EVALUATION OF ENVIRONMENTAL FLOW REQUIREMENT FOR IMPROVEMENT OF RIVER ECOLOGICAL INTEGRITY IN THE HAIHE RIVER BASIN, CHINA

摘要

Environmental flow requirement (EFR) should be assessed, and water resources should be allocated for degraded river ecosystems to improve the ecological integrity of the river ecosystem in the Haihe River Basin, China. This river basin is a semiarid area where water resources are scarce. An EFR assessment model was developed based on both the spatial structure and the dominant eco-function of the river ecosystem at the basin scale. This model was used to assess the temporal and spatial variabilities of the EFR for the river ecosystem in the Haihe River Basin. The results indicate an annual EFR of 4.771 billion m~3 for the river ecosystem; this value represents 18% of the average annual flow (26.390 billion m~3). The EFR for river reach, wetland, and estuary are 2.267 billion, 1.532 billion, and 0.972 billion m~3, respectively. The EFR for different restoration types of river reaches are as follows: the EFR for the ecological water supply type of river reach is 1.140 billion m~3, which is 4.320% of the average annual flow (26.390 billion m~3); the EFR for the water pollution control type of river reach is 1.138 billion m~3, which is 4.312% of the average annual flow (26.390 billion m~3); and the EFR for the vegetation evapotranspiration substitute water quantity cycle type of river reach is 0.154 billion m~3, which is 0.584% of the average annual flow (26.390 billion m~3).