Substratum: Most Seasonal Wetlands are underlain with a relatively impermeable substratum or hardpan, frequently underlain with pervious soils.
Organic Accumulation: The presence of a well‑developed organic layer is a feature of Seasonal Wetlands. Generally these pools have persisted since the end of the glacial period and will probably continue in their semi‑open condition for many more thousands of years unless artificially altered. These pools act as traps for organic matter, especially during the autumn when they trap quantities of airborne leaves. The presence of water‑stained leaves in a depression which is otherwise dry is a good indicator that the area temporarily serves to pool water.
Topographical Orientation: Seasonal Wetlands occupy saddles or level ground and, with the exception of pools associated with flood plains, are often adjacent to steep slopes.
Wildlife: A Seasonal Wetland must be free of adult fish populations.
Boundary: Because Seasonal Wetlands are dry much of the year, it may be necessary to determine their boundaries using indicators other than pooled water. Further, because the area inundated varies so widely from year to year, pooled water is not a good indicator of extent. A Seasonal Wetland boundary shall be determined using a combination of pooled water, if present, and by the presence of a depression covered by water‑soaked leaves. Other indicators of the temporary pooling of water, such as the presence of caddis fly cases or fingernail or pea clams, or hydric soils can also be used.
Presumption Where a proposed activity involves the removing, filling, dredging, building in, or altering of a Seasonal Wetland, the Conservation Commission shall presume that such an area, as well as the area within 100 feet of the boundaries of said Seasonal Wetland, is significant to the interests specified in Section I(B)(1). This presumption is rebuttable by clear and convincing evidence that the Seasonal Wetland does not play a role in the protection of wildlife habitat. In the event that the presumption is deemed to have been overcome, the Commission shall make a written determination to this effect, setting forth its grounds.
A proposed project in a Seasonal Wetland shall not result in the following:
Any impairment of the capacity of the Seasonal Wetland, as well as the area within 100 feet of the mean annual boundary of said Seasonal Wetland, to provide wildlife habitat. Alterations may be permitted if they will have no adverse effects on wildlife habitat.