New paper! Suspended sediment supply and transport regimes in urban watersheds across the US

Our lab’s new publication “Suspended sediment supply and transport regimes in urban watersheds across the US” in Communications Earth and Environment represents some of the most exciting work of my career. 

First, lead author Suffiyan Safdar shows that when impervious cover exceeds 40% of the watershed area, the suspended sediment response to increasing discharge is muted compared to less intensely urbanized watersheds. We think channel hardening and surface sealing explain this response. 

Then, Suffiyan creates a new Erosion and Sediment Supply Metric (ESSP) to predict the positions along the urban stream channel where sediment is most likely to enter the stream, based on geomorphometry, soil texture, and nearby impervious surfaces that may signal stream hardening. He then tests ESSP against a gigantic dataset of >50,000 storms across 117 US urban watersheds to show that ESSP is associated with the dominant sediment-discharge hysteresis pattern in a watershed. Urban watersheds cluster into four typologies with distinct sediment responses. 

Why our results matter: With ESSP, predicting sediment supply areas and sediment concentration-discharge relationships in urban streams is now a desktop exercise. This will help managers make smarter decisions about where to invest in stream restoration or protection and upgrade infrastructure to protect communities, water quality, and ecosystems. 

Read the paper here: https://www.nature.com/articles/s43247-026-03704-8

Read a UVM news story about this paper: https://www.uvm.edu/water/news/understanding-urban-sediment-dynamics

Safdar, S., Jefferson, A.J., Underwood, K.L., 2026. Stream suspended sediment supply and transport regimes in urban watersheds across the United States. Communications Earth and Environment. 7: art. 784. https://doi.org/10.1038/s43247-026-03704-8 (open access).