USING SPREADSHEETS TO PREDICT STREAM SALINITIES IN THE YAMPA RIVER BASIN COAL FIELDS, NORTHWESTERN COLORADO

摘要

Spreadsheets were used for predicting stream salinities in the Yampa River watershed. The concentration of total dissolved solids (TDS) represents salinity. The spreadsheets calculate TDS at 22 locations by summing the flow-weighted TDS values upstream from each point. The flow-weighted TDS values were compiled from publicly available monitoring data and from predicted future mining inputs. This spreadsheet method provides only a rough prediction of TDS concentrations because it does not precisely account for non-mining sources like irrigation and municipal runoff. Also, significant error is introduced by the differences in sampling times between locations. Spreadsheets were developed for eight different scenarios with various combinations of moisture conditions (precipitation), season (flow), and pumping of underground mine water to the surface. Calculated TDS values were posted on a GIS map of the watershed for visualizing mining impacts along stream segments. The eight scenarios for the spreadsheets predict the largest percentage increase in TDS occurs when there is uncontrolled mine pumping in a relatively dry year during low seasonal stream flow.