4.3 Chemical and isotopic composition
As the snowpack started to melt in the catchment in late May 2019, the
alkalinity at GS1 briefly fell, and spring water became depleted in
deuterium (Figure 8E). This suggests the contribution of snowmelt water
to the springs through infiltration, as water levels were rising (Figure
8B). However, once water levels reached a maximum in the lake on June 4,
spring temperature and alkalinity began to increase, and isotopic
compositions became less negative (Figure 8D). This could be due to the
increased hydraulic gradients forcing pre-melt groundwater out at the
springs. After July 10, alkalinity decreased with falling water levels
(Figure 8).
Water samples were collected in the three spring branches and on the
north shore of Hathataga Lake between August 7 and 14, 2019; and
analyzed for alkalinity and major ions (Figure 9). The lake had an
alkalinity of 1.8 meq L‑1, which was most similar to
S1, the warmest spring branch, and most dissimilar to S3, the coldest
spring branch.