Mississippi River spatial water chemistry Environmental Research Letters datasets

We mapped surface water chemistry along the entire length of the Upper Mississippi
River (UMR) to understand spatial patterns in nitrate sources and processing. We used a
sensor-based and boat-mounted sensing platform to continuously measure underway water
chemistry. Measurements were linked with global positioning systems (GPS) to create maps of
surface water chemistry. Here, we archive data associated with an Environmental Research
Letters publication (Loken et al. 2018). Data include a single spatial survey of the entire
length of the UMR (Minneapolis, Minnesota to Cairo, Illinois) in August 2015 and repeat
surveys in Navigation Pool 8 (located near La Crosse, WI). Data have been provided in three
formats (raw, hydraulic-corrected, and tau-corrected). Additionally, we archive laboratory
chemistry data from water samples collected during the project. Sites include a range of
main channel, backwaters, and tributaries. Water chemistry samples were analyzed at the
North Temperate Lakes - Long Term Ecological Research facility and linked with underway
sensor measurements.