Collaborative Research: Drainage network evolution following continental glaciation

当更新世冰盖从低海拔大陆内部(例如中西部上部)撤退时，它们留下了广阔的低起伏平原，点缀着湿地盆地，几乎没有成熟的溪流。从不同时代冰川平原上形成的景观来看，很明显，复杂的河流网络随着时间的推移而建立起来，减少了湿地的丰度和范围，增加了河流的范围。但是，这种“引流整合”的速度和机制还不得而知。排水一体化的后果是重大的，不仅因为侵蚀重塑改变了自然景观，而且还因为它在高地和溪流之间建立了更快和更直接的水文联系。这个合作项目将结合实验室模拟、景观演变的计算机模拟，以及对更新世冰盖在上一个冰期不同时间发现的真实中西部景观中河流网络演变的现场和地理空间分析。每一项努力的目的都是为了在真实和模拟的景观中了解河道延伸和湿地盆地破裂的过程和速率。主要目标是确定在这些环境中水流和泥沙输送的自然过程如何支配不断演变的河流网络的空间模式及其随时间的发展速度。

When the Pleistocene ice sheets retreated from low-elevation continental interiors (for example, the upper Midwest), they left behind vast low-relief plains dotted with wetland basins and few well-established streams. It is evident from looking at landscapes formed on glaciated plains of different ages that elaborate stream networks become established over time, reducing the abundance and extent of wetlands and increasing the extent of streams. However, the rate and mechanism of this "drainage integration" is unknown. The consequences of drainage integration are significant not only because erosional reshaping modifies the physical landscape, but also because it forges faster and more direct hydrological connections between uplands and streams. These hydrological connections have important implications for water resource management throughout these landscapes.This collaborative project will combine laboratory simulations, computer modeling of landscape evolution, and field and geospatial analysis of stream network evolution in real Midwestern landscapes uncovered by Pleistocene ice sheets at different times in the last ice age. Each effort will be aimed at understanding the processes and rates of channel extension and wetland basin breaching in real and simulated landscapes. The key objectives are to identify how natural processes of water flow and sediment transport in these settings govern the spatial patterns of evolving stream networks and their rate of development through time.