Document Type
Thesis
Abstract
Characterizing environmental degradation in urban ecosystems is a pressing issue in today’s rapidly developing landscape. Retention ponds, which are human-made water storage ponds intended to store excess urban runoff, are one construction measure used to mitigate degradation from hydrological changes. Strawberry Creek is a small stream system located in James City County, Virginia that has been heavily impacted by the failure of a near-by retention pond to accomplish natural water release, leading to significant geomorphological and hydrological changes over the past two decades and quickly degrading the ecosystem. This study characterizes changes in the geomorphology and hydrology downstream of the retention pond by using signals from trees, which were measured using two indicators: leaf area index surveys to measure canopy cover and dendrochronology methods to measure tree growth. Leaf Area Index (LAI) data was collected using the LP-80 ceptometer along both Strawberry Creek and a mildly impacted stream that merges with Strawberry Creek. Variation in overall LAI is greater for the stream sections impacted by the retention pond and shows decrease in canopy cover closer to the retention pond inlet. Tree cores were collected using an increment borer from beech trees in three primary settings along the stream: unimpacted trees from the hillslopes, trees partially buried by eroded upstream sediments on the stream banks, and trees heavily impacted by erosion through uprooting or burial within the stream channel. Average annual ring widths showed a change in overall growth pattern, with a greater growth suppression downstream where thick sediment deposits are present and a rebound in growth near upstream erosion. This research helps to improve our understanding of geomorphological and hydrological changes in urbanized landscapes and the interconnection to the ecosystem by leveraging trees as readily available environmental sensors.
Date Awarded
Spring 2023
Department
Geology
Advisor 1
Dominick M. Ciruzzi
Recommended Citation
Riggs, Danni, "Characterizing hydrological and geomorphological changes in urban streams through environmental signals" (2023). Geology Senior Theses. William & Mary. Paper 50.
https://scholarworks.wm.edu/geologyseniors/50
