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Evaluation of flood inundation in Crystal Springs Creek, Portland, Oregon

Open-File Report 2016-1079

Prepared in cooperation with the City of Portland Bureau of Environmental Services
By:
and
DOI:10.3133/ofr20161079

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Abstract

Efforts to improve fish passage have resulted in the replacement of six culverts in Crystal Springs Creek in Portland, Oregon. Two more culverts are scheduled to be replaced at Glenwood Street and Bybee Boulevard (Glenwood/Bybee project) in 2016. Recently acquired data have allowed for a more comprehensive understanding of the hydrology of the creek and the topography of the watershed. To evaluate the impact of the culvert replacements and recent hydrologic data, a Hydrologic Engineering Center-River Analysis System hydraulic model was developed to estimate water-surface elevations during high-flow events. Longitudinal surface-water profiles were modeled to evaluate current conditions and future conditions using the design plans for the culverts to be installed in 2016. Additional profiles were created to compare with the results from the most recent flood model approved by the Federal Emergency Management Agency for Crystal Springs Creek and to evaluate model sensitivity.

Model simulation results show that water-surface elevations during high-flow events will be lower than estimates from previous models, primarily due to lower estimates of streamflow associated with the 0.01 and 0.002 annual exceedance probability (AEP) events. Additionally, recent culvert replacements have resulted in less ponding behind crossings. Similarly, model simulation results show that the proposed replacement culverts at Glenwood Street and Bybee Boulevard will result in lower water-surface elevations during high-flow events upstream of the proposed project. Wider culverts will allow more water to pass through crossings, resulting in slightly higher water-surface elevations downstream of the project during high-flows than water-surface elevations that would occur under current conditions. For the 0.01 AEP event, the water-surface elevations downstream of the Glenwood/Bybee project will be an average of 0.05 ft and a maximum of 0.07 ft higher than current conditions. Similarly, for the 0.002 AEP event, the water-surface elevations will be an average of 0.04 ft and a maximum of 0.19 ft higher than current conditions.

Suggested Citation

Stonewall, Adam, and Hess, Glen, 2016, Evaluation of flood inundation in Crystal Springs Creek, Portland, Oregon: U.S. Geological Survey Open-File Report 2016-1079, 33 p., http://dx.doi.org/10.3133/ofr20161079.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Model Development
  • Flood Inundation Evaluation
  • Sensitivity Analysis
  • Suggestions for Future Research
  • Summary
  • Acknowledgments
  • References Cited
  • Glossary

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Evaluation of flood inundation in Crystal Springs Creek, Portland, Oregon
Series title:
Open-File Report
Series number:
2016-1079
DOI:
10.3133/ofr20161079
Year Published:
2016
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Oregon Water Science Center
Description:
Report: iv, 33 p.; Plate: 24.00 x 36.00 inches
Country:
United States
State:
Oregon
City:
Portland
Other Geospatial:
Crystal Springs Creek
Online Only (Y/N):
Y
Additional Online Files (Y/N):
Y