Maps showing channel changes in lower Pueblo Canyon since 1935, based on examination of sequential airphotos. Prior to 1960-1965, this area had a broad sandy channel which was aggrading and migrating laterally, and subsequently progressive incision of up to 3 m has occurred, resulting in a narrower incised channel with less channel migration. Incision has progressed downstream over time, producing a diachronous fill terrace. This area is about 9 km downstream of effluent release sites from the original Los Alamos technical area, and is a major storage area for plutonium released by early laboratory operations. Peak releases of Pu occurred between 1945 and 1951, and the highest concentration of Pu in channel deposits in this reach occur in deposits that pre-date 1965, particularly large sand deposits from the 1950s.

Back to Quaternary Geology and Surface Processes