SPILL PREVENTION AT INLAND MARINAS: A SHASTA LAKE, CALIFORNIA, CASE STUDY

ABSTRACT Since the enactment of the Oil Pollution Act of 1990 (OPA 90), there has been a greater focus on spill prevention and response preparedness at large marine transfer facilities. Little attention, however, has been paid to facilities that fall short of 42,000 gallons. Many of these smaller facilities, which are located on the nation's inland waterways, are marinas that fuel recreational boats. Spill prevention at facilities on inland waterways is complicated by factors such as location, hydrologic conditions, regulation under multiple jurisdictions, and lack of available technology. This paper discusses the various types of petroleum product storage, transfer, and delivery systems, as well as spill prevention measures employed by marinas on Shasta Lake, California. Shasta Lake is a mecca of recreational boating, having almost a dozen marinas along its shores. Like many inland waterways, Shasta Lake is affected by precipitation and dam control, which drastically change the surface area of the lake. To stay afloat and operational, marinas, including their fuel transfer capabilities, must be mobile. This presents complex technical and environmental issues for the marinas, which use different combinations of equipment for storing and transferring fuel. Storage systems include fixed or mobile, aboveground or underground storage tanks and floating fuel systems. The piping used to deliver fuel to dispensers located on the marina dock is usually a combination of rigid and flexible lines. Each system is subject to a variety of laws and regulations, with every facility varying in compliance levels. By evaluating the precarious situations and spill events at Shasta Lake and other marinas, we can better assist in compliance efforts and more effectively protect our nation's waterways from oil spills.

Impact of a major soil fumigant spill on the planktonic ecosystem of Shasta Lake, California

On July 14, 1991, approximately 70 000 L of the soil fumigant Vapam®, metam sodium, was spilled into the upper Sacramento River, California. Twelve hours before this spill reached Shasta Lake we sampled several sites in a subsequently impacted area and two control stations. Thereafter, samples were collected at approximately 5-d intervals for 26 d. We observed an almost immediate and subsequent 99.9% decrease in zooplankton biomass within 2.0 km of the river inflow. Lake-water chlorophyll concentrations crashed immediately to 20% of prespill values, but rebounded to approximately 750% prespill values after 9 d as a result of a spill-driven diatom bloom. Dissolved inorganic nitrogen and phosphorus concentrations increased severalfold immediately after the spill but returned to prespill concentrations as the algal bloom peaked. Effects of the spill were clearly related to distance from the river inflow with strong effects observed within 2.0 km, and weak or no effects observed at 8.0 km into the reservoir. A dilution experiment, using varying mixtures of contaminated and control station lake water, strongly confirmed the principal findings of the field study. Our field and experimental data showed far more severe effects of the spill than single species bioassays and lake pesticide concentrations predicted.