Design alternatives for the Upper Llagas Creek flood protection project could send the natural conduit’s overflow underground through downtown Morgan Hill, or through the back yards and private properties along the body’s existing path when heavy rains hit.
Design alternatives for the Upper Llagas Creek flood protection project could send the natural conduit’s overflow underground through downtown Morgan Hill, or through the back yards and private properties along the body’s existing path when heavy rains hit.
The options were presented to the public for the first time last Wednesday at the Morgan Hill city council meeting, and a former mayor suggested sprucing up the creek with recreational and aesthetic improvements over the strictly utilitarian concept that engineers and elected officials have longed for every time the downtown Morgan Hill floodplain has filled with water for the past 50 years – including a storm late last year that dumped 7 inches of rain downtown in 24 hours, flooding Monterey Road and causing about $140,000 worth of damage to public property.
Project designers, RMC Water and Environment and engineers from the Santa Clara Valley Water District, illustrated two options for each of two segments on “Reach 8” – the northernmost section of the Upper Llagas Creek flood protection project.
Regardless of which option or combination of options the U.S. Army Corps of Engineers, city and water district settle on, the entire project consists of six more segments continuing about 13.5 miles south of town to Buena Vista Avenue in north Gilroy – the total cost of which is currently estimated at about $105 million.
Most of the funding for the project is supposed to come from the U.S. Army Corps of Engineers, the lead sponsor on the project since the 1950s, but congressional allocations of federal dollars have been scarce. Last year, the city and water district decided to contribute $10 million for the design and environmental study phase of the project, hoping they will be reimbursed.
The top segment of the project, which traverses from Hale Avenue southeast to the area near Second Street and Del Monte Avenue, could take a “ballfields vs. backyards” approach, according to Steve Bui of RMC.
The ballfields option would leave the existing creekbed intact, and bury a diversion culvert underneath the sports fields next to Britton Middle School, then turn parallel to Del Monte Avenue until the intersection with Second Street – on the west side of downtown. The culvert, which would consist of two parallel concrete boxes about 10 feet by 9 feet, would connect two areas of the open creek and be designed to carry excessive runoff during heavy rains that would otherwise cause downtown flooding.
The backyards option would simply follow the existing creekbed which runs further to the west side of downtown, but the Corps would widen and deepen it in order to hold a higher capacity.
The southern segment of the project through downtown, from Second Street south to Ciolino Avenue, could take a “shopping center vs. Monterey Road” diversion path.
The shopping center option would follow the existing creek, south through the west side of town, including running both normal creek flow and storm runoff through a new culvert underneath the Dollar Tree shopping center at Dunne Avenue and Monterey Road. A culvert on that path was built “decades” ago to carry the creek from Dunne to Ciolino avenues, city manager Ed Tewes said.
However, the existing culvert is not capable of containing the kind of storms that have flooded Morgan Hill in recent years, and would have to be replaced with the same double-box design that would be used in a diversion channel to the north, Bui said.
Finally, the Monterey Road alternative on the south end of town would bury another 100-year-flood capacity culvert underground, parallel to Monterey Road from Fourth Street to Ciolino Avenue, where it would turn west at Ciolino Avenue and then meet up with the natural creek, which the Corps would improve as part of the same project.
Each option presents a unique set of advantages and disadvantages associated with their impacts on private property, tree removal, total cost and effectiveness at containing the heaviest storm runoff, according to designers and council members. Everywhere the flood channel remains above ground on the existing creek, the creekbed would have to be at least 15 feet wide and 15 feet deep, and will likely require significant concrete lining in some areas.
One possibility – an “enhancement” to the project suggested by former mayor Dennis Kennedy – received a mixed reaction from the current council. Such an enhancement might work with either design option for the flood channel, but would improve the existing creek with recreational and aesthetic improvements such as bike and walking paths, landscaping and other beautification elements, said Kennedy, who presented a similar concept “years ago” at the dais.
He likened such a “creek walk” with a park-like aquatic and pedestrian atmosphere to a similar project in San Antonio, Tex. Kennedy said such a project would complement the city’s vision for downtown and planned redevelopment projects, whose intent is partially to promote economic development and a variety of options for shopping, entertainment and travel downtown.
“The easy way out is to build a concrete ditch,” Kennedy said. “To do something like what we’re proposing is a lot more difficult, and takes a lot more work and study.”
While Kennedy and council member Gordon Siebert, who was elected in November and used to work in the city’s public works department, don’t think the city is on the verge of a windfall of federal cash for the project, two veteran council members think that pushing for a more complex design could slow down the higher-level congressional decision process.
Mayor Steve Tate said that flood control – not beautification or recreation – is the most important need for the project. He noted that the option to dig a diversion culvert under the Britton fields seems to be the most tree-friendly, would have the least impact on private properties and would benefit the school district which would gain new fields out of the project.
“(A creek walk) sounds like a nice idea – it’s bucolic, but when you get down to how much it would cost, upset the private property owners (along the creek) and what kind of benefit it would provide, it doesn’t add up,” Tate said.
Kennedy added that he doesn’t think the project will ever receive federal funding, and he thinks the city should use redevelopment agency funds for flood control.
Councilman Larry Carr also thinks the sooner the city is ready to proceed on the flood control project, the sooner it will receive federal funding. “We’ve been to Washington to lobby on this,” he said at last Wednesday’s council meeting. “Every day (of delays) starts the project over again. We should maintain our course and not send mixed messages to Washington.”
Siebert sees Kennedy’s idea of a creek walk as the third priority downtown behind flood control and a potential streetscape redesign on Monterey Road – a process that began earlier this year with community surveys. Other city officials noted that while construction on such a streetscape is a long way off, timing that construction with the Llagas Creek project – if the underground diversion culvert design is selected – would be convenient.
After flood control is taken care of, Siebert suggested perhaps the city could come back and add onto the flood protection project with recreational and aesthetic options in the future.
“The availability of a different experience (to the flood control project), and that would be a combination recreational and aesthetically pleasing path, on the west side of Monterey Road would complement the idea of people walking around (and shopping) downtown,” Siebert said.
