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Simplifying the New Stormwater Regulations: Will You be Affected?

By Matt Faris, PE, Project Manager, Koontz-Bryant, P.C.

An article in a recent newsletter discussed why getting a Stormwater Permit now was a good idea. We continue to give that advice, and we are working with our existing clients and our newest ones to take advantage of the grandfathering feature that the Commonwealth has approved.

Let’s take a closer look. The differences in the current requirements and the new requirements for Stormwater quality control are:


Current requirements

New requirements as of July 1, 2014

Land Use Classes used to determine existing conditions

Impervious Surface (buildings, parking lots, sidewalks)

Forest, Open Space, Turf and Impervious

Rainfall that is "tainted" by scrubbing the surface, requiring treatment

the first one-half inch of rainfall

the first one inch of rainfall

Required phosphorous removal

A percentage based on initial land cover

A percentage with an absolute maximum of  0.41 pounds per acre per year

Phosphorous removal  (redevelopment)


same, unless area is over 1 acre, then 20%


Simple. Design Manual, standard BMPs

Designs based on runoff reduction and a clearinghouse with oversight by a committee of 15 experts in the field


What does this mean to anyone who will develop or re-develop land?

Land Use: Until now, the sole factor that required any water quality analysis was whether there was any increase in impervious cover. After July 1, changes that have no new impervious cover may require water quality improvement, even a change from turf to forest or a landscaped area.
Rainfall: Now, the first half-inch of rain is considered affected by the scrubbing of the surface, requiring capture and treatment. After July 1st, this amount will double, requiring larger basins, etc.
Required removal: There will be an absolute maximum allowable discharge of phosphorous after July 1, regardless of the method used or the efficiency of the chosen method.
Redevelopment: After July 1, the amount of phosphorous removed will double if the area is over one acre. This will require larger and/or more expensive structures to meet the new requirements. This will particularly impact the re-development of mid-size to large commercial sites.
Methodology: Current design standards are objective, simple to implement and gain approval by local authorities. New standards will allow for more unique designs, perhaps better suited to specific situations, but will also require a continuous method of review and oversight. It will be more subjective.

What else is new?

In addition to these changes to the way we determine Stormwater quality improvements, we will also have to provide Stormwater quantity reductions. Some of the structures that provide the quality improvements discussed above can also provide quantity reduction. Some others cannot, requiring additional facilities to detain runoff for a period of time.
There are also new requirements that will consider the impact on downstream channels, creeks and streams.

How may it affect your project?

In a recent educational seminar attended by Koontz-Bryant staff, an example of a warehouse site was examined. After the new requirements were implemented, the site needed a stormwater management pond that consumed 11% of the site. Other options could include implementing features to reduce run-off, thereby reducing the size of a BMP basin.
The impact to a downstream channel was also considered. In order to reduce the stormwater quantity, the pond would need to reduce the developed runoff approximately 80%. But based on the limits of the downstream channel, the volume reduction was more than 90%! The volume of the pond would need to be much larger in order to satisfy the new requirements related to downstream channels.

Now what?

There are ways to keep ongoing project or new projects grandfathered under the current regulations for up to ten years. As illustrated above, the costs of not being grandfathered could be significant. More area dedicated to stormwater management means less area available to sell or lease. Some uses may no longer fit! In order to keep as many options available as possible, consider looking into this option as soon as possible. If you have any questions or need any further assistance contact Matt Faris, PE at 804-200-1935 or via email.