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，流入海洋的新鲜地下水与潮汐和波浪作用渗透的含盐地下水混合在一起。该区域的生物地球化学反应对滩涂生态产生了重大影响，并决定了营养物和污染物对沿海海洋的贡献。水的盐度是这些反应的一个重要因素，因此了解盐的分布是至关重要的。通常假定地下水的最大盐度等于海水的最大盐度。然而，已观察到的浓度是海水的3-6倍。由于盐浓度对流体密度的影响，蒸发与波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。这项研究将为两名来自不同背景的研究生和本科生提供密集的实地和实验室经验，他们将与教育机会计划合作招募，该计划为新泽西理工学院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认识。(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，通过将这些过程结合起来，考虑多孔介质中的水、蒸汽和热量传输，以及包含波浪作用的地下流体动力学。(2)数据收集将包括在特拉华州的三个现场对海滩盐度和流体动力学的一组详细测量，以更好地了解这些耦合效应在实际系统中的作用。(3)地点特异性和敏感性分析将对蒸发引起的盐度动力学的主要控制因素及其对潮间带混合带流动物理的影响产生新的认识。通过对一系列气候、水文地质和海洋条件的扩展分析，结果将捕捉到影响的范围，并确定考虑这些过程最重要的条件。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.