Construction General Permit
Virginia Stormwater Management Program (VSMP) Authorities are responsible determining CGP permittees’ eligibility to use NPS nutrient credits. Always consult your project’s VSMP Authority prior to purchasing NPS nutrient credits. NPS nutrient credits may generally be used when:
- Less than five acres of land will be disturbed; or
- The post-construction phosphorous control requirement is less than 10 pounds per year; or
- The permittee demonstrates to the satisfaction of the VSMP authority that:
- alternative site designs have been considered that may accommodate onsite best management practices;
- onsite best management practices have been considered in alternative site designs to the maximum extent practicable;
- appropriate onsite best management practices will be implemented; and,
- full compliance with post-development nonpoint nutrient runoff compliance requirements cannot practicably be met onsite. If an applicant demonstrates onsite control of at least 75% of the required phosphorous nutrient reductions, the applicant shall be deemed to have met the requirements.
Restrictions for CGP where local nutrient TMDL or impaired waters are present
9VAC25-900-91, which imposes additional restrictions on the use of nutrient credits, went into effect on January 1, 2021. The regulation includes provisions to protect local water quality by limiting the use of credits in areas with local nutrient TMDLs or with waters that are impaired for benthics, nutrients, dissolved oxygen, or chlorophyll, but do not have a TMDL in place to address these impairments. Guidance on Local Water Quality Protections for Nonpoint Source Nutrient Credit Use for Regulated Land Disturbing Activities is provided in DEQ GM21-2007.
DEQ has also developed the NPS Nutrient Trading Data Viewer, a web-based mapping tool that will aid in decision making for all stakeholders. The Nutrient Trading Data Viewer is available at:
https://experience.arcgis.com/experience/21b967a192c44fb89941c8265d430e39
Below is information on how the regulations should be implemented. For additional information, please see 9VAC25-900-91.
Existing Projects: Letters of Credit Availability dated before January 1, 2021, should be honored by the VSMP authority if they are in the same or adjacent 8-digit HUC as the land disturbing activity (LDA). If the letter of credit is no longer valid because the bank has sold out, the permit applicant will be required to follow the new regulations in 9VAC25-900-91.
New Projects: All land disturbing activities without letters of credit availability dated before January 1, 2021, must follow the new regulations as follows:
- The discharge from a LDA should be traced on the NPS Nutrient Trading Data Viewer to determine if and where the discharge reaches an area with an applicable impairment.
- If the LDA is in an area covered by a local nutrient TMDL, trace the discharge from the project until a) it reaches a stream with a relevant impairment or b) it leaves the TMDL area.
- The project must acquire credits generated upstream from where the discharge reaches impaired waters. (Note that the credit-generating bank must be upstream of where the discharge from the LDA reaches the impaired water, not necessarily upstream of the LDA itself. In some instances, the LDA discharge will travel through unassessed or unimpaired streams before reaching an impairment.)
- If the discharge leaves the TMDL area without reaching an applicable impairment, credits may be acquired from the same or adjacent 8-digit HUC.
- If the LDA is outside of a local nutrient TMDL, the discharge should be traced to the first assessed waterway. If this waterway has no applicable impairment as shown on the NPS Trading Data Viewer, credits may be acquired from the same or adjacent 8-digit HUC within the same tributary.
- If the LDA discharges to an area with an applicable impairment as shown in the NPS Nutrient Trading Data Viewer, credits should be acquired in accordance with the following hierarchy:
- Upstream of where the discharge reaches impaired waters, if credits are available;
- Within the same 12-digit HUC, if credits are available;
- Within the same 10-digit HUC, if credits are available;
- Within the same 8-digit HUC within the same tributary, if credits are available;
- Within an adjacent 8-digit HUC within the same tributary, if credits are available; or
- Within the same tributary.
- At no point should a project be allowed to acquire credits outside of the tributary (tributary boundaries as shown in the NPS Nutrient Trading Data Viewer).
VSMP Authorities may also restrict the use of NPS nutrient credits if the locality has determined nutrient trading is in contravention of local water quality-based limitation. Circumstances where a VSMP Authority may determine the use of NPS nutrient credits is in contravention of local water quality-based limitations may include:
- The VSMP Authority has adopted stormwater ordinance provisions more stringent than 9VAC25-870-69.
- The VSMP Authority has a municipal separate storm sewer system (MS4) program plan accepted by DEQ that is more stringent than 9VAC25-870-69.
- Locality has identified watersheds deemed necessary to protect public water supplies from demonstrated adverse nutrient impacts.
Once the VSMP Authority confirms eligibility for NPS nutrient credit use and the construction activity’s available nutrient banks are determined, nutrient bank brokers may be contacted for credit pricing and letters of credit availability
