The Research For Forecasting Urban Water Requirements In Hefei

With the rising population and the fast growing economy, many cities are lack of water, the contradiction of water supply and demand aggravate. The research for forecasting urban water requirements has become an important issue of water resources planning and management. As the capital of Anhui province, under the background of promoting the growth of central cities, hence Hefei has carried out a development strategy in the name of "141" . In order to assure the sustainable utilization of water resources of Hefei and the sustainable development of national economy, forecasting urban water demand scientifically and immediately can guide the water resource development and utilization, which is of theoretical and practical importance.Urban water requirements include domestic water demand, industrial water demand and urban eco-environmental water requirements (UEEWR).The research on UEEWR is a popular and difficult problem of water demand prediction. Economic development status, weather and hydrology and yearly water supply were surveyed, and then water consumption in Hefei was analyzed. On that basis, prediction models of three water requirements were setup respectively with reference to current literatures, planning year was predicted as well. Different models are used for the prediction of water utilization per capita, after analyzing model fitting errors, BP nervous network methods were chosen and comprehensive domestic water demand was forecast according to the population in each planning year. With the industrial product as the prediction parameter, GM(1,1) model was selected through analyzing model fitting errors, then Hefei's industrial water demand was predicted on the basis of water demand of per 10 thousand yuan output. In accordance with its theory, UEEWR includes urban greenbelt system and urban rivers and lakes system. Considering plant irrigation and growth, evaporation and leakage, oil water requirements, water surface evaporation and leakage, lake maintenance and river channels base flow and so on, and then prediction models to forecast each planning year UEEWR and urban least eco-environmental water requirements (ULEEWR) were formed respectively.Based on the analysis of balance between water supply and demand presented in the city's overall planning, the amount of residue or lack of water in each planning year was obtained. The results showed that available water supply could satisfy water demand of local residents, industries and minimum ULEEWR in each planning year, but it could not satisfy UEEWR fully, then some measures and suggestions were proposed.