THE RELEVANCE OF STREAMFLOW INFORMATION TO URBAN PLANNERS AND POLICY MAKERS

Monitoring streamflow is fundamental to managing water resources and public safety in urban areas. The U.S. Geological Survey stream-gage network provides a foundation for addressing water-resources issues (availability, quality, recreation, flooding) in the Baltimore region. The regional network is comprised of 64 monitoring sites, nearly half of which are in urban or suburban watersheds. These sites are supported by Federal, State, and local agencies, as well as research organizations, for addressing multiple stakeholder goals. The aggregate body of streamflow information can be used to assess regional trends in flow over time, and if coupled with water-quality data, can show how development and best management practices affect streamflow and water quality, and thus the health of ecosystems in the metropolitan area’s waterways.

A subset of these network sites in the Gwynns Falls and Gunpowder Falls watersheds are used by the Baltimore Ecosystem Study for evaluating long-term water-quality conditions and computing contaminant loads along the Baltimore County-Baltimore City urban-rural land-use gradient. Another subset of 10 sites in the Gunpowder Falls and Patapsco River watersheds are used by the Baltimore City Department of Public Works for drought assessment and tracking water supply In the Baltimore Reservoir System. Some of these sites are also used by recreational users, such as boaters and fishermen. Others are used by State and local jurisdictions for stream restoration and bridge design, which require representation of hydrology and hydraulics in watersheds having different combinations of drainage area sizes and land use conditions across physiographic regions. Sites with 10 or more years of record are used by hydrologists and engineers for regional analyses of flood frequency, flood inundation, and delineating floodplain boundaries.

While the continuous stream-gage network is focused primarily on riverine streamflow, a new network of temporary sensor locations has been implemented in the Chesapeake Bay region to monitor and track tidal fluctuations, wave action, and storm surge during coastal storms. Data from this network will be used to improve the accuracy of surge-forecast models, which will aid in the design of flood-resilience measures to be implemented in vulnerable coastal areas.