John Hammond

Hydrology Paper of the Day @jpgannon.bsky.social @hydrochrista.bsky.social @domciruzzi.bsky.social on understanding the teaching of hydrology at the undergraduate level: course titles, assessments, and objectives; textbooks and grading; and the need for shared educational resources and objectives.

These changes in the timing and magnitude of streamflow, driven by different types of snow drought, require updated strategies to manage water for, amongst others, agriculture, hydropower, and ecological needs.

Water management implications: Warm snow droughts are expected to become more common, increasing risk for water supplies. Many reservoirs and operating rules weren’t designed for earlier, lower flows, and linking SWE to streamflow is critical for stronger drought earlywarning and forecasting systems

Snow drought impacts vary by type and region: Warm snow droughts boost cold-season flows but suppress warm-season runoff, while dry and warm-dry types reduce flows year-round, driving larger annual declines. Effects on flow magnitude and timing differ strongly across hydroclimates.

Snow drought impacts on rivers: Across cool-dry, warm-dry, and warm-wet types, annual streamflow and runoff ratios decline, peak flows shift earlier, and both highs and lows weaken. Back-to-back snow droughts amplify losses as subsurface storage is depleted.

While all snow droughts generally lower warm-season flow, warm snow droughts uniquely increase cold-season flow, whereas dry/warm-dry types reduce it.

Snow drought types (cool & dry, warm & dry, warm & wet) and regional hydroclimates control streamflow timing and magnitude, universally reducing annual, maximum, and minimum flows, with faster, earlier, and often lower runoff.

Streamflow timing and magnitude during snow drought depend on snow drought type and regional hydroclimate Communities around the world rely on snowmelt to meet water demands, and periods of lower than normal snow accumulation, snow droughts, can decrease water supplies. Leveraging 172 minimally disturb...

The combination of precipitation and temperature contributions to snow drought control the subsequent streamflow response we’ll see in the coming months.

www.tandfonline.com/doi/full/10....

Snow drought continues across much of the western U.S. For much of the region, below normal precipitation is partly to blame (OR, CO, UT, NM), while above normal temperatures have occurred across nearly the entire region.

New preprint led by Aaron Heldmyer and Roy Sando: Random forest + donor gages to predict daily streamflow drought across CONUS. Regional drivers differ—soil moisture, precip, SWE matter most. doi.org/10.5194/egus...

A review and synthesis of post-wildfire shifts in hydrologic processes and streamflow generation mechanisms A review and synthesis of post-wildfire shifts in hydrologic processes and streamflow generation mechanisms, Ebel, Brian A, Hammond, John C, Walvoord, Michelle A, Partridge, Trevor F, Rey, David M, Murphy, Sheila F

🔥💧 New paper out in Environmental Research: Water led by Brian Ebel!

Synthesis shows how wildfires fundamentally shift hydrologic processes and streamflow generation—from infiltration and runoff to baseflow and flood response — post wildfire.

iopscience.iop.org/article/10.1...

CSAW REU Overview

If you know an undergraduate looking for a geosciences REU program, our applications are due in one month! Focus this year on community, air, and water projects!

sites.google.com/view/csaw-re...

I wrote a commentary discussing Daniele's huge new global synthesis of controls on hydrological processes in forested catchments: read it here: rdcu.be/eXTrq . Some surprising findings on the importance of overland flow, soils and antecedent conditions.

Comparing Flood Inundation Map Features and Diagnosing Decision Support Design Challenges Using visualisation typologies, we developed a diagnostic evaluation method for eight user-controlled ensemble FIM visualisations. Key design challenges include unclear messaging, non-accessible and ...

New paper! Real-time flood inundation mapping (FIM) services are an incredibly valuable tool for emergency management and affected communities. But do their visualizations help users quickly and accurately interpret information to make decisions? onlinelibrary.wiley.com/doi/10.1002/...

How do #climate, #antecedent #moisture, #soils, #topography, #geology, and #vegetation control #runoff #processes in #forested #catchments worldwide? Find this out here rdcu.be/eXTtd! @natwater.nature.com
Thanks a lot @mcmillanhydro.bsky.social for this commentary
www.nature.com/articles/s44...!

Thank you Anne!

I’ve always been more of a photographer than anything else when it comes to art. Still trying sketching sometimes, but also enjoying creating vector art versions of my #riversfromabove photos, and some other travel photos. I feel like style is “you love/hate it” without much in the middle. Thoughts?

Such a fantastic body of work!

A piece that felt particularly relevant to write

Check out the end-of-the-year blogpost about model design by Jonathan Frame!
deepgroundwater.com/blog/what-do...

Snow Sublimation Significantly Decreases Following Stand‐Replacing Fire With Minor Water Balance Impacts From Forest Thinning in a Water Limited Forest Snow sublimation is significantly reduced following a wildfire A thinning prescription that targeted ladder fuels and white fir had minimal impacts on sublimation and the overall water balance

New paper in WRR: Snow Sublimation Significantly Decreases Following Stand-Replacing Fire With Minor Water Balance Impacts From Forest Thinning in a Water Limited Forest. find it here: doi.org/10.1029/2025...

Hydrology Paper of the Day @andy-baker.bsky.social on quantifying the drip of water underground as part of rainfall recharge: groundwater monitoring near the water table in Australia; why mines, tunnels and caves are essential monitoring locations; and relating rock aquifer response to rainfall.

How do geological map details influence the identification of geology-streamflow relationships in large-sample hydrology studies? Abstract. Large-sample hydrology datasets have advanced hydrological research, yet the impact of landscape map details on identifying dominant streamflow generation processes remains underexplored. Th...

Working with large-sample hydrology datasets and curious about how maps with varying levels of detail influence the identification of geology–streamflow relationships? Check out our latest preprint at HESS!

#Hydrology #CatchmentHydrology #LargeSampleHydrology #Eawag #hightlightpaper #HESS

Make sure to check out the supplement for individual signature maps, attribute distributions, and model performance info.

Process maps derived from signatures highlight strong climate controls in the West, soils/topography in the East, and a scalable path to link process understanding to ungauged basins. Big implications for large-scale hydrologic modeling & change detection.
#Hydrology #Streamflow #Hydroclimate #EGU