BLAISDELL SLOW SAND FILTER WASHING MACHINE. VIEW LOOKING NORTHWEST. PIPING IN FOREGROUND IS NOT RELATED TO THE MACHINE. THE NORTHEAST CORNER OF SETTLING RESERVOIR NO. 3 IS SEEN AT THE LOWER LEFT. Yuma Main Street Water Treatment Plant, Blaisdell Slow Sand Filter Washing Machine, Jones Street at foot of Main Street, Yuma, Yuma County, AZ