For more than a year, engineers, hydrologists and other experts grappled with the problem of how to stem the choking tide of silt that is pouring into Buena Vista Lagoon.
Using complex computer modeling techniques and other high-tech tools, the analysts searched for ways to reduce erosion upstream from the lagoon and cut the growing volume of silt, which threatens to turn the coastal wetland into a giant sandbox within a decade.
Eventually, they found their answer and devised an innovative prescription for a healthy lagoon. But now an even tougher task looms: Officials must mobilize support for their solution and find the money to do the job, which will cost more than $1 million.
“We now know how to help Buena Vista, we just need to line up the funds to pay for it,” said Laurie Marcus of the California Coastal Conservancy, which financed a $52,500 study of the lagoon and its siltation problems. “One thing’s clear. If we don’t all get together and fund this thing soon, we won’t have a lagoon left to worry about.”
A tentative financing scheme for the project is outlined in a final version of the Buena Vista study, by Carlsbad engineer June Applegate, to be released Monday. Under this proposal, money from an assortment of state agencies would be used to finance the bulk of the project, which is designed to slow the speed of water rushing down Buena Vista Creek and thus reduce the load of silt swept into the lagoon.
The state Department of Fish and Game, the Environmental License Plate Fund and the Conservancy itself are among possible contributors to the project, which is expected to cost more than $1 million plus annual maintenance and operation expenses.
The proposal also calls for Carlsbad, Oceanside and Vista--and the developers who build within their city limits--to shoulder a share of the burden.
Marcus said that if sufficient state financing is secured, the local governments might only be required to cover the upkeep of various structures designed to slow the water flow--an annual total of $139,000 for the eight structures proposed.
In addition, Marcus said, the cities would be asked to finance an educational program--estimated at $6,000--aimed at improving grading practices among developers and farmers.
But the Conservancy has one other request, one that has sparked criticism from some local officials. Marcus has asked the three cities to pass an ordinance regulating what property owners along the creek do with the stream bed. In the past, developers have often chosen to prepare a site by lining the channel with concrete. That practice increases the velocity of water, causes severe erosion downstream and consequently increases the volume of silt that ends up in the lagoon.
Under the proposed ordinance, owners who wish to develop along the creek would be required to take measures to reduce the water speed--and thus the volume of silt--by reducing the steepness of the stream-bed grade.
Officials in Vista have opposed this suggestion, which is considered critical to the success of the anti-erosion efforts, because it would consume what is now developable land along the Buena Vista Creek.
“What she proposes is totally unreasonable and totally impractical,” said Joe Karrer, Vista’s director of public works. “The city is one of the developers on the creek, and that’s about the only commercial land we’ve got left. If they take that bread and butter away from us, poor Vista will be left to sit and rot away.”
Karrer also said he still has concerns about financing operating and maintenance costs, and is worried that because most of the proposed watershed improvements are in Vista, “we might get stuck with more than our fair share. We’re trying to be cooperative, but heck, we don’t even have the lagoon in our town.”
In other cities, reaction to the proposal was generally favorable. Oceanside Councilman John MacDonald said, “I’d need to see precise dollar figures before committing to anything, but I know we’d be willing to participate in something to avoid spending $1 million to dredge that lagoon again.
“Buena Vista is a very great asset for the three communities, visual as well as recreational and as open space. I think people now recognize we have to come up with a maintenance program to keep it clear of siltation.”
Commenting on the proposed ordinance regulating development along the creek channel, MacDonald said he would support “reasonable requirements on people that own property along that route.”
In Carlsbad, Councilman Richard Chick said he was unfamiliar with the specifics of the proposal but expected that his city “would do our part because we have a big stake in that lagoon.”
Like all of North County’s coastal wetlands, Buena Vista Lagoon has become increasingly plagued with sedimentation problems as urbanization of the watershed has proceeded. Poor grading practices on farmland and at nearby construction sites is a major cause of siltation, while erosion of the stream bed by the creek’s high-speed water flow has contributed as well.
Ordinances designed to improve grading practices and reduce the load of silt dumped into the wetland have been passed in the three surrounding cities, but enforcement has been lax. The problem is so serious it sparked the creation of an unusual “erosion control hot line” by the nonprofit Buena Vista Lagoon Foundation.
In 1983, the state Department of Fish and Game completed a $1-million dredging project at Buena Vista, scooping out nearly 175,000 cubic yards of silt. But because of the ongoing tide of silt rushing westward, dredging is only a temporary--and a very costly--solution.
Applegate, the author of the study, said the situation is complicated at Buena Vista because it is a fresh-water lagoon with a weir--or floating dam--at its mouth. Consequently, the silt has nowhere to go once it enters the lagoon. Estimates show it will become a meadow in 10 years if nothing is done to intercept the silt, Applegate said.
Marcus said she will be presenting the financing proposal to the three city councils for comment in the next month. The proposal also needs the approval of the state Coastal Conservancy Board of Directors.