Main-land Development Consultants

Vernal Pools

Vernal Pools

You’ve heard of Vernal Pools. You heard they’re important to the environment. Maybe you’ve heard they have huge setbacks. You’ve probably heard they’re project killers.Fear not! Vernal pools are tricky, but not insurmountable. They might even be an important part of your project. Please read on to find out why.

What's a Vernal Pool?

Vernal pools are shallow forested depressions that are seasonally inundated with water. They dry up in the summertime. Vernal pools are not part of a stream network but are hydrologi-

cally isolated. Vernal pools can be found anywhere in Maine, from lowland wetland areas to hilltop summits. 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 scientist who has experience and training in wetland ecology.


Why Are they important?

Vernal pools are considered an important natural resource by the Maine DEP and the US Army Corp of Engineers. Vernal pools provide a breeding place for many semiaquatic species. 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. Vernal pools are important to landowners for their natural benefits and for the regulations associated with them.


Vernal pool regulations come with some requirements for landowners. For starters, they have a 250 foot setback. Land impacts in the donut area from the 100’ setback to the 250’ setback is limited to 25%. In the past, the Army Corp’s second setback was 750 feet. As such, vernal pools could limit 40 acres of property! The Corp has since reduced their rules to match Maine’s 250’, which limits about 4.5 acres. With these and other regulations, vernal pools are a critical land feature to delineate.


Time Constraints

Vernal pools are only definitively delineated in the spring (vernal means spring) because they’re

only identifiable when there’s water and specific wildlife in them. From about mid-April to mid-May, we’re busy mapping vernal pools for landowners. This is a very limited time window to do this important field work. If you have property and are thinking about a project, call Main-Land right now at 207-897-6752 to schedule a vernal pool screening in the fast approaching upcoming spring season. What if you’re too late? What if you need to do a project but it’s after the vernal pool season?



You can still get your project mapped, designed, and permitted, even if you’ve missed the vernal pool season. We can screen your property for vernal pools outside the screening time window. If we observe no depressions which might meet a the criteria, we can make a finding that your property has no vernal pools. If we find such a depression, we will label it a “potential vernal pool.” In design and permitting, a “potential vernal pool” will be designed around and treated as if it were a real vernal pool. In this way, you won’t lose a year of schedule. This strategy assumes the worst case scenario: it is a vernal pool. If it ends up not meeting the criteria, you’ll have missed out on permitting land use on otherwise valuable developable land. This is where strategy comes into play. Would you rather lose the time or the developable property? It could turn out to not be a vernal pool.



Vernal pools can have a detrimental impact on a landowner’s right to use their land to its highest and best use. They can chew up a lot of land area. But they’re not all bad. I grew up near a vernal pool. As children, we caught turtles, chased frogs, and generally had a great time there. We were lulled to sleep in the spring to the music of the peepers. A vernal pool may not be the detriment you thought, but rather an intrinsic land feature important to the people who occupy the land.

One way or the other, vernal pools are important land features which must be identified
and delineated by landowners.
Multiple rules from multiple agencies govern land use on and around vernal pools. Impacts to vernal pools, however inadvertent, will double application fees and may incur penalties. Call Main-Land today at 207-897-6752 for more information and to schedule a vernal pool screening.

Have more questions?