The Guadalupe watershed today drains an area of . Below its origination at the confluence of Guadalupe Creek and Los Alamitos Creek, the mainstem is joined by three other tributaries: Ross, Canoas, and Los Gatos Creeks. The SCVWD manages water flows (supply) and provides flood control on the river, and recently has started to promote watershed stewardship. Six major reservoirs exist in the watershed: Calero Reservoir on Calero Creek, Guadalupe Reservoir on Guadalupe Creek, Almaden Reservoir on Alamitos Creek, Vasona Reservoir, Lexington Reservoir, and Lake Elsman on Los Gatos Creek.