蚌埠闸及上游闸坝对淮河自然水文情势的影响

The Influence on the Natural Hydrologic Regimes of the Huaihe River Dams by Bengbu Sluice and Its Upstream Dams

淮河流域建设了许多闸坝,为揭示如此密集的闸坝对河流自然水文情势的影响,选取比较典型的淮河干流上的蚌埠闸作为控制节点,用成熟的IHA法和RVA法,研究蚌埠闸及其上游闸坝对水文情势的影响程度,同时通过蚌埠水文站水文情势变化的估算来分析闸坝对淮河河流生态水文条件的影响。结果显示,这些闸坝对河流水文情势的影响强烈,特别是在枯水季节。由此得出的淮河蚌埠段生态水文目标可为蚌埠闸开展生态系统管理、生态修复以及进行生态调控提供理论支持。

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 hydro-logic regime. Using Indicators of Hydrologic Alteration and Range of Variability Approach methods, hydrolog- ic alteration at the streamgauge site was assessed to demonstrate the influence of dams on ecohydrological con- ditions 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 produc- ing 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 discharg- es, 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, subse- quently 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 cor- responding 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.