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.

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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