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首页> 外文期刊>Journal of South American earth sciences >Discharge diversion in the Patia River delta, the Colombian Pacific: Geomorphic and ecological consequences for mangrove ecosystems
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Discharge diversion in the Patia River delta, the Colombian Pacific: Geomorphic and ecological consequences for mangrove ecosystems

机译：哥伦比亚太平洋帕蒂亚河三角洲的排水量转移：红树林生态系统的地貌和生态后果

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In the Patia River delta, the best-developed delta on the western margin of South America, a major water diversion started in 1972. The diversion of the Patia flow to the Sanquianga River, the latter a small stream draining internal lakes from the Pacific lowlands, shifted the active delta plain from the south to the north and changed the northern estuarine system into an active delta plain. The Sanquianga Mangrove National Park, a mangrove reserve measuring 800 km~2, lies in this former estuary, where major hydrologic and sedimentation changes are occurring. Overall, major environmental consequences of this discharge diversion in terms of geomorphic changes along distributary channels and ecological impacts on mangrove ecosystems are evidenced by: distributary channel accretion by operating processes such as sedimentation, overbank flow, increasing width of levees, sedimentation in crevasses, interdistributary channel fill, and colonization of pioneer mangrove; freshening conditions in the Sanquianga distributary channel, a hydrologic change that has shifted the upper estuarine region (salinity ＜1%) downstream; downstream advance of freshwater vegetation, which is invading channel banks in the lower and mixing estuarine zones; die-off of approximately 5200 ha of mangrove near the delta apex at Bocas de Satinga, where the highest sediment accumulation rates occur; and recurrent periods of mangrove defoliation due to a worm plague. Further analyses indicate strong mangrove erosion along transgressive barrier islands on the former delta plain. Here tectonic-induced subsidence, relative sea-level rise, and sediment starving conditions due to the channel diversion, are the main causes of the observed retreating conditions of mangrove communities. Our data also indicate that the Patia River has the highest sediment load (27× 10~6tyr~(-1)) and basin-wide sediment yield (15001 km~(-2)yr~(-1)) on the west coast of South America. Erosion rates from the Patia catchment have been more pronounced during the decades of 1970-1980 and 1990-2000, as a result of land degradation and deforestation. The high sediment and freshwater inputs into the mangrove ecosystem create additional stress (both at ongoing background levels and, occasionally, at dramatic levels), which may periodically push local environmental parameters beyond the thresholds for mangrove survival. The future environmental state of the Sanquianga Mangrove National Reserve deserves more scientific and governmental attention.
机译：1972年，在南美西部最发达的三角洲Patia河三角洲开始了主要的引水工作。Patia河流入Sanquianga河的分流，后者是一条从太平洋低地排水的内部湖泊的小溪流。 ，将活跃的三角洲平原从南部转移到北部，并将北部河口系统变成活跃的三角洲平原。 Sanquianga红树林国家公园是一个面积达800 km〜2的红树林保护区，位于前河口，那里的水文和沉积物发生了重大变化。总体而言，这种排放转移的主要环境后果，包括沿分布通道的地貌变化以及对红树林生态系统的生态影响，可以通过以下方式得到证明：诸如沉积，堤岸流量增加，堤防宽度增加，裂缝中的沉积物，跨界分布等操作过程增加了分布通道渠道填充和先锋红树林的殖民化； Sanquianga支流河道的清新状态，是一种水文变化，已将上河口区域（盐度＜1％）向下游移动；淡水植被的下游发展，正​​在侵入河口下部和河口混合区的河岸； Bocas de Satinga三角洲顶点附近约5200公顷的红树林死亡，那里的沉积物积累率最高；和蠕虫瘟疫引起的红树林经常性脱叶。进一步的分析表明，在前三角洲平原的海侵屏障岛上有强烈的红树林侵蚀。在这里，构造诱发的沉降，相对海平面上升以及由于河道改道而导致的沉积物匮乏条件，是观察到的红树林群落后退条件的主要原因。我们的数据还表明，帕蒂亚河在西海岸的沉积物负荷最高（27×10〜6tyr〜（-1）），流域范围内的沉积物产量最高（15001 km〜（-2）yr〜（-1））。南美洲。 1970-1980年和1990-2000年的十年间，由于土地退化和森林砍伐，帕蒂亚集水区的侵蚀率更加明显。进入红树林生态系统的高沉积物和淡水输入会产生额外的压力（无论是在持续的背景水平上，还是偶尔在剧烈的水平上），这可能会周期性地将局部环境参数推高到红树林生存的阈值之上。 Sanquianga红树林国家保护区的未来环境状况值得更多科学和政府关注。

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