Saving the Bluffs

Wednesday, October 23, 2013

Saving the Bluffs

By Margaret Buranen

an excerpt from Hydroseeding Challenges for all Seasons

Published in the Nov/Dec 2013 issue of Erosion Control Magazine

For the last several years, Rob McGann, president of Hydro-Plant in San Marcos, CA, has had his hydroseeding crews working on beach bluff revegetation jobs. "We probably do two a year, on average," McGann says, noting that getting access is the most challenging part of the work.

Hydro-Plant is doing the reseeding for homeowners' beach bluff lots overlooking the Pacific Ocean in San Diego County. The residential lots range in size from one-tenth to one-half acre.

The hydroseeding follows construction of seawalls to stop erosion, which is a serious problem given the winds and water. Homes were built close to the edge of the bluffs, for the magnificent views. That practice has added to the instability of the land.

Another factor causing the high degree of erosion is the shallowness of the soil. Some of the seawalls are built on native sandstone.

"It's kind of a gamble to shoot seeds there and hope they'll find pockets of soil to grow in," McGann says.        

Installing seawalls and hydroseeding the bluffs for revegetation fall within the guidelines of the California Coastal Commission. This regulatory agency functions on a regional basis. The commission has broad powers to protect the sensitive coastal environment. It regulates what private property owners must do on their land that adjoins the beaches.

In areas where the beaches below are open for visitors, these hydroseeding jobs on bluff lots frequently draw the attention of beachgoers. They crane their necks to watch the hydroseeding crew at work with their hoses dangling from the hydroseeding equipment at the buff's edge.

"The guys have to belay down the slopes on ropes," McGann says. "Other times the contractors [for the seawalls] provide a cherrypicker for us to use."

The slopes are sheer drop-offs, though sometimes there are little walkways or ledges that the crewmembers can use. "It's 1-to-1 most of the time," McGann says.

Seeds for the beach bluff revegetation came from S&S Seeds of Carpinteria, CA. They were all for native wildflowers and shrubs. "We used two dozen coastal indigenous species, from Beach Evening Primrose to buckwheat, the more common type," McGann says. "We also included Sea Dahlia, which is unique to San Diego County."

For the hydroseeding mixture, "We used a heavier rate of application-3,000 pounds per acre instead of the usual rate of 2,000 pounds," he notes. He explains that the heavier application was necessary because of the very loose soil-lots of decomposed sandstone. "Plus, we have wind and water erosion issues," he adds.

The slurry contained guar gum binder as a tackifier and a humate product for fertilizer. Germination enhancer and soil activator were also added.

Revegetation here depends on rainfall for hydration. The Coastal Commission prohibits homeowners from installing irrigation systems. They can water with hoses, but water rates are high, and getting the water to reach the plants often isn't possible.

This type of hydroseeding work is typically done in the fall, anticipating the first seasonal rains of November and December. The heaviest rains fall in January and February, sometimes in March.

The jobs typically take one day or less to accomplish. "One in the north of the county took us three days," McGann recalls. "We had straight westerly winds [that would have blown the hydroseeding material away] that we had to wait out."

McGann says homeowners on these beach bluff properties are happy to see the hydroseeding crew arrive because they know it's the last part of work that has to be done so they are in compliance with the Coastal Commission.

Hydro-Plant's seed supplier, S&S Seeds, specializes in native seeds and native seed blends. Victor and Susan Schaff, who founded S&S in 1975, say climate changes have affected the business. "The two-year drought in California has refocused the need to use more native drought-tolerant plant seeds," Victor says.

Warmer temperatures have also changed the way that S&S Seeds grows seeds for sale to hydroseeding companies, plant nurseries, and other firms that rely on the company for high-quality native seeds in both standard and custom mixes.

"We have had to increase irrigation at our farm during the winter months, which typically were our wettest months," Schaff notes. This irrigation has, of course, added to the company's operating expenses.   

When asked about trends of recent years in the commercial seed business, Schaff says, "There has been a tremendous increase in seed usage to revegetate soils disturbed by solar site installations. They are primarily using native seeds with local origins."

S&S Seeds is a primary wholesale supplier to landscape contractors, government agencies, and seed distributors throughout the United States and abroad. The company keeps more than 450 acres in seed production and also does wildland collection of seeds. That amount of access to seeds means that customers can choose from more than 1,000 species of native grasses, wildflowers, and shrubs. They can order stock seed mixes or request custom seed mixes for commercial and residential projects.

S&S Seeds will even contract to collect seed from specific sites for a project. The seeds so collected are identified, cleaned, tested, and stored properly. S&S employees can locate stands of harvestable plants within the project's defined zones. This stand assessment helps ascertain potential yield of the plant's seeds, harvest date, and the size of collection crew required to meet a job's deadlines.

S&S Seeds maintains a state-of-the-art seed cleaning facility where harvested field material, after proper drying, is taken. The dry, conditioned seed is assigned a unique lot number and stored in the company's warehouse facility. Special long-term storage arrangements can be made if needed. If desired, samples are sent to an independent certified seed-testing laboratory for purity and germination tests. Specific reports as required by the project can be provided.

The company's acres are used not only to grow seeds for customers and obtain a ready supply of seeds needed for specific ecoregions, but also for research and trial fields. Both  new and old species can be easily compared for productivity, disease resistance, and other characteristics.

To read the full article click here.