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Urban Natural Resource Stewardship

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video: Urban Watershed Continuum
Video: Urban Watershed Continuum

The Urban Watershed Continuum is a conceptual framework for studying urban waters. This short film explains the concept to students and educators. While exploring urban waters at the Baltimore Long-Term Ecological Research site and other locations, the film explores the question: What is an urban watershed?

Produced by students of
Sujay Kaushal, Department of Geology, University of Maryland

The Urban Watershed Continuum: Effects of Urban Engineered Infrastructure on Stream Ecosystems

Research Issue

[image:] Pipe leaks can be into or out of the pipe, depending on the groundwater level (blue line) and the level of water in the pipe (blue color or dotted line), and so ground water can flow into the pipe (augmenting baseflow) or the pipe flow can recharge the groundwater.The urban watershed continuum (UWC) concept looks at urban watersheds as hybrid “ecospheres” of engineered (i.e., pipes, gutters, etc.) and natural (e.g., plants, animals, microbes) ecosystems.  In urbanized watersheds, streams are intimately connected to their landscapes through highly engineered drainage networks, resulting in excessive stormwater runoff, lower groundwater levels, increased loads of pollutants, and increased thermal loads due to direct heat transfer.  This results in negative impacts to water quality, riparian areas, civil infrastructure, and aquatic habitats.  Increasing trends in alkalinity, salinization, and water temperature in urbanized watersheds are significant for their potential to influence aquatic species population distributions and related ecosystem processes.  Urban drainage networks greatly increase organic matter delivery and breakdown rates and change how carbon and nutrients are stored and processed in the landscape.

Our Research

The research questions to be investigated in a network of urban to rural gradient streams include:  1) How do engineered urban water systems affect organic matter processing and other stream functional processes? 2) How are ecosystem processes and aquatic species presence related to chemistry (alkalinity and chloride) in urban streams? and 3) How are ecosystem processes and aquatic species presence related to temperature in urban streams? By investigating these relationships, we can better understand ecosystem processes and ecosystem health in urban stream networks.  In addition, aquatic species can be identified that can be used as indicators of chemical and thermal barriers to ecosystem function and aquatic species population interactions.  

Expected Outcomes

Results of this research will identify the importance of organic matter, alkalinity, salinity, and temperature as mechanistic drivers of aquatic ecosystem processes and aquatic species distributions in urban watersheds.  Data from this research will be used to examine thermal and chemical dynamics at varying spatial and temporal scales in relation to seasonal patterns and land covers important for management of aquatic ecosystems.   These investigations will also identify roles of impervious surfaces and riparian vegetation in chemical and temperature process management. 

Continuous water temperature and water quality parameter data have been recorded for over thirty stream sites in the Baltimore metropolitan area and Baltimore Ecosystem Study LTER network , with most sites co-located at or near USGS streamflow gauges. Collaborative efforts with the University of Maryland, Baltimore County, CUERE is also being planned to further use flow, temperature, chemical, and land use data for model development   to project long-term impacts on aquatic ecosystem health and processes.  This work will be done with a multidisciplinary approach to integrate the perspectives of urban water researchers, practitioners, stakeholders and policy makers.

Research Results

Results suggest that urban catchments, with their mosaic of vegetated and impervious areas, can present a large range of chemical and thermal impacts on urban streams.  Thermal impacts are expressed as higher summer air temperatures and higher water temperature runoff spikes.  The data also suggest that chemical and thermal stresses present large challenges to aquatic communities that can affect distributions of aquatic species related to thermal tolerance.  

Belt, KT, 2013. Organic Matter in Streams and the Urban Watershed Continuum, Marine-Estuarine-Environmental Sciences (MEES, University of MD), Ph.D Dissertation, UMBC GES, ProQuest/UMI, UMBC.

Belt, Kenneth T.; Stack, William P.; Pouyat, Richard V.; Burgess, Kimberly; Groffman, Peter M.; Frost, William M.; Kaushal, Sujay S.; Hager, Guy. . 2014. Ultra-urban baseflow and stormflow concentrations and fluxes in a watershed undergoing restoration (WS263). In: Proceedings of the Water Environment Federation, Stormwater 2012. 2012(5): 262-276.

Kaushal, Sujay S.; Belt, Kenneth T. . 2012. The urban watershed continuum: evolving spatial and temporal dimensions. Urban Ecosystems. 15: 409-435.

Sivirichi, GM, Kaushal, SS, Mayer, PM, Welty, C, Belt, KT, et al., 2011. Longitudinal variability in streamwater chemistry and carbon and nitrogen fluxes in restored and degraded urban stream networks. J of Env Monit 13, 288-303.

Kaushal, SS, Likens, GE, Jaworski, NA, Pace, ML, Sides, AM, Belt, KT, et al., 2010. Rising stream and river temperatures in the United States. Front in Ecol and the Env 8: 461-466.

Kaushal, SS, Groffman, PM, Band, LE, Shields, CA, Morgan, RP, Palmer, MA, Belt, KT et al., 2008. Interaction between Urbanization and Climate Variability Amplifies Watershed Nitrate Export in Maryland. Env Sci & Tech 42:5872-5878.

Gresens, Susan E.; Belt, Kenneth T.; Tang, Jamie A.; Gwinn, Daniel C.; Banks, Patricia A. 2007. Temporal and spatial responses of Chironomidae (Diptera) and other benthic invertebrates to urban stormwater runoff. Hydrobiol. 575:173-190.

Kim, Hyun Jin.  2007. Temperatures of urban streams: impervious surface cover, runoff, and the importance of spatial and temporal variations. MS thesis, UMBC Civil and Environmental Engineering

Pickett, Steward T.A.; Belt, Kenneth T.; Galvin, Michael F.; Groffman, Peter M.; Grove, J. Morgan; Outen, Donald C.; Pouyat, Richard V.; Stack, William P.; Cadenasso, Mary L. . 2007. Watersheds in Baltimore, Maryland: understanding and application of integrated ecological and social processes. Journal of Contemporary Watershed Research and Education. 136: 44-55.

Pouyat, Richard V.; Pataki, Diane E.; Belt, Kenneth T.; Groffman, Peter M.; Hom, John; Band, Lawrence E. . 2007. Effects of urban land-use change on biogeochemical cycles. In: Canadell, J.G.; Pataki, D.E.; Pitelka, L.F., eds. Terrestrial ecosystems in a changing world. Berlin. Springer-Verlag: 45-58.

Groffman, Peter M.; Law, Neely L.; Belt, Kenneth T.; Band, Lawrence E.; Fisher, Gary T. 2004. Nitrogen fluxes and retention in urban watershed ecosystems. Ecosystems. 7: 394-403.

Groffman, PM, Bain, DJ, Band, LE, Belt, KT, et al. 2003. Down by the riverside: urban riparian ecology. Front in Ecol and the Env. 1: 315-321.

Kaushal, SS., Groffman, PM., Likens, GE.; Belt, KT., et al. 2005. Increased salinization of fresh water in the northeastern United States. Proc, Nat Acad Sci. 102:13517-13520.

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Last Modified: March 11, 2020