Abstract
Water resources are crucial for maintaining daily life and a healthy ecological environment. In order to gain a harmonious development among water resources and economic development in Lake Watershed, it is urgent to quantify the lake inflow. However, the calculation of inflow simulations is severely limited by the lack of information regarding river runoff. This paper attempts calculated inflow in an ungauged stream through use of the coupling water balance method and the Xin’anjiang model, applying it to calculate the inflow in the Chaohu Lake Basin, China. Results show that the coupled model has been proved to be robust in determining inflow in an ungauged stream. The error of daily inflow calculated by the water balance method is between 1.4 and −19.5%, which is within the standard error range (±20%). The calibration and verification results of the coupled model suggest that the simulation results are best in the high inflow year (2016), followed by the normal inflow year (2007) and the low inflow year (1978). The Nash-Sutcliffe efficiencies for high inflow year, normal inflow year, and low inflow year are 0.82, 0.72, and 0.63, respectively, all of which have reached a satisfactory level. Further, the annual lake inflow simulation in the normal inflow year is 19.4 × 108 m3, while the annual average land surface runoff of the study area is 18.9 × 108 m3, and the relative error is −2.6% by the two ways. These results of the coupled model offer a new way to calculate the inflow in lake/reservoir basins.
Highlights
Water resources are of significance to maintain daily life because they provide directly available water resources for households, industry, and agriculture and play a key role in maintaining healthy ecosystems (Li et al, 2017; Yang et al, 2020; Yu et al, 2020)
To understand the characteristic of daily lake inflows in typical hydrological years, this research is divided into four subsections that describe the main components, including the following: (1) determination of typical hydrological years based on the bivariate frequency analysis of annual precipitation (AP) and annual highest water level (AHWL); (2) calculation of the Chaohu Lake inflows of selected flood events depends on water balance method; (3) determination of the optimal parameters of the coupled model predictions by I-single objective particle swarm optimization (SOPSO) method; and (4) generation of long-series inflow simulate results on the basis of model optimal parameters
There are many factors that affect the accuracy of the calculation, the calculated results show that the method can be applied to calculate the daily lake inflows during the flood period
Summary
Water resources are of significance to maintain daily life because they provide directly available water resources for households, industry, and agriculture and play a key role in maintaining healthy ecosystems (Li et al, 2017; Yang et al, 2020; Yu et al, 2020). In the inflow studies of lake/reservoir basins, abundant observation data of water level and the relationship of water level and capacity of lake/reservoir make it possible to use the water balance method to calculate the lake/reservoir inflow (Deng et al, 2015; Gal et al, 2016). In this method, the estimated reliable inflow is a great challenge because the detailed daily water consumption data, including agricultural water, industrial water, domestic water, infiltration, etc., is difficult to obtain accurately. The coupling of the water balance method and the hydrological model is needed to study the lake/reservoir inflows, in which flood events observations (estimated by the water balance method and called true inflows) were used to calibrate the hydrological model
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