.06 Calculation of Credits.

A. Wastewater Point Sources. Credits generated by a wastewater point source shall be based on that wastewater point sourceís performance as follows:

(1) Credits shall be calculated and reported under the terms of the required wastewater discharge permit at the end of each calendar year as the load remaining after subtracting actual annual effluent nutrient load from the performance-based benchmark load; and

(2) The annual effluent nutrient load shall be calculated using the end of the calendar year annual cumulative flow for the facility, multiplied by the actual effluent nitrogen, phosphorus, or sediment concentration converted to units of pounds per year.

B. Stormwater Point Sources and Nonregulated Sources. Stormwater point source and nonregulated source credits shall be calculated using assessment tools consistent with the Chesapeake Bay Program modeling tools and accepted by the Department.

C. Agricultural Nonpoint Sources. Nonpoint source credits generated on agricultural land shall be calculated using the Maryland Nutrient Tracking Tool in accordance with COMAR 15.20.12.

D. On-site Sewage Disposal Systems. Nitrogen credit for an on-site sewage disposal system upgraded with nutrient removal technology is calculated by subtracting the load remaining after upgrade of the system from the systemís baseline load established in accordance with Regulation .05 of this chapter.