Many elements of the Mission's extensive water treatment system, all built by Chumash Indians' labor under the direction of the Franciscans (including aqueducts, two reservoirs, a filter house, and a hydro-powered gristmill) remain to this day. The larger reservoir, which was built in 1806 by the expedient of damming a canyon, had been a functioning component of the City's water system until 1993. The original fountain and "lavadero" are also intact near the entrance to the Mission. A dam constructed in 1807 is situated in the current Santa Barbara Botanic Garden up "Mission Canyon". The ruins of the Mission's tanning vats, pottery kiln, aqueduct system, and guard house are located on the abutting land in the municipally-owned Mission Historical Park that was sold to the City in 1928.