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Denitrification potential and a series of ancillary variables (inorganic nitrogen concentrations, moisture content, organic matter content, microbial biomass carbon and nitrogen content, potential net nitrogen mineralization and nitrification, microbial respiration, root biomass) has been measured in riparian zone soils and stream geomorphic features by a series of undergraduate and graduate student researchers as part of the Baltimore Ecosystem Study since the early 2000s. These studies often center on the series of sites where there has been long-term monitoring (since 2000) of riparian water tables and groundwater chemistry along four first or second order steams in and around the Gwynns Falls watershed in Baltimore City and County, MD (https://doi.org/10.6073/pasta/f7721ec5a4fab5b031f8056824e07e7d). One site is in the completely forested Pond Branch catchment that serves as a "reference" study area for the Baltimore LTER (BES). Two sites (Glyndon, Gwynbrook) are in suburban areas of the watershed; one just upstream from the Glyndon BES long-term stream monitoring site in the headwaters of the Gwynns Falls, and one along a tributary that enters the Gwynns Falls just above the Gwynnbrook BES long-term stream monitoring site farther downstream. The final, urban site (Cahill) is along a tributary to the Gwynns Falls in Leakin Park in the urban core of the watershed. Other sites were used in different studies as described in the publications associated with each study. The different studies also varied in just which ancillary variables were measured.
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Changes in long‐term water quality of Baltimore streams are associated with both gray and green infrastructure
<italic>Abstract</italic> The steadily rising global urban population has placed substantial strain on urban water quality, and this strain is projected to increase for the foreseeable future. Considerable attention has been given to the hydrological and physico‐chemical effects of urbanization on stream ecosystems. However, due to the relative infancy of the field of urban ecology, long‐term water quality analyses in urban streams are sparse. Using a 15‐yr stream chemistry monitoring record from Baltimore, Maryland, we quantified long‐term trends in nitrate, phosphate, total nitrogen, total phosphorus, chloride, and sulfate export at several sites along a rural–urban gradient. We found no significant change in solute export at most sites, although we did find specific patterns of interest for certain solutes. For example, nitrogen export declined at the most headwater urban site, while phosphorus export declined at the most downstream urban site. Coupling long‐term monitoring with data on gray and green infrastructure management throughout the landscape, we established relationships between solute export at the most downstream urban monitoring site and sanitary sewer overflows (SSOs), best management practice (BMP) implementation, and road salt application rates. Phosphorus export was correlated with BMP implementation in the watershed, whereas nitrogen export was related to SSOs. Despite highly urbanized watersheds, water quality does not appear to be declining at most of these sites, suggesting that current management may have limited further impairment. Results of our study suggest that both gray and green infrastructure are key for maintaining and improving water quality in this highly urbanized watershed.
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- PAR ID:
- 10065960
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Limnology and Oceanography
- Volume:
- 64
- Issue:
- S1
- ISSN:
- 0024-3590
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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