Stormwater Management
In recent years, regulation of stormwater runoff has undergone drastic changes in Vermont. The design, permitting, construction and on-going operation of stormwater management systems are more involved than ever, and require careful consideration as part of the overall project.
The State
of Vermont, Water Quality Division now manages several distinct stormwater
permitting programs. The three major programs are:
Operational
Stormwater Permit (post-construction)
Construction
General Permit (runoff from construction sites)
Multi-Sector
General Permit (for industrial activities)
In
addition, other state agencies (Act 250, Wetlands) and municipalities often
have additional requirements. Navigating the various requirements is entirely
possible, but it does require someone who is intimately familiar with the
process. Long Trail Engineering, P.C. has extensive experience in stormwater
management and its varying permit programs.
This is
the “classic” stormwater permit, and what most people think of when it comes to
stormwater. This program involves stormwater treatment once a project has been completed.
Treatment is required for both quality (sediment removal) and quantity
(detaining peak runoff).
For new
projects, a permit is generally required when a project creates more than one
acre of new impervious surfaces. Impervious surfaces include paved and gravel
surfaces, rooftops, patios, sidewalks, etc.
For
expansions of existing projects, the trigger for requiring a permit can be as
little as 5,000 square feet of new impervious surfaces.
Further
complicating matters, the Water Quality Division now looks at the “common plan
of development” when determining whether a permit is required. If your project
is “linked” to another project by virtue of a state or local permit, then the
total impervious area for the entire “common plan” must be considered.
Thus, the addition of a new garage to an existing home in a subdivision could
require a permit.
This
permit deals with stormwater runoff from a project while it is under
construction. The goal is to prevent erosion from disturbed soils, and keep
what sediment does erode from reaching streams and rivers.
Projects
are segregated into three risk categories: low, medium and high. The risk
categories depend on the soil type, slope and amount of disturbed soils at any
given time.
Low risk
projects are the easiest to manage and implement, generally by complying with
the state’s low risk erosion prevention handbook. Medium and high risk projects
are more complicated, and require site-specific designs for erosion prevention
and sediment control measures.
This
program deals with stormwater runoff from industrial projects. Most people will
never have to deal with the requirements of this permit.
The goal
of this permit is to reduce to the extent possible the amount of rainfall over
potentially hazardous substances that are part of industrial activity. If you
can manage your site to avoid any rainfall exposure, the requirements of the
program become quite simple.
If not, a
detailed plan for dealing with the exposure is required, among other things.
This is incorporated in a site specific Stormwater Pollution Prevention Plan.
Note: this information is provided for general informational purposes only; please contact Long Trail Engineering, P.C. to discuss how the programs might affect you in particular.