Rainwater Harvesting from Kermanshah City Roofs and Recognizing the Suitable Places for Water Saving to Irrigate Urban Green Spaces

Document Type : Full length article


1 MA in Climatology, Razi University, Kermanshah, Iran

2 Associate Professor of Climatology, Razi University, Kermanshah, Iran

3 Assistant Professor of Climatology, Razi University, Kermanshah, Iran


Water is considered as an important and determinative factor for the continuity of human, animal and plants living on the earth and biosphere. This vital material resolves the primary requirements of human such as drinking, agriculture, and industry. Nowadays, providing water is regarded as a basic challenge in developing countries, like Iran. Given the climate tensions and excessive consumption in most major cities, the problem of water scarcity can be minimized by harvesting rainwater. Since Rainwater Harvesting of roofs in some regions in Iran is considerably remarkable, it can provide some non-drinking requirements of citizens. Basic concept of rainwater harvesting is simple; it is the water can be collected from the roofs and appropriate surfaces, and conveyed downwards by pipes for saving. This water is saved in an appropriate place which can be used in proper time. If the saved water is considered for non-drinking consumption, no filtering will be needed; desalination is enough. It should be noted that rainwater needs to be filtered for drinking. Therefore, for arid and semi-arid regions such as Kermanshah, Rainwater Harvesting from the building roofs to supply water requirement of urban green places can solve a major problem of dehydration.
Material and method
The necessary climatic data for this study are precipitation statistic of synoptic station in Kermanshah during a 65-year period, from 1951 to 2016. They were used as annually and monthly average. Due to the climate of Kermanshah, precipitation period lasts from October to June. The urban data used includes the area of building roofs, the area of urban green places and trees, and thr volume of water required for irrigation. The area of building roofs (in meter) of Kermanshah city was extracted from aerial photos in Google Earth.  
To calculate the volume of harvesting rainwater, we used three components including precipitation, the area of building roofs and run-off coefficient. Run-off coefficient of building roofs is 0.7 by default. Moreover, the required water for irrigation of the green places of Kermanshah city is 12 liters per m2 during 24 hours. Although there is rainfall during cold season of the year (January, February and March) with decrease in plant growth, irrigation is stopped. The water consumed for irrigation is on average 4 liters per m2 in fall and spring mainly due to moderate weather and rainfall conditions. In the present study, WLC and AHP methods were applied to determine the appropriate location of rainwater saving. The evaluated variables to determine the place are including green places, unused places, agricultural lands in the city, suburb agriculture lands, slope and the proximity to the buildings which were gathered by questionnaire through experts of municipality officials, parks organization and urban green places of Kermanshah city. Moreover, it should be noted that some land uses are considered as the unsuitable places to save rainwater such as asphalt surface, roof surface, and all kinds of service land uses across the city.
Results and discussion
The built area of Kermanshah city is 108365238 m2. The maximum precipitation usually occurs in March and April, 70.6 mm, while the minimum is occurs in July and August. The average annual precipitation is 441 mm. Besides, the maximum temperature of Kermanshah city is 38C in August, while the minimum is -3.6 C in January.
The biggest value is recorded for zone 3 in Kermanshah, 21.28 Km2, and the greatest area of building roofs is recorded for district 4, 23.8 % with the highest building density. Moreover, the greenest places are related to zone 5, 6.4%. The highest water requirement is also related to zone 5, due to the green places and higher number of trees (8110 ones), 14.7%. The highest ratio of harvesting rainwater is calculated for zone 4 (due to more building density), while the least ratio is calculated for zone 8 (due to less building density). The ratio of the area of urban green places is 4.3% and the ratio of water requirement is 9.8%. The most percent reserve of rainwater requirement is related to zone 4 located in the southeast of the city, 76.5%; zone 3, in the east of the city. It is regarded in the second class. The least percent of reserve rainwater requirement is recognized for zone 8, located in the southwest Kermanshah city. As a matter of fact, it is important to recognize these regions for green places may be of the far regions to gather rainwater which require the transition and saving according to the effective variables. The total volume of water requirement is about 10620000 m3 and the volume of harvesting rainwater is 6200000 m3 which can provide 58.4% of water requirement.   
The highest effectiveness of locating is related to the variable of the locations with green places.  Unused places and agriculture lands in the city are in the next priority for rainwater saving, due to easier land use conversion. In fact, the areas of lower slope are more appropriate for rainwater saving. Besides, the proximity to the place for gathering rainwater is economically efficient. Totally, 42000 m2 of the total area of Kermanshah city is more suitable for saving rainwater which is mostly located in district 5 in the northeast of the city. Building roofs, passages, medical centers, service centers, refinery and airports are not appropriate enough to save rainwater, they are approximately 42000000 m2.
Rainwater is changed into run-off and flood-water in most of the cities in Iran which is moved out of the city by water channels. Rainwater Harvesting is of considerable importance due to the conservation and management of water sources. The present study is carried out to determine the amount of harvesting rainwater from the building roofs of Kermanshah city to supply water requirement of urban green places. The suitable places for rainwater harvesting were determined by WLC models. The findings show that 6200000 m3 (58.4%) out of total 10620000 m3 of annually water requirement of Kermanshah green places, is provided by rainwater harvesting of the building roofs. According to different environmental variables, about 42000 m2 of urban area and suburb of the city are recognized as more appropriate regions for the saving rainwater. Zone 5 of Kermanshah city has better conditions compared with other zones.  


بیادی، ح.؛ ثنایی‏نژاد س.ح. و احمدیان طبسی، م.‏ج. (۱۳۸۷). بهره‏گیری از رواناب شهری در تأمین تقاضای محلی آب، سازمان هواشناسی کشور.
پرهیزگار، ا. و غفاری گیلانده، ع. (۱۳۸۵). سامانة اطلاعات جغرافیایی و تحلیل تصمیم چندمعیاری، تهران: سمت.
تاران، ف. و مهتابی، ق. (۱۳۹۵). بررسی تأمین آب مورد نیاز بخش‌های مختلف شهر از طریق استحصال آب باران: مطالعة موردی شهر بناب، فصل‌نامة علمی‌- پژوهشی مهندسی آبیاری و آب، ۷(۲۵): ۵۳-۴۰.
حنیفه‏پور، م.؛ خدابنده‏لو، ر. و حمیدی، م. (۱۳۹۴). برآورد آب قابل استفاده از استحصال آب باران جهت استفاده در ‏امورکشاورزی (مطالعة موردی: زنجان)، دومین همایش بین‌المللی پژوهش‌های‏کاربردی در کشاورزی، ٩-۱.
خاوری، ه.؛ گلدانی، م.؛ خواجه حسینی، م. و شور، م. (۱۳۹۴). تعیین درجة حرارت‌های کاردینال و واکنش جوانه‏زنی بذور به درجة حرارت‌های مختلف در پنج رقم بذر چمن، نشریةعلوم باغبانی، 30(۴): ۶۵۰-۶۴۳.
ذوالفقاری، ح. (١٣٩٠). نگاهی به روش‌های جمع‏آوری آب باران برای مصارف خانگی، دومین کنفرانس ملی پژوهش‌های کاربردی منابع آب ایران، شرکت آب منطقه‏ای زنجان: ۱-۱۱.
رسولی، ع.ا.؛ محمودزاده، ح.؛ یزدچی، س. و زرین‏بال، م. (۱۳۹۱). ارزیابی روش‏های تحلیل سلسله‌مراتبی و ترکیب خطی وزن‏دار در مکان‏یابی محل دفن مواد زاید شهری (مطالعة موردی: مرند)، جغرافیا و آمایش شهری منطقه‏ای، 4: ۵۲-۴۱.
رشیدی‏ مهرآبادی، م.ح.؛ ثقفیان، ب. و صادقیان، م.ص. (١٣٩2). ارزیابی عملکرد سطوح آبگیر پشت‌بام ساختمان‏های مسکونی در تأمین نیاز غیرشرب ساکنین در شهرهای ساحلی کشور، نشریة مهندسی منابع آب، 6(۱۹): ۱-۱۵.
زهتابیان، غ.؛ مسعودی، ر. و خسروی، ح. (۱۳۹۲). بررسی روش جمع‏آوری آب باران از سقف خانه‏ها (DRWH) (مطالعة موردی: استان گلستان)، مجلةسامانه‏های سطوح آبگیر باران، ۱(۳): ۲۰-۱۴.
سعدالدین، ا.؛ بای، م. و نعیمی، ا. (1393). امکان‏سنجی فنی و اقتصادی جمع‏آوری آب‏ باران از سطح بام ساختمان‏ها (مطالعة موردی: دانشگاه علوم کشاورزی و منابع طبیعی گرگان)، نشریةپژوهش‏های حفاظت آب و خاک، 21(۶): ۲۷-۵۰.
شادمهری ‏طوسی، ا.ح.؛ دانش، ش. و حسینی، س.م. (1396). بررسی پتانسیل جمع‏آوری آب باران از سطح ساختمان‏ها (مطالعة موردی: یکی از نواحی چندگانة شهرداری مشهد)، چهارمین کنفرانس بین‏المللی برنامه‏ریزی و مدیریت محیط زیست، تهران، دانشگاه تهران، ۱-12.
شهابی، ه.؛ خضری، س. و نیری، ه. (۱۳۸۷). بررسی فاکتورهای مؤثر در مکان‌یابی ایستگاه‌های امداد و نجات جادة سقز- سنندج با استفاده از مدل ترکیب خطی وزن‏دار (WLC)، چهارمین کنفرانس بین‏المللی مدیریت جامع بحران و پدافند غیرعامل در پایداری ملی، تهران.
شهرداری کرمانشاه (۱۳۸۸). آیین‏نامة ساختمان، معاونت معماری و شهرسازی شهرداری کرمانشاه.
شهرداری کرمانشاه (۱۳۹۱). دستورالعمل باغبانی و آبیاری سازمان پارک‌ها و فضای سبز شهرداری کرمانشاه، واحد فضای سبز سازمان پارک‌ها و فضای سبز کرمانشاه.
علیزاده، ا. )۱۳۹۴). اصول هیدرولوژی کاربردی، ویرایش هفتم، مشهد: انتشارات دانشگاه امام رضا.
کردوانی، پ. و کردپور، ب. (۱۳۹۱). استفادة بهینه از منابع آبی در ناحیة اورامانات (ذخیرة باران)، فصل‌نامة جغرافیاییسرزمین، ۹(۳۵): ۱-۱۸.
کومه، ز.؛ معماریان، ه. و تاج‌بخش، س.م. (1394). بررسی عملکرد سیستم استحصال آب باران از سطح پشت‌بام و بهینه‏سازی حجم مخزن (مطالعة موردی: شهرستان بیرجند)، مجلةسامانه‏های سطوح آبگیر باران، ۳(۷): ۲۳-۳۲.
مرکز آمار ایران (۱۳۷۸). آمار نامة استان کرمانشاه.
Abdulla, F.A. and Al-Shareef, A.W. (2009). Roof rainwater harvesting systems for household water supply in Jordan, J. Desalin, 243: 195-207.
Abu-Zreig, M.; Hazaymeh, A. and Shatanawi, M. (2013). Evaluation of residential rainfall harvesting systems in Jordan, Urban Water Journal, 10: 105-111.
Akter, A. and Ahmed,Sh. (2015). Potentiality of rainwater harvesting for an urban community in Bangladesh, Journal of Hydrology, 528: 84-93.
Alizadeh, A. (2015). Principles of Applied Hydrology, 7 Editions, Astan Quds Publication, Mashhad.
Bayadi, H.; Sanaeinezhad, S.H. and Ahmadian Tabasi, M.J. (2008). Utilization of urban runoff in supplying local water demand, Iran Meteorological Organization, pp: 22-32.
Eroksuz, E. and Rahman, A. (2010). Rainwater tanks in multi-unit buildings: A case study for three Australian cities, J. Resour. Conserv. Recycl, 54: 1449-1452.
Falkenmark, M.; Patrick, F.; Gunn, P. and Rockstrom, J. (2001). Water harvesting for upgrading rain-fed agriculture: problem analysis and research needs, Stockholm, Sweden: Stockholm International Water Institute. 94 P.
Hanifehpour, M.; Khodabandehlo, R. and Hamidi, M. (2015). Estimation of water available for use in rainwater harvesting for agricultural (case study: Zanjan province), Second International Conference on Applied Research in Agriculture, pp: 1-9.
Iran Statistics Organization (2008). Statistics of the province of Kermanshah.
Kahinda, J.M.; Taighenu, A.E. and Boroto, J.R. (2007). Domestic rainwater harvesting to improve water supply in rural South Africa, J. Phys. Chem. Earth, 32: 1050-1057.
Kardovani, P. and Kurdpoor, B. (2012). Optimum use of water resorce Auramanat zone(Rain Reservoir), Journal of Territory, 9(3): 3-18.
Khavari, H.; Goldani, M.; Khajehossaini, M. and Shour, M. (2017). Determination of Cardinal Temperatures and Germination Respond to Different Temperature for Five Lawns Cultivars, Journal Of Horticulture Science, 30(4): 643-650.
Koumeh, Z.; Memarian H. and Tajbakhsh, M. (2015). Investigation Performance of Rooftop Water Harvesting Systems and Reservoir Volume Optimization (Case Study: Birjand, Iran), Iranian Journal of Rainwater Catchment Systems, 3(2): 23-32.
Kuylenstierna, J.L.; Bjorklund, G. and Najlis, P. (1997). Sustainable water future with global implications: everyone’s responsibility, Natural Resources Forum, 21: 181-190.
Mahmoud, W.H.; Elagib, N.A.; Gaese, H. and Heinrich, J. (2014). Rainfall conditions and rainwater harvesting potential in the urban area of Khartoum, Resources, Conservation and Recycling, 91: 89-99.
Malczewski, J. (1999). GIS and Multicriteria Decision Analysis, translate: Parhizkar, A., and Ghafari Gilandeh, A., Samt press, p: 598.
Municipality of Kermanshah (2009). Building Regulations, Deputy of Architecture and Urban Development of Municipality Kermanshah.
Municipality of Kermanshah (2012). Gardening and Irrigation Recipes of Parks and Greenery organization of the Municipality of Kermanshah.
Palla, A.; Gnecco, I. and Lanza, L.G. (2011). Non-dimensional design parameters and performance assessment of rainwater harvesting systems, Journal of Hydrology, 401: 65-76.
Parhizgar A; Ghafari gilandeh A, (2006). Geographic Information System and Multi-criteria Analysis: Tehran, Samt 18-24.
Raj, S. (2011). Rain Water Harvesting Potential of Pallavapuram Area of Meerut: A GIS Study Proceedings of 12th Esri India User Conference, 8-11.
Rashidi Mehrabadi, M.H.; Saghafian, B. and Sadeghian, M.S. (2013). Performance Evaluation of Rainwater Harvesting on the Rooftops of Residential Buildings to Enhance Non-potable Water Demand in the Coastal Cities of Iran, Journal Water Resources Engineering, 6(19): 1-15.
Rasouli, A.A.; Mahmoudzadeh, H.; Yazdchi, S. and Zarinbal, M. (2012). The Application of Analytic Hierarchy Process (AHP) and Weighted Linear Combination (WLC) methods for landfill of Urban Solid Waste materials Case Study: Marand County, Geography And Territorial Spatial Arrangement, 2(4): 41-52.
Sadoddin, A.; Bai, M. and Naeimi, A. (2015). Technical and economic feasibility study of rooftop rainwater harvesting system (Case Study: Gorgan University of Agricultural Sciences and Natural Resources), Journal of Water and Soil Conservation, 21(6): 27-50.
Shadmeheri Toosi, A.; Danesh, S. and Hosseini, S.M. (2017). Evaluation of potential for rainwater harvesting (case study: a municipality district in the city of Mashhad), 4th International Conference on Environmental Planning & Management, Tehran, Tehran university, pp: 1-12.
Shahabi, H.; Khezri, S. and Nayeri, H. (2008). Investigation of effective factors in locating rescue stations of Saqez-Sanandaj Road using WLC, 4th International Conference on Integrated Management of Passive Crisis and Passive Defense in National Sustainability, Tehran.
Song, J.; Han, M.; Kim, T. and Song, J. (2008). Rainwater harvesting as a sustainable water supply option in Banda Aceh, J. Desalin, 248: 233-240.
Sturm, M.; Zimmermann, M.; Schutz, K.; Urban, W. and Hartung, H. (2009). Rainwater harvesting as an alternative water resource in rural sites in central northern Namibia, J. Phys. Chem. Earth, 34: 776-785.
Taran, F. and Mahtabi, G. (2016). Investigation of Supplying Water Requirements in Different Parts of a City through Rainwater Harvesting ;a Case Study Bonab, Iran, Journal of Irrigation & Water Engineering, 7(1): 40-53.
Winnaar, G.; Jewitt, G.P.W. and Horan, M. (2007). A GIS-based approach for identifying potential runoff harvesting sites in the Thukela River basin, South Africa, Physics and Chemistry of the Earth, Parts A/B/C, 32(15): 1058-1067.
Zehtabian, Gh.; Masudei, R. and Khosravi, H. (2013). The study of the method of collecting rainwater from the roof of houses (DRWH) (case study: Golestan province), Iranian Journal of Rainwater Catchment Systems, 1(3): 14-20.
Zhang, Q.; Wang, X.; Hou, P.; Wan, W.; Li, R.; Ren, Y. and Ougang, Z. (2014). Quality and seasonal variation of rainwater harvested from concrete, asphalt, ceramic, tile and green roofs in Chongqing china, Journal of environmental management, 132: 178-187.
Zolfaghari, H. (2012). A look at ways to collect rainwater for home use, Second National Conference on Iranian Water Resources Research, Regional Water Company of Zanjan, pp: 1-11.