Hydrology, river regimes and sediment yield
Hydrology, river regimes and sediment yield
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水文、河流状况和产沙量
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
J. Woodward
中科院分区：
文献类型：
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作者：
J. Thornes;F. López;J. Woodward
与欧洲、非洲和亚洲的其他地区相比，在地中海流域内产生和流动的大多数河流通常都是由山区源头的小集水区排出的（图8.1）。地中海流域水文受降水季节分布、流域地质、植被类型和范围、坡面地貌和河道系统等因素的强烈影响。正如前几章所示，重要的是要认识到，就上述流域水文的关键控制而言，流入地中海的区域很大，变化很大，因此不可能在水文方面定义严格的单一地中海河流类型。然而，整个流域的河流状况确实具有明显的季节性，这在很大程度上是由气候系统控制的（第3章），而且，在大多数流域，主要的流量发生在冬季——但在许多地区，秋季和春季径流也很重要。这些模式反映了整个流域的总体水量平衡，但在流域水文和产沙量方面存在关键的地理模式，在湿润的北部与半干旱的南部和东部之间存在明显的对比（Struglia et al. 2004；第21章）。此外，由于人类活动对植被和山坡的长期改造，以及最近广泛实施的水资源管理项目，地中海地区几乎没有天然河流，特别是在河流集水区的中下游（Cudennec et al. 2007）。如第6章所述，地中海山坡上的径流生成与降雨强度和地表特性密切相关。虽然这可能对大多数集水区都是正确的，但由于降雨的季节性动态和极端事件所起的作用，地中海的径流产生对植被覆盖非常敏感。这些特征的累积效应是一套具体的管理问题和恢复问题，虽然这些问题在该区域的各种社会政治制度中相当不同，但可以认为，它们在许多方面是地中海流域所特有的。
In comparison to the rest of Europe, Africa, and Asia, most rivers arising and flowing within the Mediterranean watershed typically drain small catchments with mountainous headwaters (Figure 8.1). The hydrology of Mediterranean catchments is strongly influenced by the seasonal distribution of precipitation, catchment geology, vegetation type and extent, and the geomorphology of the slope and channel systems. It is important to appreciate, as the preceding chapters have shown, that the area draining to the Mediterranean Sea is large and enormously variable in terms of the key controls on catchment hydrology outlined above, and it is therefore not possible to define, in hydrological terms, a strict single Mediterranean river type. However, river regimes across the basin do have a marked seasonality that is largely controlled by the climate system (Chapter 3) and, in most basins, the dominant flows occur in winter—but autumn and spring runoff is also important in many areas. These patterns reflect the general water balance of the basin as a whole, but there are key geographical patterns in catchment hydrology and sediment yield and a marked contrast is evident between the more humid north and the semi-arid south and east (Struglia et al. 2004; Chapter 21). Also, because of the long history of vegetation and hillslope modification by human activity and the more recent and widespread implementation of water resource management projects, there are almost no natural river regimes in the Mediterranean region, especially in the middle and lower reaches of river catchments (Cudennec et al. 2007). Runoff generation on hillslopes in the Mediterranean is very closely related to rainfall intensities and land surface properties as discussed in Chapter 6. While this is probably true of most catchments, runoff generation in the Mediterranean is very sensitive to vegetation cover because of the seasonal dynamics of rainfall and the role played by extreme events. The cumulative effect of these characteristics is a specific set of management problems and restoration issues and, although these are rather different in the various socio-political regimes of the region, it can be argued that they are in many ways unique to Mediterranean catchments.