Development of a model to assess coastal wetland stability

建议的研究是针对开发一个模型，用于预测沿海湿地的稳定性。在过去的三十年里，由于人类对沿海地区的干扰，加拿大沿海湿地的数量减少了90%以上。人们现在认识到，沿海湿地在促进沿海地区的生物多样性、改善当地水质和为易受侵蚀地区提供海岸保护方面发挥着不可或缺的作用。人们对控制沿海湿地稳定性的因素知之甚少，这些因素包括水位波动、入射波气候、波浪对植物生长的土壤基质的侵蚀潜力以及现场普遍存在的冰情。拟议的研究是针对量化这些控制参数和开发一个模型来预测可能的湿地稳定性为一个给定的位置。这项研究将导致合理的设计原则，可直接实施到实践中的沿海湿地的发展。该研究计划将利用实地和实验室研究以及数值模拟技术。将在三个地点进行实地研究，以确定沿海湿地兴旺的典型特征。这些地点将安装仪器，以便确定这些地点的事件和透射波气候和水位波动。湿地的生长将在三个生长季节的过程中绘制地图。将记录各种植物的植物几何形状、植物密度和植物强度特征以及植物生长的基质性质。将在波浪水槽中进行实验室研究，以进一步评估在受控条件下波浪通过沿海湿地的传播情况。将进行试验，以研究植物类型，植物密度，淹没深度，植物床的宽度和入射波特性对波浪通过湿地的影响。最后，将开发一个数值模型，用于评估湿地中的流体动力学，并将其与湿地稳定性联系起来，包括波浪与湿地植物的相互作用、基质的稳定性、水位波动和植物强度提供的阻力。

The proposed research is directed towards developing a model for the prediction of coastal wetland stability. Over the past three decades, the number of coastal wetlands in Canada has been reduced by over 90 percent as a result of human interference in the coastal zone. It is now recognized that coastal wetlands play an integral role in fostering bio-diversity in the coastal zone, improving local water quality and providing a means of shore protection in erosion prone areas. Very little is known about the factors controlling the stability of coastal wetlands, which include water level fluctuations, incident wave climate, the erosive potential of the waves on the soil matrix in which the plants grow and ice conditions prevalent at the site. The proposed research is directed at quantifying these controlling parameters and developing a model to predict probable wetland stability for a given location. This research will lead to the development of sound design principles for coastal wetlands which can be directly implemented into practise. The research program will utilize field and laboratory studies and numerical modelling techniques. Field studies will be undertaken at three sites to identify typical characteristics under which coastal wetlands thrive. These sites will be instrumented to enable determination of the incident and transmitted wave climate and water level fluctuations at the sites. Wetland growth will be mapped over the course of three growing seasons. Plant geometry, plant densities and plant strength characteristics of various species and the nature of the substrate in which the plants are growing will be documented. Laboratory studies will be undertaken in a wave flume to further evaluate wave transmission through coastal wetlands under controlled conditions. Tests will be conducted to investigate the influence of plant type, plant density, depth of submergence, width of plant bed and incident wave characteristics on wave transmission through the wetland. Finally, a numerical model will be developed which evaluates the hydrodynamics in the wetland and relates this to wetland stability and will include wave interaction with wetland plants, stability of the substrate, water level fluctuations and resistance provided by the plant strength.