26.08.11.05

.05 Baseline Requirements.

A. General Policies.

(1) All baselines shall be consistent with the 2010 Chesapeake Bay TMDL, as may be amended from time to time, or, if more restrictive, a local TMDL.

(2) In the event of an amendment to the Chesapeake Bay TMDL, the:

(a) Baseline established in a permit remains in effect until a new permit or a permit modification is issued by the Department; and

(b) Credits calculated with a baseline established under the previous Chesapeake Bay TMDL and approved by the Department prior to the effective date of the amendment shall remain available for sale until the certification period ends for that credit.

B. The baseline for an agricultural nonpoint source shall be determined by the Department of Agriculture in accordance with COMAR 15.20.12.

C. The baseline for a wastewater point source shall be determined by the Department based on an annual loading limit wasteload allocation established in the wastewater point source’s NPDES discharge permit.

D. The baseline for a stormwater point source is the restoration requirement of the stormwater point source’s current NPDES discharge permit.

E. Except as may be revised pursuant to subsequent versions of the Chesapeake Bay Watershed Model, the baseline for a nonregulated source shall be the pollutant load generated under the conditions that existed prior to installation of the BMP, as calculated using assessment tools consistent with the Chesapeake Bay Program modeling tools and accepted by the Department.

F. Except as may be revised pursuant to subsequent versions of the Chesapeake Bay Watershed Model, the baseline load per equivalent dwelling unit for an on-site sewage disposal system is:

(1) 18.56 pounds of nitrogen per year for a system located in the Critical Area for the Chesapeake and Atlantic Coastal Bays;

(2) 11.60 pounds of nitrogen per year for a system located within 1,000 feet of surface water; and

(3) 6.96 pounds of nitrogen per year for all other systems.