Baltimore Long Term Ecological Research

Objectives

USGS operates a basic network of hydrologic data-collection stations in collaboration with BES. Analysis of data from these stations provides fundamental information used by many BES researchers. USGS is working with other investigators and potential collaborators to support and develop scientific investigations, including topics in meteorology, streamflow, ground water, water quality, toxic substances, and sediment.

Statement of Problem

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

BES scientists conduct many investigations of the urban ecosystem, but all address one or more of three central questions. Studies by USGS address two of 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 four "small watershed" and two "boundary condition" gaging stations:

01583570 Pond Branch at Oregon Ridge, 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 sites; 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).