关键词: 蚌埠闸, 闸坝, 水文情势, 影响, 参数

Abstract:

There are many dams constructed in the Huaihe River basin which are drastically altering the natural hydrologic regimes of the river. In order to demonstrate the influence on the natural hydrologic regimes of the river by such intensive dams, the Bengbu Sluice which lies on the mainstream of the Huaihe River as a typical control node was selected to study the influence of the Bengbu Sluice and all its upstream dams on the hydrologic regime. Using Indicators of Hydrologic Alteration and Range of Variability Approach methods, hydrologic alteration at the streamgauge site was assessed to demonstrate the influence of dams on ecohydrological conditions in the Huaihe River basin. The results show that dams profoundly affect the Huaihe River hydrology, primarily through changes in the timing, magnitude, and frequency of high and low flows, ultimately producing a hydrologic regime that differs significantly from the pre-impoundment natural flow regime. They reduce annual peak discharges, decrease the ratio of annual maximum/mean flow, decrease the range of daily discharges, increase the number of reversals in discharge, reduce the daily rates of ramping, alter the timing of high and low flows, and change the timing of the yearly maximum and minimum flows. Dams in the Huaihe River basin have more drastic impact on low-flow events. In the post-dam period, large-scale cease-to-flow events began to occur and last for long periods of time in the basin, which is seriously destructive to the riverine ecosystem. The elimination of floods following impoundment has extirpated native riparian forest communities, subsequently reducing biodiversity and causing major changes in river food webs. It has significantly disrupted aquatic life cycles and contributed to adjustments in the riparian community structure, ultimately promoting the dominance of invasive exotics. Other components of the hydrograph and flow duration curve also have corresponding ecological responses, especially those associated with changes in the timing and duration of flows and in the rates of change and frequency of hydrograph rises and falls. The river ecohydrological targets for the Bengbu section defined by this study can support ecosystem management and restoration plans, and provide ecological operations for the Bengbu Sluice.

Key words: Bengbu Sluice, dams, hydrologic regime, influence, parameters