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

Abstract

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.

Concentration–discharge relationships reflect chemostatic characteristics of US catchments

“…This consistency in b can be ensured by simultaneously fitting all solutes in a given catchment. Johnson et al (1969) suggest that a should be thought of as the 'rainwater' concentration of each solute. However, the best-fit a values exceed measured volume-weighted precipitation concentrations for Ca, Mg and Na [as reported in Mast and Turk Inverse relationship between C and Q as specified by the Hubbard Brook 'working model' (Johnson et al, 1969) generally matches the form for each solute, but best-fit a parameters (Eq.…”

“…Another well-known model that we consider is the Hubbard Brook 'working model' (Johnson et al, 1969) which assumes that discharge is proportional to storage volume (V, [m 3 ]), and that solute concentrations (C, [ppm]) associated with each storage volume are fixed. Storage volume is defined as the subsurface pore space available above an 'impermeable' layer.…”

“…Typical concentration-discharge analyses have centered on mixing models of different source waters (e.g. event and pre-event water; old and new water; or soil water, groundwater and precipitation) inferred from the shape of the concentration-discharge relationship for different solutes (Johnson et al, 1969;Hall, 1970Hall, , 1971. In other studies, researchers have inferred the relative timing of mixing from hysteresis loops observed in concentration-discharge plots (Evans and Davies, 1998;Evans et al, 1999;House and Warwick, 1998;Hornberger et al, 2001;Chanat et al, 2002).…”

Chemistry of precipitation, streamwater, and lakewater from the Hubbard Brook Ecosystem Study: a record of sampling protocols and analytical procedures

“…On the basis of hourly, daily, and weekly sampling during the first 2 years of the study, and because concentrations were weakly correlated with discharge for most solutes, and Johnson et al (1969) concluded that weekly samples were appropriate for characterizing average annual streamwater chemistry. At that time, only concentrations of sodium, aluminum, hydrogen ion (pH), nitrate, and dissolved silica were significantly correlated (slope significantly different from zero, at p < 0.01) with discharge in W-6.…”

Theoretical predictions of observed to expected ratios in RIVPACS-type predictive model assessments of stream biological condition

“…Site-specific predictions.-Most water-chemistry predictive models have been developed to make predictions at single sites. The pioneering work of Johnson et al (1969), who modeled stream water chemistry as a joint function of soil water and precipitation with empirically derived parameters, led to much of the later research that explored both empirical and physical modeling approaches. However, physical modeling quickly became the dominant approach once the Birkenes Model had been developed (Christophersen et al 1982).…”