NS 2023 Annual Report For EPA

• IBM Index Class Name: Hydrology
• Doc Date: 8/28/2025
• Archive: No

Natural Soda LLC 2023 Project Status Report& Annual Plan of Development
29 January 2024

NS data indicated a precipitation decrease at the NS location in 2023 (9.81”) compared
to 2022 (10.35”). The 2023 precipitation at NS and was similar to the 2022 (10.35”),
2021 (10.09”), and 2020 (9.79”) values, and approximately half that of 2019 (20.8”). A
similar pattern of annual total precipitation (2019 WY through 2023 WY) can be
observed thorough Piceance Creek Basin. Decreases and increases in precipitation
and/or changes to irrigation diversions may be affecting stream flow discharge at some
level, but it cannot account for the 2023 discharge increase. The increase in discharge
is likely attributable to the measured snow pack levels (Snow Water Equivalent
(Inches)) found in the Yampa-White-Little Snake Basin and the Colorado Headwaters
Basin to the East and Northeast of NS. In 2011 WY the snow pack measurements in
these two basins was similar to 2023 WY and the four streams experienced similar
discharge rates. Figure 8 and Figure 9 below show the difference between 2022 WY
and 2023 WY with regards to snow pack levels in the two basins and the discharge
rates in the four streams. The maximum snow pack for the basins were recorded in
1984, 1985, and 1986 WY’s, this also corresponds to the maximum stream discharge
rates for all four streams.
The 2023 Specific Conductance data from USGS for the four stations were all within the
range values for the period of record. The 6200 (Piceance Creek below Ryan Gulch)
was the only stream location that had a slight increase in Specific Conductance in 2023,
the other three streams had decreases in Max Specific Conductance from the 2022 to
2023 WY. The 2023 water temperature values were within the range of historic PR
data. The water temperatures maximums for all four streams were approximately half
the value of the PR all time maximums. Post review of the USGS data, no effect on
stream water quality or quantity was noted due to the NS mining operations.