In its efforts to maintain its critical infrastructure, the Vallecitos Water District undertook a challenging update to a wastewater system pipeline constrained by its precarious location.
In its efforts to maintain its critical infrastructure, the Vallecitos Water District undertook a challenging update to a wastewater system pipeline constrained by its precarious location.
The existing eight-inch gravity sewer pipeline conveys wastewater from the intersection of Rock Springs Road and Bennett Avenue west through a greenbelt area to an existing 12-inch pipeline in Rock Springs Road at Lancer Park Avenue. To expand capacity for current and future growth, it was replaced with a new 15-inch PVC pipe west of Matthew Lane and a 12-inch PVC pipe north and east of Matthew Lane.
The location of the affected manhole put equipment and crews close to a SDG&E gas line inside a greenbelt park area. Photo: Vallecitos Water District
The District always prefers to perform work in a street or public right-of-way. Neither were possible for this project due to its greenbelt and park location within feet of residential homes.
“We took every environmental precaution prior to construction,” said Lito Santos, Vallecitos Water District Project Engineer. “We performed a nesting survey, a raptor survey, and we also worked to tunnel under the bridge,” within the Environmental Protection Agency’s “Clear Water Rule.”
San Marcos Woods Homeowners Association board member Ross Fisher acted as a liaison between homeowners and the HOA with the District. Fisher expressed concern about access to the work area by the District’s large combination truck. The original proposal to create a concrete strip to drive over wasn’t feasible.
Due to its incredible strength, the grass-crete and existing lawns can handle the weight of a large service vehicle driving on it without significant damage. Photo: Vallecitos Water District
Working together with Vallecitos Water District engineers, the group chose an alternative material called “grass-crete.” Grass-crete is a green porous paving solution that comes in easy-to-install rolls. It’s flexible, lightweight, durable and provides design versatility to the project. Due to its incredible strength, the grass-crete and existing lawns can handle the weight of a large service vehicle driving on it without significant damage.
Manholes were waterproofed, coated, and sealed as an additional precaution and to extend their longevity. Photo: Vallecitos Water District
Vallecitos Water District engineers also worked with San Diego Gas & Electric to perform its work with enough safety clearance from a 16-inch transmission main artery gas line pressurized at 800 pounds per square inch. The District secured permission to dig within two to three feet from the line instead of the standard five feet.
The work area is also prone to flooding after large rain events, raising the water levels in the nearby creek high enough to infiltrate and inflow into the manholes. The District moved the manholes clear of the creek embankment, and lifted the manholes two feet above ground and clear of the flood plain to prevent runoff intrusion. Manholes were waterproofed, coated, and sealed as an additional precaution and to extend their longevity.
The District moved the manholes clear of the creek embankment, and lifted the manholes two feet above ground and clear of the flood plain to prevent runoff intrusion. Photo: Vallecitos Water District
“Overall Vallecitos left the greenbelt area as good or better when they started,” said Fisher of the HOA. “On a scale of one to ten, I have to give them a 9.5 or a ten. Working with the inspectors and Lito Santos the engineer, everything we asked for was done in a timely manner.”
“The project was a huge success,” said Santos. “Working with the Vallecitos Engineering Team, the Inspection Team and Mr. Fischer, it was not just a Vallecitos highlight but a career highlight.”
Encinitas, Calif. — Olivenhain Municipal Water District and Vallecitos Water District have entered into an agreement that will allow for cooperative use of Vallecitos’ Double Peak Reservoir site in San Marcos. The arrangement is expected to save OMWD ratepayers over $100,000.
Panelists from several water districts will give updates on new laws affecting water consumption in California during an American Liberty Forum of Ramona event set for Saturday, June 27.
The free forum on Water Regulations Today and Tomorrow will be held at Ramona Mainstage, 626 Main St. Doors open at 11 a.m. and a video program starts at 11:30 a.m.
The focus will be on Senate Bill 606 and Assembly Bill 1668.
SB 606 is in response to mandates that California achieve a 20 percent reduction in urban per capita water use by Dec. 31, 2020. Existing law requires each urban retail water supplier to develop urban water use targets and an interim urban water use target.
AB 1668 would require the state Water Resources Control Board to adopt long-term standards for the efficient use of water and would establish specified standards for per capita daily indoor residential water use.
Vallecitos Water District crews sprang into action to repair and rehabilitate a manhole in danger of failing, successfully preventing a spill, which could have resulted in significant environmental damage.
Located just off Palomar Airport Road in a shared 30-foot easement with the Buena Sanitation District in Carlsbad, the manhole is part of a 30-inch outfall providing a main sewage drain for the City of San Marcos. The line feeds directly into the Encinas Wastewater Treatment plant a half-mile from the project site.
Vallecitos Water District crews sprang into action to repair and rehabilitate a manhole in danger of failing, successfully preventing a spill, which could have resulted in significant environmental damage.
Located just off Palomar Airport Road in a shared 30-foot easement with the Buena Sanitation District in Carlsbad, the manhole is part of a 30-inch outfall providing a main sewage drain for the City of San Marcos. The line feeds directly into the Encina Wastewater Treatment plant a half-mile from the project site.
Originally constructed in the 1980s, turbulence generated by a hard right-turn along the sewer easement creates hydrogen sulfide gases. These gases corrode concrete and weakened the manhole over the years. Flooding also occurs in the area and allows rainfall to infiltrate the manhole.
Vallecitos Water District staff became concerned the structure could fail. The result would be a major sewage spill affecting the nearby Encinas Creek Habitat Conservation Area, ultimately spilling into the Pacific Ocean a mile downstream. The Habitat Conservation Area is owned by the Center for Natural Lands Management, which supports its management through an endowment.
The Encinas Creek HCA is also part of the City of Carlsbad’s habitat management preserve. It includes riparian habitat and is known to be home to state and federally protected species. The Center for Natural Lands Management works to protect the property from trespassing, nonnative invasive plant and animal species, and other issues.
The District determined emergency repairs were required. Although the Vallecitos Water District has proper easement rights to access, operate, and maintain the pipeline, the agency must avoid any impact to the existing habitat while repairing the manhole. This required some creativity by the work crews.
A look at the newly repaired manhole. Photo: Vallecitos Water District
The District kept all construction activities within its existing easement to avoid any impacts to existing riparian vegetation. Crews constructed a temporary bridge over an existing stream obstructing access to the manhole. The bridge installation was designed to be temporary, and not affect the existing stream with footings or other supports. Constructing the bridge for access turned out to be the most complex part of the repair project.
District crews working with a contractor team took advantage of the lower sewage flow during the early morning hours, starting work at 3 a.m. to get as low into the waterline as possible. Repairs like this take advantage of the low flows to keep critically important sewer systems in operation.
Instead of replacing the manhole, the District used a polymer concrete replacement product to build a new manhole within the old manhole. As a result, no excavation was needed. Unlike regular concrete, the new material is corrosion-proof and should provide District customers in San Marcos with many years of reliable service while protecting the environment.
Vallecitos Water District provides 5.25 million gallons of recycled water for irrigation every day. To fulfill the demands of modern irrigation systems, it is important to maintain low TSS levels. This is a challenge during the warm months in California, as algae that occur with raising temperatures, increase the level of TSS and clog the filters that are meant to remove TSS before the distribution of water to the irrigation systems.
Vallecitos Water District is known for its’ sustainable and innovative focus when it comes to water and wastewater treatment.
This feature highlights water utility employees in the San Diego region working during the coronavirus pandemic to ensure a safe, reliable and plentiful water supply. The water industry is among the sectors that are classified as essential. Dale Austin, Vallecitos Water District Senior Pump & Motor Tech, is the Water Utility Hero of the Week.
Editor’s Note: This feature highlights water utility employees in the San Diego region working during the coronavirus pandemic to ensure a safe, reliable and plentiful water supply. The water industry is among the sectors that are classified as essential. Dale Austin, Vallecitos Water District Senior Pump & Motor Tech, is the Water Utility Hero of the Week.
I had friends and a neighbor that worked for different agencies and different jobs. They all talked highly of their agencies and the jobs they did. I wasn’t sure where I would fit into the industry so I took classes in Water Distribution, Water Treatment, and Wastewater Treatment. I learned so much in those classes. I applied and got my first job in Water Distribution where I could apply my skills as a Certified Pipe Line Welder and Machinist, but my passion has always been in mechanical, so I transferred to a treatment plant which led me to my current job with Vallecitos.
I pride myself in having my equipment 100% available, so with the pandemic Vallecitos is doing a rotating schedule to help with distancing and safeguarding the crews. Staying in contact with the crew on duty via email and phone. Prioritizing work loads and talking to vendors. I don’t personally like to carry my phone when not at work but with the pandemic it is a very important tool to stay in contact with everyone.
By following guidelines from the CDC, maintaining social distancing, and following good hygiene.
Sitting down at a restaurant for dinner and going to the movies with my wife.
Seventeen above ground steel tanks and two underground concrete reservoirs play a vital role in the Vallecitos Water District’s mission to provide clean, safe, and reliable water to its 105,000 district residents. Maintenance and cleaning of the tanks and reservoirs is a critically important process.
Without regular washouts, tanks can accumulate large amounts of sediment, prohibiting proper inspections.
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