|Name of Data Source
|Population Estimates for Watersheds
|Datasource Abbreviation (dataset)
|Description of Datasource
|Population estimates for watersheds derived from available Census block and block group data. Data from 1970 through 2010 is from the Decadal Census. Beginning in 2015, data is from the American Community Survey, updated every 5 years.
|Method of Transferring Data to the Atlas
|Manual transfer via HTTP
|How Often Data is Transferred to the Atlas
|Every 5 years
|Date of Most Recent Data Transfer
|Estimates are generated by taking the centroids of Census blocks (2000 and 2010) and block groups (1970, 1980 and 1990) and assigning the population of each to the watershed the centroid falls within. Over time, Census geographic boundaries may change, causing centroid locations to shift and the corresponding population to be assigned to a different watershed than the decade prior. Please view these population numbers strictly as estimates and not as exact population totals.