5.7 Phosphorus Load Reduction

One of the water quality goals for this subwatershed is the achievement and maintenance of the Christmas Lake in-lake phosphorus concentration goal of 15 μg/L.  The primary means of achieving and maintaining that goal will be limiting new phosphorus loads from development and other sources through the regulatory program, loading reduction allocations to LGUs, and operational programs.  Table 13 below sets forth a summary plan for how this could be accomplished.

The table breaks down modeled phosphorus loading in the subwatershed by source: atmospheric deposition, external sources, and internal sources.  Atmospheric deposition is a regional issue and is not dealt with here.  The primary means of addressing external loading are through the regulation of new loads generated by development and the reduction of existing loads through the general application of BMPs.  Application of the current regulatory program to new development would also reduce the expected load from ultimate development conditions. 

Table 13.  Phosphorus load reduction plan for Christmas Lake.

Source 

Reduction 

Ultimate Phosphorus Load[lb/yr]  

Planned Reductions [lb/yr]  

Final Loading
[lb/yr]
 

Atmospheric 

Atmospheric Deposition

NA

62

NA

62

External Loads 

External Load Determined from Modeling Land Use

 

76

 

 

 

LGU allocation (Table 12)

-

10

 

 

Existing regulations

 

1

 

Total After Reductions

 

 

 

65

Internal / "Unknown" Loads 

 Internal / "Unknown"

 Loads Determined from   

 Modeling Land Use

 

0

 

 

 

 Internal Load

 

-

 

 Total After Reductions

 

 

 

0

Total Load 

 TOTAL 

 

138

11

127

 LOAD GOAL  

 

 

 

135

 DIFFERENCE 

 

 

 

(-8)