Water quality measurements, stream order, channel slope and hydraulic equations of conterminous USGS sites: 1919-2009.

Streams and rivers emit petagrams of CO2 yet there is little known
about how discharge (Q) variability impacts stream CO2 at broad
scales. Herein, we compiled historical water quality (including pH,
alkalinity and temperature) measurements for conterminous USGS sites
and coupled them with daily Q for this analysis (the water_quality.csv
dataset, 10,822 sites). Based on this dataset, NHDplus channel slopes
(NHDplus_slopeSO.csv, 24,764 sites) and hydraulic geometry equations
(lm_vQ.csv, 12,854 sites), we calculated partial pressure of dissolved
CO2 (pCO2), gas transfer velocity (k) and CO2 effluxes (F) for a total
of 813 USGS sites across conterminous US. We derived hydrologic
responses (log-linear regressions) for pCO2, k and F versus Q at each
site and explored how these responses varied across stream order and
different regions. Ancillary datasets provided coordinates
(coor_sites.xls), hydrologic unit code (HUC.csv), and watershed area
of conterminous USGS sites (watersheds_area.csv).