Publication Citation

USGS Series Water-Resources Investigations Report
Report Number 92-4010
Title Estimation of ground-water recharge from precipitation, runoff into drywells, and on-site waste-disposal systems in the Portland Basin, Oregon and Washington
Edition -
Language ENGLISH
Author(s) Snyder, D. T.; Morgan, D. S.; McGrath, T. S.
Year 1994
Originating office
USGS Library Call Number (200) WRi no.92-4010
Physical description v, 34 p. :ill., maps (some col.) ;28 cm.
ISBN

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Abstract

The average recharge rate in the Portland Basin, in northwestern Oregon and southwestern Washington, is estimated to be about 22.0 inches per year. Of that amount, precipitation accounts for about 20.8 inches per year, runoff into drywells 0.9 inches per year, and on-site waste disposal about 0.4 inches per year. Recharge is highest, about 49 inches per year, in the Cascade Range. Recharge is lowest, near zero, along and between the Columbia and Willamette Rivers. Recharge is higher locally in discrete areas owing to recharge from runoff into drywells and on-site, waste-disposal systems in urbanized parts of the study area. In these urbanized areas, recharge ranges from 0 to 49 inches per year.