Interdisciplinary Climate Change Expedition (ICCE): Impacts of glacial ice recession on the chemical, physical and biological properties of the upper Dinwoody Creek, The

Global climate change has exacerbated the recession of glaciers throughout the world, resulting in some instances in increased glacial runoff. In the short term this may be seen as a positive consequence for downstream users. Increased flow can lead to an increase in biodiversity-including macroinvertebrates, and increased water availability for people, animals, and vegetation. A change in discharge can also impact the physical, chemical, and biological properties of the water. Increased meltwater can result in a higher flow rate, which can increase erosion. Chemical constituents stored in the ice for centuries, or deposited from recent pollution may also be released. On Dinwoody Creek, fifteen macroinvertebrate grab samples and two composite samples were removed from two 100-foot long runs. Analysis identified the presence of several benthic macroinvertebrate genera including: Zapada oregonensis, Cinygumula spp., and Ameletus spp. Eight riffle sites were also sampled to measure chemical parameters. The results across all eight sites varied little, and indicated good to excellent water quality. The average temperature was 5.6⁰C, average electrical conductivity 7.4 µS, nitrate values were no greater than 0.23 mg/L, average dissolved oxygen equaled 7.1 mg/L, and the average pH was 6.5. Over time, with continual reduction of glacial ice, chemical measurements are expected to include values indicative of broader changes in source ice volume. Future research includes additional macroinvertebrate and chemical sampling and assessment, and additional sampling to assess the presence/absence of E. coli.