CAREER: Dynamic Water Transport Timescales: Quantifying Hydrodynamic Responses to Perturbations Across Time and Space in a River Delta

通过沿海环境的地表水运动受到海洋和陆地过程的控制，这产生了随时间和空间变化的复杂水循环模式。水在一个环境中移动所需的时间通常被用作水质和生态系统健康的重要估计指标。在河流三角洲，由于河道中深而快的水流与植被湿地中慢而浅的水流相连，这种情况变得更加复杂。重要的是要了解河流三角洲的水运时间是如何随着时间的推移而演变的，因为人们对利用自然三角洲造陆过程进行海岸恢复非常感兴趣。本项目通过在路易斯安那州沿海地区的实地考察和在不断增长的河流三角洲中对水运动的计算机模拟来研究这些问题。教育计划建立在这些主题的基础上，通过训练大学生使用沿海水文学的创新实地测量，将沿海水文学研究纳入本科和研究生课程，并让K-8学生参与示范、指导研究项目和实地考察。河流三角洲是高度动态的生态系统，具有复杂的水文特征，具有重要的社会和环境意义。本研究解决了水文学的迫切需要，即利用数值模拟、野外观测和图论来理解水文过程如何在非平稳生态系统中演变。该项目将发展动态水运时间尺度的概念，并建立一个量化三角洲形态和水动力学变化如何影响水运时间的框架。本研究将探讨多年代际形态动力学变化对河流三角洲短期水文运输的影响、地表水对内外扰动的时空响应以及三角洲河道网络结构与水运时间之间的联系等基本问题。该奖项由地球科学部的水文科学项目和教育与人力资源项目共同资助。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。

Surface water movement through coastal environments is controlled by both marine and terrestrial processes, which yields complicated patterns of water circulation that vary through time and space. The time it takes for water to move through an environment is often used as an important estimator of water quality and ecosystem health. In river deltas, this is complicated by the presence of deep, fast-moving water in channels that is connected to slow, shallow moving water in vegetated wetlands. It is important to understand how water transport times in river deltas evolve over time because of the considerable interest in using natural deltaic land-building processes for coastal restoration. This project investigates these issues using field work in coastal Louisiana and computer simulations of water movement in growing river deltas. An educational plan builds on these themes by training university students using innovative field measurements for coastal hydrology, integrating coastal hydrology research into undergraduate and graduate coursework, and engaging K-8 students with demonstrations, guided research projects, and field trips. River deltas are highly dynamic ecosystems with complicated hydrology that are of significant societal and environmental importance. This research addresses an urgent need in hydrology to understand how hydrological processes evolve in non-stationary ecosystems using numerical modeling, field observations, and graph theory. The project will develop the concept of Dynamic Water Transport Timescales and establish a framework for quantifying how changes to delta morphology and hydrodynamics impact water transport time. Fundamental questions will be addressed concerning the impacts of multi-decadal morphodynamic change on short-term hydrological transport in river deltas, the surface water responses to internal and external perturbations across time and space, and the links between deltaic channel network structure and water transport times. This award is co-funded by the Hydrologic Sciences program and the Education & Human Resources program in the Division of Earth Sciences.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.