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A System Dynamics Approach to Urban Water Demand
Forecasting
---A Case Study of Tianjin ∗
Xuehua Zhang Hongwei Zhang
School of Environmental Science and Engineering Department of Environmental System Analysis
Tianjin University Tianjin Polytechnic University
Tianjin China 300072 Tianjin China 300160
E-mail:xuehua671231@163.com
Baoan Zhang
Department of Environmental System Analysis
Tianjin Polytechnic University
Tianjin China 300160
Abstract
A system dynamics (SD) approach to urban water demand forecasting was developed based on the
analysis of urban water resources system, which was characterized by multi-feedback and
nonlinear interactions amongst system elements. As an example, Tianjin water resources system
dynamic model was set up to forecast water resources demand of the planning years. The practical
verification showed forecasting relative error was lower than 10%. Furthermore, through
comparing and analyzing the simulation results in different development modes framed in this
paper, the forecasting results of the water resources demand of Tianjin was achieved in
sustainable utilization of water resources strategy.
Keywords: system dynamics; water resources demand forecasting; nonlinearity
1 Introduction
Population growth and economic expansion have been increasingly stimulating the demands for water supplies,
which results in serious water shortage and water quality degradation in many cities of China. Effective plan of
sustainable utilization of water resources has been one of the major concerns with regard to sustainable urban economic
development. Correct forecasting of water resources demand is the key to water resources plan and waterworks building.
A better understanding of the significant contribution to urban water resources supply-demand balance and of the water
resources system reacts to certain policy is necessary for water demand forecasting. System dynamics (SD) was
considered to be an appropriate method to illustrate the complex dynamics and analyze the relative implications of
regulatory policies and have been applied to global scale and national and regional scales
[1-5]
systems’ research. Liu
used the SD approach to solve the urban water demand problem
[6]
with focus on population factors. This paper
develops a system dynamics model which takes population, economy, environment, and policy factors into account to
forecast and analyze the water resources’ supply and demand of a city.
2 Methodology
SD, proposed by Forrester
[7]
, aims at solving the simulating problems of large-scale systems by integrating system
* Supported by: National Natural Science Foundation of China (No.50578108), Ph.D. Programs Foundation of Ministry of Education
of China (No. 20050056016), National Key Program for Basic Research (“973” program, No. 2007CB407306-1), Science and
Technology Development Foundation of Tianjin (No. 033113811 and No. 05YFSYSF032), Educational Commission of Hebei
Province of China (No. 2008324), and Tianjin Social Key Foundation (No. tjyy08-01-078).
http://www.paper.edu.cn