جستجوی مقالات مرتبط با کلیدواژه "rainwater harvesting" در نشریات گروه "آبخیزداری، بیابان، محیط زیست، مرتع"

During the past years, based on predetermined goals, relatively appropriate financial resources have been spent in the field of agricultural research and natural resources. Nevertheless, the effectiveness of research activities in Iran has always been accompanied by many debates by its supporters and opponents. With this approach, this study, with the aim of evaluating the effectiveness of watershed research, evaluates and measures the effectiveness of applied research projects including flood spreading, rain catchment surface system, underground dam and various soil protection treatments in Razavi Khorasan, North Khorasan, Kermanshah, Fars, Tehran, Qazvin, Zanjan and Semnan provinces. In order to investigate this issue, the key research projects that are based on solving the problems of watersheds in the aforementioned provinces, their identification and effectiveness in achieving the goals of watershed management from an economic and social point of view were examined. In the current research, the effectiveness of the research was evaluated using the cost-benefit method and the level of satisfaction of watershed criteria before and after the implementation of measures. The research results showed that in all the selected provinces, the implemented research projects were economically and socially effective, and among them, flood spreading projects had the highest economic index with an average benefit-cost ratio of 24. 5.

The present study aimed to determine the most appropriate methods to increase moisture retention in the soil profile. This research was designed in the form of a randomized complete block design with six treatments including three treatments using wheat straw with different compositions and methods, one treatment using sponge waste and gravel filter, one treatment using animal manure and natural soil treatment (control). The soil moisture content of the treatments was measured every 15 days by gypsum blocks for 3 years and their weight percent moisture content was compared to each other and the control treatment. The results showed that the treatment using sponge and gravel filter was significant and effective in increasing the soil moisture retention compared to the control treatment with values of 15.2 and 10.8 percent moisture at the 1 percent level of significance, respectively. It is worth to mention that between the three treatments using wheat straw with different compositions and methods, with a range of 12.3 to 12.8 percent moisture content, no significant difference was observed therefore none of them has a preference over the other in terms of maintaining soil moisture content.

During the last few decades, the ecosystem of natural areas has suffered as a result of improper exploitation of water and soil resources. To revive and develop renewable natural resources, it seems important to analyze and optimize rainfall storage systems and provide integrated techniques. Rainwater harvesting, in conjunction with plant species cultivation, is critical in the restoration and improvement of rangeland, particularly in dry areas. The present research was conducted with the aim of investigating the effect of rainwater harvesting methods (contour furrow and microcatchment) on increasing the percentage of vegetation cover in the Khajeh research station in East Azerbaijan province. To accomplish this, two methods of rainwater harvesting system, contour furrow and microcatchment, were established in the form of a randomized complete block design with three repetitions, in a land with a slope of 2-6%. After preparing the plots, Agropyron elongtum was planted in the form of seeding. Vegetation cover percentage was measured from the second year of planting for three years. A linear transect was used to determine vegetation cover percentage. The results showed that the microcatchment treatment significantly increased vegetation cover compared to the control. So that with the construction of the microcatchment, the vegetation cover increased about 183% (three times) compared to the control. In the case of contour furrow treatment, an increase of about 53% was observed compared to the control treatment. The microcatchment method performed better than the contour furrow, so that it increased the vegetation cover by about 85%. Therefore it seems the microcatchment is the best rainwater harvesting system in terms of increasing vegetation cover in the study area.

This research has been carried out with the aim of investigating the use of gravelly filters in rainfed gardens on sloping lands in order to optimize infiltration and increase soil moisture storage in the conditions of using micro catchment systems during the years 2013-2018 in Chaharmahal and Bakhtiari province. The research rejoin has an average annual rainfall of 300 mm, soil with silty clay loam texture, and an average slope of 15%. Towards this attempt, micro catchments were made with five different treatments including a removed surface with and without using a gravelly filter, an isolated surface with and without using a gravelly filter, and the control treatment(natural surface), along with three cultivars of almond(Rabie, Mamaei, and Shahroud 21) and were constructed in 5 repetitions. The soil moisture at the depths of 25, 50, and 75 cm of the seedling hole in each of the systems was accurately measured and recorded using a TDR device. In order to determine the role of filters and to determine the difference between similar treatments with the different presence or absence of gravelly filters in them, Paired-Samples T-Test was used in SPSS software. The results showed that there is a significant difference between the treatments with filter and without filter in terms of soil moisture percentage. In other words, using the gravelly filter in the seedling pit will optimize the infiltration of extracted runoff into the soil, increase humidity in the place of tree root development, and increase its growth. Therefore, it is recommended to use the gravelly filter in the seedling pit in the conditions of using rainwater catchment systems.

The purpose of this study is to accurately measure the watershed potential for constructing rainwater harvesting structures. To carry out this research, the DEM digital-elevation model layer was used to prepare slope, hydrological soil groups and land use maps in the Arc GIS 10.3 software. The drainage density map was prepared by combining the DEM layer, topographic map, drainage density and hydrography data. A map of precipitation levels was prepared by using the pluvial method. CN map was prepared by combining land use and vegetation maps with hydrological soil groups. Runoff calculations were used to prepare runoff potential and coefficient maps. By combining them with the maps of drainage density, slope, and using analytical hierarchy process (AHP), a map of potential runoff production was prepared. The underground water fluctuation map was prepared using the base data and the water demand map was produced using (AHP). By combining this map with runoff production potential map, a water demand map was prepared. According to the obtained results, about 72 percent of the area has medium potential for the implementation of water extraction structures. It also shows about 22 percent of the area of low potential and about 6 precent of good potential.

Arid and semi-arid regions with highly variable rainfall and periods of drought or unpredictable floods have severely affected residents' water shortages and they are often living in insecure areas. Rainwater catchment systems are one of the available solutions to overcome water shortage and runoff management in these areas. Surface runoff is a potential source of water that, with proper management and rainwater extraction methods, can be used to meet demand in various sectors, including agriculture and drinking. This study was conducted with the aim of introducing suitable places for establishing rainwater catchment systems in Latyan Watershed. Essential maps of the watershed for this study included land cover coefficient, permeability of formations and soil, average long-term rainfall, slope, land use, and drainage network were prepared. The mentioned maps were each divided into five categories and by overlaying in ARC/GIS 10.7.2 environment, finally suitable places for runoff production of the watershed were obtained to create catchment levels. The results showed that slope percentage, type of land use, NDVI and climate in this watershed were effective factors for runoff production. In addition, the map of runoff production potential classes showed that the frequency percentages related to runoff production potential classes were very high, high, medium, and low, respectively 3.2, 22, 33.6 and 23.5%. For the construction of these systems, priority is given to areas that have the potential and frequency of upper class in terms of runoff production, which areas with medium runoff production potential have this feature. Introducing suitable places to establish rainwater catchment systems can maximize the probability of success of rainwater harvesting projects.

Soil infiltration is one of the most crucial parts for designing rainwater catchment systems and has an essential role in determining the area for rainwater harvesting. Using the Kamphorst field rain simulator, the infiltration rate of the suitable sites for the rainwater catchment systems has been determined. After selecting the suitable site, the soil was saturated, and the experiments were performed a day later. Simulation experiments have been conducted in two sites. The first site was Pishkamr city in Golestan province and the second site was near Sararood research station in Kermanshah province. The constant slope was at 12%, and the rain intensities were 33, 64, and 110 mm/h for 15 minutes in four repetitions. At the end of the experiment, the total volume of runoff was collected, and the infiltration rate was calculated. The results showed that with increasing rainfall intensity from 64 to 110 mm/h, the runoff volume of Pishkamr and Sararood increased 6.1 and 13.7 times, respectively. The infiltration rate in comparison with rain intensity showed that by increasing rainfall intensity from 64 to 110 mm/h, the infiltration rate increased 16.6% and 25.3% in the Pishkamr and Sararood, respectively. The comparison of the infiltration rate in the two sites also showed that the infiltration rate in the Sararood site was higher than the Pishkamr site. Therefore, with the knowledge of soil Infiltration, suitable rainwater catchment systems can be designed to supply water for plants.

In this research, a plan for the intelligent design of dry landscaping has been proposed for urban green spaces, non-residential, and administrative units with a rainwater harvesting approach. In this plan, by using two infiltrate and non-infiltrate layers and designing a drainage network between the two layers, due to the appropriate slope of the area, rainwater runoff can be extracted. Also, to prevent using different drains with an economic justification approach, we have created systems to collect and direct rainwater to the exit point of the system and guide rainwater to the desired source. By implementing these systems, soil moisture, especially in the output range of each section, and the efficiency of this project will increase. Executing this project will reduce water consumption and increase efficient use of harvested water, and as a result, will have significant economic profitability and help conserving water resources. Daily rainfall, runoff, evaporation, and soil temperature were determined by the equipment. The results showed that with this design, runoff can be doubled, soil moisture of the region can be increased up to 5%, rainwater runoff can be stored to a large extent to be used for different purposes, and reduce the intensity of soil temperature and evaporation, which can reduce water consumption for green space irrigation. On the other hand, with the implementation of this project and the design of suitable artificial feeding systems, rainwater runoff can be intelligently directed to the groundwater aquifers. This positive environmental approach can play a crucial role in reducing land subsidence, especially in the plains of Iran.

Low rainfall and its poor distribution in the West Azerbaijan province have hampered agricultural production in dry-land. One of the important solutions in this regard is converting rainfall into runoff. In this study, a field experiment in Khoshalan village of Urmia on grapes in rainfed conditions with supplementary irrigation and rainwater harvesting was carried out in a split-plot design based on randomized complete blocks for six years from 2000 to 2006. The first four years were for seedlings of plants, and recording of yield was possible in 2005 and 2006. The three factors studied include fertilizer application factor in 30 and 70% of the usual recommendation for irrigated cultivation, watershed area factor in areas of 12, 20, and 30 m2, and runoff surface status factor including normal traffic, plastic cover, and paving stones. In this study, the benefit is calculated based on the cost and income of 2019. The results showed that with increasing fertilizer consumption, yield decreased from 1755 to 1461 kg/ha, and benefit decreased from 81.2 to 46 million rials. This result indicates that under semi-dry conditions, fertilizer, cannot be consumed in large quantities. With decreasing watershed area, yield and benefit increased from 1018 to 2451 kg/ha and from 6.2 to 148 million rials, respectively. Plastic with 2208 kg/ha and 113.6 million rials had an increase in yield and profit of 54 and 86% compared to the control. Also, paving stones compared to the control, experienced 1 and 49% yield reduction, and profit respectively. According to the results of this study, an area of 12 m2, with plastic cover with 70% of the usual fertilizer recommendation for irrigated cultivation, increases the yield of rainfed grapes.

The present research has been executed in order to investigation of rainwater harvesting systems capability in runoff generation for supplying part of water required for hillside orchards. It is an innovative effort to establish a close link between watershed management activities and the production of horticultural products with a food security approach. Towards this attempt, in Chaharmahal and Bakhtiary province, 9 rectangular rainwater harvesting systems with dimensions of 4 × 3 m2 and 3 different managerial treatments (insulator surface, removed surface and natural vegetation cover) with 3 replicates and completely randomized design were made on a slope of 20 percent. At the end of each system, a reservoir has been installed to collect runoff coming from the plot. Rainfall amounts are estimated using a rain-gauge nearby and runoff volume was measured in the reservoir. Compare of the mean of treatments indicated that the system with insulator surface has generated the maximum runoff volume. The runoff volume generated by insulator surface was 5 times that of removed surface and 17.5 times that of natural vegetation cover. The results showed that the mean runoff coefficient derived from the systems with insulator surface, removed surface and natural vegetation cover were respectively 64.3, 7.7 and 1.8 percent. Also, the results showed that rainfall less than 5 mm has generated runoff only at insulator surface. Therefore, the other advantage of using insulator surfaces can be considered in the production of runoff in minimum rainfall. This issue, due to the frequency of rainfall events with values less than 5 mm in arid and semi-arid regions, makes it more necessary to use the insulator surfaces for harvesting of rainwater in these areas. So the use of insulator surfaces along with the installation of a runoff storage system and distribution of stored water in dry months is recommended to supply part of the water needed for hillside orchards.

In this study, the possibility of using a combination of gravel filters with plastic cover to increase water infiltration and soil moisture storage in rainwater catchment systems was investigated. For this purpose, five treatments (with three replications) including control treatment, vegetation removal with filter, vegetation removal without filter, semi-insulated system with filter, and semi-insulated system without filter were considered, and Apricot was planted in all treatments. Then, soil moisture storage was recorded by the soil moisture data recorder at two depths of 20 and 60 cm in each treatment. The data were analyzed using a completely randomized block design. The results showed that there was a significant difference between treatments. During the growing season, the highest soil moisture storage was related to the dry months of the year (June, July, August and September) and semi-insulated treatment with gravel filter. In other words, the moisture content of semi-insulated system with gravel filter was significantly higher than other treatments. The results of this study indicated that rainwater harvesting through semi-insulated surfaces and infiltrating it by gravel filter is a good way to increase soil moisture storage.

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.

Lack of stored soil moisture is an essential factor in intensification of the problems of arid and semi-arid areas in Kohgiloyeh va Boyerahmad Province. In these areas, limited surface water and groundwater have rendered vast areas of the region’s fertile lands useless. Despite these problems, appropriate conditions can be provided to plant resistant and adapted species such as olive through increasing moisture durability in the soil profile and optimizing precipitation. The aim of this research is to evaluate water supply for olive trees through rainwater harvesting and select the most appropriate method of increasing moisture durability in the soil profile in a semi-arid area of Kohgiloyeh va Boyerahmad province. Rhombic insulation systems on steep lands were used for fast collection of rainwater; gravel filters were installed to reduce evaporation and facilitate the rapid transfer of collected water; and stubble, manure, peat, waste sponge, and super absorbent were employed to store water and increase moisture durability. This study was performed in randomized complete block design with five treatments including stubble, manure, peat, waste sponge and super absorbent with gravel filter and control (natural soil) treatment in 3 replication on north-facing lands with 15-20% slope. To make comparisons, plants were chosen randomly from the treatments and control with similar root systems, leaves and the number of branches. The system for the precipitation harvesting was rhombus-shaped (dimensions 2×2) with nylon insulation. This project tried to maximize precipitation utilization to meet plants’ water demand. However, when rainfall was less than the minimum water requirement for olive trees, supplementary irrigation was provided based on the minimum water requirement.

In recent decades, extensive research has been carried out to collect and store rain and runoff around the world. In addition to applying different water harvesting methods, and reducing the risk of runoff, other measures such as increasing soil moisture content and cultivation of tree and rangeland species have been studied. There are many water-related environmental problems which, according to researchers, are partly due to the use of new technologies. Part of the body of research focuses on the importance of the indigenous knowledge of water harvesting techniques, and even its integration with new knowledge as a means of sustainable development in this sector. Identifying these traditional methods, which are usually local and consistent with the ecosystem of the region, is the first step towards using them. Since ancient times, different methods have been used for collecting runoff and rainwater in different parts of Iran, in accordance with different climates of Iran. In this paper, one of the native methods of collecting rainwater, known as Perch, used in the past in the mountainous regions of Kohgiluyeh and Boyerahmad province is introduced for the first time.

Due to the lack of adequate sources of drinking water and uncertainty about the quality of these sources, along with rising water demand due to population growth, it is important to find a suitable solution to supply drinking water. Rainwater harvesting from roofs and use of natural discharge from springs are among techniques which can replace surface and underground water resources. The city of Divandareh in Kurdistan province has a strong potential to utilize these two sources. According to population statistics from 2011, the annual water consumption per capita of the city is 1871110 cubic meters. Our results showed that these two sources can provide 1001235 cubic meters of water per year. Based on the average annual consumption of each person in the city, springs and harvested rain can meet  53.5% of the city’s water demand, priced at 5,256,483,960 rials per year using the price of drinking water, and 4,246,463,320 rials per year using the price of raw water. The results indicated that in the case of comprehensive management of these two resources for optimal storage and utilization, they could be suitable options to compensate for abnormal water consumption, and in some cases the conditions of permanent stress and water shortage in the city would be prevented.

Water, along with issues such as preserving the environment and eradicating poverty and hunger, is a fundamental issue in sustainable development and is an essential element of human survival and well-being. The lack of water in the arid and semi-arid regions of the world has caused the environmental conditions to be fragile. Therefore, the purpose of this research is to identify areas susceptible to rainwater harvesting in order to rehabilitate water resources in different ecosystems using a hierarchical decision making method based on spatial analysis in the GIS environment.
In this research, the factors affecting rainwater penetration and storage in the soil profile of the Ghiran and Khosrowabad watersheds of the city of Sangar, Kermanshah Province, were identified and entered the hierarchical analysis process. At first, by using expert opinions, relevant faculty members and experts, by means of paired comparison and in accordance with the method of time, the tables of value were completed and then analyzed by special vector method. For each matrix, the result of the division of the inconsistency index into the random matrix inconsistency matrix, then the matrix, is a suitable criterion for judging the incompatibility, which is called incompatibility rate. If this number is less than 0.1, the system compatibility is acceptable. Then, their importance coefficients were determined and the paired comparison tables completed. In this regard, the weight of 11 variables of vegetation, canopy, percentage and direction of gradient, rainfall, lithology, land use, soil hydrologic groups, geomorphology, elevation and erosion classes were calculated using MATLABR2009a software and based on the ArcGIS10.3 environment. Which were respectively 0188/0, 0254/0, 1365/0, 048/0, 2509/0, 0608/0, 0575/0, 1539/0, 0589/0, 0808/0, 1084/0 Came out. After determining the weight of each of these criteria, the susceptible areas of rainwater storage were identified and in the GIS environment, five levels were classified as very suitable, appropriate, moderate, unsuitable, and unsuitable, respectively, for the areas of beer and Khosrowabad, respectively (% 33, 32/41, 46/8, 47/7 and 47/5, 08/41, 53/37, 31/8, and 64/5 of the area of ​​the basin. 59 benchmarks were expressed in general, of which 11 were the main criteria and 48 sub-criteria were considered. The selected indicators were used by the questionnaire and by experts, experts and experienced experts by group method during the process of engineering value and Individual and comparative method was double-valued. Tables (1 to 9) show the results of pairwise comparison of the parameters and weights obtained after the formation of a pair comparison matrix. In the AHP method, the criteria are first qualitatively and then are presented quantitatively using the table. In this process, the ratio of incompatibility is determined and if its value is less than 0.1, then there is an indication of the acceptable level of compatibility of the pairwise comparisons. In this study, the degree of inconsistency for each of the main criteria and its sub-criteria is indicated separately in the tables below given.
The results of this study showed that, in addition to the rainfall factor which is the main factor, two slope factors and soil hydrological groups as the other main factors for collecting rainwater from the rest of the factors have more and more impact. According to the results obtained and the tables shown, the lowest inconsistency rate related to the gradient direction, which is equal to 0.123 (Table 8), and the highest is related to erosion, which is equal to 0906 (Table 1). The results also showed that slopes of 20-30%, which are mostly pasture and pastures, are suitable places for storing runoff. Areas with Ptanicyle have a very good harvest area that is best suited to store atmospheric precipitation in terms of coverage, slope and permeability. According to the obtained map of Figure 2, the total area of Khosrow Abad watershed (1819.68 hectares) has a total of 26.26 hectares, has a very suitable potential, 769.79 hectares suitable, 696.59 hectares average, 154.27 hectares inappropriate and 77/104 hectares are very inappropriate for collecting rainwater.
Discussion and The results of this study indicate that the method used has high credibility in zoning the suitable areas for implementing rainwater harvesting projects and using the process of analyzing hierarchy in the GIS environment as an effective spatial decision system in the location of areas susceptible to rainwater harvesting.

Various methods have been used for collecting water, but each one by itself has shortcomings that have prevented or limited its application. The method of rainwater collection by using a rainwater harvesting device (rainwater harvesting machine or R.H.M) is a new technique that was inspired by pitcher irrigation, techniques of water harvesting, and drip irrigation. Combination of these three methods had led to the manufacturing of a very simple and practical device that can be used in various parts of the world (including Iran), especially in arid and semi-arid and even in semi-humid regions where access to water is limited or impossible. This device has applications in supplying the water required for agriculture, drinking, tourism, etc. Rainwater harvesting devices have completely overcome the disadvantages of the three methods mentioned above. It is a simple and multi-purpose tool, and its main application is to provide sufficient water for establishing and developing orchards, planting trees in regions where water is scarce or unavailable, and job creation. Protection of groundwater resources and prevention of erosion are among the most important additional goals in utilizing this device. In the present research, two samples of rainwater harvesting devices with the capacities of storing 430 and 1800 liters of rainwater were first designed, produced, and installed. A rain gauge was then used to measure daily rain and the volume of rainwater stored in the tanks of the devices, and to study their ability to store and save rainwater. Results showed that the devices had the necessary efficiency for harvesting and storing rainwater for when water was needed. The total water loss during the processes of rainwater entrapment and storage until the time it was used amounted to less than five percent.

Reduction in rainfall, population growth, environmental issues, and a need for development of green areas in residential buildings have become a major challenge for water resource management. The majority of urban surfaces are impermeable and as a result precipitation mostly flows on the surface as runoff. Hence, storage of rainfall in dry urban areas has an important role in water resource management. Tehran, with a population of more than 10 million people, has a dry semi-arid climate. Storage of rainfall can be effective in providing water for various purposes. The aim of this study was the evaluation of rainfall in Tehran and to assess the required volume of storage units to be built on roofs by designing and optimizing collection reservoirs for irrigation of green areas in residential units. To this end, precipitation data of two synoptic stations of Shemiran and Mehrabad, have been used for the northern and southern parts of Tehran, respectively. The evaluations were performed under two scenarios. In the first scenario, the highest monthly rainfall, and in the second scenario, the average annual precipitation was considered and storage volumes of tanks were calculated for roofs with areas ranging from 100 to 550 square meters. The results showed that in Tehran, using rainwater harvesting system in the months with the highest rainfall can meet the needs of green areas in drier month, as well as some other non-drinking water uses. Under the scenario which utilized the months with the highest rainfall, for every 100 m² of roof space, about 5000 liters of rainwater can be stored which lessens the pressure on the municipal water supply network and offers economic benefits .

Providing water to people in arid and semi-arid areas of the world is especially important. Therefore, identification of suitable sites for the construction of rainwater harvesting systems is an important step towards maximizing available water for agriculture and other uses. The purpose of this study is to identify areas susceptible to penetration by rainwater, where rainwater can be collected to restore water resources and enhance vegetation cover, and to be used in different ecosystems of Khosrowabad watershed using hierarchical decision making method based on spatial analysis in a GIS environment. In this research, the factors affecting rainwater penetration and storage in the soil profile of Khosrowabad watershed in the city of Sonqor were identified and entered into the Analytical Hierarchy Process (AHP) process. The selected indices were evaluated using a questionnaire and evaluated by experts’, academics’ and specialists’ opinion by group method during the process of value engineering and were later compared individually and in pairs. Then, their importance coefficients were determined and the paired comparison tables completed. The completed tables were analyzed by the special vector method. In this regard, the weight of seven criteria of vegetation, slope, precipitation, land use, hydrological groups, elevation classes and erosion were calculated using MATLABR2009a software and the required layers were prepared in Arc GIS10.3 environment. Then, using natural breaks in GIS environment, the five levels determined as very appropriate, appropriate, moderate, inappropriate, and unsuitable. From 1855/67 hectares, the total area of ​​the catchment area is 862,600 hectares. The total area of ​​the basin has a suitable and very suitable potential for collecting rainwater and 259.49 hectares of the catchment area with inappropriate and very inappropriate potential for this purpose, reflecting the very high capacity of this basin to store and collect rainwater. The results of this study showed that in addition to the precipitation factor which is one of the main factors, the two factors of gradient and soil characteristics in terms of soil hydrological groups are the more important factors for collecting rainwater compared to the rest of factors and have a more significant impact.

Rainfall is a source of water with the best quality in the nature. Therefore, harvesting and using of the runoff resulted from rainfall, can help better management of water resources in our country. As a considerable part of urbanized areas are building roofs, quantity of water harvested from roof catchments will be considerable and can prepare a part of water required for the residents. In this study, rainfall and runoff events were measured in cities of Mashhad (with arid and semi-arid climatic condition) and Noor (with sub-humid and humid climatic condition). The surfaces selected to collect rainwater were two roof catchments (one in each city) with almost the same conditions. After preparing the rooftops, the required storages and the related equipments were established and the amount of runoff was measured after each rainfall event for whole the rainy seasons of the year. Information of precipitation events was received from the closest meteorological synoptic stations. Using appropriate statistical analysis, the volume of runoff as well as runoff coefficient for different levels of rainfall depth and intensity was determined after each event. The results of this research show that average runoff coefficient for the fall season in Mashhad is 0.66 and is 0.75 in Noor, for the winter it is 0.69 and 0.76 respectively in Mashhad and Noor, and for the spring season, the average runoff coefficient was measured 0.62 in Mashhad and 0.69 in Noor. The threshold values (minimum values) of rainfall for runoff generation 0.3 mm in Noor and 0.7 mm in Mashhad. The total depth of rainfall and runoff for the measured period in Mashhad were 217.5 and 139.9 mm, respectively, and in the Noor they were 496.8 and 356.1 mm. The highest amount of seasonal runoff generated in Mashhad belongs to the spring but in Noor it has been occurred in autumn season.