Zhongjing Wang

A Comparative Study of the Performance of Public Water Rights Allocation in China

Pubic water rights allocation, in which water resources are allocated to users administratively as shared public property, is an effective and powerful policy for water resource management. Dozens of public water right allocation systems have been established in China since 1998 without any unified standard across the country. An indicator-based assessment approach, based on equity, efficiency and sustainability, is proposed in this study to evaluate the performance of public water rights allocation systems in China in a quantitative way. The approach was applied in 11 river basins of China in which water rights have been defined. The results show that the performance of the allocation systems depends on the spatial density and exploitation ratio of the water resources. The performance of allocated water rights systems is better in river basins with greater resource densities and smaller water exploitation ratios. This assessment approach is very useful for evaluating policy options for public water rights allocation with appropriate consideration of the local conditions of the river basins.

Adaptive Reservoir Operation Model Incorporating Nonstationary Inflow Prediction

AbstractLong-term changes in reservoir inflow due to climate change and human interferences have caused doubts on the assumption of hydrologic stationarity in reservoir design and operation. Incorporating uncertain predictions that consider nonstationarity into an adaptive reservoir operation is a promising strategy for handling the challenges that result from nonstationarity. This study proposes rules for multistage optimal hedging operations that incorporate uncertain inflow predictions for large reservoirs with multiyear flow regulation capacities. Three specific rules for determining the optimal numerical solution are derived. A solution algorithm is then developed based on the optimality conditions and the three rules. The optimal hedging rules and the solution algorithm are applied to the Miyun Reservoir in China, which exhibited a statistically significant decline in reservoir inflow trend from 1957 to 2009, to determine an annual operating schedule from 1996 to 2009. Nonstationary inflows are pred...

Seasonal Water Allocation: Dealing with Hydrologic Variability in the Context of a Water Rights System

AbstractIn China, the allocation of water rights in river basins is customarily determined by annual mean volumes of water resources. However, seasonal variability of water availability should be considered for an effective and flexible allocation policy. This paper summarizes a framework for seasonal water allocation. It proposes a modified rule for seasonal water allocation on the basis of the traditional rule used in China and introduces a risk analysis model to assess the performance improvement of the proposed rule when dealing with hydrologic variability in the context of a water rights system. The framework and models were applied to the Shiyang River Basin, Gansu Province, China, and they indicated that seasonally allocated water under the modified rule is more stable and has a lower risk for water use than a rule based on annual mean volumes. This leads to more reliable supplies over the seasons and could provide an effective method for water rights operation in the Shiyang River Basin. It also p...

Optimal Hedging Rules for Two-Objective Reservoir Operation: Balancing Water Supply and Environmental Flow

AbstractAnalytical optimal hedging rules are derived for two-objective reservoir operation based on the characteristics of economic and multilevel environmental water demands. This approach is employed to balance current and future economic and environmental water demands using a two-period model. According to the marginal values of utilities, the derived three-step hedging rule curves (THRCs) consist of three steps and six stages. The Huaihe River basin of China is taken as an example to regress the THRCs from a two-objective optimization model. Results show that the derived THRCs can be regressed from the optimal release decision, thereby confirming the derivations and theoretical analysis. The shapes of the THRCs are sensitive to the weight parameters of the objectives and capture the core concern of multiobjective reservoir operation. The THRCs tend to widen and flatten the stages with increasing storage capacity, which implies more water storage and more consideration for future demands.

Assessment of the Water Market in the Xiying Irrigation District, Shiyang River Basin, China

AbstractA water market is an effective way to increase water-use benefits. A preliminary market for irrigation water trading among villages has emerged in the arid area of northwestern China since 2008. This study conducts a quantitative evaluation of the water market at the Xiying irrigation district of the Shiyang River Basin in western China. Network analysis method is employed to assess trading activity and market centrality. The characters of case water market are compared with that of the United States and Australia to discuss the foundations and barriers for developing a mature water market in China. Results show that the case water market in China is undeveloped and is highly regulated by local government although water transactions continuously occur among villages for years. Insufficient incentives and high transaction cost are the key barriers in further developing the market. The indicators proposed in this study for market network analysis are useful for quantitatively evaluating the characte...

A Comparative Study of Flexibility in Water Allocation in the Context of Hydrologic Variability

River flow that is characterized by variability requires commensurate flexibility in allocating water so that water users are able to plan their activities and respond accordingly. An indicator-based assessment method is proposed in this study to evaluate the flexibility of water allocation, based on a concept that a flexible water allocation regime provides greater opportunity for users to freely decide individual water use and leads to more variability and diversity for water consumption among the users. This is demonstrated by using historical water-use data and applying the assessment method in three river basins with different water allocation regimes. These allocation regimes include the seasonal and volumetric water allocation system in the Yellow River of China, duration-based water allocation in Northwestern China, and capacity sharing in southern Queensland in the northern Murray Darling Basin of Australia. Historical water-use variability and diversity are defined and assessed. The result shows that water allocation flexibility varies across the different water entitlement regimes. Duration-based water allocation, a type of allocation that provides the highest degree of water-use autonomy, is ranked as the most flexible regime. Seasonal water allocation, which has the highest level of centralized regulation, shows the lowest flexibility. The proposed indicator based assessment method would be useful for evaluating the flexibility of policy options for water allocation. This could be helpful for improving the capability of water allocation regimes to cope with the changing environment and improving the effectiveness of water allocation systems.

Changes in hourly precipitation may explain the sharp reduction of discharge in the middle reach of the Yellow River after 2000

The Hekou-Longmen reach, together with local floods, is the main source area for coarse sedimentations into the Yellow River. When total rainfall slightly increased in the area, discharge dramatically decreased by 40%–70% after the year of 2000, and attracting extensive attention in the context of global climate change. High temporal resolution precipitation (timescales between 1 and 4 h) data from the June to September period from 270 rain gauges over the past three decades was mined in order to help explain the phenomenon. Each rainfall event was classified as light/moderate rain, large rain, heavy rain or rainstorm by the event’s rainfall amount, and further classified as low intensity rain, medium intensity rain and high intensity rain by the event’s rainfall intensity. The Mann-Kendall trend test was applied to detect the presence and significance of monotonic trends, and to find the change points in the mean and variance of the precipitation characteristics series, including the amount, intensity, frequency and duration of each rainfall category. Results show that although the total amount of precipitation has slightly increased, the average rainfall intensity has significantly decreased. The larger change happened in light/moderate rain events and low/medium intensity rain events, and the intensity changes have a great extent occurred around the threshold of Non-Runoff Rainfall regime, which was proposed for the approximate calculation of initial losses. Changes in rainfall distribution between different classes of the Runoff Rainfall regime in the 2000s could lead to 0.9 mm less runoff depth (17.3% of the total reduction) than the 1980–1999 period. The study indicates that changes in hourly precipitation may be responsible for the sharp reduction of discharge.

Improvement of Duration-Based Water Rights Management with Optimal Water Intake On/Off Events

Water rights management modeling was considered the useful measure to ensure efficient water resources allocation and to avoid intensifying conflicts over water rights. Regarding to the two major patterns of water rights across the world, namely, quantitative water rights (QWR) and duration-based water rights (DWR), the corresponding measures are fastidious. Since QWR was established to set water entitlements instead of DWR in Heihe River Basin, China, the disability of usual DWR tool, managing water diversion by water intakes closing (WIC) during a certain period, has arisen increasingly. The historical data also reflected the low reliability of DWR in allocating water resources quantitatively without modeling guidelines. Aimed at the challenge, a modeling framework and a mixed integer optimization model (MIOM) combing QWR objectives and DWR tools were developed, by which the optimal schemes in Pareto frontier were found to improve the water intake on/off events, including WIC stages, duration days, and starting date through long term series probability analysis and historical data. Results showed that the reliability of DWR allocation was enhanced and WIC duration was reduced significantly compared with current regulation. Scenario analyses indicated that MIOM was powerful for assisting DWR tool to manage QWR and the proposed framework was able to manage water rights efficiently in comparable basins.

A satellite-based energy balance algorithm with reference dry and wet limits

Based on the assumption of a linear relationship between near-surface temperature difference and radiometric surface temperature such as the surface energy balance algorithm for land (SEBAL), a satellite-based energy balance algorithm with reference dry and wet limits (REDRAW) is proposed to estimate evapo-transpiration (ET) for the regional scale. REDRAW supposes that extreme hydrological conditions can be represented by the reference dry and wet limits, which consist of four reference limits: reference bare soil dry limit (RBD), reference vegetated soil dry limit (RVD), reference bare soil wet limit (RBW), and reference vegetated soil wet limit (RVW). These reference limits should be derived geographically and used to estimate actual ET under common hydrological conditions. A comparison is made between REDRAW and a commonly used model, SEBAL, at two sites: the Tongyu in China and the Cabauw in The Netherlands. The performances in both cases show that REDRAW can provide more reliable ET estimation in relatively arid and humid areas. Meanwhile, error analysis shows that estimation of sensible heat flux is sensitive to meteorological data, and further study is needed to make REDRAW more robust to environmental conditions.

Water Rights Allocation, Management and Trading in an Irrigation District - A Case Study of Northwestern China

Hang Zheng1, Zhongjing Wang1, Roger Calow2 and Yongping Wei3 1State Key Laboratory of Hydro-Science and Engineering, Department of Hydraulic and Hydropower Engineering Tsinghua University, Beijing 2Overseas Development Institute, London 3Australia-China Water Resource Research Center, Department of Civil and Environmental Engineering, University of Melbourne, Melbourne, Victoria 1China 2UK 3Australia