The polygon features were selected based on their spatial location within the extent of the Russian River basin and contains reach codes for networked features and isolated lakes, flow direction, names, stream level, and centerline representations for areal water bodies. Reaches are also defined to represent waterbodies. This dataset describes the lakes of the Russian River basin and is intended for hydrography analysis and planning. Circuit Rider Productions and National Oceanic and Atmospheric Administration (2002). Waterbody Reach: Russian River Basin, California, 1999-2002. Circuit Rider Productions. Available at: http://purl.stanford.edu/mg798hj5833 The accuracy of the attributes of the Digital Line Graph data is estimated to be 98.5 percent. One or more of the following methods were used to test attribute accuracy: - manual comparison of the source with hardcopy plots. - symbolized display of the digital line graph on an interactive computer graphic system. - Selected attributes that could not be visually verified on plots or on screen were interactively queried and verified on screen. In addition, software validated feature types and characteristics against a master set of types and characteristics, checked that combinations of types and characteristics were valid, and that types and characteristics were valid for the delineation of the feature.
Feature types, characteristics, and other attributes conform to the Standards for National Hydrography Dataset (USGS, 1999) as of the date they were loaded into the database. All names on reaches were validated against a March 1999 extract from the Geographic Names Information System. The entry and identifier for the names match those in the Geographic Names Information System.
Features found on the ground may have been eliminated or generalized on the source graphic because of scale and legibility constraints. In general, streams longer than one mile (approximately 1.6 kilometers) were collected. Most streams that flow from a lake were collected regardless of their length. Only definite channels were collected so not all swamp/marsh features have stream/rivers delineated through them. Lake/ponds having an area greater than 6 acres (approximately 2.4 hectares) were collected. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.