Comment on hess-2022-81

Abstract

Large sample datasets are transforming hypothesis testing and model fidelity in the catchment sciences, but few large stream water chemistry datasets exist with complementary streamflow, meteorology, and catchment physiographic attributes. Here, we pair atmospheric deposition and water chemistry related information with the existing CAMELS (Catchment Attributes and Meteorology for Large-sample Studies) dataset. The newly developed dataset, CAMELS-Chem, comprises U.S. Geological Survey water chemistry data and instantaneous discharge over the period from 1980 through 2014 in 506 minimally impacted headwater catchments. The CAMELS-Chem dataset includes 18 common stream water chemistry constituents: Al, Ca, Cl, Dissolved Organic Carbon, Total Organic Carbon, HCO3, K, Mg, Na, Total Dissolved Nitrogen [nitrate + nitrite + ammonia + organic-N], Total Organic Nitrogen, NO3, Dissolved Oxygen, pH (field and lab), Si, SO4, and water temperature. We also provide an annual wet deposition loads from the National Atmospheric Deposition Program over the same catchments that includes: Ca, Cl, H, K, Mg, and Total Nitrogen from deposition [precipitation NO3 + NH4, dry deposition of particulate NH4, + NO3, and gaseous NH3], Na, NH4, NO3, SO₄. We release a paired instantaneous discharge (and mean daily discharge) measurement for all chemistry samples. To motivate wider use by the larger scientific community, we develop three example analyses: 1. Atmospheric-aquatic linkages using atmospheric and stream SO4 trends, 2. Hydrologic-biogeochemical linkages using concentration-discharge relations, and 3. Geological-biogeochemical linkages using weathering relations. The retrieval scripts and final dataset of > 412,801 individual stream water chemistry measurements are available to the wider scientific community for continued investigation.