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Baltimore Long-Term Ecological Research (LTER) Project


The National Science Foundation’s Long-Term Ecological Research (LTER) Network was created in 1980 and seeks to understand how specific ecosystems change over time. For more than three decades, the LTER Network has generated rigorous, sitebased scientific research that has led to important findings on both regional and continental scales.


Prior to 1998, most LTER research sites had been focusing efforts on undisturbed watersheds and ecosystems, and little, if any, LTER research had focused on urban ecosystems. Beginning in 1998, Baltimore became one of two urban LTER project locations to be added to the national network of LTER sites, operating a basic network of hydrologic data-collection stations in collaboration with BES. Analysis of data from these stations provides essential information used by BES researchers. USGS is working with other investigators and potential collaborators to support and develop scientific investigations, including topics in meteorology, surface/ground water, water quality, toxics and sediment.

The U.S. Geological Survey is a participant in the Baltimore Ecosystem Study (BES), an urban Long-Term Ecological Research (LTER) Project, which is a collaboration of federal, state, local, non-profit, and academic research sponsored by the National Science Foundation.



The goal of the Long-Term Ecological Research, Baltimore Ecosystem Study (BES) is to explore, quantify, and document knowledge of urban ecosystems, with primary focus on the Baltimore Metropolitan Statistical Area, and with intensive plots situated in the Gwynns Falls Watershed.

BES collects long-term data on urban ecosystem structure, function and change. It also conducts research to improve understanding and application of the concept of sustainability to an urban system, based on testing hypotheses concerning the social and bio-geophysical processes in Baltimore that can help achieve local sustainability policy.

The research employs complementary strategies of experimentation, comparison, long-term measurement, and modeling. Models of feedback between social and bio-geophysical processes linked through ecosystem services of water quality and flow, and net carbon storage place the variables and spatial patterns measured in a practical context

BES scientists conduct many investigations of the urban ecosystem, but all address one or more of three central questions. Studies by USGS address these questions:

  • What are the fluxes of energy and matter in urban ecosystems, and how do they change over the long term?
  • How does the spatial structure of ecological, physical, and socio-economic factors in the metropolis affect ecosystem function?


Strategy and Approach

Small watershed and stream-gaging stations will be maintained for the Baltimore Ecosystem Study. There are five "small watershed" and two "boundary condition" gaging stations:

  • 01583570 Pond Branch at Oregon Ridge, MD
  • 01583580 Baisman Run at Broadmoor, MD
  • 01589180 Gwynns Falls at Glyndon, MD
  • 01589238 Gwynns Falls tributary at McDonogh, MD
  • 01589300 Gywnns Falls at Villa Nova, MD (boundary)
  • 01589340 Rognel Heights Storm Sewer Outfall at Baltimore
  • 01589352 Gwynns Falls at Washington Blvd. (boundary)

Standard USGS operations produce a digital data base of stage and discharge with a 15-minute time step. The time step has been reduced to 5 minutes at some stations; an approach used in previous urban work in Baltimore on small, highly impervious watersheds. A relationship is established between stage and discharge at each station, and regular field work is done to develop this relationship and to regularly assess its validity. Data are recorded using an autonomous electronic data logger. Typical USGS stations are visited every 6 weeks, but some stations may be visited more frequently especially during the development of the initial stage-discharge relationship. Data are processed and analyzed promptly and entered into USGS data bases. These data will be available immediately as provisional data to BES and will be available as tab-delimited format for input into other data management systems. Final review and publication of data will be done on an annual basis approximately within 6 months after the end of each Water Year (ending each September 30).

Although publication only includes daily-mean discharge values ("Daily Values"), all discrete data ("Unit-Values") will be maintained and available in the data base. Quality assurance and quality control includes review of records for errors due to site conditions, equipment problems, and weather impacts (such as freezing), comparisons with nearby stream gages for regional consistency, and review and verification of field measurements and stage-discharge relationships. Storm sewer sites require unique approaches to gaging and discharge measurement; they are not likely to have continuous flow, may not have a suitable surface site to house equipment and may require specialized equipment (e.g. a flume within the sewer).


For Additional Information...

Just a note about the Annual USGS Water Data Reports: 

Water Resources Data reports  were published annually for many decades for use by engineers, scientists, managers, educators, and the general public. These static archival products supplemented direct access to current and historical water data provided by the National Water Information System web interface (NWISWeb), the authoritative source for USGS water data.

Beginning with Water Year 2006 and ending with Water Year 2013, annual water data reports were made available as individual electronic Site Data Sheets for the entire Nation for retrieval, download, and localized printing on demand. Over that time, NWISWeb capabilities have become more comprehensive. Building on these capabilities, USGS has moved the Site Data Sheet functions into NWISWeb. As of 2014, NWISWeb now provides an on-demand, print-ready Water-Year Summary as an annual water-data product.

Water Data for the MD-DE-DC Water Science Center can be retrieved here:

Other valuable resources:

Baltimore Ecosystem Study project website:

Cary Institute of Ecosystem Studies:

UMBC Center for Urban Environmental Research and Education:

The Long Term Ecological Research Network: