Collaborative Research: Impact of evaporation and waves on groundwater dynamics in tidally influenced beaches

海滩是海岸带的重要组成部分，流入大海的淡水与潮汐和海浪作用下渗入的咸水混合在一起。该区域的生物地球化学反应极大地影响了海滩生态，并决定了营养物质和污染物对沿海海洋的贡献。水的盐度是这些反应中的一个重要因素，因此了解盐的分布是至关重要的。通常假定地下水中的最大盐度等于海水的最大盐度。然而，已经观察到的浓度是海水的3-6倍。由于盐分浓度对流体密度的影响，蒸发与波浪的相互作用可能是改变盐度分布和地下水流动路径的重要机制。这项研究将为来自不同背景的两名研究生和本科生提供密集的实地和实验室体验，他们将与新泽西理工学院教育机会计划合作招募，该计划为代表不足的少数族裔学生提供服务。该项目将为学生提供独特的学习体验。这项研究将在三个主要领域产生新的理解。(1)模型的开发和升级将建立在模拟海滩含水层蒸发和波浪动力学的最新进展的基础上，将这些过程结合起来，以考虑与结合了波浪作用的地下流体动力学耦合的多孔介质中的水、蒸汽和热传输。(2)数据收集将包括对特拉华州三个现场地点的海滩盐度和水动力学的一套详细测量，以更好地了解真实系统中的这些耦合效应。(3)现场分析和敏感性分析将使人们对蒸发引起的盐度动态的主要控制因素及其对潮间带混合带流动物理的影响有新的认识。通过扩展对一系列气候、水文地质和海洋条件的分析，结果将捕捉到影响的范围，并准确地确定在什么情况下考虑这些过程是最重要的。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Beaches are an important part of the coastal zone where fresh groundwater flowing to the sea mixes with salty groundwater that infiltrates from tide and wave action. The biogeochemical reactions in this zone greatly impact beach ecology and determine the contribution of nutrients and contaminants to the coastal ocean. Salinity of the water is an important factor in these reactions, so understanding the distribution of salt is critical. It is typically assumed that the maximum salinity in the groundwater is equal to that of seawater. However, concentrations 3-6 times that of seawater have been observed. Evaporation interacting with waves may be an important mechanism that could change both salinity distributions and groundwater flowpaths, due to the influence of salt concentration on fluid density. The research will provide an intensive field and laboratory experience for two graduate students and undergraduates from diverse backgrounds who will be recruited in collaboration with the Educational Opportunity Program that serves under-represented minority students at New Jersey Institute of Technology. The project will provide a unique learning experience for students. This research will generate new understanding in three primary areas. (1) Model development and upscaling will build on recent advances in modeling evaporation and wave dynamics in beach aquifers by combining these processes to account for water, vapor, and heat transport in the porous medium coupled to subsurface hydrodynamics that incorporate wave action. (2) Data collection will include a set of detailed measurements of beach salinity and hydrodynamics at three field sites in Delaware to better understand these coupled effects in real systems. (3) Site-specific and sensitivity analyses will generate new understanding of the primary controls on evaporation-induced salinity dynamics and the resulting effects on flow physics in intertidal mixing zones. By extending analysis over a range of climatic, hydrogeological, and oceanic conditions, results will capture the range of effects and pinpoint conditions under which it is most important to consider these processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.