Predicting the effects of water consumption control policy on the per capita of urban water using systems thinking (Case study: Birjand city)

Recently in Iran, with regard to the rising trend of population growth rate and water demand, the volume of groundwater and surface water resources have faced with significant reduction. One of the ways to prevent from reduction of resources and to protect them is the management of water consumption especially in the urban sector. This study aimed to control the Birjand water consumption using systems thinking and the Vensim software. In this model at first, available per capita during 2008 to 2013 was simulated and then was proceeded to predict urban water per capita by 2042. Then per capita obtained based on the definition of consumption control policy that consider the parameters leakage reduction, increased use of components of consumption reducer in the household sector and public in the city, reduced bath time, increased price of water, reduction of the holidays and separation of water supply network of green spaces from the urban water supply network. The simulation results was compared with the existing per capita in Birjand. The results indicated that with control consumption, urban water per capita was decreased by 29.11% as compared with the usual conditions of the region. It consequently caused a reduction of the volume of water abstracted from groundwater resources due to reducing the volume of water entering the municipal sector.