Morro Bay Water Reclamation Facility Project:  Issues, Concerns, and Solutions


Collection System Issues


Introduction and Background

Morro Bay’s sewage collection system has been neglected for many years, and has fallen into a state of serious disrepair, leaking sewage into the soil and polluting  groundwater, Estero Bay and the ocean. These problems have been verbally reported and well documented, but work to repair the system has moved slowly.

2007 research by residents, one of whom is a state-certified collections system expert, determined that, on average, every 11.4 feet, there is an opening in the sewer lines through which sewage can leak into the ground.  

The issue was also mentioned in a December, 2008 letter from CCC staff to Morro Bay City staff.  The letter states, “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 any deficiencies in these related WWTP facilities to eliminate future spills or contamination and ensure that coastal water quality is appropriately protected.”   

The DEIR produced in 2010 did not address the issue.  Residents plan to press the matter when the DEIR for the new site is prepared.


Evidence of the Problem

Many residents have learned first hand of damaged sewer lines after roots entering the lines caused backups in their neighborhoods. When the lines are intact, sewage does not leak out, and tree roots seeking a water source cannot enter the lines.

Both Morro Bay and Cayucos have had numerous video inspections of their lines over the years, going back as far as 1995.  The inspections show numerous breaches in the sewer lines all over the City.  Cracks, holes, and openings between pipe sections are common.  Little, if anything, was done to address the serious public health issues associated with the damage the inspections revealed, and City records do not indicate that City staff ever raised the issue with the City Council.

In October, 2007, Morro Bay residents Richard Sadowski and Marla Jo Bruton reviewed a  sizeable portion of the evidence, in the form of  several miles’ worth of City video inspections of sewer lines throughout Morro Bay.  Sadowski has considerable experience in sewer collection system management, and holds a California Water Environment Association (CWEA) level 4 collection system operator certification — the highest level of certification available.

Sadowski and Bruton issued a report, “Condition of the Morro Bay Wastewater Collection System – Video Inspection Review and Analysis”, which provides detailed information on the evidence and its implications.

In May, 2013, in response to resident comments, City staff claimed, “Exfiltration of sewage from the Main Street trunk line is minimal because the elevation of the sewer line is below the water table. This creates a pressure that causes groundwater to flow into the pipe, but prevents sewage in the pipe from flowing out under normal conditions.”

That claim is probably false, as the City Council was told, by a certified collection systems expert, at the May 28, 2013 Council meeting.  The line lies above the water table except in the very wettest of weather. Were that not the case, video inspections of the line would show groundwater flowing into the line through the many holes,cracks, and misaligned sections.  The video inspections show absolutely no infiltration of groundwater.


Ramifications

Obvious ramifications of a dilapidated, leaking collection system include contamination of the ground water, the Bay and the ocean, resulting in health implications for swimmers, surfers, and wildlife.  Also a serious problem is contamination of City wells.  Many residents have long believed that sewage is a major factor in the nitrate contamination of the City’s Morro Basin well field.  

A less obvious consequence of a leaky sewer system is the inability to accurately estimate the capacity needs for the new water reclamation facility.  

While the amount of leakage is unknown, the potential amount (and thus the scope of the ramifications) is alarming.  The study, “Exfiltration in Sewer Systems”,  by Robert S. Amick, P.E., and Edward H. Burgess, P.E., .discusses some sewage exfiltration (leakage into the soil) rate measurement projects.  The authors refer to one 1989 study that measured leakage rates of 56% of total sewage flow passing through the sewer line on 7th Street in Berkeley, California, and 34% of the flow from the line along Pardee Street, also in Berkeley.

A complete history of the contamination of the contamination of the Morro Basin aquifer by leaking sewage was compiled in 2016.