Trivariate Copula Based Evaluation Model of Water Accessibility

Abstract

Water accessibility is an important factor in water use assessments for water users. Water accessibility is affected by climate and socio-economic changes, and notably large regional differences exist. Therefore, understanding water accessibility is essential for effective water management. Based on the length, runoff and viewshed value of each water consumption grid, this paper characterized the corresponding water accessibility using the standardized accumulative probability distribution of the three variables. The Copula function was used to connect the accumulative probability distributions of the three variables and construct a joint distribution. The joint probability distribution was applied to characterize the water accessibility of all of the water consumption grids, and a grid-scale water accessibility evaluation model-LRV (Length-Runoff-Viewshed) was constructed. This paper chose the Yongdinghe River Basin as a case study to evaluate water accessibility using the LRV model. The T Copula function was chosen as the joint distribution function to obtain the water accessibility distribution pattern of the Yongdinghe River Basin. This model obtained the water accessibility of every water consumption grid and provided technical support for refined water resources management.

Evaluating Water Resource Accessibility in Southwest China

“…Yu et al [28] selected four factors including the slope, relative height difference, distance, and runoff to comprehensively analyze the accessibility of river water resources in the Hanjiang River Basin. Li et al [29] constructed a grid-scale water accessibility evaluation model based on the length, runoff and viewshed value. Li et al [57] constructed a water accessibility index by selecting indicators such as distance, altitude, ditch density, road density, and culvert number to study the water resource accessibility of freshwater wetland.…”

“…The former is mainly measured by quantity or quality, reflecting the attractiveness of the destination, and the latter is mainly measured by indicators such as time, distance, or cumulative cost, reflecting the convenience of reaching the destination [17,18].The quantity, quality, and accessibility of water resources are the basic requirements for ensuring water resource security [19,20]. However, the existing water resource evaluations mostly focus on the assessment of water quality and water quantity [21][22][23][24][25], but less attention has been paid to water resource accessibility [10,[26][27][28][29]. Water resource accessibility refers to the difficulty of obtaining water resources from water sources [30], which is the fundamental factor determining the quantity, quality, and the efficiency of the water supply.…”

Design of Water Quality and Quantity Ecological Compensation Monitoring System based on Wireless Sensor Network

“…The Yongding River is about 747 km, with a vast drainage area of up to 47016km 2 [9].Its upstream flows through China's water-deficient provinces-Inner Mongolia, Shanxi, and Hebei, and its downstream flows through the Chinese capital Beijing, and the municipality of Tianjin into the Bohai Sea. As the mother river of the capital Beijing, Yongding River is the main source of groundwater resources in western Beijing [10].With the accelerated development of urbanization of cities and towns along the Yongding River, problems such as water scarcity, water environmental pollution, and degradation of water ecological functions have become increasingly apparent [11].Especially due to the over-exploitation of water resources in the upstream and the vigorous construction of water conservancy facilities to intercept river water, and the impact of sewage discharge from power plants, coal mines, and farmland irrigation along the line, the water quality of the Yongding River Basin has deteriorated and the eutrophication trend is obvious [12].The pollution and resource problems in the Yongding River Basin have attracted the attention of the National Committee of the Chinese People's Political Consultative Conference, the Ministry of Ecology and Environment, the Ministry of Water Resources, and the four provincial governments, etc., in order to maintain and realize the sustainable use of water resources and a clean water environment in the Yongding River Basin. Safety, better realization of the goal of coordinating economic development and environmental protection, and speeding up the construction of a comprehensive, accurate and efficient monitoring system are the necessary prerequisites for the establishment of a sound river basin ecological compensation mechanism.…”

Surface Water Resource Accessibility Assessment of Rural Settlements in the Yellow River Basin

“…Xu et al added a location attribute factor to the SHRD model to evaluate water prices [8]. Besides the SHRD model, Li et al constructed a grid-scale water resource accessibility evaluation model (LRV) to evaluate water resource accessibility based on the cumulative probability distribution of three variables, namely length, runoff, and sight of the water network [9]. Assefa et al evaluated the water resource accessibility based on the accessibility distance of water resources [10].…”