Tierra Group developed a water balance model to track flows into a backfilled pit at the closed Big Ledge Mine Barite Operation near Wells, Nevada. The Model was used to determine pipeline sizing to a remote treatment pond that is used to dispose of flows through water treatment and evaporation. The water balance model included treatment pond for sizing, assessing evaporation rates at two different elevations, as well as the impact of elevated total dissolved solids (TDS) content on evaporation rates.