scholarly journals Urban Industrial Water Supply and Demand: System Dynamic Model and Simulation Based on Cobb–Douglas Function

2019 ◽  
Vol 11 (21) ◽  
pp. 5893 ◽  
Author(s):  
Li ◽  
Ma ◽  
Wei ◽  
Zhang
Keyword(s):  
Water Supply ◽  
Production Function ◽  
Water Demand ◽  
Supply And Demand ◽  
Industrial Water ◽  
Labor Input ◽  
Control Variables ◽  
Suzhou City ◽  
Water Supply And Demand ◽  
Industrial Water Demand

In order to meet the needs of water-saving society development, the system dynamics method and the Cobb–Douglas (C–D) production function were combined to build a supply and demand model for urban industrial water use. In this model, the industrial water demand function is expressed as the sum of the general industrial water demand and the power industry water demand, the urban water supply function is expressed as the Cobb–Douglas production function, investment and labor input are used as the control variables, and the difference between supply and demand in various situations is simulated by adjusting their values. In addition, the system simulation is conducted for Suzhou City, Jiangsu Province, China, with 16 sets of different, carefully designed investment and labor input combinations for exploring a most suitable combination of industrial water supply and demand in Suzhou. We divide the results of prediction into four categories: supply less than demand, supply equals demand, supply exceeds demand, and supply much larger than demand. The balance between supply and demand is a most suitable setting for Suzhou City to develop, and the next is the type in which the supply exceeds demand. The other two types cannot meet the development requirements. We concluded that it is easier to adjust the investment than to adjust the labor input when adjusting the control variables to change the industrial water supply. While drawing the ideal combination of investment and labor input, a reasonable range of investment and labor input is also provided: the scope of investment adjustment is , and the adjustment range of labor input is .

scholarly journals Dynamic Modeling and Simulation of Urban Domestic Water Supply Inputs Based on VES Production Function

Mathematics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 89
Author(s):  
Kebai Li ◽  
Zhilei Ding
Keyword(s):  
Water Supply ◽  
Production Function ◽  
Water Demand ◽  
Early Stage ◽  
Supply And Demand ◽  
Labor Input ◽  
Domestic Water ◽  
Straight Line ◽  
Per Capita ◽  
Domestic Water Supply

The Gompertz growth curve is used to describe the urban water population, the linear function is used to represent the per capita disposable income, and the domestic water demand is described combined with the factors of population, income, and the water-saving consciousness. The VES production function is used to describe the production function of the domestic water supply. Combined with system dynamics, the supply and demand management model of urban domestic water in Jiangsu province, China, is developed. The process of water supply investment and labor input in the urban domestic water system is studied with two depreciation methods: the straight-line depreciation method and the sum of years digits method. In the case that the water consumption population is expected to decline, four water demand scenarios composed of different per capita disposable income and the growth rate of water-saving consciousness are investigated. Investment and labor input are taken as control variables to conduct water supply and demand simulations for the four scenarios. The results show that the control schemes in all four scenarios reach a balance between water supply and demand. Moreover, the investment of the sum of years digits method is larger than that of the straight-line depreciation method in 2005–2019 but less than that of the straight-line depreciation method in 2020–2034. The sum of years digits method has the characteristics of more depreciation in the early stage and less depreciation in the later stage, which is conducive to timely compensation for the large loss of fixed assets in the early stage.

scholarly journals The optimal allocation of water resources oriented to prioritizing ecological needs using multiple schemes in the Shaying River Basin (Henan Section), China

2021 ◽  
Author(s):  
Hang Li ◽  
Xiao-Ning Qu ◽  
Jie Tao ◽  
Chang-Hong Hu ◽  
Qi-Ting Zuo
Keyword(s):  
Water Resources ◽  
Water Supply ◽  
River Basin ◽  
Water Conservation ◽  
Water Demand ◽  
Optimal Allocation ◽  
Supply And Demand ◽  
Allocation Model ◽  
Water Supply And Demand ◽  
Ecological Objectives

Abstract China is actively exploring water resources management considering ecological priorities. The Shaying River Basin (Henan Section) serves as an important grain production base in China. However, conflicts for water between humans and the environment are becoming increasingly prominent. The present study analyzed the optimal allocation of water while considering ecological priorities in the Shaying River Basin (Henan Section). The ecological water demand was calculated by the Tennant and the representative station methods; then, based on the predicted water supply and demand in 2030, an optimal allocation model was established, giving priority to meeting ecological objectives while including social and comprehensive economic benefit objectives. After solving the model, the optimal results of three established schemes were obtained. This revealed that scheme 1 and scheme 2 failed to satisfy the water demand of the study area in 2030 by only the current conditions and strengthening water conservation, respectively. Scheme 3 was the best scheme, which could balance the water supply and demand by adding new water supply based on strengthening water conservation and maximizing the benefits. Therefore, the actual water allocation in 2030 is forecast to be 7.514 billion (7.514 × 109) m3. This study could help basin water management departments deal with water use and supply.

scholarly journals Scenario Analysis of Water Supply and Demand using WEAP Model: A Case of Yala Catchment, Kenya

2017 ◽  
Author(s):  
Jared Ouma okungu
Keyword(s):  
Water Supply ◽  
Water Demand ◽  
Environmental Changes ◽  
Supply And Demand ◽  
High Growth ◽  
Reference Scenario ◽  
Activity Levels ◽  
Time Step ◽  
Weap Model ◽  
Water Supply And Demand

The counties traversed by Yala River Catchment in Kenya have been constrained by acute shortages of water resources because of the declining stream flows, which is occasioned by environmental changes, increasing population and changing land uses. This study applied Water Evaluation and Planning (WEAP) model to evaluate past trends and simulate current demand scenarios for the purposes of planning by authorities in regard to future use. The study used historical data (1970-2015) to assess water supply and demand in the catchment for the period 2016 to 2045 by simulation. Calibration and validation were each performed on 10-year streamflow datasets (1991-2000 and 2001-2010 respectively), drawn from 4 gauging stations. Simulations were then conducted for the scenarios namely: Reference (at 2.8% growth rate), High Growth (3.2%), High Growth (3.5%), and Moderated Growth (2.2%). The categories of water demand evaluated in WEAP included: Domestic-Institutional-Municipal, Agriculture, and Industry uses. In a 5-year time-step, WEAP demonstrated resultant increase in water demand for year 2020 by 7.46% from 2016 at Reference Scenario. WEAP further simulated a gradual increase in water demand during subsequent years. This trend would continue for the rest of the scenarios but with variations occasioned by adjustment of variables in WEAP such as population growth rates, monthly variations, annual activity levels, water use rates, water losses and reuse rates, industrial production units, agricultural acreages, and varied demand sites. In conclusion, there were demonstrated substantial increases in water demands within individual scenarios between 2016 to 2045, but these increases were significantly different scenario-by-scenario. The study recommends that supply and demand measures be employed with the aim of regulating activity levels, losses and consumptions so as to meet demands in case any of the studied scenarios would be applicable.

scholarly journals Urban Comprehensive Water Consumption: Nonlinear Control of Production Factor Input Based upon the C-D Function

2019 ◽  
Vol 11 (4) ◽  
pp. 1125 ◽  
Author(s):  
Kebai Li ◽  
Tianyi Ma ◽  
Tom Dooling ◽  
Guo Wei
Keyword(s):  
Water Supply ◽  
Production Function ◽  
Water Consumption ◽  
Water Demand ◽  
Demand Function ◽  
Production Factor ◽  
Urban Water ◽  
Urban Water Supply ◽  
Labor Input ◽  
Urban Water Demand

Utilizing the urban water demand function and the Cobb-Douglas (C-D) production function, an economic control model for the multi-input-multi-output (MIMO) nonlinear system was designed and implemented to describe urban comprehensive water consumption, where the urban water demand function was expressed as the product of the number of water users and per capita comprehensive water consumption, and the urban water supply function was expressed as a C-D production function. The control variables included capital investment and labor input for the urban water supply. In contrast to the Solow model, Shell model and aggregate model with renewable labor resources, the proposed model eliminated value constraints on investment and labor input in the state equations and hence avoided the difficulty in applying these models to urban water supply institutions. Furthermore, the feedback linearization control design (FLCD) method was employed to accomplish stability of the system. In contrast to the optimal control method, the FLCD method possesses an explicit solution of the control law and does not require the solution of a two-point boundary value problem of an ordinary differential equation, making the method more convenient for application. Moreover, two different scenarios of urban water consumption, one for the growth period and the other for the decline period, were simulated to demonstrate the effectiveness of the proposed control scheme.

Assessing Relations between Water Supply and Demand in the Odra and Morava River Basins/ Posouzení Vazby Vodárenských Zdrojů A Nároků Na Vodu V Oblastech Povodí Odry A Moravy

2012 ◽  
Vol 58 (4) ◽  
pp. 41-48
Author(s):  
Jan Thomas ◽  
Miroslav Kyncl ◽  
Silvie Langarová
Keyword(s):  
Drinking Water ◽  
Water Resources ◽  
Water Supply ◽  
Water Demand ◽  
Supply And Demand ◽  
River Basins ◽  
Climatic Changes ◽  
Water Supply And Demand ◽  
Morava River ◽  
The Given

Abstract Periods of drought represent a serious problem in the management of water resources. Currently used climatic models assume the onset of major climatic changes and periods of drought. Irrespective of whether the forecasts will be fulfilled or not, it is essential to prepare measures to ensure the supply of drinking water in dry periods. This paper deals with the preparation of water balances for the areas of the Odra and Morava River basins and the prediction of relationships between water supply and water demand in the given area.

scholarly journals Analysis of the Water Demand-Supply Gap and Scarcity Index in Lower Amu Darya River Basin, Central Asia

2022 ◽  
Vol 19 (2) ◽  
pp. 743
Author(s):  
Zheng Wang ◽  
Yue Huang ◽  
Tie Liu ◽  
Chanjuan Zan ◽  
Yunan Ling ◽  
...  
Keyword(s):  
Water Resources ◽  
Water Supply ◽  
Water Scarcity ◽  
Water Demand ◽  
Supply And Demand ◽  
Aral Sea ◽  
Amu Darya ◽  
The Status ◽  
Water Supply And Demand ◽  
Amu Darya River

Lower reaches of the Amu Darya River Basin (LADB) is one of the typical regions which is facing the problem of water shortage in Central Asia. During the past decades, water resources demand far exceeds that supplied by the mainstream of the Amu Darya River, and has resulted in a continuous decrease in the amount of water flowing into the Aral Sea. Clarifying the dynamic relationship between the water supply and demand is important for the optimal allocation and sustainable management of regional water resources. In this study, the relationship and its variations between the water supply and demand in the LADB from the 1970s to 2010s were analyzed by detailed calculation of multi-users water demand and multi-sources water supply, and the water scarcity indices were used for evaluating the status of water resources utilization. The results indicated that (1) during the past 50 years, the average total water supply (TWS) was 271.88 × 108 m3/y, and the average total water demand (TWD) was 467.85 × 108 m3/y; both the volume of water supply and demand was decreased in the LADB, with rates of −1.87 × 108 m3/y and −15.59 × 108 m3/y. (2) percentages of the rainfall in TWS were increased due to the decrease of inflow from the Amu Darya River; percentage of agriculture water demand was increased obviously, from 11.04% in the 1970s to 44.34% in 2010s, and the water demand from ecological sector reduced because of the Aral Sea shrinking. (3) the supply and demand of water resources of the LADB were generally in an unbalanced state, and water demand exceeded water supply except in the 2010s; the water scarcity index decreased from 2.69 to 0.94, indicating the status changed from awful to serious water scarcity. A vulnerable balanced state has been reached in the region, and that water shortages remain serious in the future, which requires special attention to the decision-makers of the authority.

scholarly journals Economic Determinants of Industrial Water Demand: A Review of the Applied Research Literature

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1684
Author(s):  
Pilar Gracia-de-Rentería ◽  
Ramón Barberán
Keyword(s):  
Water Demand ◽  
Research Literature ◽  
Industrial Water ◽  
Methodological Issues ◽  
Economic Determinants ◽  
Future Studies ◽  
Know How ◽  
Level Of Activity ◽  
Industrial Water Demand ◽  
Available Information

This paper surveys the empirical, economic literature focused on the determinants of industrial water demand. Both the methodological issues and the outcomes of the previous studies are presented and discussed. Attention is given to key methodological issues, such as the available information, the type of data used, the specification of the variables, the choice of the estimated function, its functional form, and the estimation techniques used, highlighting the issues that require greater attention in future studies. Regarding the results, we focus on the estimated elasticities in order to know how the price of water, the level of activity, and the prices of the other inputs influence the demand for water.

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