JOURNAL OF RAINWATER CATCHMENT SYSTEMS
Year:2021 | Volume:9 | Issue:1 (28)|Papers Count:6

Despite their vital role in the sustainability of agriculture, the environment, and human life, the Zagros oak forests are facing severe anthropogenic deforestation and climate change. The purpose of this study was to harvest rainwater and store it in the soil to deal with drought in the Zagros forests, which is part of the forests of Southeastern Kermanshah province. The experiment was conducted as a randomized complete block design with four treatments including crescent-shaped bound with preservation (CSB+P), preservation treatment (PT), crescent-shaped bound without preservation (CSB-P), and control treatment (CT). The results showed that CSB+P treatment attributed to the re-growing of some dried trees (19 tree ha-1) and the reduction in dieback rate (36. 7 tree ha-1), and in total 55. 7 ha-1 trees in the Zagros forests. Therefore, both the reduction of dieback rate and re-growing of dried trees are two main positive effects demonstrated by the CSB+P treatment. There is no effect of PT treatment on the re-growing trees, while it contributes to the reduction of dieback severity (37. 7 tree ha-1). Finally, the CSB-P treatment has the lowest effect among other treatments on dieback reduction (6 tree ha-1). The results also showed that after three years, the soil organic carbon (SOC) in the CSB+P, PT, CSPP, and CT treatments were 3. 25, 2. 90, 2. 05, and 1. 90 %, respectively. In addition, the SOC increased significantly in the CSB+P and PT treatments (P <0. 05). CSB+P significantly reduced bulk density (BD) from 1. 46 (1st year) to 1. 31 (3rd year) enhancing soil moisture content from 16. 53 to 19. 17%. The CSB+P and PT are significantly improved the SOC, BD, and soil moisture content. It was concluded that forest soil should be protected and in our experience, rainwater harvesting through micro-catchment was the simple and effective short-term technique for increasing soil moisture and consequently combating forest drought in the Zagros regions of Iran.

Due to population growth, global warming, changing precipitation patterns, and decreasing precipitation, water and soil are two of the most important human issues. Water and soil resources management in arid and semi-arid regions is one of the methods that can solve water and soil issues. Covering the soil surface with permeable natural materials can reduce water and wind erosion and evaporation from the soil surface and increase soil moisture storage. In this study, the effect of sand cover on runoff and soil erosion was investigated. The results showed that the sand cover reduces runoff from 5. 14 lit/m2 to 4. 24 lit/m2 and reduces erosion, from 97. 4 gr/m2 to 9. 37 gr/m2 during the census period (2 years). The results indicated that the sand cover reduces soil erosion and degradation due to environmental and physical factors such as temperature, wind, and raindrops. In addition, sand cover reduces evaporation and runoff, increases moisture, and more durability in the soil, which is very important in water and soil management.

Flood spreading schemes have been implemented in Iran to control floods, feed groundwater aquifers, improve vegetation, and increase pasture production. The proper evaluation of these projects is possible when the scheme is evaluated based on the opinions of residents and users. The purpose of this study is to evaluate the effectiveness of the Jajarm flood spreading from the neighboring villages' viewpoints. This study is an applied and field research in terms of control and supervision. The statistical community of this research is villagers living in the margins of the aquifer in the Jajarm flood spreading. The data collection tool is a questionnaire. To assess the validity of the questionnaire, the opinions of watershed management experts were used, and to evaluate the reliability of the questionnaire, Cronbach's alpha was applied. The results show that the inhabitants of neighboring villages have positive viewpoints about implementing flood-spreading projects. Also, the outcomes show that the highest effect of flood spreading in villagers' opinion is in reducing the flood damages on residential buildings, farms, and gardens.

Irrigation channels, which are parts of rainwater catchment systems, have been used for water supply in agriculture for a long time. Seepage loss in irrigation channels is one of the farmers' concerns. Seepage loss, especially in earthen channels, can be noticeable. Different equations have been developed to estimate seepage loss amount in irrigation channels. However, the accuracy of the equations can be determined only by seepage loss measurement. In this research, three earthen channels of the "Dorodzan" irrigation and drainage network were selected. These earthen channels are Abadeh Ramjerd, Zargaran, and Hasan Abad, which are supplied by the "Hamoon" channel. By conducting field experiments, the amount of seepage loss along some reaches of these channels was measured, and conveyance efficiency was determined. Also, the accuracy of different equations for the estimation of seepage loss was evaluated. The results show that the seepage loss rate in each kilometer length of the channel in Abadeh Ramjerd, Zargaran, and Hasan Abad is 4. 56% and 10. 6, and 19. 19%, respectively. To evaluate the accuracy of different equations for estimation of seepage loss in the mentioned earthen channels, the Mean Average of Absolute Error (MARE) statistical criterion was utilized. The outcomes show that under channel conditions, the accuracy of each equation for estimation seepage loss was different. It means that among several equations to estimate seepage loss, in Abadeh Ramjerd channel, the equation developed by Etcheverry, in Zargaran channel Moritz's equation, and in Hasanabad channel, Offengeden's Equation has more accuracy than other equations. The MARE values for the best seepage loss estimator in Abadeh Ramjerd, Hasan Abad, and Zargaran were 0. 168, 0. 397, and 0. 319, respectively.

Geomorphological zoning of the earth's surface is the basis of land use planning. The first step of land use planning is to determine homogeneous zones of the earth's surface in terms of geomorphological characteristics. Geomorphologically homogeneous areas can be managed in one approach. Ground zoning is the detection of land features by basic surface features such as height, slope, and slope direction. In this research, the appearance of the earth from the quantitative point of view and geomorphological zoning of the earth's surface are studied. The quantitative zoning is conducted using automated and predefined based on zoning criteria. Quantitative zoning does not involve the expert's taste and skill level, and the zones will be obtained using specific quantitative strategies. The specified zones are determined by coefficients, which changes of these coefficients in different regions can be used to compare zones. In this study, quantitative zoning was performed by a digital elevation model, Arc GIS 9. 3, Matlab 7. 1, and Envi 4. 8, and applying relationships for the mountainous region in the Gerbaigan plain of Fasa. For this research, digital elevation data with an accuracy of 10 meters from the surveying organization has been used. Using the level fitting tool in MATLAB software, the relationship related to each form to limited parts, or limited windows, has been fitted from the surface. These windows are selected in such a way that they have a square shape and their dimensions are, for example, 3*3, or 9*9. By applying for the given programs, each of the quantitative coefficients is presented as zones. To determine the degree of fit, the RMSE has been used. Evans-Shary quantitative parameters have the highest and lowest values for the valleys and peaks, respectively.

Drought is one of the most complex natural hazards that affect natural systems and different parts of an ecosystem in various ways. Evaluation of drought behavior such as determining the time of its occurrence, understanding the relationships between types of drought, and recognizing its characteristics such as magnitude, severity, and duration of drought periods can be an important aid in water resources management. This study was conducted to determine the meteorological, hydrological, and groundwater drought characteristics and the relationship between their occurrence using SPEI, SDI, and GRI indices over a period of 29 years (1987-88 to 2015-16) of the Kashmar and the Bardaskan plains. According to the results, in general, the occurrence of meteorological, hydrological, and groundwater drought in the region is increasing. The increase in drought events is quite evident in the groundwater drought. The highest correlation coefficient of drought types with each other is related to SPEI and SDI indices in return periods of less than 3-months and SPEI and GRI indices, with a return period of 6-month, which indicates a slight association of meteorological droughts with hydrological and/or groundwater droughts in the region. In general, the correlations between SPEI with GRI, and SDI with GRI are not significant at a 95% level of significance. It can be mentioned that there is no significant relationship between groundwater drought and hydrological drought or meteorological drought in the study area. Therefore, it can be stated that groundwater and hydrological drought are affected by factors other than meteorological drought (and precipitation). The continuous decrease of groundwater level in the study area can be another reason for this remark. Also, the study of drought characteristics showed that in the short scales, the GRI index is more intense than other indices and the most deficiencies were identified by the SPEI index. It is suggested that the effect of extraction from surface water and groundwater resources on the quantity and quality of water resources be further investigated.