Interaction between Urbanization and Climate Variability Amplifies Watershed Nitrate Export in Maryland

Thumbnail Image

Files

es800264f.pdf (6.11 MB)
es800264f_si_001.pdf (556.59 KB)

Links to Files

https://pubs.acs.org/doi/abs/10.1021/es800264f

Permanent Link

https://doi.org/10.1021/es800264f
 http://hdl.handle.net/11603/29162

Collections

UMBC Geography and Environmental Systems Department
UMBC Center for Urban Environmental Research and Education (CUERE)
UMBC Faculty Collection

Author/Creator

Author/Creator ORCID

https://orcid.org/0000-0002-9763-9630

Date

2008-07-09

Type of Work

journal articles
Text

Department

Program

Citation of Original Publication

Kaushal, Sujay S., Peter M. Groffman, Lawrence E. Band, Catherine A. Shields, Raymond P. Morgan, Margaret A. Palmer, Kenneth T. Belt, Christopher M. Swan, Stuart E. G. Findlay, and Gary T. Fisher. “Interaction between Urbanization and Climate Variability Amplifies Watershed Nitrate Export in Maryland.” Environmental Science & Technology 42, no. 16 (August 1, 2008): 5872–78. https://doi.org/10.1021/es800264f.

Rights

This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
Public Domain Mark 1.0

Subjects

Abstract

We investigated regional effects of urbanization and land use change on nitrate concentrations in approximately 1,000 small streams in Maryland during record drought and wet years in 2001−2003. We also investigated changes in nitrate-N export during the same time period in 8 intensively monitored small watersheds across an urbanization gradient in Baltimore, Maryland. Nitrate-N concentrations in Maryland were greatest in agricultural streams, urban streams, and forest streams respectively. During the period of record drought and wet years, nitrate-N exports in Baltimore showed substantial variation in 6 suburban/urban streams (2.9−15.3 kg/ha/y), 1 agricultural stream (3.4−38.9 kg/ha/y), and 1 forest stream (0.03−0.2 kg/ha/y). Interannual variability was similar for small Baltimore streams and nearby well-monitored tributaries and coincided with record hypoxia in Chesapeake Bay. Discharge-weighted mean annual nitrate concentrations showed a variable tendency to decrease/increase with changes in annual runoff, although total N export generally increased with annual runoff. N retention in small Baltimore watersheds during the 2002 drought was 85%, 99%, and 94% for suburban, forest, and agricultural watersheds, respectively, and declined to 35%, 91%, and 41% during the wet year of 2003. Our results suggest that urban land use change can increase the vulnerability of ecosystem nitrogen retention functions to climatic variability. Further work is necessary to characterize patterns of nitrate-N export and retention in small urbanizing watersheds under varying climatic conditions to improve future forecasting and watershed scale restoration efforts aimed at improving nitrate-N retention.