Checking for non-preferred file/folder path names (may take a long time depending on the number of files/folders) ...

Saturated, suffocated, and salty: Human legacies produce hot spots of nitrogen in riparian zones

Owners: This resource does not have an owner who is an active HydroShare user. Contact CUAHSI ( for information on this resource.
Type: Resource
Storage: The size of this resource is 101.3 KB
Created: Nov 22, 2022 at 9:20 p.m.
Last updated: Nov 22, 2022 at 9:27 p.m.
Citation: See how to cite this resource
Sharing Status: Public
Views: 71
Downloads: 2
+1 Votes: Be the first one to 
Comments: No comments (yet)


The compounding effects of anthropogenic legacies for environmental pollution are significant, but not well understood. Here, we show that centennial-scale legacies of milldams and decadal-scale legacies of road salt salinization interact in unexpected ways to produce hot spots of nitrogen (N) in riparian zones. Riparian groundwater and stream water concentrations upstream of two mid-Atlantic (Pennsylvania and Delaware) milldams, 2.4 and 4 m tall, were sampled over a two year period. Clay and silt rich legacy sediments with low hydraulic conductivity, stagnant and poorly-mixed hydrologic conditions, and persistent hypoxia in riparian sediments upstream of milldams produced a unique biogeochemical gradient with nitrate removal via denitrification at the upland riparian edge and ammonium-N accumulation in near-stream sediments and groundwaters. Riparian groundwater ammonium-N concentrations upstream of the milldams ranged from 0.006 to 30.6 mg L-1 while soil-bound values were 0.11- 456 mg kg-1. We attribute the elevated ammonium concentrations to ammonification with suppression of nitrification and/or dissimilatory nitrate reduction to ammonium (DNRA). Sodium inputs to riparian groundwater (25-1504 mg L-1) from road salts may further enhance DNRA and ammonium production and displace sorbed soil ammonium-N into groundwaters. This study suggests that legacies of milldams and road salts may undercut the N buffering capacity of riparian zones and need to be considered in riparian buffer assessments, watershed management plans, and dam removal decisions. Given the widespread existence of dams and other barriers and the ubiquitous use of road salt, the potential for this synergistic N pollution is significant.

Subject Keywords

Deleting all keywords will set the resource sharing status to private.



Coordinate System/Geographic Projection:
WGS 84 EPSG:4326
Coordinate Units:
Decimal degrees
Place/Area Name:
Roller & Cooch Milldams
North Latitude
East Longitude
South Latitude
West Longitude



Funding Agencies

This resource was created using funding from the following sources:
Agency Name Award Title Award Number
National Science Foundation (NSF) Hydrologic Sciences 1929747

How to Cite

Peck, E. K., s. inamdar, M. Peipoch, A. J. Gold, M. Sherman, J. Hripto, P. M. Groffman, T. L. E. Trammell, D. J. Merritts, K. Addy, E. Lewis, R. C. Walter, J. Kan (2022). Saturated, suffocated, and salty: Human legacies produce hot spots of nitrogen in riparian zones, HydroShare,

This resource is shared under the Creative Commons Attribution CC BY.


There are currently no comments

New Comment