Samples were collected in triple DI-washed 500 ml polyethylene bottles from 14 sites distributed around the terminus of the Canada Glacier and 4 sites located on the east side of the Seuss Glacier terminus. Water was collected from the ground, catching waterfall flow mid-air before reaching the proglacial stream. Samples were brought back to the field camp where water was distributed into a 20 ml glass scintillation vial, two triple DI-washed 60 ml polyethylene bottles, and a 20 ml plastic scintillation vial. Both scintillation vials were stored at 4º C and the two 60 ml bottles were frozen at -20º C. An additional 120 ml was poured into a clean glass beaker to measure pH and electrical conductivity. One of the 60 ml bottles was thawed at 4º C in the Crary Lab and analyzed by ion chromatography for Cl^-, Ca²⁺, Na⁺, K⁺, Mg²⁺, and SO₄^-. The second 60 ml bottle was shipped back to Boulder, Colorado where it was thawed at 4º C and analyzed by Latchet for N (as NO₃^- + NO₂^-) and using a colorimetric method for Si in the Arikaree Lab. The remaining sample was brought to the Crary Lab at McMurdo Station and filtered using a pre-weighed GF/F filter to capture sediment. Bottles were thoroughly rinsed to ensure all sediment was captured on the filter. Filters were then dried and weighed to determine sediment mass. All sample water was accounted for in calculating the sediment concentration of each sample. Samples were analyzed for water isotopes using cavity ring-down spectroscopy on a Picarro in the Barnard Lab at the University of Colorado Boulder

Contributing areas to each waterfall were calculated using a MD-Infinity flow routing algorithm on a sink-filled 1 m lidar-derived DEM.