Littoral river plumes are complex optical environments. To begin to resolve this complexity we use hyperspectral data, and an extension of ‘dark pixel correction’ methods (Chavez 1988), to produce radiance maps that allow us to distinguish different constituents in the water column ranging from glacial rich sediments (silica’s) to muds and algae. We present data from two sites: the Columbia River in the Northwest of the United States, and the Otago Shelf fed by the Clutha River on the South Island of New Zealand. For this study the instrument used to collect data was HICO (Corson 2010; Davis et. al. 2010) — the Hyperspectral Imager for the Coastal Ocean — developed by the United States Naval Research Lab (NRL) and currently flying on the International Space Station. HICO has 90 channels between 400-900 nm and a ground sampling distance of 90 m. These early results illustrate how space borne hyperspectral imaging can enhance our view of the suspended matter in iver plumes along a coast.