Date of Award


Degree Name

MS in Environmental Sciences and Management


Natural Resources Management


College of Agriculture, Food, and Environmental Sciences


Bwalya Malama

Advisor Department

Natural Resources Management

Advisor College

College of Agriculture, Food, and Environmental Sciences


The efficacy of hydraulic pumping as a remediation method of a petroleum, or Light Non-Aqueous Phase Liquid (LNAPL) spill in Arroyo Grande, California will be assessed by determining aquifer properties, assessing the chemical properties of the contaminant, recovering the contaminant from the subsurface, and proposing alternative remediation techniques. Soil, groundwater and contaminant characteristics, cumulative volume of LNAPL skimming test data, pumping rates, and LNAPL thicknesses in wells installed within the contaminant plume were collected. Sediments around the LNAPL source are contaminated with hydrocarbons in the gas and diesel range. Pumping efficacy is expected to continue to decrease at the site, at which point alternate remediation techniques are evaluated. Skimming test data for each well reached an equilibrium discharge rate at approximately 60 minutes between discharges. Pumping rates in each well were variable with an average pumping rate of 20 gallons per week. LNAPL thicknesses in each well were variable, with maximum thicknesses of over seven feet and minimum thicknesses of less than two feet. Results from groundwater monitoring demonstrate that the plume is at low risk of migrating to neighboring properties. LNAPL testing and successful recovery progress of 6,169 gallons of LNAPL demonstrates that hydraulic pumping is an efficient first step towards containing the spread of the oil spill and removing the oil from the plume.