Effects on Fluvial Geomorphology and Vegetation Cover following Hydroelectric Power Plant Operation: A Case Study in the Maule River (Chile)
Effects on Fluvial Geomorphology and Vegetation Cover following Hydroelectric Power Plant Operation: A Case Study in the Maule River (Chile)
复制标题
水力发电厂运营对河流地貌和植被覆盖的影响：以马乌莱河（智利）为例
作者：
F. Pacheco;O. Rojas;E. Hernández;D. Caamaño
水力发电厂的建设对世界河流系统产生了多重环境影响。在智利中部，水电水库运行的影响已在生态和水文制度方面得到记录。本研究评估了水电站启动后，Maule河中段河道形态、植被分布和流量的变化。利用LANDSAT图像量化河流形态（活动面积）和土地覆盖的变化，并与植被采样和流量分析进行对比。结果显示，河流活跃区域减少了12%，表明地貌多样性的丧失。在活动水道内，植物覆盖面积逐渐增加，1989年至2018年达到159%，主要原因是水（- 61%）、活动沙洲（- 35%）和裸露土壤表面积（- 29%）减少。在工厂开始运营十年后，这种变化很明显，并在智利中部（2008-2018年）的特大干旱期间加剧。1985年以后，流量值超过概率(P)在85%以下呈下降趋势，而小流量值超过概率（P = 85%）略有增加。在稳定性较好的区域，入侵物种如金合欢（Acacia dealbata）占主导地位，它们擅长利用干扰来定居和稳定活动区域，从而缩小形态变化的可能性。
The installation of hydroelectric plants has generated multiple environmental impacts on the world’s river systems. In central Chile, the impacts of hydroelectric reservoir operation have been documented in ecological and hydrologic regime terms. This investigation assesses the changes in channel morphology, vegetation distribution, and flows in the middle section of the Maule River during the period following the start-up of a hydroelectric plant. Changes in fluvial morphology (active area) and land cover are quantified using LANDSAT images, contrasted with a vegetation sampling and flow analysis. The results show a 12% decrease in active areas of the river, indicating a loss of geomorphological diversity. Within the active channel, there was a gradual increase in plant-covered surface area, which reached 159% between 1989 and 2018, mainly due to reductions in water (−61%), active bar (−35%), and bare soil surface areas (−29%). The changes were evident ten years after plant operations began and intensified during the period known as the megadrought in central Chile (2008–2018). The flow magnitudes present a decrease for exceedance probabilities (P) below 85% in the period after 1985, with a slight increase recorded for low flows (P > 85%). In the segments with superior stabilization, invasive species such as Acacia dealbata (silver wattle) predominated, which are specialists at taking advantage of disturbances to settle and stabilize active areas, narrowing the possibilities for morphological change.