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MODEL SIMULATION STUDIES OF SCALE-DEPENDENT GAIN IN STREAM NUTRIENT ASSIMILATIVE CAPACITY RESULTING FROM IMPROVING NUTRIENT RETENTION METRICS
Citation:
FAULKNER, B. R. MODEL SIMULATION STUDIES OF SCALE-DEPENDENT GAIN IN STREAM NUTRIENT ASSIMILATIVE CAPACITY RESULTING FROM IMPROVING NUTRIENT RETENTION METRICS. Presented at 2nd National Conference on Ecosystem Restoration, Kansas City, MO, April 22 - 27, 2007.
Impact/Purpose:
To inform the public.
Description:
Considering the difficulty in measuring restoration success for nonpoint source pollutants, nutrient assimilative capacity (NAS) offers an attractive systems-based metric. Here NAS was defined using an impulse-response model of nitrate fate and transport. Eleven parameters were examined, along with interaction effects. Literature search was used to determine their distribution functions. A multifactorial simulation design was employed, and the response of the system was the NAS as total fraction of nitrate impulse attenuated. For reaches less than 200 m, increases in dispersion and volume of storage region caused a negative gain on NAS, but positive for longer reaches. This means that for shorter reaches greater mixing caused more nitrate to be flushed through the system but longer reaches behaved more like well-mixed reservoirs. Denitrification increased NAS in these systems. For reaches longer than about 400 meters the positive effect of increasing storage volume became more important than that of increasing denitrification potential. These results imply that restoration techniques that add bioavailable carbon sources may be more effective at enhancing NAS than increasing mixing with ground water, but in longer reaches the reverse may be true.