The vast majority of theses in this collection are open access and freely available. There are a small number of theses that have access restricted to the WWU campus. For off-campus access to a thesis labeled "Campus Only Access," please log in here with your WWU universal ID, or talk to your librarian about requesting the restricted thesis through interlibrary loan.

Date Permissions Signed


Date of Award

Winter 1990

Document Type

Masters Thesis

Degree Name

Master of Science (MS)



First Advisor

Kelsey, H. M.

Second Advisor

Talbot, James L.

Third Advisor

Easterbrook, Don J., 1935-


Three types of groundwater systems occur within glacial sediments in a 10 mi2 (25 km2) area near Sumas, Washington: an unconfined sand and gravel aquifer, a confined sand and gravel aquifer, and a generally unproductive clay aquitard. Water levels in the area were mapped from measurements of wells and points along stream courses in October 1988 and March 1989. The water-level configurations for the two aquifers roughly parallel surface topography. Water level maps were used to estimate direction of groundwater flow, which is generally to the southeast in the unconfined aquifer and to the northeast in the confined aquifer. Water level measurements made within the clay aquitard indicate that most water horizons are perched and water level is controlled by the surface topography of the clay. The highest water levels throughout the study area occur during the spring, following high precipitation during winter months. Water levels vary seasonally in response to changing recharge and discharge conditions. Recharge is principally by direct precipitation onto surficial units. Discharge is to streams, drainage ditches and springs and by pumping. Hydrostratigraphic cross-sections were made using data from well drillers' lithologic logs, existing geologic maps, and field exposures. Five hydrostratigraphic units were delineated based on porosity, permeability, geographic location, and lateral extent of the hydrostratigraphic horizons. By using hydrologic properties associated with water-bearing units and hydraulic gradients measured from water-level maps, average linear velocities within the aquifers were estimated at 4.0 gal day-1ft-2 in the confined aquifer and 7.4 to 120 gal day-1ft-2 in the unconfined aquifer.




Goundwater systems, Groundwater flow, Hydrostratigraphy



Western Washington University

OCLC Number


Subject – LCSH

Groundwater--Washington (State)--Sumas Region; Aquifers--Washington (State)--Sumas Region; Geology--Washington (State)--Sumas Region; Geology, Stratigraphic

Geographic Coverage

Sumas Region (Wash.)




masters theses




Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Included in

Geology Commons