包头市市区居民生活用水量预测分析

用水量预测对区域水资源规划、利用和管理提供重要依据.运用灰色关联度分析法分析包头市市区居民生活用水量影响因素的基础上,分别建立多元线性回归模型、灰色GM(1,1)模型及灰色线性组合模型对该地区2009年和2010年的生活用水量进行预测分析,同时比较了三个模型的预测精度.结果表明:城市居民生活用水量与城市用水人口、人均居住面积和水价的关联度较高;2009年和2010年用水量的预测采用组合灰色模型精度最高,相对误差分别为13.6％％和6.5％,均方根相对误差为10.7％.组合预测模型的预测精度明显优于单一模型,使结果更加准确、合理,符合实际情况.     

我国城镇居民家庭生活需水函数的推求及分析

通过对我国全国及6个区域的城镇居民家庭生活需水函数的建立，分析了在我国进行此类研究的困难，研究了水价、职工平均工资和供水人口对城镇居民家庭生活需水的影响程度。研究结果表明，对需水影响最大的是供水人口，职工平均工资的增长对需水的增加也产生重要的影响。价格对需水的影响并不显著，但在现阶段，价格仍然可以作为一个抑制需求的有效手段。     

Residential Water Use: Efficiency, Affordability, and Price Elasticity

In practice, water pricing is the main economic instrument used to discourage the wasteful use of residential water. Owing to considerations of affordability, residential water is systematically underpriced because water is essential for life. Such a low price results in water being used inefficiently. This paper proposes a system that supplements the existing price system with a cap-and-trade measure to reconcile conflicts among the goals of residential water use. It forces all people (independent of income) to be faced with reasonable price signals and to use water efficiently. The poor could, however, gain from trade and afford water. By taking advantage of the agent-based model, a simulation of this system applied to Taipei, Taiwan shows that those with lower income per capita are better off under this system even though the equilibrium price of residential water is higher. The simulated average price elasticity of market demand is ?0.449.     

Simulating the Impact of Pricing Policies on Residential Water Demand: A Southern France Case Study

The case study conducted in this paper looks at residential water pricing from three different points of view. It first describes existing urban water-pricing practices in Southern France, emphasizing that pricing is not yet being used as a tool for providing economic incentives to save water. It then looks at the observed impact of pricing on water consumption, through an econometric analysis of a cross-sectional data set. The analysis suggests that demand, with an estimated price elasticity of −0.2, is not yet very responsive to price variation. A regional water model (300 municipalities) is then developed and used to simulate the potential impact of various water-pricing scenarios on aggregate water demand, aggregate water sales revenue, and consumer surpluses. The results illustrate the trade-offs that have to be made between the search for environmental effectiveness, cost recovery, and equity when implementing complex water-pricing structures such as block rates or seasonal water pricing.     

Determinants of Small-Area Water Consumption for the City of Phoenix,Arizona

Rapid population growth in the face of an uncertain climate future challenges the desert city of Phoenix, Arizona to consume water more prudently. To better understand the demand side of this important issue, we identified the determinants of water consumption for detached single-family residential units using ordinary least squares regression (OLS). We compared the results from the OLS model to those of a geographically weighted regression (GWR) model to determine whether there are spatial effects above and beyond the effects of the OLS variables. Determinants of residential water demand reflect both indoor and outdoor use and include household size, the presence of swimming pools, lot size, and the prevalence of landscaping that requires a moist environment. Results confirm the statistical significance of household size, the presence of a pool, landscaping practices, and lot size. Improvement of the GWR over the OLS model suggests that there are spatial effects above and beyond the effects for household size and pools – two of the four determinants of water demand. This means that census tracts exhibit water consumption behavior similar to neighboring tracts for these two variables. Model parameters can be used to investigate the effects of policies designed to regulate lot size, pool construction, and landscaping practices on water consumption and to forecast water demand in areas of new construction.     

城市化对郑州市居民用水的影响分析

根据郑州市近60 a人口、经济、降水、供水等资料,利用SPSS软件对城市化和城市居民用水的多个指标进行主成分分析,得到城市化水平指数和城市居民用水综合指数,并运用回归分析法定量描述两者之间的关系。结果表明:城市化水平指数与城市居民用水综合指数之间高度线性相关,城市化水平越高,城市水资源需求越大,城市居民用水量越大。     

The energy trade-offs of adapting to a water-scarce future: case study of Los Angeles

Abstract

Increasing water competition, population growth and global climate change will intensify the tension between water and energy resources in arid climates of the world, since energy costs underscore the challenges facing water security in dry regions. In few places is the tension between water and energy resources more pronounced than in Los Angeles, California. This article analyzes the city’s current water supply and estimates its future energy requirements based on water supply projections from the Los Angeles Department of Water and Power. Results suggest that while increasing local water management strategies could reduce the future energy intensity of the water supply, an increased reliance on water transfers could worsen its future energy intensity.     

Assessing and Modelling the Influence of Household Characteristics on Per Capita Water Consumption

Sustainable urban water supply management requires, ideally, accurate evidence based estimations on per capita consumption and a good understanding of the factors influencing the consumption. The information can then be used to achieve improved water demand forecasts. Water consumption patterns in the developed countries have been extensively investigated. However, very little is known for the developing world. This paper investigates per capita water consumption resulting from water use activities in different types of households typically found in urban areas of the developing world. A data collection programme was executed for 407 households to extract information on household characteristics, water user behaviour and intensity and the nature of indoor and outdoor water use activities. The rigorous statistical analysis of the data shows that per capita water consumption increases with income: 241, 272 and 290 l/capita/day for low, medium and high income households, respectively. Additionally, the results suggest that per capita consumption increases with the number of adult female members in the household and almost one-third of consumption is via taps. The collected data has been used to develop statistical models using two different regression techniques: multiple linear (STEPWISE) and evolutionary polynomial regression (EPR). The inclusion of demographic parameters in the developed models considerably improved the prediction accuracy. Two of the best performing models are used to forecast the water demand for the city, using four future scenarios: market forces, fortress world, policy reform and great transition. The results suggest that the domestic water demand would be highest in the fortress world scenario due to the increase in population and size of built-up area.     

Demand function estimate for residential water in Oman

Current subsidies to residential water users in Oman are estimated at USD 314 million/y. This study estimates the demand function for residential water in Muscat, Oman, for households living in villas. A two-stage least squares econometric model with lagged average water price was used with socio-economic variables. Price elasticity for residential water in Muscat was estimated as –2.10. This high price elasticity is explained by the large proportion of water used for outdoor purposes. This study indicates that it may be possible to manage water demand in Muscat through modifying the price of water and reforming subsidies for residential water.     

Comparison of water pricing for publicly and privately owned water utilities in the United States

The relation between water utility ownership structure and price of water is explored in this study, along with other factors such as water source, population size, population density, population growth trends, service area size, and drought condition. Pricing data were obtained from water utilities in 485 cities in the US (333 publicly owned, 152 privately owned), representing a range of city sizes and geographic distribution. The data were analyzed to explore the significance of variables for water price. On average, privately owned water utilities have higher prices for water.     

基于随机森林模型的需水预测模型及其应用

为解决需水预测模型精度问题,尝试基于随机森林模型的分类和回归功能构建需水预测模型。以苏州市需水量预测为研究实例,首先应用随机森林模型的分类功能将需水预测因子分类,经计算发现第一产业比例、人口、灌溉面积、万元产值用水量和国民经济生产总值为最重要的解释变量。在此基础上,用随机森林模型的回归功能对需水进行预测,同时采用相同的训练数据建立基于BP神经网络和RBF神经网络的需水预测模型,通过对比3个模型的预测结果,发现随机森林模型能有效预测需水量,且精度较高。     

南水北调受水区生活用水影响因素与节水潜力

为持续推进水资源节约工作,保障南水北调受水区经济社会可持续发展,开展居民用水习惯问卷调查,分析 南水北调东线和中线受水区各省（直辖市）居民家庭用水现状及差异特点,识别生活用水的主要影响因素,设计节 水情景模拟家庭节水潜力。结果表明,受水区居民用水习惯呈现较明显的地域性差异,其中：天津市和河北省居 民整体节水意识较高,河南省和山东省现状人均日用水量比北京市、安徽省和江苏省低 12%;从用水行为上看,家 庭洗浴日均用水量浮动范围达 30%,是造成用水差异的主要环节。节水情景模拟结果显示,通过进一步提高居民 节水意识、替换高等级节水器具、增强家庭内部废水循环利用等措施,受水区居民人均日用水量可下降 12%～29%。根据受水区各省 (直辖市) 针对其生活用水特点,提出了进一步开展节水器具普及工作、完善节水管 理体制机制、提升居民节水意识以及合理利用废水等节水建议,因地制宜持续推进节水工作。     

Spatial Determinants of Urban Residential Water Demand in Fortaleza,Brazil

This paper aims at estimating the residential water demand function for the city of Fortaleza, Brazil, considering the potential impact of including spatial effects in the model. The empirical evidence is a unique micro-data set obtained through a household water consumption survey carried out in 2007. We estimated three econometric models, which have as explanatory variables the average/marginal price, the difference, income, number of male and female residents and the number of bathrooms, under different spatial specifications: the Spatial Error Model (SEM), the Spatial Autoregressive model (SAR), and finally, the Spatial Autoregressive Moving Average model (SARMA). Results suggest that the SARMA model is the “best” as shown by a series of tests. Such results contradict conclusions drawn by Chang et al. (Urban Geogr 31(7):953–972, 2010), House-Peters et al. (JAWRA J Am Water Resour Assoc 46(3), 2010), and Ramachandran and Johnston (2011). This means, among other things, that not controlling spatial effects is a key specification error, underestimating the effect of almost all variables in the model. Sometimes, these differences can be as high as 24.66 % and 13.32 % for price elasticity in the Average Price and the McFadden models, respectively.     

Reservoir Inflow Prediction by Ensembling Wavelet and Bootstrap Techniques to Multiple Linear Regression Model

In this study, a new hybrid model, bootstrap multiple linear regression (BMLR) is suggested to investigate the potential of bootstrap resampling technique for daily reservoir inflow prediction. The proposed model compares with three other models: Multiple linear regression (MLR), wavelet multiple linear regression (WMLR) and wavelet bootstrap multiple linear regression (WBMLR). River stage data of monsoon season (1st July 2010 to 30 September 2010) from three gauging stations of Chenab river basin are used. In wavelet transformation, input vectors are decomposed using discrete wavelet transformation (DWT) into discrete wavelet components (DWCs). Then suitable DWCs are used to provide input to MLR model to develop WMLR model. Bootstrap technique coupled with MLR model to build up BMLR model. While WBMLR model is the conjunction of suitable DWCs and bootstrap technique to MLR model. Performance indices namely root mean square error (RMSE), mean absolute error (MAE), Nash-Sutcliffe coefficient of efficiency (NSC), and persistence index (CP) are used in study to evaluate the performance of model. Results showed that hybrid model BMLR produce significantly better results on performance indices than other models MLR, WMLR and WBMLR.

     

Water Pricing Under Joint Benefits

Abstract

A cubic functional form of an econometric model for residential water demand estimation is used in order to accommodate different price elasticities for different levels of water demand. Precise estimates of these different price elasticities offer a useful tool to water authorities for urban water demand management through price-based policies. Panel estimation methods (fixed and random effects) are employed to estimate model parameters. The results show that a cubic form of the demand equation can provide appropriate estimates of price elasticities for different “consumption groups” of residential customers. In addition, the effect of public awareness and information on water conservation is also evaluated after controlling other parameters affecting demand for water. Thus, another implication of this study is that well-informed consumers, aware of issues of water conservation and of techniques for water efficient use, may be more inclined to reduce their water consumption.     

Urban Household Water Demand in Beijing by 2020: An Agent-Based Model

Beijing is faced with severe water scarcity due to rapid socio-economic development and population expansion, and a guideline for water regulation has been released to control the volume of national water use. To cope with water shortage and meet regulation goal, it has great significance to study the variations of water demand. In this paper, an agent-based model named HWDP is developed for the prediction of urban household water demand in Beijing. The model involves stochastic behaviors and feedbacks caused by two agent roles which are government agent and household agent. The government agent adopts economic and propagandist means to make household agent optimize its water consumption. Additionally, the consumption is also affected by the basic water demand deduced from extended linear expenditure system. The results indicate that the total water demand of urban households in Beijing will increase to 317.5 million cubic meters by 2020, while the water price keeps growing at a low level. However, it would drop to 294.9 million cubic meters with high growth of water price and low increment in per capita disposable income. Finally, some policy recommendations on water regulation are made.     

Determinants of Water Connection Type and Ownership of Water-Using Appliances in Ireland

Developing optimal policies on management of water resources, investment in relevant infrastructure and the protection of the environment requires data on the current and likely future demand for water services. In jurisdictions without water metering, information on the factors influencing demand tends to be limited. Microdata from household surveys can provide some relevant information. Domestic water demand is influenced both by the number of households and their characteristics, in particular the extent to which they employ water-using appliances. This paper focuses on domestic ownership of water-using appliances in the Republic of Ireland, a country where rapid economic and demographic change have put pressure on water and sewerage infrastructure but where there is little domestic metering. Using a large household micro-dataset, we use regression analysis to examine the determinants of the water and sewage mains connection status of Irish homes and to identify the characteristics of households that are associated with having larger or smaller numbers of appliances. Our empirical results suggest that Ireland will have a rising share of mains water and sewerage connections in the future. Household income, house price, dwelling types other than ‘detached’, younger dwellings, and urban location are all positively associated with having a mains connection. The number of types of water-using appliance in a household is positively associated with income, house price, number of residents, owner-occupation, having children (or, to a lesser extent, multiple people) in the household, having a detached house, being located in a rural area and living in a dwelling built after 1997.     

Urban Water Demand for Service and Industrial Use: The Case of Zaragoza

Increased efforts to improve urban water management are focused on demand side policies, seeking to affect the behavior of users so that a “reasonable” use of water resources is reached. In this framework the accurate characterization of water demand play a major role in obtaining sufficient knowledge about this behavioral response to changes in price. In this paper we focus on the water demand of the services and industries connected to the public water network. To this end, we carry out an empirical estimation of urban water demand for service and industrial use in Zaragoza (Spain). The proposed model is a Koyck flow adjustment demand model, and a price specification, which is constructed as a function of the lagged average price, current marginal price and a price perception parameter. We use a dynamic panel data methodology to estimate the water demand function. As far as we are aware, this approach to service and industrial urban water demand is new in the literature. The analysis suggests that although price has a negative relationship with consumption, such an effect is reduced given that the price elasticity is lower than one in absolute value. Another relevant finding is that service and industrial urban users think that they pay a lower price than the actual price they pay.     

GM组合模型用于城市生活用水量预测

以天津市为例,采用GM组合模型预测城市生活用水量,力求提高预测的精度。首先,通过对往年城市用水特点的分析,运用多元逐步回归的方法和等维灰数递补动态模型对天津市城市生活用水量进行预测,预测的平均误差分别为7.59%和11.55%;然后,采用上述两种模型的GM组合模型对天津市城市生活用水量进行预测,预测的平均误差降低为5.06%。实践证明,GM组合模型适用于城市生活用水量的预测,精度令人满意。     

泉州市城镇居民综合生活需水预测方法研究

本文采用定额法、趋势分析法、年均增长率法、回归分析法等需水预测常用的方法,对泉州市城镇居民综合生活用水进行预测分析,经多种预测结果比较得出泉州市2030年城镇居民综合生活需水量为8.62亿m 3。其中定额法、回归分析法预测结果较好,趋势分析法和年均增长率法更常用于经济社会发展指标的预测。随着中国城镇化水平不断推进,居民综合生活用水量的影响愈加多元化、横向化,建立多元回归预测分析模型来预测用水量是很好的选择,该研究可为其他城市预测规划水平年居民生活用水量提供借鉴。