Forest fires are an increasing problem over recent decades. The fires, among other consequences, lead to an increase in the soil vulnerability to water erosion and a consequent increase in sedimentation rates. When barriers are present, such as dams or weirs, there is an amplified risk of sediment and ash deposition in their reservoirs, causing siltation. Thus, there is an interest in studying in more detail the risk of siltation of barriers and reservoirs in the Douro River watershed following wildfires. A detailed barrier inventory was lacking for the Douro River, hampering the identification of siltation-prone areas. In order to fill in this gap, an extensive inventory of barriers in the Douro river basin was carried out for the present study. The result was an abundant and reliable dataset on the Douro River barriers, which allowed a prognosis on the watershed siltation risk. The method for calculating the siltation risk relied on the relationship between the frequency of forest fires, the erosion risk and the frequency of reservoirs. The sub-basins with the greater siltation risk are the Tâmega, Corgo, Sousa and Paiva river basins. Most reservoirs with the highest siltation risk were from small dams. The modelling results were compared with stream connectivity and concentrations of stream water phosphorus (associated with the sediments that flow into the rivers due to the fires). With regard to connectivity, only two reservoirs were at high risk of sedimentation due to fires, so the categories of connectivity risk and fire-based sedimentation risk are probably not related. With regard to risk of high phosphorus loadings, in 8 basins the upper classes for fire-based erosion risk coincided with the upper class for phosphorus loadings suggesting that high phosphorus loading could be associated with fire-based erosion. This study works as a simple but reliable example on the assessment and mapping of siltation risk in stream networks intersected by abundant barriers. It allowed for identifying barriers that can accumulate a large quantity of fine sediments and ashes, interfering with water quality and soil erosion as well as with the storage capacity of the respective barriers.

中文翻译：

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火灾易发流域大坝水库淤积风险估算方法：葡萄牙杜罗河研究

近几十年来，森林火灾是一个日益严重的问题。除其他后果外，火灾导致土壤对水蚀的脆弱性增加，从而导致沉积速率增加。当存在障碍物（例如水坝或堰）时，它们的水库中沉积物和灰烬沉积的风险会增加，从而导致淤积。因此，有兴趣更详细地研究野火后杜罗河流域的障碍物和水库淤塞的风险。杜罗河缺乏详细的屏障清单，阻碍了对易淤积区域的识别。为了填补这一空白，本研究对杜罗河流域的障碍进行了广泛的清查。结果是关于杜罗河屏障的丰富而可靠的数据集，这允许对流域淤积风险进行预测。淤积风险的计算方法依赖于森林火灾频率、侵蚀风险和水库频率之间的关系。具有较大淤积风险的子流域是 Tâmega、Corgo、Sousa 和 Paiva 河流域。大多数具有最高淤积风险的水库来自小水坝。将建模结果与河流连通性和河流水磷浓度（与因火灾流入河流的沉积物有关）进行了比较。在连通性方面，只有两个水库火灾沉积风险较高，因此连通性风险与火灾沉积风险的类别可能不相关。关于高磷负荷的风险，在 8 个流域中，火灾侵蚀风险的上层与磷负荷的上层一致，表明高磷负荷可能与火灾侵蚀有关。本研究作为一个简单但可靠的例子，用于评估和绘制与大量障碍相交的河流网络中的淤积风险。它允许识别可以积聚大量细粒沉积物和灰烬的屏障，干扰水质和水土流失以及各个屏障的存储能力。本研究作为一个简单但可靠的例子，用于评估和绘制与大量障碍相交的河流网络中的淤积风险。它允许识别可以积聚大量细粒沉积物和灰烬的屏障，干扰水质和水土流失以及各个屏障的存储能力。本研究作为一个简单但可靠的例子，用于评估和绘制与大量障碍相交的河流网络中的淤积风险。它允许识别可以积聚大量细粒沉积物和灰烬的屏障，干扰水质和水土流失以及各个屏障的存储能力。