Wave dissipation over macro-tidal saltmarshes: Effects of marsh edge typology and vegetation change
Wave dissipation over macro-tidal saltmarshes: Effects of marsh edge typology and vegetation change
复制标题
DOI：
10.2112/1551-5036-36.sp1.506
复制
发表时间：
2002-03
影响因子：
--
通讯作者：
I. Möller;T. Spencer
中科院分区：
文献类型：
--
作者：
I. Möller;T. Spencer
摘要为了实现可持续的海岸管理和规划，需要更好地了解细粒-特别是植被-潮间带环境和入射波之间的相互作用。先前的研究已经确定，在盐沼的波衰减可以显着大于在无植被的潮间带表面。然而，详细的，量化的信息沼泽海拔的影响，在潮汐框架，沼泽宽度，向海沼泽边缘配置（如悬崖与斜坡沼泽），季节性变化的沼泽表面粗糙度（如小溪密度，植被组成）和入射波的条件，但是，一直缺乏。基于一个10个月的波浪/潮汐数据集从两个网站上的登吉沼泽，英格兰东部，本研究解决了（一）沼泽边缘地形的影响;（二）沼泽宽度;（三）淹没深度;（四）沼泽表面植被覆盖的季节性变化对波高和波能耗散。在21个地点记录了方向波和水位，包括浅坡和悬崖（悬崖高度约为100米）。1.5m）潮间带剖面。此外，沼泽表面植被覆盖和组成的变化记录的季节性基础上。在监测期间，310 m以上的浅斜坡剖面波高衰减平均为92%。进一步的分析表明，波高的最快速的减少发生在最向海的10米的永久盐沼植被，波高衰减平均每米2.1%和1.1%，分别在缓坡和悬崖网站。在整个泥滩和盐沼，波高耗散率显着较低，平均每米分别为0.1%和0.5%。盐沼悬崖的存在使平均波高每米增加了0.5%。观测到的波高衰减在这两个站点（平均波能衰减附近的沼泽边缘是最高的9月至11月和最低的3月至7月），似乎与季节性植被生长的周期。这项研究提供了标准的波消散潜力的沼泽特征不同的宽度，边缘配置和坡度，水深的变化，和植被覆盖/密度的季节性变化的评估。
ABSTRACT To achieve sustainable coastal management and planning, the interaction between fine-grained - in particular, vegetated - intertidal environments and incoming waves needs to be better understood. Previous studies have established that wave attenuation over saltmarshes can be significantly greater than over unvegetated intertidal surfaces. However, detailed, quantitative information on the effect of marsh elevation in the tidal frame, marsh width, seaward marsh edge configuration (e.g. cliffed versus ramped marshes), seasonal changes in marsh surface roughness (e.g. creek density, vegetation composition) and incident wave conditions, however, has been lacking. Based on a 10-month-long wave/tide dataset from two sites on the Dengie marshes, eastern England, this study addresses the effect of (i) marsh edge topography; (ii) marsh width; (iii) inundation depths; and (iv) seasonal changes in marsh surface vegetation cover on wave height and wave energy dissipation. Directional waves and water levels were recorded at 21 locations across both shallow-sloping and cliffed (cliff height of ca. 1.5m) intertidal profiles. In addition, changes in marsh surface vegetation cover and composition were recorded on a seasonal basis. Wave height attenuation over 310m of the shallow-sloping profile averaged 92 % over the monitoring period. Further analysis shows that the most rapid reduction in wave heights occurs over the most seaward 10 meters of permanent saltmarsh vegetation, where wave height attenuation averaged 2.1% and 1.1% per meter at the shallow-sloping and cliffed site respectively. Across the mudflat and the saltmarsh as a whole, wave height dissipation rates were significantly lower with an average of 0.1% and 0.5% per meter respectively. The presence of a saltmarsh cliff increased average wave heights by up to 0.5% per meter. Observed wave height attenuation showed a seasonal pattern at both sites (average wave energy attenuation near the marsh edge was highest in September – November and lowest in March – July) and appears to be linked to the cycle of seasonal vegetation growth. The study provides criteria for the assessment of the wave dissipation potential of marshes characterised by different widths, edge configurations and slopes, variability of water depths, and seasonal variations in vegetation cover/density.