thumbnail

Assessing roadway contributions to stormwater flows, concentrations, and loads with the StreamStats application

Transportation Research Record

By:
https://doi.org/10.1177/0361198118758679

Links

Abstract

The Oregon Department of Transportation (ODOT) and other state departments of transportation need quantitative information about the percentages of different land cover categories above any given stream crossing in the state to assess and address roadway contributions to water-quality impairments and resulting total maximum daily loads. The U.S. Geological Survey, in cooperation with ODOT and the FHWA, added roadway and land cover information to the online StreamStats application to facilitate analysis of stormwater runoff contributions from different land covers. Analysis of 25 delineated basins with drainage areas of about 100 mi2 indicates the diversity of land covers in the Willamette Valley, Oregon. On average, agricultural, developed, and undeveloped land covers comprise 15%, 2.3%, and 82% of these basin areas. On average, these basins contained about 10 mi of state highways and 222 mi of non-state roads. The Stochastic Empirical Loading and Dilution Model was used with available water-quality data to simulate long-term yields of total phosphorus from highways, non-highway roadways, and agricultural, developed, and undeveloped areas. These yields were applied to land cover areas obtained from StreamStats for the Willamette River above Wilsonville, Oregon. This analysis indicated that highway yields were larger than yields from other land covers because highway runoff concentrations were higher than other land covers and the highway is fully impervious. However, the total highway area was a fraction of the other land covers. Accordingly, highway runoff mitigation measures can be effective for managing water quality locally, they may have limited effect on achieving basin-wide stormwater reduction goals.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Assessing roadway contributions to stormwater flows, concentrations, and loads with the StreamStats application
Series title:
Transportation Research Record
DOI:
10.1177/0361198118758679
Edition:
Online First
Year Published:
2018
Language:
English
Publisher:
SAGE Journals
Contributing office(s):
Oregon Water Science Center