The condition of Morro Bay's sewer lines has been a subject of concern and of debate for several years. Local activists have alleged that the situation is serious, and that sewage leaking from the lines is contaminating ground water, City wells, and the Bay. City staff members have denied these allegations, although recently some City officials have acknowledged that the aging system does need repair and rehabilitation.
In October, 2007, Morro Bay residents Richard Sadowski and Marla Jo Bruton issued a report on the condition of Morro Bay's lines. The report stated that, ". . . openings in the (sewer) pipes permit infiltration of water into the system in wet conditions, and exfiltration (leakage) of raw sewage into the soil when the soil surrounding the lines is dry. The pipe damage documented in this report makes it clear that serious pollution of our soil by untreated sewage is going on all over the City. In addition, Morro Bay is paying for the processing of large amounts of rainwater/runoff that enter the system in wet weather."
The report was based on a review of video inspections of about 8,065 feet (1.52 miles) of sewer line. Morro Bay's collection system includes about 60 miles of gravity sewer line, and about 2.5 miles of force main, so the sample represented about 2.4% of the total system. Several agencies discharge into the Morro Bay system and are considered satellite agencies. They are Morro Bay High School, the Morro Bay State Park, and the Bayshore Village Home Owners Association. The Cayucos Sanitary District discharges into a shared trunk line that runs down Main Street and Atascadero Road to the wastewater treatment plant.
The defects reported by Sadowski and Bruton included openings in the lines at 716 pipe joints, 59 cracked areas, 2 major breaks, and 5 bad lateral connections. All were considered large enough to allow leakage of sewage out of the lines. The defects in the lines were identified and categorized by Sadowski, who holds a California Water Environment Association (CWEA) Grade IV wastewater collection system operator certification.
The video inspections reviewed covered lines in a variety of areas of the City, including downtown, lower Morro Heights, the Beach Tract, several sections of North Morro Bay east of the highway, a section of Atascadero Road, and major portions of the Main Street Trunk Line. The report authors indicated that the video inspections selected for review were a random sample chosen from about 30 inspection tapes made available to them by the City of Morro Bay in response to a Public Records Act request.
The City's official response to the Bruton-Sadowski report was not favorable. In a December 31, 2007 letter, the Regional Water Quality Control Board (RWQCB) asked the City for a response to the allegations made in the report. Dylan Wade, then a City of Morro Bay Senior Civil Engineer, responded in an undated letter to Roger Briggs of the RWQCB.
Wade alleged that the report authors were unqualified to evaluate the condition of the collections system, stating, "The analysis contained in these reports was certainly independent as claimed by the author; however, there is some question about the validity of an engineering analysis being performed by a person not licensed to do so. Since the preparation of this analysis may constitute the practice of engineering, the Regional Water Quality Control Board may wish to engage the Department of Consumer Affairs for a determination in this matter."Mr. Wade further asserts that, "the authors appear to be untrained in the review of video inspections in a professional capacity."
Sadowski and Bruton responded in a May 29, 2008 letter to Briggs, noting that it was Sadowski's certification as a CWEA Grade IV Wastewater Collection System Operator that qualified him to analyze the condition of the Morro Bay wastewater collection system; not his education and experience in mechanical engineering. The CWEA, an organization that works closely with the regional and state water boards, provides a variety of training and certification programs for collection system workers. Grade IV is the highest level of certification available for a collections system operator.
Addressing the allegation that many system problems were due to deferred maintenance, Wade stated, "The overall level of rehabilitation required is to be expected for a collections system that has an average pipe age of more than 50 years,"and "The report authors also put forth the claim that the damage observed in our system was largely caused by deferred maintenance. While there is damage to portions of the some of the clay pipe in the collections system, the damage was not caused by deferred maintenance 'Because vitrified clay pipe is chemically inert, it is not vulnerable to damage due to domestic sewage, sulfide attack, most industrial wastes and solvents or aggressive soils' (Clay Pipe Engineering Manual). Furthermore the City has a long history with an aggressive cleaning schedule that exceeds industry norms. Our cleaning intervals range from less than monthly to a maximum of biannual cleanings depending on the condition of the pipes. The type of damage observed to some of the pipes in the collections system would appear to be mostly from earth movement, with cracks at bells or displaced joints and damage from faulty lateral installations."
Sadowski and Bruton responded, "Yes, the overall level of rehabilitation needed IS what is to be expected for a system with an average pipe age of more than 50 years IF that system was NOT properly maintained during those 50 years. We are very puzzled by Mr. Wade's statement that, since pipe damage was caused primarily by earth movement, the state of the lines cannot be attributed to deferred maintenance. Maintaining a collections system involves far more than cleaning out the pipes regularly. It involves regular, pro-active inspections of ALL of the system, and prompt action to repair defects that the inspections reveal."
Referencing allegations that leaking sewage presented a health and environmental hazard, Wade stated, "There is no evidence to support the belief that the system in its current condition presents a danger to the community's health or the environment."
Sadowski and Bruton found a more sympathetic audience in the California Coastal Commission (CCC). In a letter dated December 8, 2008, CCC Coastal Planner Mike Watson wrote to Bruce Ambo, "As you know, the Commission recently acted on an appeal brought by local residents claiming that breaches in the City's wastewater pipes was causing the City's potable water wells to be cross-contaminated with undesirable constituents. Although the Commission chose not to take jurisdiction over the CDP in that case, it was clear from our review of the appeal that there may be problems with the City's wastewater infrastructure. Thus, the DEIR should address how the proposed upgrade will also correct deficiencies in these related WWTP facilities to eliminate future spills or contamination and ensure that coastal water quality is appropriately protected."The Draft Environmental Impact Report (DEIR) is, according to a CCC representative, to be completed and submitted to the agency this summer.
Further support for the report authors' theory that sewage leaking from damaged lines could be contaminating the Morro Basin well field was obtained in 2009, when a resident asked the California Department of Public Health (CDPH) for the well water test results that had been submitted to that agency by the City. The data, covering the years 2003 through 2007, included results for tests done, on average, about 5 times per year. Test results showed that coliform bacteria were found in Morro Basin well 3 in September, 2003, January and May, 2006, and June, September and December, 2007. In January, 2006, and September, 2007, e-coli was found in the well 3.
City staff have repeatedly denied that sewage might be the source of the nitrates in the wells. During a Public Works Advisory Board meeting, Wade cited a quote from an EPA study, "Exfiltration in Sewers"by researchers Amick and Burgess, as evidence that exfiltration (leaking) from damaged sewer lines is minimal. "Despite a hydraulic potential for exfiltration along Main Street when the City well field is pumping, gravity sewer leaks quickly become plugged by sewer film and settleable solids in the sewage, theoretically reaching steady-state leakage rates in approximately one hour. A research study conducted at several locations in Germany, where sewer systems are generally older and in poor condition, showed that when system pressure heads are below the sewer pipe crown (typical for gravity sewers) exfiltration rates were minimal."
Resident researchers reviewed the study and allege that the quote was taken out of context. The complete statement by the study authors is, "This study determined that the most significant VCP sewer damages which permit exfiltration are leaking service junctions, leaking sewer joints, pipe cracks, and pipe fractures. At a pressure head below the sewer crown, which is typically the case in gravity flow sewer lines, exfiltration rates were minimal. At a pressure head of one pipe diameter, the exfiltration rate increased dramatically, to more than 26 gal/hour (gph) per joint in some segments. This high leakage rate can, in part, be attributed to the generally poor condition of the old sewer systems. A linear correlation between pressure head and exfiltration rate for several types of sewer defects was noted for pressure heads greater than 500 mm (20 inches). It was also noted that at lower flows and pressure heads, the exfiltration rate decreases exponentially, most likely from self-sealing from sewer film and settleable solids in the sewage. If the flow and pressure head increases, however, this self-sealing property is broken and the exfiltration rate increases rapidly."
The residents also cited this quote from the same study. "Over the years, many of these systems have experienced major infrastructure deterioration due to inadequate preventive maintenance programs and insufficient planned system rehabilitation and replacement programs. These conditions have resulted in deteriorated pipes, manholes, and pump stations that allow sewage to exit the systems (exfiltration) and contaminate adjacent ground and surface waters, and/or enter storm sewers.
The Amick and Burgess study also discussed other studies that attempted to quantify the amount of sewage leaking from damaged sewer lines in Santa Cruz, California. For one of the lines studied, it was estimated that approximately 34% of the flow was exfiltrating in to the soil. For another, the estimate was 56% of total flow. The study did not indicate that such rates are typical; only that they are possible.
According to the study, in order for significant exfiltration to occur, sewer lines must lie above the water table. If they do not, infiltration (water coming into the lines from the surrounding soil) is more likely. Sadowski, who was employed for several years by the Cayucos Sanitary District and worked on their collection system, stated that nearly all of the lines in the Morro Bay and Cayucos area lie above the water table except during extremely rainy, wet conditions. Wade has said that many of the lines lie below the water table. Only one of the video inspection tapes viewed by Sadowski and Bruton showed any water entering from outside the line. The subject of that inspection was the line running down Atascadero Road toward the wastewater treatment plant. Despite the presence of large openings in the other lines studied, there was no evidence of water coming in.
Despite what some residents interpreted as a reluctance of City staff to expedite repair of the damaged lines, work to do so has begun by order of the State Water Resources Control Board which, in 2006, adopted Order No. 2006-003 General Waste Discharge Requirements for Wastewater Collections Agencies. The order requires that every public wastewater collection system owner in California develop and adopt a Sewer System Management Plan. Approved plans were required to be completed by August, 2009. The Morro Bay City Council voted to adopt Morro Bay's plan on June 8, 2009.
Among the requirements for such plans are regular inspections, rehabilitation and replacement of damaged lines, and a focus on those lines that are most at risk of collapsing and those that are most prone to frequent blockages due to defects.
In May, 2010, a resident submitted a Public Records Act request for "documents describing the work done thus far to rehabilitate the sewers, as mandated by the SSMP (just the documents about the work done after the SSMP was written), and rehabilitation work planned for the remainder of 2010 " In response, the City provided documentation on the rehabilitation of a 90-foot section of 6-inch line on Whidbey Way. No information on any other completed or planned rehabilitation work was provided.
