Seed for Restoring Wetlands

Thursday, May 01, 2014

Seed for Restoring Wetlands

By Janis Keating

an excerpt from Sprouting BMPs

Published in the May 2014 issue of Erosion Control Magazine

North of San Diego, CA, near the Del Mar Fairgrounds, I-5 crosses the 460-acre San Dieguito Wetlands. A recent $90 million project expanded and restored this area, which has become a boon for wildlife; ocean fish migrate in to use deeper water as hatcheries, and the salt marsh vegetation provides nesting sites for endangered birds. Migrating birds that travel the Pacific Flyway also find San Dieguito a comfortable resting place.

During certain periods between 2010 and 2013, Hydrosprout Inc. of Escondido, CA, seeded 100 acres of the wetlands. "The general contractor, Marathon Construction Corp., did the grading, building berms around the wetland areas," says Hydrosprout operations manager Mark Webster. "When they were finished with a section, we'd follow up by hydroseeding. Although there's water onsite, most of the time we applied seed and hydromulch in the fall and winter months to take advantage of the rains."

The hydroseeding mix included Profile Products' Terramatrix SFM and a wetlands seed mix from S&S Seeds of Carpinteria, CA. "The project designers came up with the specs for the mix," Webster explains. "Seeds had to be collected within a 25-mile radius of the project. S&S came up with the mix we needed, which we applied at 22.85 PLS pounds to the acre."

The wetland mix included four species of saltbush (Atriplex lentiformis lentiformis, Atriplex lentiformis, Artemisia californica, Artriplex canescens); a native primrose (Camissonia cheiranthifolia); Menzies' goldenbush, from the daisy family (Isocoma mensiesii); an evening primrose (Oenothera elata); desert broom (Baccharis sarothroides); California plantain (Plantago erecta); California buckwheat (Eriogonum fasciculatum); black sage (Salvia mellifera); coyote brush (Baccharis pilularis); heliotrope (Heliotropium curassavicum); deer weed (Lotus scoparious ssp. scoparious); and Cuman ragweed (Ambrosia psilostachya).

Hydrosprout's work progressed with very few hitches. "A couple times during winter rains, the area got a little muddy, so we'd wait. They had water onsite for us to use with the mix, so we didn't have to truck any in. Everything we did was truck accessible," Webster says. "In some dredge areas, we had access up to a point, then we had to attach up to 500 feet of hose to spray the area. We had a small problem when working around the I-5 freeway. We had to go under the bridge, and our 3,000-gallon Bowie seeder wouldn't fit. We had to bring in a 1,500-gallon hydroseeding machine to work that area."

Few re-dos were necessary. "There were some areas that might not have grown as well, so we did some touchups, and in places that were regraded we had to hydroseed again," he says. Hydrospout, which performs jobs of all sorts, from residential to public works and Caltrans projects, has been in business since 1988, and "we've used S&S Seeds all that time," Webster says.

To read the full article click here.