The San Dieguito River watershed is a drainage area of approximately 346 square miles in west-central San Diego County.  The watershed includes portions of the cities of Del Mar, Escondido, Poway, San Diego, and Solana Beach, and unincorporated San Diego County.  In terms of land area, the majority of the watershed (79.8%) is within the unincorporated jurisdiction.  The San Dieguito River watershed is presently divided into vacant/undeveloped (54%), parks/open space (29 %), and urban (18%) land uses.  Nearly half of the vacant land area is open to future development, most of which is zoned for residential usage.  The current watershed population is approximately 125,000 however; this level is projected increase to over 210,000 residents by 2015.