Site observational work plan for the UMTRA project site at Grand Junction, Colorado

This site observational work plan (SOWP) is one of the first Uranium Mill Tailings Remedial Action (UMTRA) Ground Water Project documents developed to select a compliance strategy that meets the UMTRA ground water standards for the Grand Junction site. This SOWP applies information about the Grand Junction site to the compliance strategy selection framework developed in the UMTRA Ground Water Project draft programmatic environmental impact statement. This risk-based, decision-making framework identifies the decision logic for selecting compliance strategies that could be used to meet the ground water standards. The US Department of Energy (DOE) goal is to implement a cost-effective site strategy that complies with the ground water standards and protects human health and the environment. Based on an evaluation of the site characterization and risk assessment data available for the preparation of this SOWP, DOE proposes that the most likely compliance strategy for the Grand Junction site is no remediation with the application of supplemental standards. This proposed strategy is based on a conceptual site model that indicates site-related contamination is confined to a limited-use aquifer as defined in the ground water standards. The conceptual model demonstrates that the uranium processing-related contamination at the site has affected the unconfined alluvial aquifer, but not the deeper confined aquifer