Solute concentrations in atmospheric deposition and stream water were measuredfrom 1984 through 1993 to determine the fate and mobility of solutes in twogauged mixed-conifer catchments (Tharp's and Log creeks) located in theSierra Nevada, California. The two catchments contain mature forest standsdominated by Abies concolor (white fir), Sequoiadendron giganteum (giantsequoia), Abies magnifica (red fir) and Pinus lambertiana (sugar pine).Ammonium, Cl-, Ca2+ and NO- 3were highest in concentration of the solutes measured in wet deposition;bulk deposition was highest in SO2- 4, NH+ 4,Cl- and H+. Net retention ofH+, NO3 -, NH4 +,SO4 2- and Cl- occurred in both catchments.Discharge was dominated by spring snowmelt with the largest export yieldsfor acid neutralizing capacity (ANC), SiO2, andCa2+. Export yields of H+,NO3 -, NH4 + and PO4 3-were relatively small (0.5 kg ha-1 y-1).Discharge-concentration relationships for ANC, SiO2,Na+, K+, Ca2+ andMg2+ were inverse and their concentrations in stream waterwere primarily influenced by discharge and annual differences in the relativecontributions of snowmelt and groundwater. The mobility of these solutes iscontrolled by the rates of mineral weathering and ion exchange. The positiverelationship of SO4 2- concentration with increasingdischarge suggests that atmospherically deposited SO4 2-is temporarily stored and that its release is controlled by the extent of soilwater flushing.