The Rivers & Streams Layer is based on data from the National Hydrography Dataset. All STREAM/RIVER line features for Pennsylvania were extracted from the NHD data to create this layer. NHD defines a STREAM/RIVER feature as "a body of flowing water". The features are symbolized in SoilMap according to the Hydrographic Category, or the portion of the year the feature contains water. Three possible values exist for Hydrographic Category in SoilMap with each value getting a different symbol:

FCODE 46000 - feature type only: no attributes
FCODE 46003 - Hydrographic Category|intermittent; Positional Accuracy|not applicable
FCODE 46006 - Hydrographic Category|perennial; Positional Accuracy|not applicable

Intermittent features are features that contain water for only part of the year, but more than just after rainstorms and at snowmelt.
Perennial features are features contain water throughout the year, except for infrequent periods of severe drought.

The Streams & Rivers layer is only visible at map scales less than 1:125,000.

The National Hydrography Dataset (NHD) is a comprehensive set of digital spatial data that contains information about naturally occurring and constructed bodies of water, natural and artificial paths through which water flows, and related hydrographic entities.

For More Information - Visit the National Hydrography Dataset Web site at http://nhd.usgs.gov to obtain more comprehensive user documentation, data, tools, training materials, and technical support.

The data and documentation on SoilMap are provided 'as is' and the User assumes the entire risk as to their quality and performance. SoilMap source data was produced at a variety of scales and may not be suitable for use at larger scales.