International Research Fellowship Program: Variable Flow and Sediment Transport in Speleogenetic Models

[0754495]科文顿国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Matthew Covington博士与Franci Gabrovsek博士在斯洛文尼亚Postojna喀斯特研究所开展为期24个月的研究。全球大约20-25%的人口依赖于喀斯特含水层的地下水。尽管这一资源很重要，但由于缺乏对给定含水层中喀斯特管道的位置和几何形状的了解，目前的模型并不能准确地预测流量和污染物的输送。洞穴成因模型是近年来发展起来的一种计算岩溶含水层形成和演化的模型。然而，目前的模型并没有考虑到实际管道系统中发生的许多过程，并且这些模型与现场数据之间的联系是有限的。本工作的目的是：1)研究变流量对管道演化的影响；2)建立沉积物输运及其对洞穴形成的影响的建模框架；3)扩大洞穴形成模型对实际岩溶系统的适用性。这些目的是通过现场工作、管道流动网络建模和修改宿主先前构建的洞穴成因模型来实现的。PI正在使用雨水管理模型（SWMM）开发一套理想的洞穴管道网络系统，并使用后处理来计算溶解速率和热传输。这些探讨了模拟输出如何随管道几何形状、粗糙度和充电而变化。在斯洛文尼亚古典喀斯特的两个不同的洞穴系统中设置了连续监测点。这些地点位于已知管道系统的长度上，可以记录深度、温度和电导率。拟议的项目使用SWMM来帮助解释这些数据，并探索可变流量和沉积物运输对管道演变的影响。PI正在开发算法，将这些影响包括在进化模型中。该研究通过纳入可变流量、泥沙运移和机械侵蚀，扩大了洞穴形成模型的适用性。由于沉积物运输对污染物运输和洞穴生态都至关重要，因此该研究将洞穴形成与这些领域联系起来。此外，洞穴沉积物提供了有价值的年龄记录，扩展模型将有助于探索通道成因与沉积物沉积之间的关系。

0754495CovingtonThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four month research fellowship by Dr. Matthew Covington to work with Dr. Franci Gabrovsek at Karst Research Institute in Postojna, Slovenia.Roughly 20-25% of the global population relies on groundwater from karsticaquifers. Despite the importance of this resource, current models do not accurately predict flow rates and contaminant transport due to lack of knowledge concerning the location and geometry of the karst conduits in a given aquifer.Speleogenetic models, which calculate the formation and evolution of karst aquifers, have been developed in recent years. However, current models do notaccount for many of the processes that occur in real conduit systems, and connections between these models and field data are limited. The purposes of this work are to: 1) study the effects of variable flow on the evolution of conduits, 2) develop a framework for modeling sediment transport and its effects on speleogenesis, and 3) expand the applicability of speleogenetic models to real karstic systems. These purposes are addressed through field work, conduit flow network modeling, and the modification of a speleogenetic model previously constructed by the host. The PI is developing a set of idealized cave conduit network systems using the Storm Water Management Model (SWMM) and using post-processing to calculate dissolution rates and heat transport. These explore how simulated outputs vary with conduit geometery, roughness, and recharge. Continuous monitoring sites are in place in two different cave systems in the classical Slovenian karst. These sites are located along the length of known conduit systems and can record depth, temperature, and conductivity. The proposed project uses the SWMM to aid in the interpretation of these data and to explore the effects of variable flow and sediment transport on conduit evolution. The PI is developing algorithms for including these effects within speleogenetic models. The proposed study expands the applicability of speleogenetic models by including variable flow, sediment transport, and mechanical erosion. Because sediment transport is crucial for both contaminant transport and cave ecology, the study connects speleogenesis with these fields. Furthermore, cave sediments provide valuable age records, and the extended model will allow explorations of the relationship between passage genesis and sediment deposition.