Up to journal
for Research & Developement
Journal of Materials Science: Materials in Electronics
Impact Factor
2000 - 2020
Open Access

Iranian Water Researches Journal
Reliability and Storage analysis of rainwater Reservoirs: Comparison between North, Center, and West of Tehran

 submission: 22/10/2018 | acception: 03/06/2019 | publication: 27/09/2020


Oweis Mollaei1*, Mehdi Kouchakzadeh2, Fereshteh Haghighi feshi3

1-Tarbiat modares university،mollayei555@gmail.com

2-Tarbiat Modares University, Water Engineering Department, Associate Professor،Kouchakm@modares.ac.ir

3-University of Tehran, Ph.D.،Haghighif634@yahoo.com



With increasing population and changing climate regime, water supply systems in many cities of the world are under stress. To tackle this problem, water authorities are adopting several measures including demand management and identifying alternative water sources such as stormwater harvesting, greywater and wastewater reuse and desalination. Among all the alternative water sources, stormwater harvesting perhaps has received the highest level of attention. Regarding to excessive water consumption in large cities, the problem of water shortage can be reduced to the extent desirable by using rainwater harvesting systems. “Reliability” is percentage of total days in a year when the water collected in the reservoirs is able to supply the demand of residents. “Rainwater storage potential” is the volume of runoff that is collected and used by a series of actions in the tank, before becoming a flood. The aim of this study was to estimate the reliability of rainwater storage tanks and to investigate the potential of rainwater storage. In the current study, the daily water balance between the rainfalls as input and domestic water-consumption per capita as output were used for the performance analysis and design the optimum of rainwater tanks, at three different regions of Tehran (center, north and west). These three different regions of Tehran are distinct due to notable different rainfall and topography characteristics. Charts of reliability of rainwater storage were produced for domestic rainwater tanks due to tank volume, roof area, number of people in a house (i.e. water demand) and percentage of total water demand to be satisfied by the harvested rainwater. In this study, the reliability of rainwater harvesting system was investigated for rainwater saving and non-potable water supply in three different regions of Tehran. It was found that for a relatively small roof area (۱۰۰ m۲), ۱۰۰% reliability could not be achieved even with applying a very large tank (۱۰,۰۰۰ L). This roof area was very small to collect the appropriate amount of rainfall. In this case, the accumulated rain was used quickly and the reservoir remained empty until the next rain event occurred. For the larger reservoirs, the reliability remained constant; in which case, part of the volume of the reservoir or the entire volume remained in most of the time because the roof area for collecting rainwater was enough, or the demand for water was not high. For a large roof area (۳۰۰ m۲), about ۴۰% reliability can be achieved with a tank size of ۱۰,۰۰۰ L. Reliability was independent of tank size for the sizes larger than ۵۰۰۰–۸۰۰۰ L; in these rang of size, the reliability depends on the region (location). Also, the average rainwater storage in reservoirs was determined annually for each of the three locations. The results showed that the amount of rainwater storage increases with increasing roof area. It was found that with increasing the daily water demand of building residents, the days of water supply by rainwater saving from roofs would decrease. According to the results, it can be stated that the effect of increasing the volume of the reservoir in storing rainwater for the roofs with larger areas were greater than the roofs with small areas because, the roofs with the small area do not fill the reservoir. The runoff overflow from the reservoir was often carried out on the large roofs, which can be reduced by increasing the volume of the reservoir (reducing the runoff from the reservoir and adding to the amount of rainwater stored). The maximum rainwater storage for a roof area of ۳۰۰ m۲ were ۱۰۰ m۳, annually in north of Tehran. The minimum storage for a roof area of ۱۰۰ m۲ were ۱۷ m۳, annually in west of Tehran. In general, the results showed that north of Tehran has more reliability and also more rainwater storage than the center and west of Tehran. The considered rainfall stations (which are located ۱۰ to ۲۰ km apart) produced significantly different results due to the difference in rainfall conditions and topographic variability. The results revealed that rainwater tank reliability can vary significantly within a large city like Tehran, which emphasizes the need to change the design pattern of considering a single annual rainfall value for the purpose of rainwater tank sizing.


Climatic conditions  Daily water balance  Reliability  Rainwater storage tanks 

Download fulltext PDF

Open Access


ملائی خلیلی‌ها ا. کوچک‌زاده م. و حقیقی ف. 1399. بررسی پتانسیل ذخیره‌ی آب باران و قابلیت اطمینان مخازن سامانه استحصال آب باران: مقایسه‌ای بین شمال، مرکز و غرب تهران. مجله پژوهش آب ایران. 38: 1-9.


Abu-Zreig M. and Shatanawi M. 2013. Evaluation of residential rainfall harvesting systems in Jordan. Urban Water Journal. 10: 105-111

Basinger M. Montalto F. and Lall U. 2010. A rainwater harvesting system reliability model based on nonparametric stochastic rainfall generator. Journal Hydrology. 392(3-4): 105-118

Campisano A. and Modica C. 2011. Optimal sizing of storage tanks for domestic rainwater harvesting in Sicily. Resources, Conservation and Recycling. 63: 9-16

Coombes P. and Kuczera G. 2003. Analysis of the performance of rainwater tanks in Australian capital cities. In 28th International Hydrology and Water Resources Symposium: About Water; Symposium Proceedings. Institution of Engineers, Australia, p. 2

Ghisi E. Tavares D. F. and Rocha V. L. 2009. Rainwater harvesting in petrol stations in Brasilia: potential for potable water savings and investment feasibility analysis. Resources, Conservation and Recycling. 54: 79-85

Hashim H. and Hudzori A. Ho W. S. 2013. Simulation based programming for optimization of large-scale rainwater harvesting system: Malaysia case study. Resources, Conservation and Recycling. 80: 1-9

Imteaz M. A. Shanableh A. Rahman A. and Ahsan A. 2011a. Optimization of rainwater tank design from large roofs: A case study in Melbourne, Australia. Journal of Resources, Conservation and Recycling. 55: 1022-1029

Imteaz M. A. Ahsan A. and Rahman A. 2011b. Reliability analysis of rainwater tanks in Melbourne using daily water balance model. Resources, Conservation and Recycling. 56: 80-86

Imteaz M. A. and Ahsan A. 2012. Reliability analysis of rainwater tanks: A comparison between South-East and Central Melbourne. Resources, Conservation and Recycling. 66: 1-7

Khastagir A. and Jayasuriya N. 2010. Optimal sizing of rain water tanks for domestic water conservation. Journal of Hydrology. 381: 181-8

Komeh Z. and Tajbakhsh S. M. 2017. Reservoir volume optimization and performance evaluation of rooftop catchment systems in arid regions: A case study of Birjand, Iran. Water Science and Engineering. 10: 125-133

Lee K. E. Mokhtar M. Hanafiah M. M. Halim A. A. and Badusah J. 2016. ‘Rainwater harvesting as an alternative water resource in Malaysia: potential, policies and development’. Journal of Cleaner Production. 126: 218-222

Muthukumaran S. Baskaran K. and Sexton N. 2011. Quantification of potable water savings by residential water conservation and reuse –a case study. Resources, Conservation and Recycling. 55: 945-52

Notaro V. Liuzzo L. and Freni G. 2016. Reliability Analysis of Rainwater Harvesting Systems in Southern Italy., Procedia Engineering. Elsevier. 162: 373-380

Rashidi Mehrabadi M. H. R and Fashi F. H. 2013. Assessment of residential rainwater harvesting efficiency for meeting non-potable water demands in three climate conditions. Resources, Conservation and Recycling. 73: 86-93

Rostad N. Foti R. and Montalto F. A. 2016. Harvesting rooftop runoff to flush toilets: Drawing conclusions from four major U.S. cities. Resources, Conservation and Recycling. 108: 97-106

Silva C. M. and Carvalho N. V. 2015. Evaluation of rainwater harvesting in Portugal: Application to single-family residences. Resources, Conservation and Recycling. 94: 21-34

Song J. Han M. Kim T. and Song J. 2009. Rainwater harvesting as a sustainable water supply option in Banda Aceh. Journal of Desalination. 248: 233-240


  •  No announces available