Modeling multisource multiuser water resources allocation

Water shortage emerges and restricts the urban construction and the socio-economy development due to the rapid expansion of the cities throughout the world. Recently treated wastewater reuse, including rainwater collection and utilization, and seawater desalination, etc., has been put in practice in some cities. This paper presents the characteristics of urban multisource water and multiuser and a multi-objective optimization model of reasonable allocation on multisource water for multiuser under sufficiently considering the harmonious development among economy, society and environment. As a case study this model had been applied to the reasonable allocation of water supply and demand in Dalian City in 2010, 2015 and 2020, in which the maximal benefit of economy, society and environment was regarded as the multi-objectives and the step method was adopted to solve the model. The result indicates that the proportion of the reused water to the total water consumption is gradually increasing, but the proportion of the high quality water to the total water consumption is decreasing. In other words, as a secondary water resource, the reused water has replaced partial high quality water gradually. Consequently, the reasonable allocation of urban multisource water for multiuser is the available approach to alleviate urban water crisis and achieve the sustainable utilization of urban water resources.