Heavy rains yesterday are being blamed for a sewage spill that dumped thousands of gallons of sewage into the ocean off Shell Beach. Health officials say, about 8,000 gallons of sewage made its way from a manhole at Ocean Avenue and into a storm drain that leads directly to the ocean. Another spill happened when 5,000 gallons of treated wastewater was accidentally released from the South SLO County Sanitation District wastewater treatment plant in Oceano. Health officials say signs have been posted at the beaches impacted by the spills.