Influence of stormwater control measures on water quality at nested sites in a small suburban watershed

ABSTRACT

Stormwater control measures (SCMs) are designed to mitigate the deleterious impacts of urban runoff on the water quality of receiving waters. To assess the cumulative effects of SCMs at the watershed scale, we monitored longitudinal changes in storm discharge and stream water chemistry at high temporal resolution in a suburban headwater stream in Charlotte, NC. SCMs significantly decreased or stabilized instream concentrations of reactive solutes (nitrate, soluble reactive phosphorus, and dissolved organic carbon) relative to the upstream control site. However, SCM outflows minimally influenced concentrations of less reactive solutes (major ions) which increased with urbanization. Additionally, instream concentration variability correlated with antecedent moisture conditions – representative of watershed storage availability – highlighting the role that SCM storage availability plays in the timing of solute delivery to the stream. Our results show that SCMs decrease instream concentrations of biogeochemically reactive solutes but the mitigation potential is temporally dynamic and influenced by antecedent conditions.

KEYWORDS:

• Stormwater management
• water quality
• urban development
• stormwater control measure

Acknowledgements

We thank our lab groups for advice and assistance with data collection, and Sayan Dey and Julian David Reyes Silva for help with HEC-RAS. We thank Charlotte Stormwater Services for logistical and technical support.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work is funded by a National Science Foundation Grant, No. CBET-1034043. We also acknowledge the support of USDA/NIFA S-1063.