Classification of instream ecological water demand and crucial values in a semi-arid river basin

Fang Liu; Tianling Qin; Denghua Yan; Yu Wang; Biqiong Dong; Jianwei Wang; Hanjiang Nie; Shan He; Shanshan Liu

doi:10.1016/j.scitotenv.2019.136409

Classification of instream ecological water demand and crucial values in a semi-arid river basin

Sci Total Environ. 2020 Apr 10:712:136409. doi: 10.1016/j.scitotenv.2019.136409. Epub 2020 Jan 2.

Authors

Fang Liu¹, Tianling Qin², Denghua Yan³, Yu Wang⁴, Biqiong Dong⁵, Jianwei Wang⁵, Hanjiang Nie⁶, Shan He⁵, Shanshan Liu⁵

Affiliations

¹ State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, 100038 Beijing, China; College of Environmental Science and Engineering, Donghua University, 201620 Shanghai, China.
² State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, 100038 Beijing, China. Electronic address: qintl@iwhr.com.
³ State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, 100038 Beijing, China. Electronic address: yandh@iwhr.com.
⁴ Yellow River Institute of Hydraulic Research, Yellow River Engineering Consulting Co., Ltd, 450003, Zhengzhou, China.
⁵ State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, 100038 Beijing, China.
⁶ State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, 100038 Beijing, China; Department of Hydraulic Engineering, Tsinghua University, 100084, Beijing, China.

PMID: 31935543
DOI: 10.1016/j.scitotenv.2019.136409

Abstract

Analyzing the instream environmental flow demand by coupling the hydrological cycle and the hydrodynamic process with aquatic ecological processes at watershed scale remains one of the most important yet most difficult issues. One or two of the above processes have been the focus in the evaluation of intra-annual ecological water demand in recent studies. In this study, a hydrology-hydrodynamic-habitat model was developed and applied to the Huangshui River basin. A new classification method for instream ecological water demand (IEWD), which considered sensitive species was proposed. The suitable level of IEWD and crucial values with different flow frequencies were analysed, including runoff, water level, water surface width and weighted usable areas (WUA). The results of the study indicated that monthly IEWD had an increasing trend during the flood season and a decreasing trend during the non-flood season in three sections at different suitable levels. With the increase of suitable levels, the range of IEWD in three sections also increased. The IEWD and crucial values were the lowest in March with the smallest range and were the highest from July to October because the amount of precipitation during that period accounted for nearly 84.3% of that of the entire year. Furthermore, the lower the flow frequency in three sections, the higher the suitable levels of IEWD, as well as water level and water surface width every month. When the flow frequency of 90% decreased to 75%, the value of IEWD increased by at least 55% during the wet season and doubled during the dry season. The WUA with the lowest or highest flow frequencies were relatively poor, especially reproduction period. The IEWD and crucial values at different suitable levels agreed with the actual situations. Thus, this study provided a new method for implementing river ecosystem restoration and aquatic ecosystem management.

Keywords: Classification; Crucial values; Hydrology–hydrodynamic–habitat model; Instream ecological water demand.