Vernal Pools

What is a Vernal Pool?

Vernal pools are temporary or seasonal bodies of water that typically form in the spring from melting snow and other runoff.  Most pools dry out completely in the hotter months of summer. Vernal pools range from broad, heavily vegetated lowland bodies of water to smaller, isolated upland bodies with little permanent vegetation. They provide a breeding place for many semiaquatic species such as frogs, salamanders, and turtles. Vernal pools provide the eggs and the young of these species a safe place away from many predators, allowing them to develop through their life cycle. In time the young leave the pools before the pools dry up in mid to late summer.

Evidence of a vernal pool being occupied for breeding can only be documented through close observation during a short time period in the spring.

In Maine, vernal pools with high value for wildlife are called significant vernal pools. Not all vernal pool habitats are considered “significant.” In general, a vernal pool is considered “significant” if it has a high habitat value, either because threatened, endangered or rare species use it to complete a critical part of their life cycle or if there’s a notable abundance of specific wildlife. The specific criteria describing a significant vernal are listed in DEP Rules, Chapter 335, and allow these resources to be identified in the field by a person who has experience and training in wetland ecology.

Significant vernal pool habitat includes the vernal pool itself and may include the area within a 250 foot radius of the spring or fall high water mark of the pool, which is considered critical terrestrial habitat.

How Might a Vernal Pool Impact My Project?

Significant vernal pools are a protected natural resource with the State of Maine. Their existence on your property could have an impact on development plans that you may have. State, federal, and some local regulations require that vernal pools be documented in the spring. If they are not documented by doing a search, your project may be held up for the entire year until the following spring, when observation is able to be performed once again.

The standards do not create a mandatory setback or a no-build zone, but do affect what you can do and where you can do it, so it is advisable to plan ahead.

If you are considering a project for 2013, remember to keep your options open by scheduling a vernal pool assessment this April or May to complete these necessary observations. Main-Land is currently scheduling our wetland scientist to complete vernal pool assessments for this spring. Spring is here, so don’t let deadlines pass you by because you missed your opportunity to do your vernal pool assessment.