A Working Model for the Variation in Stream Water Chemistry at the Hubbard Brook Experimental Forest, New Hampshire

Stream water chemistry varies hyperbolically with stream discharge through four decades of discharge change within the Hubbard Brook Experimental Forest, New Hampshire. This dilution process is most simply explained by the mixing of rain water or surface water with deeper soil water. The resultant mixture of waters subsequently appears as stream water. Sodium and silica concentrations in stream water are markedly diluted during high discharge periods while hydrogen ion, aluminum, and nitrate concentrations are increased. Magnesium, calcium, sulfate, chloride and potassium concentrations are changed very little by stream discharge variations. During the summer, biologic activity measurably reduces the concentration of nitrate and potassium in stream water.