Department of Ecology and Hydrology, Faculty of Biology, University of Murcia, Espinardo Campus, 30100, Murcia, Spain.
Environ Manage. 2011 May;47(5):992-1004. doi: 10.1007/s00267-011-9661-0. Epub 2011 Mar 26.
Hydrological classification constitutes the first step of a new holistic framework for developing regional environmental flow criteria: the "Ecological Limits of Hydrologic Alteration (ELOHA)". The aim of this study was to develop a classification for 390 stream sections of the Segura River Basin based on 73 hydrological indices that characterize their natural flow regimes. The hydrological indices were calculated with 25 years of natural monthly flows (1980/81-2005/06) derived from a rainfall-runoff model developed by the Spanish Ministry of Environment and Public Works. These indices included, at a monthly or annual basis, measures of duration of droughts and central tendency and dispersion of flow magnitude (average, low and high flow conditions). Principal Component Analysis (PCA) indicated high redundancy among most hydrological indices, as well as two gradients: flow magnitude for mainstream rivers and temporal variability for tributary streams. A classification with eight flow-regime classes was chosen as the most easily interpretable in the Segura River Basin, which was supported by ANOSIM analyses. These classes can be simplified in 4 broader groups, with different seasonal discharge pattern: large rivers, perennial stable streams, perennial seasonal streams and intermittent and ephemeral streams. They showed a high degree of spatial cohesion, following a gradient associated with climatic aridity from NW to SE, and were well defined in terms of the fundamental variables in Mediterranean streams: magnitude and temporal variability of flows. Therefore, this classification is a fundamental tool to support water management and planning in the Segura River Basin. Future research will allow us to study the flow alteration-ecological response relationship for each river type, and set the basis to design scientifically credible environmental flows following the ELOHA framework.
“水文变化的生态极限 (ELOHA)”。本研究旨在根据 73 个水文指标对塞古拉河流域的 390 个河道段进行分类，这些指标描述了它们的自然水流状况。水文指标是根据西班牙环境和公共工程部开发的降雨径流模型得出的 25 年自然月流量（1980/81-2005/06）计算得出的。这些指标包括按月或按年计算的干旱持续时间和流量大小的中心趋势和离散度（平均、低流量和高流量条件）的措施。主成分分析（PCA）表明，大多数水文指标之间存在高度冗余，以及两个梯度：主流河流的流量大小和支流的时间变异性。选择具有 8 个水流状况类别的分类作为塞古拉河流域最易于解释的分类，这得到了 ANOSIM 分析的支持。这些类别可以简化为 4 个更广泛的组，具有不同的季节性排放模式：大河、常年稳定的溪流、常年季节性溪流和间歇性和短暂性溪流。它们表现出高度的空间凝聚性，遵循与西北到东南的气候干旱度相关的梯度，并且在描述地中海溪流的基本变量方面定义明确：流量的大小和时间变异性。因此，这种分类是支持塞古拉河流域水资源管理和规划的基本工具。未来的研究将允许我们研究每种河流类型的水流改变-生态响应关系，并为按照 ELOHA 框架设计科学可信的环境流量奠定基础。
