USGS Washington Water Science Center
|Project Summaries | Publications and Products | Partnerships ||
WA244 - Quantitative Evaluation of the Water Resources of the Tulalip Indian Reservation and Surrounding Areas, Snohomish County - Completed FY1983
Problem - Our 1975 study of the Tulalip Reservation showed that population had doubled since 1960. Growth has continued since 1975 with an additional influx of about 1,600 residents each summer. The well field established in 1975 is experiencing a water-level decline of about 1.5 feet per year and is estimated to have a remaining useful life of 15-20 years under present conditions. However, there is potential for industrial development that would require additional water supply. Seawater intrusion has occurred on the reservation but is not a serious problem at this time. The ground-water phase of our previous study did not supply data sufficient to answer these new questions--it was limited to interpretation of data available from existing wells and two test holes drilled on the Reservaton.
Objectives - A comprehensive study is proposed to determine in terms of areal distribution and quantity the availability of ground water on the reservation from aquifers generally above sea level.
Approach - Quantification of the ground-water resources of the reservation requires mapping of aquifers in the unconsolidated deposits underlying the Reservation, determination of aquifer characteristics, and the determination of the hydraulic relationship between the ground-water system and streams. Two years of data collection, interpretation, and preliminary modeling will be required. The third year of the project will consist primarily of final model analysis and report preparation. The study will include modeling of ground-water flow in aquifers at our above sea level to quantify the available supply and ascertain the effects of future development.