Appendix 5. Calculation of Trading Values for Phase
and Phase II
The total agricultural
load,
was estimated at 52,200
P and
N based
1982 nutrient budget conducted by DEM (NCDEM,
593,000
1982). The percent of the total load attributable to animals, A, was estimated at
69
P and 57 percent for N, based on mass balance models (Craig and
Kuenzler, 1983). The treatment effectiveness for both N and P was estimated at
50 percent, based on the results of a BMP effectiveness study in Fiorida
(Heatvvole et al., 1986) and on values used by the state of Virginia (Virginia Water
treated was calculated as 20
Control Board, 1985). The percent of
percent, based on 1987 North Carolina Agricultural Statistics and state cost-share
program records.
Management Practices
DEM used the following equation to estimate nitrogen and phosphorus load
reductions from
I
where
1989 total P (or N) load reduction attributable to cropiand
1982 total P (or N) load attributable to agricultural
sources
A=
Percent of
attributable to crops
Treatment effectiveness for
=
Treatment effectiveness for acres affected for acres affected by water
control structures
Percent of harvested
treated with
only
Percent of harvested
treated with
and water
control structures.
and A were estimated as discussed above. The treatment
The values for
effectiveness for
was assumed to be 30 percent. Since very little
BMP effectiveness monitoring had been conducted at that time, this value was
based on the best professional judgment of agricultural researchers at North
Carolina State University (NCDEM, 1982). The treatment effectiveness of crop
management practices with water control structures was estimated at 60 percent,
based on published monitoring results for urban detention basins, assuming 48
hours of settling (Schueler, 1987). The percent of land treated for each practice
(C, and
was determined from State cost-share data.
After using the above equations to calculate load reductions, these values were
divided into the total cost-share expenditures to determine cost per kilogram.
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