1,100-year reconstruction of baseflow, indicates that high baseflow extremes are decreasing for the Santee River, South Carolina, USA.
Abstract
Understanding the long-term natural flow regime of rivers enables resource managers to more accurately model water level variability. However, many stream gauges have relatively shorter records, making it difficult to understand multidecadal to mulitcentennial variability. Further, the magnitude of both low and high flow extremes is generally underestimated with shorter records. Changes in both drought and extreme precipitation due to anthropogenic climate change create the need to better understand past extremes to put current events into context. Historically, tree rings have been used to reconstruct streamflow for many US streams. However, new work suggest that trees represent baseflow better than overall streamflow. Here, we provide a 1,100 year reconstruction of May-August baseflow for the Santee River in South Carolina, USA. The river provides water for a large populous region along the Atlantic Southeast Coast. The 1,100 reconstruction of baseflow explains over 60% of the variance and shows years with extreme high levels of baseflow ( 0.99 quantile) have significantly decreased throughout the reconstruction. These results provide a more nuanced representation of past streamflow by focusing on the baseflow. Further, high extremes in seasonal baseflow levels are getting lower, suggesting years with extreme wet conditions are getting drier, reducing the chance of flooding but also making it more difficult to recover from drought. While anthropogenic climate change is projected to create extreme precipitation, more frequent drought in this region, is also more likely. Our results indicate that this drying is already occurring for this region.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.H54I..03M