Why Manage Stormwater?

Healthy rivers and lakes provide sources of drinking water, recreation, and aesthetic beauty. However, pollutants such as phosphorus, sediment, and hydrocarbons can degrade the water quality.

Stormwater runoff carries pollutants.  Stormwater – rainwater or snowmelt – does not soak into developed surfaces, such as paved or compacted gravel roads, parking lots, or rooftops. Instead, it flows over these surfaces, directly into local waters, carrying pollutants with it.

Vermont’s ‘3-acre Rule’

In order to meet water quality goals, Vermont has adopted a new stormwater rule. Parcels with more than 3 acres of developed (impervious) surfaces will now need a permit – even if they didn’t need a stormwater permit before. Properties that don’t comply may be fined, though monetary credit opportunities exist when stormwater management goals are exceeded.

Managing stormwater will have local and downstream benefits. Local impacts include flood reduction, as well as swimming hole and fishing preservation. Downstream, Lake Champlain will receive fewer pollutants and experience improved water quality.

If you have received a notification from Vermont Department of Environmental Conservation that your property will now need to treat stormwater, we can help.

Details of the Rule

The details of the rule are complex. Watershed can navigate the details and tailor solutions to your site – no matter how complex.

‘First Flush’ (Water Quality Volume – WQv)

The ‘first flush’ of stormwater carries the most pollutants – usually in the first 1” of rainfall. 50% of the first 1” of rain must be treated. There are two options:

  • Treat 50% of the runoff from the site:
  • Treat 100% of runoff from half the site:

Groundwater Replenishment (Recharge Volume – Rev) and Stream Erosion (Channel Protection Volume – CPv)

The rule also requires replenishing groundwater and managing stream-eroding rainstorms. Not complying can cost up to $25,000/acre.

Management Practices

Watershed can help you identify solutions by:

  • Assessing site conditions
  • Conducting Engineering Feasibility Analysis (EFA)
  • Reviewing permit needs and costs/benefits
  • Overseeing design and implementation of management practices

Possible solutions include:

  • Permeable pavers or porous asphalt:
    • Allow stormwater to infiltrate into the ground, reducing runoff.
    • No additional space is required; it replaces traditional paving material.
  • Green infrastructure:
    • Water is slowed and pollutants are removed.
    • Contributes to interesting landscape features.
  • Cisterns and subsurface storage chambers
    • Allow for use of non-potable water for other purposes.
    • Stores water for slow release.
    • Additional space is not required for some practices; parking lots can be built above the chambers.

Please reach out to us with your stormwater permitting questions.