Definition - What does Vernal Pool mean?
Vernal pools are wetlands usually found in forests in the Mediterranean atmosphere of the West Coast and Northeastern and Midwestern states where glaciated areas exist.
These pools hold water only seasonally from rains and are separate from other water systems such as streams and rivers. The delicate ecosystem that inhabits these vernal pools can be protected by using trenchless construction methods such as horizontal directional drilling (HDD) when it is necessary to lay pipelines passing through such areas. HDD is carried out below the ground surface and clearly bypasses any environmentally sensitive locations such as vernal pools and other wetlands.
Trenchlesspedia explains Vernal Pool
Vernal pools provide a unique habitat supporting a variety of organisms, many of which rely exclusively on this environment to complete their life cycle. Though seemingly minuscule, these habitats are essential to a healthy forest ecosystem. There are two types of species that inhabit vernal pools namely, obligate and facultative.
Obligate species depend on the vernal pool for a part of their life cycle i.e. to breed and survive. Their presence indicates that the wetland is a vernal pool. Examples of obligate species are spotted, Jefferson and blue spotted salamander, wood frog and fairy shrimp. Facultative species do not depend on vernal pools but also use other wetlands for their life cycles, however; they can be found near them. Examples of facultative species are green frogs, American toads, red spotted newts and four-toed salamanders.