Identifying some wetlands is quite easy: they are the area where you sink up to your knees and fear that strange and dangerous creatures live beneath the surface. In most cases, especially when dealing with inland wetlands, it may not be that simple. Some wetlands are not wet for much of the year and while the presence of wetland plants may provide a clue, given that only a fraction of the plant types are found exclusively in wetlands, plant life alone is often an inadequate indicator.

The Corps and/or the states are responsible for the jurisdictional determination of wetlands and the delineation of their boundaries.

To facilitate this process, the Corps has published a rigid standard and methodology for determining the existence of wetlands. The 1987 Corps of Engineers Wetlands Delineation Manual (Technical Report Y-87-1) with guidance provided in the 6 March 1992 USACOE memorandum entitled Clarification and Interpretation of the 1987 Manual contain the standards used by both Corps and PADEP. The document is approximately 140 pages long and actually makes for some interesting reading in a demented sort of way. Both the manual and the clarification may be accessed from the links below.

1987 Manual
1992 Clarification

The primary criteria for an area to be classified as a wetland include the existence of plant and soil types commonly associated with wetlands as well as the presence of wetland hydrology.

Areas that do not possess all three properties are unlikely to be considered jurisdictional wetlands. If the Corps will not certify that an area is a wetland, then local municipalities are effectively prevented from imposing use limits.

How wetlands are identified and delineated

Often the first stage in the identification of potential wetlands within a project area is the utilization of maps from one or more of three sources.

1. USGS Quadrangle maps
2. FWS National Wetlands Inventory maps*
3. Soil and Conservation Service (SCS) maps**

* A word of caution... Since the FWS use a different definition of wetlands than does the Corps, the areas identified as potential wetlands on these maps may not be jurisdictional wetlands.

** Since SCS maps and information are generated locally (generally at a county or parish level), they are often the most valuable tool in the first stages of wetland identification.

Who can Delineate Wetlands

In addition to the use of maps, field identification of potential wetland areas during surveying or project design is common in Pennsylvania. This is an area where the system can fall apart quickly in that almost all such field surveys are performed by people hired by the developer. Even though the plans and the integrity of their contents must be certified by professional engineers, many environmentalists are justifiably concerned that this is a blatant case of the fox guarding the hen house.