SCENARIO 4 – Total phosphorus reduction of 90%
The only realistic way seen to achieve the 90% phosphorus load reduction is to plant all
of the cropland in the watershed to perennial crops. This practice would lead to an 88.5%
reduction in P. To reach the reduction goal, however, the proposed or slightly smaller
sedimentation basin would need to be built.
Plan – Total P reduction only
Practice Area (ha) TP Reduction
(kg/yr)
30-yr Cost
(2007 basis)
Annual Cost
kg-1 reduced
Annual Cost
lb-1 reduced
Perennial
crops
16,888 5,666 $379,980,000 $2,235.44 $1,013.99
Proposed
sedimentation
basin
16,478 314 $4,523,500 $480.20 $217.82
TOTAL 5,980 $384,503,500 $2,143.27 $972.18
These practices would not only reduce the P load by 93% but would also reduce the N
load by 79% making the overall nutrient reduction cost per unit somewhat more
reasonable. In these combined nutrient reductions it is not possible to assign costs to each
nutrient individually.
Plan – 93% total P reduction + 79% total N reduction
Practice Area (ha) Nutrient
Reduction1
(kg/yr)
30-yr Cost
(2007 basis)
Annual Cost
kg-1 reduced
Annual Cost
lb-1 reduced
Perennial
crops
16,888 315,787 $379,980,000 $40.11 $18.19
Proposed
sedimentation
basin
16,478 20,530 $4,523,500 $7.34 $3.33
TOTAL 336,317 $384,503,500 $38.11 $17.29
1Nutrient reduction for combined total P and nitrate is the sum of both nutrients
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