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Urban Watershed Delineation: Incorporation of Storm Sewer Networks. James Bornemann Undergraduate Student Dept. of Geodesy and Geomatics Engineering University of New Brunswick. Background. Fredericton Area Watersheds Association (FAWA) Community based monitoring and research
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Urban Watershed Delineation:Incorporation of Storm Sewer Networks James Bornemann Undergraduate Student Dept. of Geodesy and Geomatics Engineering University of New Brunswick
Background • Fredericton Area Watersheds Association (FAWA) • Community based monitoring and research • City of Fredericton • Population ~ 50,000 • Environmental management by watershed • Socioeconomic and biophysical conditions • Need: Accurate watershed boundaries
Previous Delineations • New Brunswick DELG small scale delineation • Wade MacNutt • Local scale • Combined automatic and manual method
Storm Sewer Networks • Are storm sewer networks significant to watershed delineations? • Historical Evidence • Ditch to divert headwaters of the swamp • ~155 acres for development • Unknown location of early pipes • Size vs. land use of area
Watershed Delineation Methodology • Based on Digital Terrain Model (DTM) • Analyze topological relationships to model hydrological processes • Assumption: Surface Flow Only Digital Terrain Model
Topographical Watershed Delineation Filled DTM Flow Direction Accumulation Grid Generated Streams Identify Outlets Watershed Delineation
Storm Sewer Delineation Identify Storm Sewer Network Delineate Catch BasinWatersheds • Other Considerations • Roads • Other Drainage Networks Final Delineation
Types of Watersheds • 3 Types of Watersheds: • Urban-Topographic • Composite • Shared Maps of the 3 types
Accuracy • Process vs. Accuracy • Precision of elevation data • +/- 10 ft. Vertical • <100 ft. Spacing of Elevation Data
Environmental Management Application • Require good information to make good management decisions • Overlay watersheds and land use to help determine cause and affect • Corbett Brook Watershed Management Example…
Corbett Brook Land Use
Summary • Methodology for delineating urban watersheds with storm sewer networks • Storm sewer networks can significantly alter watershed boundaries • Accuracy must be considered • Land use of additional area can be as important as the increase in area
Questions? • Contact: James Bornemann, d191d@unb.ca