The Lord Fairfax Health District has issued an advisory against swimming in the stretch of…
This past Sunday, May 2, 2021, Chris Bolgiano presented on how deforestation in the late 1800s and early 1900s led to a huge loss of tree cover and thus sediment following that time period, as the sediment was no longer held in place by tree root systems. This sediment is referred to as ‘legacy sediment’ and was washed into the bottom of watersheds where it still can be found today. These thick layers of sediment (on the scale of three or more feet) that represent historic occupation in the Shenandoah Valley since 1740, are overlain on top of thinner layers (on the scale of centimeters) of sediment that represent much longer time periods (on the scale of thousands of years). The magnitude of the thickness of this sediment is visible in in-cut banks you can see if you take a float or walk along the North Fork of the Shenandoah River, and can lead to severe water channelization, consequent erosion, and large sediment loads in the North Fork of the Shenandoah—acting as a concerning pollutant in our waters and downstream.
If you missed the event on Sunday and want to learn more, check out the recorded lecture by Chris on our Youtube channel or below.
Thanks to Chris for presenting, and thanks to all who attended the lecture—we look forward to connecting with you all through continued programming in 2021. Keep an eye out on the Events page of our website to learn more about what’s on the docket from the summer onwards!