This earthcache was set up for SEMAG Meet & Greet #100 - The Centennial Event (GCA56E4). Special thanks to groopsoop for the help with the earthcache description!
Vernal pools may look inviting, but don’t dive in! First, they are rarely deeper than four feet, so diving could be hazardous to your health! Secondly, most states, including Massachusetts, have laws that protect these pools from any potential damage, even unintentional. Thirdly, they are usually only around during the cooler/colder months of fall, winter, and spring: by summer, most have dried up (although there are exceptions that can remain for over a year). This occasional drying prevents fish from establishing permanent populations. The resulting vernal pool habitat, with its absence of fish, is critical to the reproductive success of many amphibian and invertebrate species that rely on breeding habitats that are free of predators. It also benefits other organisms such as the fairy shrimp, which spend their entire life cycles confined to the vernal pool habitat.
In general, 90 or more consecutive days of water are needed over the winter and spring to allow insect and amphibian larvae to develop. A shallow wetland with a limited watershed⊃2; in a sunny location is likely to dry up every year and may not provide enough time for salamander and frog larvae to develop. However, a deep wetland with a large watershed in a shaded location may never go dry. Once the water is gone, it may be difficult to identify the area as a vernal pool. Some clues that may alert you to the presence of a seasonally dry pool include: dark stained leaves, caddis fly larvae cases, fingernail clams, aquatic snails, bright green sedges (grass-like plants), and a lack of trees growing in the depression. Because of its temporary status, two people visiting the pool at different times of the year may see very different evidence of the pool; in fact, some will see no pool at all!
Vernal ponds are good for the physical environment as well. They help protect watersheds by capturing and holding water, allowing time for the water to seep into the surface and recharge groundwater supplies. This reduces the amount of water runoff, lessens erosion, and decreases the potential for flooding. Vernal ponds also capture sediment, thereby protecting water quality in nearby streams and rivers.
Geological factors
Vernal pools are geologic depressions that can form in a variety of ways. According to Pennsylvania Natural Heritage Website, the geological factors include:
- Floodplains - when a stream overflows its banks entering the floodplain. Some of the overflow pockets do a good job of retaining water and become vernal pools. If this continues over the years it can lead to the creation of vernal pool habitats in the form of oxbow wetlands.
- Glaciers - glaciers created many isolated depressions through freezing, thawing and erosion that fill with rainwater and snowmelt. This process is similar, in fact, to the way in which kettles are created.
- Sag Ponds - sag ponds form when surface water gathers in depressions formed by easily dissolved bedrock (such as limestone) underneath an impermeable soil layer. Eventually the soil sags and water gathers in the depression.
- Pingos – Pingos are formed by freezing and thawing processes on moist mountainous slopes. The upper layers of soil thaw first and slowly slide over the underlying frozen soil. The result is a landscape peppered with crescent-shaped wetlands.
- Human Activities - some vernal pools are created deliberately by people who wish to create wildlife habitat or to replace a seasonal wetland that was destroyed. Other pools are inadvertently created during any kind of surface disruption (mining, roadside ditches, agricultural fields, etc.) that creates shallow depressions that hold water long enough to support seasonal pool wildlife.
When a vernal pool obtains official certification status in Massachusetts, it is protected under the Wetlands Protection Act (WPA) regulations. The protections under this law often extend to up to 100 feet beyond the pool’s boundaries. Certified pools also receive protection under the
following:
Title 5 of the Massachusetts Environmental Code
Section 401 of the Federal Clean Water Act
The Massachusetts Surface Water Quality Standards which relate to Section 401, and
The Massachusetts Forest Cutting Practices Act.
Definitions:
Vernal pools: (also known as ephemeral pools, autumnal pools, and temporary woodland ponds), are depressions in woodland areas that typically fill with water in the autumn or winter due to rainfall and rising groundwater.
Watershed: an area of land that contains a common set of streams and rivers that all drain into a single larger body of water, such as a larger river, a lake or an ocean. Through our watersheds, pollution is distributed far away from its original source.
Logging Requirements
1) As you stand near the area of the vernal pool consider the geological factors listed above that may have formed it and decide which one is most likely to have occurred. Provide visible, physical evidence that contributed to and supports your decision.
2) At the time of your visit, what is the length, width, and approximate depth of the pool?
3) Please upload a photo of you or a geocaching item at or near GZ as a proof of visit.