How is East Sacramento’s new McKinley Park water vault holding up in recent rainstorms?

When Sacramento was drenched in the October bomb cyclone storm that set the record for the most rain fallen in a 24-hour period, the new McKinley Park water vault was just a few months old.

Construction on the vault, which is meant to alleviate flooding in the East Sacramento neighborhood, was completed at the end of the summer. McKinley Park, which is in the East Sacramento neighborhood, officially reopened in October, about a week before the storm arrived.

Now, the vault is facing its second big rain storm: Another atmospheric river is dousing Sacramento. Parts of the region have received more than two inches of rain since Sunday.

So how did the vault hold up in October, and what should residents expect this week? The Bee caught up with a city official and two members from the Stantec project team. Stantec is the design firm that executed the project.

How did the vault hold up in October?

The McKinley Water Vault was designed for a 10-year storm over a six-hour duration, Stephen Chavez, Stantec principal and constructability lead, said. But in October, Sacramento saw a 100-year storm that lasted about a day and a half.

Carlos Eliason, spokesperson for the City of Sacramento’s utilities department, said that the city’s systems were filled to 100% capacity during the storm, including the new vault. That means the vault was holding 6 million gallons of water.

Chavez explained the vault works through a connection the combined sewer system, or CSS, drain pipes. CSS means that rainwater and wastewater are stored together Before those pipes fill up completely, they overflow into a weir, which is a kind of dam.

“The water then is drained into the tank, and it’s stored there and that helps prevent more flooding in the streets because otherwise they would come up through the manholes, the manholes would pop up when the pipe gets full or the drain inlets that capture storm drain flow starts running reverse,” Chavez said.

How is the vault doing now?

The vault at McKinley Park has not filled as a result of this current storm, Eliason confirmed Tuesday. This storm is dropping less rain over a longer period of time than the storm in October, so systems aren’t expected to be as burdened.

What happens when the vault gets full?

When the vault fills up, areas around the park might still experience outflows of water. On Oct. 24, the vault filled up by about 5:30 p.m. After that, water started flowing back out into the streets.

Because that area of the city uses a combined sewer system, outflow includes sanitary sewage. When outflows occur, Eliason said tests have shown that on average, the water includes less than 5% of sanitary sewage.

Still, Eliason indicated that flooding could have been much worse during the October storm given how much rain fell. Though there were outflows, six million gallons of water were held in the vault rather than allowed to inundate the streets. And by 9:40 p.m., the vault had begun to empty, according to Eliason.

“I’m confident East Sacramento would have seen much worse flooding if not for the vault,” City Councilmember Jeff Harris, a supporter of the project, said in a statement.

Some of the city’s ability to weather the October storm likely came down to the drought that meant reservoirs and rivers in Sacramento were running low when the rain began. Still, Eliason said the vault held up in its first big test.

“A storm like this has never been recorded,” Eliason added. “And so I think when you compare that to having just completed the McKinley Vault, you know, months earlier, I think we feel fortunate that the facility was functioning as it was designed.”

Flooding or not, the McKinley Water Vault holds water on a temporary basis. Crews pump water out of the vault as soon as they can.

“We’ll pump that to the county basically, to regional sanitation, because they will be the ones who will ultimately treat it, and then they’ll pump it back into the river,” Eliason said. “So as our system began to fill up, and empty, and we had capacity and other areas, other reservoirs, that’s where the water would go when the McKinley Vault would start to empty.”

What else is new at the park?

The implementation of the new vault came with other upgrades and changes, too. One change that was the subject of some controversy is the conversion of the baseball field to multi-use soccer fields.

In 2018, a group of unnamed residents filed a lawsuit that complained the park renovations would harm historical aspects of the 33-acre park, which opened in 1872 and is on the National Register of Historic Places.

The lawsuit, which ultimately failed to prevent construction, argued converting the baseball field goes against federal standards for sites on the national register. In November 2021, an appeals court for California’s third appellate district affirmed in full the judgment of the lower court, disagreeing with the complaints of the plaintiff, a group called Citizens for a Safe and Sewage-Free McKinley Park.

Dalton LaVoie, Stantec’s lead landscape architect, explained that the baseball field was converted because there was a need for something more multi-functional than a single-purpose baseball field. There will eventually be a commemorative plaque honoring George “Butter” Cole Field, Eliason said.

LaVoie also explained that new structures in the park were designed to maintain the historic look and feel of the park, adhering to the craftsman style of the existing building. Now, all three shade structures in the park share the same coloring and details.

“The new restroom that we added borrowed detailing from the Clunie Center,” LaVoie said.

And in one example of how the design married form and function, the new bathroom features a chimney that serves as a part of the exhaust system. Rather than building a pipe that sticks out of the ground, the team integrated the system into the design of the new structure in a way that matches the existing restroom, which also has a chimney on it.

Trees were also a concern for the group that filed the lawsuit. Fewer than seven trees were removed, and none were mature growth trees. More than 60 new trees were planted, LaVoie said.

Do you have questions or concerns about the changes at McKinley Park, or how the vault works? Send us an email at utilityteam@sacbee.com.

This story was originally published December 14, 2021 at 12:23 PM.