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Storm Water Grandfathering - What Does it Really Mean?

By Greg Koontz, PE, President, Koontz-Bryant, P.C.

The new state stormwater regulations passed in 2014 have complicated the design process and increased construction expense for site development projects. Design professionals are finding it difficult to determine which treatment methods local jurisdictions will allow for compliance. Currently many of the regulations and requirements have not been finalized and are in various draft versions for the design community to try and figure out..

In 2013, as the design and development communities braced for the issuance of revised regulations, grandfathering projects was at the top of everyone’s mind. Throughout 2013 our firm worked to grandfather our clients’ current and future work to the old stormwater regulations. Projects that were successfully grandfathered prior to the 2014 regulations taking effect are currently allowed to use PART II C of the current regulations that contain the requirements from the 2009 VSMP permit.

Pre 2014

Prior to the 2009 VSMP permit cycle, almost all the state requirements for development were either in the Erosion Control Manual or the two-volume State Storm Water Manual (Blue Book). In 2009 the state changed course and added several design requirements within the VSMP permit: the requirements for detention and water quality (outside Chesapeake Bay areas) statewide. Because the permit had never previously been used to require specific project design criteria, many localities and design firms did not realize that these requirements had been put within the VSMP Permit. These criteria were inconsistently enforced, if at all, unless the DEQ came directly to your site and requested supporting information. Some of the jurisdictions were even at odds with the state and did not want to require detention under certain conditions, which added even more confusion to the process.

Post 2014

Today the DEQ has turned over the management of the Stormwater Program to the local jurisdictions, similar to the process used with the Erosion Control Program. With both programs, the DEQ provides only guidance and audits the local jurisdictions for compliance with the regulations. As local jurisdictions implement their Stormwater Programs (some localities are still being managed by the DEQ) and come up to speed with the new regulations, they have become more consistent at understanding and enforcing the stormwater requirements under the grandfathering provision. Since grandfathering for a project only goes back to the 2009 regulations, older developments that have been worked on for years without any detention requirements will now have detention, and projects outside the Chesapeake Bay Preservation Area will have water quality requirements. So what are the real differences between grandfathered projects and ones using the current 2014 regulations?

2014 VSMP Regulations

Flood Control – 10/10 Detention
Channel Protection – Energy Balance with Improvement Factor
Water Quality - 0.41 lb/ac/yr

2009 VSMP Regulations

Flood Control – 10/10 Detention
Channel Protection – MS19
Water Quality - 0.45 lb/ac/yr

The two biggest differences are the channel protection requirement using the new energy balance equation, and that turf areas are now counting against you for water quality. So if you have a project and have been told it is grandfathered, be aware that today it may look a lot like a project that was not grandfathered; you may see detention and water quality requirements being enforced on future phases when they were never required in the past. If you have concerns or questions regarding your projects please contact Greg Koontz, PE at 804-200-1901 or via email.