Dynamic model of in-lake alkalinity generation
In-lake alkalinity generation (IAG) is important in regulation of alkalinity in lakes with long residence times, particularly seepage lakes. An IAG model based on input/output modeling concepts is presented that describes budgets for each ion involved in alkalinity regulation by a single differential equation that includes inputs, outputs, and a first-order sink term. These equations are linked to an alkalinity balance equation that includes inputs, outputs, IAG (by sulfate and nitrate reduction), and internal alkalinity consumption (by ammonium assimilation). Calibration using published lake budgets shows that rate constants are generally similar among soft water lakes (k/sub SO/sub 4// approx. 0.5 m/yr; k/sub NO/sub 3// approx. = 1.3 yr/sup -1/; k/sub NH/sub 4// approx. 1.5 yr/sup -1/). Sensitivity analysis shows that predicted alkalinity is sensitive to water residence time, but less sensitive to modest changes in rate constants. The model reflects the homeostatic nature of internal alkalinity generation, in which internal alkalinity production increases with increasing acid input and decreases with decreasing acid inputs of HNO/sub 3/ or H/sub 2/SO/sub 4/.
- Research Organization:
- Univ. of Minnesota, Minneapolis (USA)
- OSTI ID:
- 6924836
- Journal Information:
- Water Resour. Res.; (United States), Vol. 24:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACID NEUTRALIZING CAPACITY
MATHEMATICAL MODELS
LAKES
ACID RAIN
ACIDIFICATION
AMMONIUM COMPOUNDS
CALIBRATION
HOMEOSTASIS
NITRATES
SULFATES
ATMOSPHERIC PRECIPITATIONS
CHEMISTRY
NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
RAIN
SULFUR COMPOUNDS
SURFACE WATERS
WATER CHEMISTRY
520200* - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)
500200 - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)