Sewer History: Photos and Graphics


	On September 7, 2002, two sinkholes appeared on Speedway Blvd., a major street in Tucson, Arizona. The initial cause of the sinkholes remains unclear, but the 42" sewer main which was crushed and plugged was aging and scheduled for renovation in the near future. The sewer line was a large interceptor that carried 32 million gallons of sewage (peak dry weather flow) a day from the south side of Tucson to the 42 mgd Roger Road Treatment Plant.This is the western sinkhole, the second and smaller of the sinkholes that appeared within hours of the first signs of pavement disturbance. Photo date September 7, 2002. Source: Jaime Rivera, Pima County Wastewater Management Department.
	The eastern sinkhole, the larger of the two, rapidly filled with sewage and stormwater. Photo date September 9, 2002. Source: Jaime Rivera, Pima County Wastewater Management Department.
	Another view of the eastern sinkhole, showing two intact manholes. Photo date September 10, 2002. Source: Bob Buecher, Pima County Wastewater Management Department.
	The eastern sinkhole shown in a panorama. Photo date September 10, 2002. Source: Bob Buecher, Pima County Wastewater Management Department.
	A view toward the east showing both sinkholes. Photo date September 10, 2002. Source: Jan McDonald, Pima County Wastewater Management Department.
	The western sinkhole. Photo date September 9, 2002. Source: Jan McDonald, Pima County Wastewater Management Department.
	A view of the western sinkhole showing extensive damage to underground utilities. Photo date September 9, 2002. Source: Jan McDonald, Pima County Wastewater Management Department.
	A pavement depression began to appear a few blocks away from the main sinkholes, but it stabilized and did not collapse further. Photo date September 9, 2002. Source: Jaime Rivera, Pima County Wastewater Management Department.
	A storm water outlet releasing sewage into the Santa Cruz River. Some sewage continued to flow through the damaged line to the Roger Road Plant, but much of it flowed into the sinkholes and then flowed by storm water sewer into the Santa Cruz River. All flows to the Santa Cruz were stopped by September 17. This was accomplished when thirteen large heavy-duty pumps were obtained from California, Texas, Utah, and New Mexico. Photo date September 10, 2002. Source: Bob Buecher, Pima County Wastewater Management Department.
	Chlorine was delivered by truck and fed into storm water drains throughout the area to disinfect sewage before it reached the Santa Cruz. Photo date September 10, 2002. Source: Jan McDonald, Pima County Wastewater Management Department.