Wetland Hydrology
Wetland hydrology is the driving force behind creating and sustaining a wetland. Wetland hydrology encompasses all hydrologic characteristics of areas that are periodically inundated or have shallow saturated soils periodically during the growing season. Areas with evident characteristics of wetland hydrology are those where the presence of water has an overriding influence on vegetation and soils due to anaerobic and reducing conditions. Inundation or soil saturation may occur due to: flooding of streams and rivers, flow of surface water, ponding of water, discharge of groundwater, and/or a high water table.

Many wetlands are found along rivers, water bodies and estuaries where flooding and inundation are most likely to occur. Wetlands are also formed in isolated depressions, surrounded by uplands, where surface water collects. Others develop on slopes of varying steepness, in surface water drainageways or where groundwater discharges.

The following field indicators of wetland hydrology provide evidence that inundation and/or soil saturation has occurred:

* Visual observation of inundation
* Visual observation of soil saturation
* Watermarks
* Drift lines
* Sediment deposits
* Drainage patterns within wetlands


Ponding in a wetland - Berks Co.

One sign that flooding has occurred is the presence of flood debris - Berks Co.

Disturbances to hydrology in the form of ditching and drain tiles - Lancaster Co.

Sinkholes can significantly alter hydrology in karst areas - Snyder Co.

Trees may form buttressed roots in the presence of a high water table - Berks Co.

Tidally influenced freshwater wetlands, such as this, are very uncommon in Pennsylvania - Delaware Co.