环境流量研究的前沿问题与挑战

为了应对水文、气候和生态系统变化背景下环境流量研究的新挑战,梳理了国内外环境流量研究成果,指出目前环境流量研究主要存在5个方面的不足,也是该研究目前的前沿问题与挑战:①全球环境变化与非稳定性;②生态水文过程的动态模拟,重点是水文情势静态评价向动态特征评价研究的转变;③生态水文关系的时空特性,重点是生态系统状态、过程变量和物种特征的耦合研究,环境流量的生态特征和时空尺度研究;④环境流量评估的关键指标;⑤环境流量预测的生态学延展。为解决这些问题,提出了人类世背景下环境流量研究的发展方向,认为未来环境流量研究应加强生态目标的动态适应性管理,加强局域到区域的生态学基础研究,完善基于过程的生态水文响应机理,强化环境流量分阶段实施的非水文指标耦合,加强适应性管理方式下的环境流量评估和实践,以保障适应性管理框架下的生态完整性。     

塔里木河生态水流情势分析及其适应性利用

综合分析了外界干扰下的塔里木河流域生态水流情势,采用组合回归模型建立了适应生态变化的水流利用关系,修正了水文-生态响应关系和生态水流估算结果,进一步讨论了适应生态过程的水流情势利用策略。结果表明:自20世纪60年代以来,塔里木河源流与干流水流情势变化不一致,源流来水保证率递减,源流区间耗水量呈增加趋势。相比ARMA(auto-regressive and moving average)模型,基于不同利用方式的生态水流组合回归模型模拟效果较好,可作为参考性预报;结合生态水流预测方程,制定了适应生态的水量调度对策。     

环境流计算新方法:水文变化的生态限度法

水文变化的生态限度框架(ELOHA)是环境流理论最新成果。ELOHA要求对河流按照水文情势特征进行分类,相同类型河流的水文—生态关系具有相似性。ELOHA还要求对开发前后水文情势变化进行分析,计算现状水文条件与基准水文条件的偏离程度。ELOHA提出了水文情势变化预期生态响应的若干假定,总结了一套为建立水文—生态关系采用的生态指标。在建立大型水文和生物数据库的基础上,运用统计学方法拟合水文—生态函数关系。最后,各利益相关者对水文变化引起的生态风险进行评估,认定可以接受的生态风险水平,再依据水文—生态曲线,确定环境流标准。     

水文改变指标体系在生态水文研究中的应用综述

回顾了水文改变指标体系的发展历程,详细介绍了水文改变指标体系所包含的水文改变指标、变化范围法和环境流量成分3部分内容,总结了水文改变指标体系在水文情势改变评估、生态环境影响评估、生态环境流量估算等方面的应用;指出水文改变指标体系是一种简便有效的评估工具,在水文情势变化及其生态效应评估和水资源管理实践上具有广泛的应用前景,但水文改变指标体系也存在参数冗余问题,未来发展可以耦合生态水文模型。     

乌鲁木齐河渠道流量测验精度分析

本文通过和平渠六公里水文断面推流分析，详细叙述了临时曲线关系与改正系数法推流理论与实践，并指出水草生长是受气候及水流影响的一个渐变过程，随时间推移而变化。     

渭河中下游水文变异点识别及生态保障流量计算

针对水文变异引发的基于水文统计学的生态保障流量分析方法在实践应用上存在的问题,提出通过水文变异点分析找出受环境变化影响的转折年,以该年份之前的水文序列计算生态系统需要的保障流量的思路,可有效避免因水文变异而导致的水文统计学方法失效问题。以渭河中下游为例,通过累积曲线法和Mann-Kendall(M-K)检验法对渭河干支流7个关键控制断面进行水文变异点识别,并以此为基础,应用改进Tennant法计算渭河中下游各控制断面的生态低限流量与适宜生态流量。该成果可作为渭河开展流域综合治理和生态保护的参考数据。     

一维圣维南方程组在非恒定流计算中的应用

天然情况下，河道水流在某河段内可能是恒定流，亦可能是非恒定流。一般地，山区性河流多视为恒定流，但在河道干支流的汇合口、河道与湖泊的交汇处、以及潮汐河段等处的水流常常为非恒定流。对于非恒定流， 用常规的水文学方法难以分析计算出河道水流的各个水文特征值，圣维南方程组则是解决此类问题的途径之一。运用圣维南方程组建立一维数学模型，应用芙蓉江江口水文站、长江徐六烃水文站实测水文资料进行分析验算，对解决非恒定流方面的一些实际的水文问题进行初步分析和探讨。     

基于流量分级的生态流量过程线确定方法——以东江水库为例

河流生态流量是生态水文研究的重要部分。鉴于不同等级流量有其特殊生态作用,本文借鉴水文变化指标体系(IHA)评价参数及环境流量组成(EFC)分类方法,将河道流量分为特枯流量、低流量、高流量、洪水过程,并以此为基础绘制生态流量过程线。最后以东江水库为例,绘制其枯水年、平水年、丰水年的年生态流量过程线。结果来看:1高流量过程发生于3-10月,但不同典型年有所差异,年径流越大,高流量量级相应变大,并且首次发生高流量时刻也有所提前。2特枯流量主要发生于11、12、1、2月,来流越大其持续时间越短,但其量级基本不变。3在相同典型年内,高流量有个先增后减的过程,在5月或6月达到最大值;特枯流量持续时间则在1月或12月取得最大值。     

塔里木河干流生态堰闸流量系数研究

本文通过选取包含渐变形翼墙、非渐变形平翼墙、八字形翼墙3种不同形式的12座生态堰闸,根据堰闸形式、闸门开启情况、水流形态等因素,用流速仪法分别施测其出流情况,按水力学基本公式求算其在不同水流条件下的流量系数。实测表明,三种形式的生态闸堰在同一流态下,八字形翼墙出流系数最大,非渐变形平翼墙出流系数最小。     

潮白河生态流量估算及恢复保障措施

针对潮白河水资源过度开发导致的生态与环境问题,从生态流量的视角进行分析,以潮白河控制性水文站———戴营、下堡站47年(1956年-2002年)的实测日径流资料为基础,利用水文指标法(IHA)及范围变化法(RVA)计算潮白河流量均值、极值及其发生时间、频率、历时和变动率等5组33个指标,对比分析人类活动影响较小的参照期(1956年-1974年)与人类活动影响强烈的影响期(1975年-2003年)的系列水文指标的变化,分析影响期内潮白河流量与目标范围的差距,明确生态流量的恢复目标,提出了实现恢复目标的保障措施。     

塔里木灌区引水前后环境流特性变化

基于水文改变指标基本分析方法,筛选建立了环境流评价指标,着重分析了塔里木灌区引水对塔里木河干流阿拉尔和新渠满断面环境流变化的影响。结果表明:在灌区大量引水灌溉前后,干流两个主要水文站的环境流组成分别呈现出不同程度的变化,环境流组成趋于单一化;各水文站的流量事件以枯水流量事件为主;引水对特枯流量事件、高流量脉冲事件和大洪水事件的影响较大。结合环境流指标和生态系统响应关系,制定了面向生态的水资源优化调度方案,为流域生态治理和水量分配提供了参考。     

CLASSIFICATION OF FLOW REGIMES FOR ENVIRONMENTAL FLOW ASSESSMENT IN REGULATED RIVERS: THE HUAI RIVER BASIN,CHINA

Flow regime characteristics (magnitude, frequency, duration, seasonal timing and rates of change) play a primary role in regulating the biodiversity and ecological processes in rivers. River classification provides the foundation for comparing the hydrologic regimes of rivers and development of hydro‐ecological relationships to inform environmental flow management and river restoration. This paper presents a classification of natural flow regimes and hydrologic changes due to dams and floodgates in the Huai River Basin, China, in preparation for an environmental flow assessment. The monthly natural flow regime of 45 stations in the upper and middle Huai River Basin were simulated for the period 1963–2000, based on the hydrological model SWAT (Soil and Water Assessment Tool). Six classes of flow patterns (low or high discharge, stable or variable, perennial or intermittent, predictable or unpredictable) were identified based on 80 hydrologic metrics, analysed by hierarchical clustering algorithms. The ecologically relevant climatic and geographic characteristics of these flow classes were tested for concordance with, and to strengthen, the hydro‐ecological classification. The regulation of natural flow patterns by dams and floodgates changed flows at some locations within each flow class and caused some gauges to shift into another class. The research reported here is expected to provide a foundation for development of hydro‐ecological relationships and environmental flow methods for wider use in China, as well as setting a new scientific direction for integrated river basin management in the Huai River Basin. Copyright © 2011 John Wiley & Sons, Ltd.     

基于生径比的淮河流域中上游典型断面生态流量研究

基于选取的淮河中上游5条河流,11个断面的典型鱼类调查资料以及长系列(1956年-2000年)天然和实测逐月径流数据,运用流速法(最小,平均,最大)、月最小径流法、逐月频率法设定四种生态流量的计算方案。首先,根据Tennant法提出针对丰、平、枯、特枯四种年型和年内汛期、非汛期差异的生径比标准。然后,根据流速法三种计算结果满足生径比标准的情况选取合理的生态流量计算方案。研究表明:5条河流的最小和适宜生径比大小关系均为涡河沙颍河淮河干流淠河洪汝河;满足生径比标准的难易程度为洪汝河淮河干流淠河沙颍河涡河。涡河、沙颍河生态需水满足程度低,应提高生态用水比例。     

中国水电工程生态流量实践主要问题与发展方向

梳理了2001—2015年96个水电工程的生态流量数据,基于ArcGIS平台分析了工程时空分布特征,回顾分析了生态流量的落实情况,分析了生态流量计算方法、泄放方式、保障措施和监测措施的差异及其对保护坝下河段珍稀、濒危保护鱼类的生态效益;重点分析水电工程下泄生态流量的保障情况、目前存在的不足与改进措施。总结了中国水电工程下泄生态流量实践的主要问题,并从生态流量计算原则与流量过程线要求、梯级水库联合调度的考虑、加强河流生态修复中生态流量研究与实践等方面提出了未来的发展方向。     

Hydrological changes and ecological impacts associated with water resource development in large floodplain rivers in the Australian tropics

The majority of rivers in the Australian tropics possess near‐natural flow regimes and are an ecological asset of global significance. We examined flow variability in large floodplain rivers in the Gulf of Carpentaria, northern Australia, and the potential ecological impacts of future water resource development (WRD). Flow metrics based on long‐term records were used to classify flow regimes and predict hydrological drivers of ecological function. Flow regimes of selected rivers were then compared with those simulated for pre‐ and post‐WRD flows in the Darling River, a highly modified river in Australia's south‐east. Generally, rivers were classified as typically ‘tropical’ (more permanent, regular flows) or ‘dryland’ (more ephemeral, with greater flow variability). In addition, all rivers displayed wet–dry seasonality associated with changes in flow magnitude or number of zero‐flow days. We propose that these features (flow permanence and regularity; flow variability and absence; wet–dry seasonality) are the key hydrological drivers of biodiversity and ecological function in the floodplain rivers of Australia's north. In terms of WRD, inter‐annual flow variability was predicted to increase or decrease depending on rivers' natural flow regimes, specifically their tendency toward lower or higher flow magnitudes. Either outcome is expected to have adverse effects on the biodiversity and ecological function of these relatively pristine rivers and floodplain habitats. In particular, reduced and homogenized habitat, loss of life‐history cues, inhibited dispersal and shifts in community composition, as a result of WRD, threaten the ecological integrity of rivers adapted to the three hydrological drivers above. These findings serve as a caution for careful consideration of WRD options for rivers in the Australian tropics and for those with similar flow regimes the world over. Copyright © 2008 John Wiley & Sons, Ltd.     

The ‘natural flow paradigm’ and Atlantic salmon—moving from concept to practice

The ‘natural flow paradigm’ is becoming an important first principle in the setting of managed flow regimes throughout the world, including Canada. The principle states that managed flow regimes should consider the natural hydrological variability of a river system, both seasonally and interannually, to maintain its ecological integrity. While laudable, this principle is in direct conflict with hydropower development and irrigation interests. Therefore, both regulatory agencies and developers are struggling to identify the elements of hydrological variability that are critical to maintain the ecological health of rivers. In this paper, we identify flow requirements for different life stages of anadromous Atlantic salmon (Salmo salar L.). We then explore the potential effects of different flow regime scenarios on a wild Atlantic salmon population, using Harry's River in Western Newfoundland as an example. First, we link the life history patterns of Atlantic salmon to the scenario of the natural hydrological variability, incorporating the flow requirements for migration, spawning and rearing. In a second scenario, we present a flow regime managed for optimal hydropower production. Finally, we propose a conceptual model for a hypothetical managed flow regime that provides the necessary hydrological flow variations to support the life history requirements of Atlantic salmon, while permitting flow regulation and modification. This exercise identified data gaps and further research needs. Particularly, more information is needed on the amplitude of spring flooding necessary to initiate downstream migration while minimizing spill, which could potential be used for hydropower production. Copyright © 2008 John Wiley & Sons, Ltd.     

面向河流生态完整性的黄河下游生态需水过程研究

提供适宜的生态流量对维护河流健康和支撑人类社会发展具有重要意义。尽管栖息地模拟法物理机制清晰、应用广泛,但对生物群落考虑不足、生命节律信号缺失等问题长期存在。以维护河流土著生物群落完整性为目标,本文将天然水文情势作为参照系统,结合栖息地模拟与水文参照系统特征值,建立了一种面向河流生态完整性的生态需水过程评估方法,兼顾指示物种生存繁衍和土著生物群落基本生存。黄河下游利津断面评估结果显示:利津断面年最小生态需水量119亿m³,适宜生态需水量130～137亿m³,涨水期需提供1～2次持续时间不低于7 d、流量不低于1220 m³/s的高流量脉冲。对比历史实测流量过程与本文生态需水成果,发现利津断面水量充足,但流量过程不满足生态需求。黄河需加强水库群调度,协调径流年际和年内分布,塑造适宜的生态流量过程,并适时塑造高流量脉冲。     

变化环境下韩江生态流量演变特征分析

选取位于粤东、闽西南地区的韩江流域为研究对象,基于CA-Markov模型对2050年流域土地利用空间格局进行预测,构建SWAT分布式水文模型,以未来土地利用情景和气候变化情景为变量进行水文模拟,分析不同情景下韩江生态流量的时空演变特征。结果表明,未来城镇化扩张将使梅江支流中上游成为韩江流域内生态流量对土地利用变化最为敏感的区域;土地利用和气候变化将导致韩江流域枯水期流量整体减小,枯水期流量对环境变化更加敏感;韩江流域生态流量变化特征将呈现从西南到东北由升到降的趋势,梅江支流中上游地区的生态流量将得到改善;梅江和汀江两大支流上游区域生态流量对气候变化更为敏感;韩江流域径流总量下降,但丰枯流量分化加剧,长期来看枯季生态流量保障风险可能进一步增大。