مجله سامانه های سطوح آبگیر باران
سال هفتم شماره 3 (پیاپی 22، پاییز 1398)

Kowsar Floodwater Spreading, Aquifer Management, Training and Extension Station was established in 1982 on the Gareh Bygone Plain at 1140 m above sea level. The area has an arid climate and is located 190 km southeast of Shiraz, Iran. Thirteen floodwater spreading systems, covering 2445 ha, were designed and constructed during the 1983-2003 period to artificially recharge groundwater. Eucalyptus and Acacia species have always been considered for plantation in arid areas due to their drought resistance, flexibility in harsh habitat conditions, and the use of their wood and other by-products. Results of previous field experiments showed that E. microtheca, A. salicina, A. victoriae, E. oleosa, and E. camaldulensis were very successful, with more than 80% survival at the station. Therefore, more than 600 hectares of extensive and 100 hectares of intensive forest plantations with Eucalyptus and Acacia species have been established in the region.  Using the clipping and weighing method and organic carbon measurements in the laboratory, carbon storage capacity in Eucalyptus and Acacia forests at the station was estimated to be 7.8 tonnes/haannually. The average total dry biomass of E. camaldulensis trees in this area during the study period (16 years) was 247.07 tonnes/ha, of which 136.66 tonnes were trunk timber, 46.72 tonnes were leaved branches, and 39.94 tonnes were bark. Eucalyptus species flower twice a year in this area, providing  a source of pollen and nectar throughout the year for beekeeping. The average honey production at this station was 11 kilograms/hive. Moreover, the area attracts many eco-tourists, particularly during the holidays because of the beautiful landscape of the forest in a desert region. As Eucalyptus species use large amounts of water, it is proposed to replace these species with less water-demanding trees.

In this research, a method is proposed to identify and determine rainwater harvesting potential in a watershed based on geomorphological factors through integrating Geographical Information System (GIS) and Analytical Hierarchy Process (AHP). For this purpose, land use, land cover, topography, geology, soil, vegetation, and soil permeability factors were considered the as main geomorphological factors in the Kalat watershed of Gonabad and the corresponding data layers were obtained. Then, weights of the criteria and their classes were calculated using AHP and the results were applied to the existing layers, creating a rainwater harvesting potential map. The results showed that hydrological soil group had the most relative importance for rainwater harvesting potential (0.444). Soil hydrological groups are determined based on soil texture and permeability. Therefore, soil texture and permeability can be considered as the most relatively important factors for rainwater harvesting. In this study, 56.2% of the watershed had medium potential and 16.5% had a high and very high potential for runoff generation. The results showed that the analytical hierarchy process can be used as a method to qualitatively assess  rainwater harvesting potential at the watershed scale.

In recent years, Iran in Southwest Asia it has been affected by drought. The purpose of the present study is to analyze and forecast drought in Iran. For this research at first, the precipitation and temperature climatic parameters over a 29 year period (1990- 2018) at 30 stations in Iran Collected. For modeling, the M.S.S fuzzy index, at first uses three indices (SET, SPI, MCZI) using fuzzy logic in Matlab software. Then the indicators are compared and compared with Topsis multivariate decision making model, For Prioritization Drought affected areas were used and finally to forecast the RBF artificial neural network model was used. The Research findings showed that the new M.S.S Index drought class fuzzy index reflected the above three indices with high accuracy and the accuracy of the M.S.S model was confirmed with high confidence. In the drought monitoring years, southern and southwestern stations of Iran such as Bandar Abbas and Ahvaz were more prone to drought (24.30 and 18.47%). In the years to forecast, the drought is expected to extend to the central parts of Iran. Including these stations Semnan and Yazd with drought frequency percent (0.86 and 0.91) are based on M.S.S fuzzy index, respectively.

Agriculture dates back to several millennia in Mesopotamia and Khuzestan plain. Alongside agricultural production, people in this region have preserved water and soil, reduced water and wind erosion, and mitigated the impact of floods and drought based on experience, simple techniques, and using rocks and soil as construction material. The Khuzestan plain is located at the end of the drainage basin, where dust has become an issue in recent years. Therefore, the main aim of this research is to investigate the role of gourabs, a type of pond, as an indigenous structure for supplying water to the villages of desert areas in Khuzestan province. Initially, basic information was collected by reviewing the available resources. Then, some gourabs were identified and site selection was done in Google Earth using satellite imagery. For a more detailed study of the subject, field visits and interviews with experts were carried out, and questionnaires were distributed. The results indicate that in general, the shape of a gourab is either circular, square, or rectangular, and the structure is built in three sizes (small, medium, and large). We also found five types of function for these structures. In some areas circular gourabs are used for various functions, but in other areas each type of gourab serves a specific function.

Sustainable utilization and conservation of natural resources has a key importance in intelligent development. To attain sustainable utilization and conservation of water resources, it is vital to discover and implement alternative and non-conventional resources and methods of water supply to various sectors. One of alternative methods of supplying water for household consumption which has been historically practiced in many parts of the world, particularly in arid and semi-arid regions of Iran, is rooftop rainwater harvesting and storage in cisterns. Although rainwater harvesting is considered as an interesting and effective means of water resource management, numerus limitations such as climatic variability, irregular rainfall pattern, insufficient storage space, financial incapability, health issues, legal and regulatory restriction, and lack of installation and maintenance services hinder the adoption and expansion of rainwater harvesting systems among societies. Both preparing and enacting of compulsory laws and regulations and offering incentives is necessary for widespread adoption of rainwater harvesting. To this end, many countries, mainly arid and semi-arid countries and recently countries with temperate or even humid climates, have made and implemented policies regarding water conservation and supply through alternative methods. These countries have developed laws and regulation as well as financial incentives. A review of the experiences of these countries, which is the aim of this paper, will benefit policy making for rainwater harvesting in Iran. Therefore, in this paper the rainwater harvesting programs, projects, laws and regulations in USA, Germany, Australia, Brazil, China, Malaysia, India, Japan, Thailand, Barbados, and Kenya are briefly introduced as examples.

Agricultural residues and various other materials are currently being used as additives to improve the physical and chemical properties of soil. Iran is located in an arid and semiarid region, so using strategies to reduce water use will reduce the problem water scarcity. The use of superabsorbent to increase water uptake and retention is one of the solutions that have been applied to improve water productivity in recent years. In this study, four types of superabsorbents (A200, Trachothem, Herbazorb and Stacosorb) and six soil samples (categorized in three groups) from the southern slopes of the Alborz  were used. In the laboratory research phase, transparent plexiglass cylinders were used for monitoring changes. The results showed that the addition of superabsorbent to three soil samples increased soil moisture uptake compared to the control treatment. The percentage of moisture uptake in the treatment using 25% A200 in soil was 50% more than other superabsorbent. In the field phase of the research, the combined use of a water catchment system and superabsorbent was investigated. The results showed that the use of superabsorbent in the rain catchment resulted in about 75% increase in water uptake and retention. The rate of water absorption into the absorbent is proportional to the ambient temperature and inversely proportional to the size of the absorbent particles. The results of the field survey showed that water retention was increased and 75% of precipitation loss was prevented. Therefore, simultaneously using water catchment systems and absorbents in soil is recommended for improving water productivity.