Lawrence County, NY has documented distinct changes in pH, buffering capacity, elemental concentrations and LY2109761 solubility dmso ratios, and total dissolved solids along their length during long-term average summer discharge volumes (Chiarenzelli et al., 2012). Water from each of the four major rivers (from west to east – Oswegatchie, Grasse, Raquette, and St. Regis) was sampled at points within the three geologic terranes (from south to north – Adirondack Highlands, Adirondack Lowlands, and St. Lawrence River Valley) during typical (non-event) summer flow conditions. During these sampling events distinct changes in water chemistry were noted

from south to north (i.e. downriver) including an increase in pH (e.g. from 4.67 to 7.49 in the Oswegatchie River watershed), decrease in Al (e.g. 373–25 ppb in the Raquette River watershed),

and increase in Ca (e.g. from 4.6 to 47.6 ppm in the Grasse River watershed). The study concluded that the downriver variation in water GSK J4 datasheet chemistry was related to acidification of the headwaters of these rivers, which are underlain by crystalline rocks with limited buffering capacity (Colquhoun et al., 1981), and subsequent buffering by carbonate lithologies downriver in the Adirondack Lowlands (marble and calc-silicate gneisses) and St. Lawrence River Valley (limestone and dolostone). In this follow up study, the control(s) on water chemistry along the length of the Raquette River was investigated during high and low flow events. Compared to previous work, downriver chemical changes were muted during both stormflow and baseflow conditions (Fig. 5); however, these differences provide additional insight into controls on the hydrogeochemistry of the Raquette River drainage basin. The average specific conductance (Table 2; Fig. 4) was greater during baseflow (41.66 μS cm−1) than stormflow (29.50).

Several elements, on the average, are more concentrated in Raquette River water during stormflow conditions (Table 2; Fig. 3) including Al (3.31x), Ce (4.85x), Fe (2.79x), La (4.44x), Mn (3.70), Nd (3.31x), and Y (3.08). In contrast Ca, K, Mg, Na, Rb, and Sr were slightly more enriched (1.14-1.50x) during baseflow conditions. until The downriver concentration trends of elements and anions can be visually estimated from Fig. 3 and Fig. 4, and were quantitatively evaluated by determining the correlation coefficients (r2) between water concentration and the distance of sampling sites downriver ( Table 2). During stormflow Ba (0.22), Ca (0.70), Fe (0.84), K (0.23), Mg (0.80), Mn (0.80), Rb (0.05), and Sr (0.34) have positive r2 values indicating a general, but variable, trends of increasing concentrations downriver. In contrast Al, Ce, La, Na, Nd, Y, and Zn have negative correlation coefficients ranging between −0.22 to −0.39, indicating a slight decrease in concentration downriver. Similar trends are shown during baseflow with the exception that Fe (−0.10) and Mn (−0.25) show slight decreases in concentration downriver rather than steep increases.