Graduation Date

Spring 2025

Document Type

Thesis

Program

Master of Science degree with a major in Environmental Systems, option Environmental Resources Engineering

Committee Chair Name

Dr. Tesfayohanes Yacob

Committee Chair Affiliation

Cal Poly Humboldt Faculty or Staff

Second Committee Member Name

Jim Graham

Second Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Third Committee Member Name

Dr. Margaret Lang

Third Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Fourth Committee Member Name

Christine Manhart

Fourth Committee Member Affiliation

Community Member or Outside Professional

Keywords

Stream depletion, Streamdepletr, Hydrogeology, Groundwater, Wells, Well, Northern California, Drought, Humboldt County, Northern California hydrology, California groundwater, California stream depletion, Groundwater pumping, Groundwater-surface water interaction, Water resource management, Aquifer drawdown, Baseflow reduction, Analytical groundwater models, Field hydrology data, R, Streamflow monitoring, Groundwater modeling, Hydrogeologic assessment, Groundwater impact modeling, Environmental water management, Sustainable water use, Watershed hydrology, Water policy in California, Groundwater regulation, Sgma, Environmental engineering, Civil engineering, Geology, Water resources engineering, Friends of the Eel, Water wells

Subject Categories

Environmental Systems

Abstract

This study addresses the significant concern of stream depletion from groundwater pumping in Humboldt County, CA. The objective of this study is to develop an analytical model for estimating stream depletion and integrating field data into model parameters.

The methodology involved conducting a field study near three operating wells by a stream, installing stream gages upstream and downstream of the wells, and recording pumping rates and schedules for two of the wells. The third well’s pumping data was synthetically generated, for privacy concerns of the well owner. The StreamDepletR package was used for estimating depletion rates in a stream in the Eel River Basin from July to September 2023. Depletion apportionment equations were employed to distribute depletion across stream segments, and the Hunt method was used for depletion estimation.

The results showed that the model, using reasonable hydraulic conductivity and storativity values, aligns with field data, capturing similar diurnal response in the rate of stream depletion. A Generalized Additive Model explained 14.5% to 16.5% of the data variance between the stream depletion flow rate and the stream water level. A Monte Carlo simulation revealed high uncertainty in the model’s predictive power.

Despite limitations such as the inability to validate estimated stream depletion due to the limited equipment availability and not accounting for all potential water use sources, the model successfully identified wells likely to cause depletion, captured temporal dynamics, and estimated the spatial distribution of the depletion. This study provides valuable insights into identifying “at-risk” systems and stream depletion estimates.

Citation Style

APA

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