This polyogn shapefile describes the riparian extent of the Alexander Valley reach of the Russian River in 2000. The Middle Reach extent is defined by the Wohler Bridge and the Healdsburg, 101 bridge. Riparian habitat is defined as the river channel and all areas covered by riparian vegetation along the Russian River's "main stem", including the wetted channel, active channel, vegetated channel, channel banks, and that portion of the floodplain between the top of the channel bank and the outer limit of "typical" riparian vegetation. This habitat supports various seral stages of riparian vegetation, and it is assumed to be subject to relatively frequent flooding wherever there are no artificial flood control structures.The mainstem Russian River riparian habitat boundaries were interpreted from Sonoma County Water Agency (SCWA) Aggregate Resources Management (ARM) Plan aerial photos. Some areas of the SCWA aerial photos were missing and limited the extent of the riparian habitat. Aerials from the County of Sonoma Information Systems Department / GIS Group were used to complete the riparian extent.This layer can be used for land use analysis and planning in the Russian River region of California.