黄河河口生态需水研究进展与展望

黄河河口生态需水包括河流生态需水、湿地生态需水和近海生态需水。系统梳理了近20年来黄河河口生态需水目标、需水类别和需水量计算结果;结合黄河河口演变特点,提出生态需水研究的重点和主要方向。河流生态需水以满足重要渔业物种生境为主,重点研究指示物种对天然径流量节律的响应特征,量化水文-生态响应关系,在某种程度上恢复自然水文情势的生态功能。湿地生态需水应深入研究植被、土壤、水体的水盐平衡和蒸散发规律,从植被和鸟类生态位的合理设计以及生物多样性维持出发构建生态系统结构,确定湿地合理规模。近海生态需水应研究入海冲淡水对渔业物种低盐产卵育幼场的塑造和维持机制,以及重要渔业物种习性、适宜营养盐水平与磷酸盐输送扩散机制。小浪底水库运用以来,利津断面径流量满足已有生态需水径流量各项研究成果要求的年份比例为37%～58%,春季经流过程经常缺乏流量脉冲。初步分析以湿地、河道鱼类和近海鱼类为主要目标的全年生态需水量为86亿m~3,径流过程需要阶段性场次洪水。建议对小浪底水库调度方案进行多年优化调整,兼顾春季流量脉冲的塑造,在更大程度上满足河口生态需求。

Advances and prospects of ecological water demands in the Yellow River Estuary

Ecological water demands of the Yellow River estuary include river ecological water demand,wetland ecological water demand and offshore ecological water demand. In this paper, the target, content and calculation results of the ecological water demands in the estuary of the Yellow River in the past 20 years are systematically summarized. Based on the evolvement feature of the Yellow River Estuary, the key points and main research directions of ecological water demand are put forward. For the river ecological water demand, it is mainly to meet the habitat of important fishery species, focusing on the response process of the indicating species to natural runoff rhythm and quantifying the hydrologic and ecological response relationship to restore ecological function of the natural hydrological situation to a certain extent. For the wetland ecological water demand, vegetation, soil, water-salt balance and evapotranspiration law should be studied in depth, and the ecosystem structure should be built from the rational design of vegetation and birds niche and the maintenance of biodiversity, so as to determine the reasonable scale of wetland. For the offshore ecological water demand, it is necessary to study the mechanism of shaping and maintaining the spawning grounds of low salinity fishery species by flushing fresh water into the sea,and study the habits of important fishery species, appropriate nutrient levels and phosphate transport and diffusion mechanism. Since the operation of Xiaolangdi reservoir, the proportion of years in which the runoff of Lijin section meets the requirements of existing ecological water runoff results is 37%~58%, and there is often lack of flow pulse in spring. Primary analysis shows the annual ecological water demand of wetland, river fish and offshore fish is 8.6 billion m³,and the runoff process needs periodic floods. It is suggested to optimize and adjust the multi-year operation scheme of the Xiaolangdi reservoir, giving consideration to the shaping of spring discharge pulse, which may meet the ecological needs of the estuary on a much larger scale.