The Magic is in the Mix

Monday, May 13, 2013

By Margaret Buranen

June 2013

Erosion Control magazine, the official journal of the International Erosion Control Association

Working Across Ecozones

Dangerous animals are also present in areas being hydroseeded by Hydro-Plant Inc. of San Marcos, CA. Safety classes for workers stressed awareness of rattlesnakes and the possibility of mountain lions. So far the snakes have been spotted, but no mountain lions-only the tracks they left. Hydro-Plant is hydroseeding a utility corridor that stretches from east of San Diego to the coast. The crews are revegetating and providing erosion control following the installation of above ground power towers for different utility systems. "The weather's been a big factor on this job," says Rob McGann, president of Hydro-Plant. "In southern California we don't usually experience high winds and rain storms like we've had." On some winter days, the wind chill temperatures dipped into the high teens. To the wildlife and the cold, wet weather add the difficulty that remoteness brings. "Some sites were basically off-road so that we had to truck water in from miles away," McGann says. Work sites ranged from 5 to 30 acres, and each was different. McGann says best management practices (BMPs) varied among the sites. Work covered five distinct ecozones: coast, foothills, mountain, mountainous-desert, and desert.  Seed mixtures for each distinct ecozone within the project were custom-blended by S&S Seeds in Carpinteria, CA, a company that specializes in native and rare seeds.  Choosing and then obtaining the exact seeds meant working far ahead of the project. "We had some nurse crop seed," McGann says. Soil types varied from sand in the desert ecozone to some areas with limestone deposits.  No soil additives were used. "The environmental consultants [working] with us wanted the sites to be as close to their natural states as possible," McGann explains. Except for seeds specific to a particular ecozone, the mix-water, mulch, and tackifier-was "pretty much the same on all sections," McGann says. "On the flat sites the tackifier was more for fugitive dust prevention." For the tackifier, the Hydro-Plant crews used Super Tack, a dispersable, biodegradable guar gum tackifier from Rantec Corp. of Ranchester, WY. Super Tack improves pump performance and keeps the slurry mixture flowing smoothly.  It mixes easily and is safe for the environment.  Slopes were rarely greater than 2 to 1. Coir blankets were used in some areas. Wattles were also used in some sections. In the arid regions, the Hydro-Plant crews used imprinting, or mechanical seeding.  By creating tiny microclimates, the resulting seedlings had a much stronger chance of thriving. The most challenging part of this utility corridor project was managing access to the remote areas. Reaching these areas in the future will require using helicopters. "They had to regrade the road so that we could move our equipment," McGann says. "They were closing the road behind us. We had to get it right the first time." These hydroseeding professionals prove that the magic of their successful projects is in the mixtures they use.  While the results look like magic that would delight the old alchemists, they come about from knowledge, experience, and a lot of hard work.

 

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