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

海滩是沿海地区的重要组成部分，流入大海的新鲜地下水与潮汐和波浪作用渗透的含盐地下水混合。这一地带的生物地球化学反应极大地影响着海滩生态，并决定着营养物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，因此了解盐的分布至关重要。通常假定地下水的最大盐度等于海水的盐度。然而，观测到的浓度是海水的3-6倍。由于盐浓度对流体密度的影响，蒸发与波浪的相互作用可能是改变盐度分布和地下水流路径的重要机制。这项研究将提供一个密集的领域和实验室的经验，为两个研究生和本科生从不同的背景谁将被招募与教育机会计划，服务于代表性不足的少数民族学生在新泽西理工学院合作。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最近的进展，在海滩含水层的蒸发和波动力学建模，结合这些过程来考虑水，蒸汽和热传输耦合到地下水动力学，包括波的作用多孔介质。(2)数据收集将包括一套详细的测量海滩盐度和水动力学在三个现场在特拉华州，以更好地了解这些耦合效应在真实的系统。(3)特定地点和敏感性分析将产生新的认识的主要控制蒸发引起的盐度动态和潮间混合区的流动物理的影响。通过对一系列气候、水文地质和海洋条件的分析，结果将捕捉影响的范围，并确定考虑这些过程的最重要条件。该奖项反映了NSF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.