Heal the Bay released its annual report card last week, measuring the quality of water at California's beaches.
The same day, the Imperial Beach shoreline was reopened after six days of closure due to sewage contaminated runoff from the Tijuana River.
Overall, IB beaches received high marks in dry weather and low grades in wet weather.
Carnation Avenue A+ A F A Imperial Beach Pier A+ A D
South end of Seacoast Drive A A F A 3/4 mile north of Tijuana River A A F A Tijuana River mouth A A F A Monument Road A+ D F F U.S. Border Fence A+ A F C
Countywide, San Diego received some of its best marks ever during the 21 years of Heal the Bay's annual report card.
During year-round dry weather, water quality at San Diego County beaches received good to excellent marks with 96 percent of beaches receiving an A or B, a 12 perent improvement from last year.
During wet weather in the fall and winter, 72 percent of beaches received an A or B grade, 2 percent received a C, and 26 percent received D or F grades.
Imperial Beach results came entirely from the San Diego County Department of Environmental Health, though five different agencies contributed data to San Diego County's evaluation.
Samples were generally collected where runoff and ocean water mix, or 25 yards away from a flowing storm drain, creek or river, the report said.
Border Field State Park at Monument Road and the San Luis Rey River outlet in Oceanside received the county's only F grades during dry winter weather, but no San Diego County beaches were counted among the top 10 best or worst beaches in California. Four of the 10 worst beaches, which received an F grade, are located in Los Angeles County.
Beaches from the end of Seacoast Drive to the U.S.-Mexico border have been closed since Dec. 18 due to sewage contaminated runoff from the Tijuana River, according to the San Diego County Department of Environmental Health.
About half of the report's evaluation of the San Diego coastline was devoted to the Tijuana River Bacterial Source Identification Study.
The study was conducted to determine the source of fecal matter and to identify best practices or ways to potentially reduce bacteria in the Tijuana River watershed.
Analysis during wet weather found the potential of damaged or leaking sewer lines in Mexico.
Separate from the Tijuana River, nine sewage spills occurred between April 1, 2010, and March 31, 2011. According to the report, as a result of the spills, a total eight million gallons of sewage spilled into the water, or more than the rest of California coastal counties combined.
Twenty-one separate beach closures occurred in IB during that period, accounting for 237 days of closure, the report said.
Closures are carried out by the San Diego County Department of Environmental Health and often occur as a precaution when rain, the river's flow, current and sewage spill conditions pose a potential threat to human health. Closures are lifted when tests prove water is fit for human contact.
Efforts to improve water quality in the area continue.
The International Wastewater Treatment Plant, which was recently brought up to federal Clean Water Act standards, can process 25 million gallons of sewage daily.
Two new sewage plants were recently opened in Tijuana as well.
contributed to this portion of the report.