibility of monitoring precipitation, temperature and river stage variables in the Chehl-Chai Watershed with the participation of citizens/stakeholders. Simple and low-cost measurement tools were designed and provided to the local volunteers (two students, three ...
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The aim of this study is to assess the feasibility of monitoring precipitation, temperature and river stage variables in the Chehl-Chai Watershed with the participation of citizens/stakeholders. Simple and low-cost measurement tools were designed and provided to the local volunteers (two students, three women and one man) and they monitored the variables for five months. The data were recorded on paper forms and/or communicated through cellphones (text messages and social media applications of WhatsApp and Telegram). The citizen-collected data were compared with formal gauging stations using different statistical metrics including correlation coefficient, paired-sample t-test and kappa index. Results revealed that, the difference between the recorded data by the participants and those of gauging stations were not statistically significant. A female citizen with academic education of bachelor’s degree recorded the highest frequency of data that had the highest correlation with the recorded data in the formal precipitation and temperature monitoring stations, while the technical staff man from the Natural Resources Management Office recorded the least frequent data that had the least correlation with the recorded data in the formal monitoring stations. In overall, the promising level of citizens’ performance in monitoring the watershed, suggests that it is really feasible to collect reliable, on-time, and long-term data that can be used to obviate lack of data, particularly in remote mountainous areas and facilitates the decision-making and watersheds management process.
Roya Jafari; Mohsen Hosseinalizadeh; Hasan Rezaii Moghadam
Abstract
Accurate estimation of a watershed response to rainfall events plays an important role in its soil and water resources management as well as civil works design within watersheds and over or around its downstream rivers. Nowadays, due to improvement in our knowledge and understanding from watershed systems ...
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Accurate estimation of a watershed response to rainfall events plays an important role in its soil and water resources management as well as civil works design within watersheds and over or around its downstream rivers. Nowadays, due to improvement in our knowledge and understanding from watershed systems and enhancement in hardware and software technology as well as facilitation in learning and application of these technologies, researchers prefer to design and apply their required models themselves according to their aims and availability of data. The aim of this research is to develop a spatio- temporally distributed model within PCRaster GIS and programming environment to achieve a better representation of watershed processes at a small scale agricultural micro-watershed. In this study, based on the available local data, an event based rainfall – runoff hydrological simulation model was developed within PCRaster GIS and programming software and its performance was evaluated using observed data from a 27.6 ha agricultural micro-watershed discharging to the Shahrak – Behzisti residential area in the Gorgan city. This is a tightly coupled GIS model. During the research period, only two rainfall events leading to runoff generation occurred on 2/11/2014 and 16/9/2015 which were, respectively, used for calibration and validation of the model. Statistical comparison of the simulated and observed hydrographs of the rainfall - runoff events on 2/11/2014 and 16/9/2015 showed the correlation coefficients of of 0.69 and 0.65 and Nash-Sutcliffe criteria of 0.5 and 0.51, respectively. The results indicate that the developed model has a good performance at simulating rainfall-runoff processes during events.
Zeinab Karimi; Vahedberdi Sheikh
Abstract
In this paper the watershed management activities on some part of the Hablehroud Watershed was evaluated on the basis of the stakeholders’ attitude using the questionnaire (face to face interview and recording) and qualitative research method. The respondents’ community was randomly selected ...
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In this paper the watershed management activities on some part of the Hablehroud Watershed was evaluated on the basis of the stakeholders’ attitude using the questionnaire (face to face interview and recording) and qualitative research method. The respondents’ community was randomly selected among males and females and gathered data was analyzed using the SPSS statistical software. The descriptive results showed that, despite its high necessity and importance, the number and diversity of offered educational and extension programs are insufficient from the Hablehroud stakeholders’ point of view. Assessment of stakeholder’s viewpoints regarding key influencing factors on natural resources and environmental degradation as well as stakeholders’ awareness and feeling of responsibility about environment indicated that local people have a relatively good environmental knowledge and feel themselves highly responsible. Furthermore, stakeholders very highly acknowledge the effects and importance of implementing soil and water conservation measures from various dimensions. Therefore it is crucial to provide educational and extension programs, to benefit from local knowledge and to involve the local stakeholders in order to succeed in the projects. However, low incomes and lack of employment opportunities, which are main issues of rural communities, lead to migration from some locations. In fact, stakeholders declared that lack of financial resources is the main hindrance to willingness to implement soil and water conservation measures. Moreover, lack of awareness and information about soil and water conservation measures and their effects and absence of pilot and demonstration farms are the second and third most hindering factor to adopt soil and water conservation measures.
