《Wetlands》杂志刊登“美国北弗吉尼亚州波托马克河河口淡水潮汐沼泽退化的速度和原因”

作者：Ronald J. Litwin, Joseph P. Smoot, Milan J. Pavich, Erik Oberg, Brent Steury, Ben Helwig, Helaine W. Markewich, Vincent L. Santucci, Geoffrey Sanders

刊物：《Wetlands》,2013年10月

关键词：疏浚；国家公园；波托马克河；波浪侵蚀；湿地侵蚀；北行气旋风暴

摘要：戴克沼泽是一个毗邻波托马克河河口的潮汐沼泽，其区域范围迅速减少。本研究记载了从19世纪60年代初期到目前的戴克沼泽侵蚀率，期间经历了开采前、采矿、采矿后的阶段。从20世纪30年代到70年代中期，戴克沼泽和毗连的浅河床底部碎石被开采，导致了55%的初始面积亏损。沼泽损失在采矿后阶段（1976-2012）仍继续。采矿后沼泽损失的原因不明，但被认为可能包括波托马克河洪水的原因。采矿后面积侵蚀率从0.138公顷/年增加到0.516公顷/年，海岸线侵蚀率从0.76米/年增加到2.6米/年。结果表明，加速的采矿后侵蚀反映了过程驱动的反馈效应，使湿地严重改变了地貌和水文基准系统，主要的采矿后降解过程来自北气旋风暴的波浪侵蚀。戴克沼泽侵蚀率接近甚至超过了相同区域近沿海沼泽的侵蚀率。停止采矿后的持久和加速的沼泽侵蚀说明其具有长期的、潜在的毁灭性，对河口沼泽系统具有时间上的、且人为的不稳定的影响。

Rates and Probable Causes of Freshwater Tidal Marsh Failure, Potomac River Estuary, Northern Virginia, USA

Authors: Ronald J. Litwin, Joseph P. Smoot, Milan J. Pavich, Erik Oberg, Brent Steury, Ben Helwig, Helaine W. Markewich, Vincent L. Santucci, Geoffrey Sanders

Journal:Wetland, October 2013

Key words: Dredging; National park; Potomac River; Wave erosion; Wetland erosion; Northbound cyclonic storms

Abstract: Dyke Marsh, a distal tidal marsh along the Potomac River estuary, is diminishing rapidly in areal extent. This study documents Dyke Marsh erosion rates from the early-1860s to the present during pre-mining, mining, and post-mining phases. From the late-1930s to the mid-1970s, Dyke Marsh and the adjacent shallow riverbottom were mined for gravel, resulting in a ~55 % initial loss of area. Marsh loss continued during the post-mining phase (1976–2012). Causes of post-mining loss were unknown, but were thought to include Potomac River flooding. Post-mining areal-erosion rates increased from 0.138 ha yr−1 (~0.37 ac yr−1) to 0.516 ha yr−1 (~1.67 ac yr−1), and shoreline-erosion rates increased from 0.76 m yr−1 (~2.5 ft yr−1) to 2.60 m yr−1 (~8.5 ft yr−1). Results suggest the accelerating post-mining erosion reflects a process-driven feedback loop, enabled by the marsh's severely-altered geomorphic and hydrologic baseline system; the primary post-mining degradation process is wave-induced erosion from northbound cyclonic storms. Dyke Marsh erosion rates are now comparable to, or exceed, rates for proximal coastal marshes in the same region. Persistent and accelerated erosion of marshland long after cessation of mining illustrates the long-term, and potentially devastating, effects that temporally-restricted, anthropogenic destabilization can have on estuarine marsh systems.

原文链接：http://link.springer.com/article/10.1007/s13157-013-0461-6