Document Type
Thesis
Abstract
Vegetated strips of land bordering perennial streams, known as riparian buffers, are recommended as a best management practice for reducing nitrogen and phosphorus contaminants leaving agricultural fields from entering waterways. In Virginia, riparian buffers are suggested to be 100 feet wide, though an effective riparian buffer width within the Coastal Plain of Virginia has never been specifically tested. We tested N and P loading within undisturbed natural buffers, within an agricultural field, and through buffers bordering agricultural fields. Using the undisturbed natural buffers as a control, we determined a natural base loading of N as 40-100 dekagrams per square meter. P loading in a natural setting was measured as 5-25 grams per square meter. Nutrient movement down-slope through an agricultural field was also observed, with P pools roughly correlated with sediment transport. Dissolved nutrient loading within the groundwater showed no variation across the buffer, but were comparatively lower in the stream. Concentrations of dissolved nitrate were particularly high. The effectiveness of buffers bordering agricultural fields was mixed, though most nutrient entrapment seemed to occur within the first 15 meters of the buffer. We observed mechanisms preventing even runoff from fields, including channelization and berms, hypothesized as accounting for some variability within nutrient entrapment. We conclude that if channels or other mechanisms divert nutrient runoff from riparian buffers, the effectiveness of the buffer is independent of thickness.
Date Awarded
2010
Department
Geology
Advisor 1
James M. Kaste
Advisor 2
Gregory S. Hancock
Recommended Citation
Newman, Eric, "The Effective Entrapment of Contaminants in Riparian Buffers: A Question of Thickness" (2010). Geology Senior Theses. William & Mary. Paper 236.
https://scholarworks.wm.edu/geologyseniors/236
