Decline of N and P Uptake in the Inner Protection Zone of a Terminal Reservoir during Inter-Basin Water Transfers

Abstract

Inter-basin water transfer projects are designed to relieve water scarcity around the world. However, ecological problems relating to reductions in protection zone functions can occur during inter-basin transfers. This paper uses the largest inter-basin water transfer project in the world, namely, the South-to-North Water Transfer Project (SNWTP) in China, as an example to analyze the variation of Miyun Reservoir's inner protection zone functions when water is transferred. Specifically, a riparian model (RIPAM) coupled with remote sensing data were used to calculate the nitrogen (N) and phosphorus (P) losses due to plant uptake, and these results were validated by in situ survey data. Then, correlations between water levels and N and P removal were analyzed. The results show that water table disturbances resulting from elevated water levels strongly influence the growth of plants and have obvious negative impacts on N and P removal in the inner protection zone. With the implementation of the middle route of the SNWTP, the water level of Miyun will rise to 150 m in 2020, and subsequently, the total net primary productivity (NPP) could decline by more than 40.90% from the level in 2015, while the N and P uptake could decline by more than 53.03% and 43.49%, respectively, from the levels in 2015, according to the modeling results. This will lead to declines in the inner protection zone's defense effectiveness for N and P interception and increases in risks to the security of water resources. The results of this study provide useful knowledge for managing the defense function of the terminal reservoir's inner protection zone and for ensuring that water quality is maintained during the diversion process.

The Influences of the South-to-North Water Transfer Project on Nitrogen Removal by Soil in a Terminal Reservoir in a Critical State in China

“…This framework integrates an ecological model assessment model and scenario setting method, and the specific parts are introduced in the following. Because the ecological model assessment model in Figure 2 has been successfully used in a Guanting Reservoir that has a similar geographical conditions and climate with Miyun Reservoir, the model parameters of the Guanting Reservoir are used to apply to the Miyun Reservoir simulation (Yang et al, 2018b). Meanwhile, a field experiment in the nearby (39°40.4'-40°27.6'N, 116°28.2'-117°1') of Miyun Reservoir has been conducted (Geng et al, 2018).…”

“…Every sample plot was divided using an iron plate in the middle, the left and right parts were measured at the beginning and end of April and May, respectively. The N uptaken by plants was calculated using the biomass and N uptake ratio coefficients (Yang et al, 2018b).…”

“…(2019) andYang et al (2018b). Additionally,Yang et al (2018b) reported that the EcoHAT has been successfully applied to simulate the N emissions at a region that has similar geographical conditions and climate than the Miyun reservoir; therefore, experimental model parameters inWang et al (2010) were chosen for this study.…”

Recent Advances in Adaptive Catchment Management and Reservoir Operation

“…Jiang et al [21] investigated the effects of the impoundment and the operation of the Jinghong Reservoir on downstream thermal regimes through a three-dimensional hydro-and thermodynamic model. Yang et al [22] evaluated the impacts of water transfers on nitrogen (N) and phosphorus (P) uptake in the inner protection zone of the receiving reservoir of the largest inter-basin water transfer project in China, i.e., the South-to-North Water Transfer Project in China.…”