RPA Mitigation

RPA Mitigation

Tidewater Virginia is a land of peninsulas. Its endless shorelines provide hundreds of miles of rivers, marshes and creeks to explore. Naturally, we’re drawn to all those beautiful views and we want to enjoy them as much as possible, maybe even make them our home. So with all the waterfront development in our area, it’s no surprise that RPA issues arise time and again.

Not familiar with the term RPA? An RPA, or Resource Protection Area, is an area designated for conservation by the Chesapeake Bay Protection Act. Enacted in 1988, this law regulates activity on land that is within 100’ of shorelines, wetlands, and perennial streams in Virginia. Though there are plenty of examples of pre-1988 construction that are now within these protected areas, new construction in RPAs is no longer allowed. If you happen to own one of those pre-1988 houses perched right above of some tidal creek, consider yourself lucky!

Having said that, there are exceptions to the ‘no construction’ rule. Things like clearing vegetation for vistas, installation of fences, and construction of access paths to water are often permitted—pending official review and approval of course. Occasionally even larger encroachments into RPAs are allowed, depending on the special conditions of individual lots. Your local municipality will make that call on that on a case by case basis, and you need to make a very strong case to be granted a construction permit.

At Hertzler & George, we’ve dealt with the regulations of the Bay Act on many projects. As an example of what can be done, let’s take a look at a patio we built in the Kingspoint neighborhood of Williamsburg. 

The lot for this project was planned long before the Chesapeake Bay Protection Act went into effect, and due to the limited buildable space on the lot the house was allowed to intrude into the 100’ stream buffer. In fact the RPA limit ran right through the middle of the house, so the front yard didn't need county approval for landscaping, while the back yard was almost entirely restricted.

For this property, H&G had already worked to address drainage problems in the front yard (read more about that here), but the client also hoped to get more use out of their back yard, which overlooked a beautiful wooded ravine. To give them more space for entertaining and relaxing,  we designed a new patio right off their existing back deck. 

Because Hertzler & George cares about the environment, building in an RPA is not something we take lightly. But for this property, we felt there were some good reasons why the patio might be built:

  • The existing back yard was sloped and unusable for any kind of recreational activity. Creating a flat patio would allow the owners to enjoy their yard

  • This particular lot had a higher percentage of RPA area within the lot compared to most houses in the neighborhood

  • The patio and adjacent walkway provided a paved walking surface from the back to the front of the house, where there previously was none

  • The patio was kept at a reasonable size

For projects like this, the proper way to proceed is to first fill out the necessary paperwork. In James City County, we contacted the Division of Engineering and Resource Protection. The first step was to fill out the county’s Sensitive Area Activity Application. After H&G's application had been reviewed and commented on, it was determined that the project would need to be referred to the county's Chesapeake Bay Board for final approval. At the CBB meeting we presented our plan to the board members and made our case as to why the new patio should be allowed. The Engineering division also weighed in with their recommendation to approve the plan.

To support our case for building within the RPA, we incorporated several mitigation measures into our design. The purpose of the mitigation was to ensure that the storm runoff created by the patio would be equal in quality to the runoff that would be generated in a natural environment (which naturally cleanses stormwater runoff).

Our main solution involved constructing a gravel infiltration trench to filter rain runoff from the patio as well as from parts of the existing roof. To determine the size of the trench, we completed calculations based on typical rainfall and infiltration rates. And to ensure our methods would work, we had the clay soil analyzed to test the percolation rate. Luckily, the results were positive.

The infiltration trench was constructed with pea gravel, sand and drainage stone, as well as perforated pvc pipes. When runoff reaches the trench, it fills the pipes and the voids between the stone and slowly seeps into the ground where it recharges the water table. To keep leaves from clogging up the new trench, we installed leaf guards on the gutter downspouts. 

Another way H&G mitigated the extra runoff from the patio was by installing new plantings to cover the bare, eroding soil in the back yard. Native plants are required for mitigation plantings in RPA’s due to their suitability for our climate and for the habitat they provide for native wildlife, especially our local songbirds. 

For this shady wooded ravine we planted a sweetbay magnolia, dwarf yaupon and sweetspire shrubs, and christmas fern as a groundcover. All these plants help store and filter water.

As you can probably tell from this story, RPAs bring up a lot of tricky issues for homeowners (and even experienced designers!). You should be very cautious before trying to tackle something like this on your own. Your best bet is to call Hertzler & George. With our extensive experience in dealing with environmental regulations, we'll be happy to talk through your project and give you a realistic idea of what to expect and what you can accomplish, while still protecting our critical natural resources.


Hertzler & George

 is a design, build and maintenance firm in Williamsburg, Virginia dedicated to the development of extraordinary gardens and properties.

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Hertzler & George

GreenGuard Associates, Inc

PO Box 457

Williamsburg, VA 23187-0457

tel: (757) 229-9668

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