At the March 21 San Juan Bautista City Council meeting, City Manager Don Reynolds presented a report on the flooding at Mission Farm RV Park, with photographs of the high waters and devastation.
Reynolds told BenitoLink that there is still no clear reason for the flooding of the park.
“It is clear it came from the unincorporated area into the city,” he said. “And why it came at that volume or that speed nobody knows. When the water comes down the canyon, some of it goes behind the homes on Main Street in the Alameda and some of that water poured out of its banks and down the Alameda to the intersection to the highway storm drains that were clogged with trash cans and other debris.”
Another problem, he said, was a retention pond at the Copperleaf development which seemed to be diverting water into the park.
Damage assessments are still being made, with representatives of FEMA having visited the site. Reynolds said that Caltrans had also been asking about the damages to assess whether the recent work on the highway expansion had contributed to the flood.
Mission Farm RV Park owner Kurt Kurasaki told BenitoLink he got word on the morning of March 10 that a storm was coming and it was going to be a big one. He went to check out his property and discovered a problem immediately.
“It’s 8 o’clock in the morning and I am driving through the Alameda,” he said. “And I can’t get through. The Alameda had become a river and all that water from the canyon was just coming down and flooding. There was already a vehicle stuck in the high waters.”
The deluge on that day brought serious flooding to opposite ends of San Juan Bautista. The heavy rains drowned Mission Farm RV Park, between Hwy 156 and San Juan Hollister Road, and overwhelmed the drainage system of the Rancho Vista development on First Street.
For Kurasaki, it spelled disaster. The creek running by his property parallel to Hwy 156 was overflowing and by 10 a.m. Water was cresting over from the Caltrans property onto his.
“The berm started to erode and give way,” he said. “That’s when the flood happened and I started to evacuate everyone. Most people were out by noon, but we did not realize the severity of it until later. FEMA came out and did an assessment but made no promises in terms of who is going to get assistance.”
Kurasaki called City Councilmember John Freeman and asked him to help assess any dangers posed by toxic waste on the site.
“I went out on Sunday, the water had receded a bit,” Freeman said. “But there was still severe flooding and Kurt was trying to build up the levee that broke. I saw four or five rigs that were flooded past their entrance ways and into the flooring, pretty much ruined and ready to junk. I saw areas that were still flooded with three or four feet of water.”
Doug Pike of MMS Engineering Services, acting as city engineer, was also at the March 21 City Council meeting and presented a report on the drainage problems at Rancho Vista, which he described as resulting from constrictions in the flow of water at various points, causing the system to overflow into areas intended for vehicular or pedestrian use. He estimated the cost of repairing the damage at $250,000.
The problems begin south of the development where, he said, there is a creek that is full of sediment, leaving it unable to carry large amounts of water. Overflow spills onto the field behind Rancho Vista and flow through the development is stifled at a completely occluded culvert near the playground at the south end.
To further complicate things, the culvert near First Street is only 25% of the capacity of the culverts flowing into it, creating more overflow, he said, and the stormwater basin and pedestrian bridge culverts both exceed their capacity.
Pike had several suggestions for contending with the problems, beginning with cleaning out the creek channels and the occluded culverts running under the roadway. He also suggested further studies of the existing design and to estimate the rainfall intensities of atmospheric river events in this area as a way to prepare for future deluges.
“I think we can agree these storms were not normal,” he said. “I have never seen rain like that in 45 years. We need to identify weaknesses and determine specific recommendations to enhance the capacities and flows from the downstream creek channel.”
Pike also said that there should be lessons learned from building the Rancho Vista development, which he said was designed for 10-year events—large storms that can be expected to exceed normal rainfall on average every 10 years—instead of being designed for 100-year rainfall, which he said we should expect in the future.
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