The Piner Creek watershed consists of , approximately three-fourths of which lies within the municipal boundaries of the city of Santa Rosa. About one-third of the watershed is developed as residential use, and about one-sixth of the land is open space or used for recreation or agriculture. One of the early surviving architectural features of Sonoma County is within the Piner Creek catchment basin: A well preserved "Round Barn", constructed in 1899, a testament to the 19th century pasturage uses within this watershed.