Virginia Administrative Code › Title 9 - ENVIRONMENT › Agency 25 - STATE WATER CONTROL BOARD › Chapter 720 - WATER QUALITY MANAGEMENT PLANNING REGULATION › Section 9VAC25-720-40 - Implementing Nitrogen and Phosphorus Waste Load Allocations in the Chesapeake Bay Watershed

Current through Register Vol. 40, No. 24, July 15, 2024
A. Nitrogen and
				phosphorus waste load allocations assigned to individual significant
				dischargers in
				9VAC25-720-50
				C,
				9VAC25-720-60
				C,
				9VAC25-720-70
				C,
				9VAC25-720-110
				C, and
				9VAC25-720-120 C
				may be exchanged in accordance with the Chesapeake Bay Watershed Nutrient
				Credit Exchange Program established under Article 4.02 (§ 62.1-44.19:12 et
				seq.) of Chapter 3.1 of Title 62.1 of the Code of Virginia. Exchanges must
				account for the delivery factor applicable to each discharge based upon its
				location within the river basin and calculated by the Chesapeake Bay Program
				watershed model.
B. The nitrogen
				and phosphorus waste load allocations assigned to individual significant
				dischargers in
				9VAC25-720-50
				C,
				9VAC25-720-60
				C,
				9VAC25-720-70
				C,
				9VAC25-720-110
				C, and
				9VAC25-720-120 C
				are considered to be bioavailable to aquatic life. On a case-by-case basis, a
				discharger may demonstrate to the satisfaction of the department that a
				significant portion of the nutrients discharged by the facility is not
				bioavailable to aquatic life. In these cases, the department may limit the
				permitted discharge to reflect only that portion of the assigned waste load
				allocation that is bioavailable. Such limits shall be consistent with the
				assumptions and methods used to derive the allocations through the Chesapeake
				Bay watershed and water quality models.
C. Unless otherwise noted, the nitrogen and
				phosphorus waste load allocations assigned to individual significant
				dischargers in
				9VAC25-720-50
				C,
				9VAC25-720-60
				C,
				9VAC25-720-70
				C,
				9VAC25-720-110
				C, and
				9VAC25-720-120 C
				are considered total loads including nutrients present in the intake water from
				the river, as applicable. On a case-by-case basis, an industrial discharger may
				demonstrate to the satisfaction of the department that a significant portion of
				the nutrient load originates in its intake water. In these cases, the
				department may limit the permitted discharge to reflect only the net nutrient
				load portion of the assigned waste load allocation. Such limits shall be
				consistent with the assumptions and methods used to derive the allocations
				through the Chesapeake Bay watershed and water quality models.
D. The board may amend this regulation to
				adjust individual nitrogen and phosphorus waste load allocations. Reasons for
				considering such an adjustment include, but are not limited to:
1. A discharger completes or does not
				complete a plant expansion as evidenced by issuance of a Certificate To Operate
				by December 31, 2010; or
2. A river
				basin nutrient load allocation is not achieved.
Any adjustment to an individual waste load allocation must
				  ensure water quality standards are maintained.