Construction vehicles wheeled near the Oso Diversion Dam one day late last month as workers removed sediment from water. … The Oso Diversion Dam, part of the San Juan-Chama Project, marks the beginning of the nearly 13-mile Azotea Tunnel, which transports water from the Colorado River basin to the Rio Chama and then to the Rio Grande, where it flows to Santa Fe, Albuquerque and other municipalities … Burn scars are susceptible to increased erosion, sending vast amounts of sediment into waterways.