With your competition striving to complete jobs under budget and before deadline, being flexible and open to the way you approach a particular project can help you compete with the best and brightest the industry has to offer. While it’s true that most jobs have already been spec’d prior to bidding, most specifications include only an outline of the basic materials required by the project developers, leaving the decision of whether to use additional materials and the choice of application method up to the contractor. Being aware of the factors that affect the production of a successful vegetative stand can be helpful in choosing not only the best possible materials for a particular project, but also the best way to apply them.
Managing erosion control projects from Malibu, CA, to the rainforests of Peru has helped Chuck Austin, president/owner of Revex Inc. in Longmont, CO, develop a unique perspective regarding the vital factors in getting a stand of vegetation to grow. “First you have to understand that erosion control is basically just another branch of farming. At the very heart of this business is getting the seeds in the soil, and every extenuating factor that makes this process more difficult requires you to raise the stakes in terms of the materials and types of application that are required.” For example, consider what might be required to apply seed to a flat, dry area. Then make that surface a 2:1 slope, and suddenly things have become somewhat more difficult. Add an inability to access the area by large vehicles and then factor in a high probability of rain over the next few months, and now a relatively simple job has become something much more challenging. The ability to move from a base level of application to something more complicated while understanding the whys and hows of the process is the ultimate goal.
“No two project sites are exactly the same,” continues Austin. “While the environments may be similar, they will never be exact. By looking at all the variables of a particular project and learning to appreciate how they might affect your choice of materials or application method, you’ll already be ahead of the game.” The basic factors to consider at every project site are derived from the arsenal of common sense that most EC professionals already possess. While the factors themselves are not particularly difficult to grasp, the real trick is applying them to a particular job and achieving the desired results.
The Basic Factors for Your Project
Natural Habitat of the Area. Spending time to develop an appreciation for the area’s native species of plant life can save a lot of time and resources on any project. While the benefits of using native species have been well documented in regard to the long-term vitality of a vegetative stand, they may also extend to your bottom line as the use of native materials can go beyond just your choice of seed. With some creativity, native materials are often a less expensive substitute for non-native or synthetic mulches, soil amendments, and fertilizers that must ordinarily be shipped in from significant distances.
Soil. A simple soil test can be an invaluable tool in assessing the success of a project. Determining what is in the soil also allows you to identify what isn’t in the soil and what needs to be added in order to get the plants to grow. Knowing what needs to be added to the soil in terms of fertilizers and biostimulants can dictate the mode of application, as well as help transform uncertainty and guesswork into an efficient and successful operation.
Weather and Atmospheric Conditions. Another factor to consider is the typical weather patterns of an area and especially how those weather events might affect the project site; i.e., whether sudden rain events cause sheetflow down the slope or if the water is harmlessly diverted to storm drains. Knowing the weather and how it interacts with the environment will influence material selection and application and might also determine what, if any, extra measures are needed to keep soil on-site while work is completed.
Type of Slope and Terrain. Obviously, steeper slopes will require more care, and the accessibility that the slope provides will influence the choice of application method.
Availability of Materials. Using materials that are readily available versus those that need to be procured from abroad and then shipped to the job site can keep costs down and also dictate the choice of application method. “A good example is a project we did in Taiwan,” recalls Austin. “While cereal grains were scarce, there was an abundance of water, so a hydraulic application was the best choice.”
Cost. Once you have determined the ideal choice of materials and application based on the above factors, the next task is to fit that approach into the budget. Some tradeoffs are inevitable; however, creativity and flexibility can often keep costs down without too much compromise.
Remember that this list of factors is not exclusive, and each factor rarely operates alone. As you know, the job site is always a unique and unpredictable place to work, and often various factors will operate together to ultimately influence your choice of materials and application.
For Michael Hogan, president of Integrated Environmental Restoration Services Inc. in Tahoma, CA, near Lake Tahoe, the overall approach to every project is to look at the disturbed ecosystem, find out what’s missing, and develop the most efficient and feasible strategy to replace it. A soil scientist by training, Hogan has been involved in the development of what is called the “Wildlands Approach” to EC projects. The approach stems from a belief that attempting to re-create the native ecosystem is a far more reliable approach than the standard procedure of throwing down seed and fertilizer and hoping something will grow. “The crucial difference between the Wildlands Approach and the traditional Agronomic Approach is that [the former] strategy focuses on what would normally exist in this environment and how to put it back,” he explains. “Nothing fosters successful growth and longevity like mimicking the natural ecosystem.”
Working in the high Sierra Nevada mountain range that runs between northeastern California and the Nevada border, Hogan often deals with a host of unique factors that has helped develop this individualized approach to erosion control. On a recent project, Hogan first analyzed the various factors that might have affected the success of the project before getting down to business.
“The Spatz Parking Lot Project in Incline Village, Nevada, is a good example of how I used this approach,” explains Hogan. A barren, 300-ft. slope ranging from 1:1 to 0.75:1 across a 2.5-ac. project site was not only an eyesore, but it was also one of many areas contributing to increased water pollution in Lake Tahoe. To make things challenging, the slope was bordered closely at the bottom by a busy parking lot and at the top by numerous residential dwellings. But, true to form, Hogan applied the Wildlands Approach and ultimately met with success.
The first job was to attempt to capture renegade sediment and slow any water traveling down the slope by using barriers running perpendicular to the slope. The wattles were made of coir fabric filled with pine needles—a native material found in almost annoyingly great abundance in this mountainous region. The 10-ft.-long wattles, ranging from 8 to 12 in. in diameter, were staked into the soil before any other work was started. “Because the terrain was so steep, gravity was a major issue,” notes Hogan. “We had to find an efficient way of slowing the water and keeping the soil on-site.” By using the native pine needles and employing Hogan’s Shred-Vac Systems material spreader to fill the coir tubes, a creative and inexpensive solution to a common problem was born.
The type of seed to use was chosen based on surrounding species of plant life. “We selected a combination of grasses and shrubs to better re-create the surrounding environment,” Hogan explains. A blend of blue wild rye, mountain brome, Idaho fescue, manzanita shrubs, white thorn, and bitter brush was ultimately chosen based on the success of those species in nearby areas. Application of the seed was done both by hand and with the Shred-Vac Systems material spreader. “We hand-seeded the areas around the wattles as they were installed,” says Hogan, “but we didn’t want to hand-seed the entire site because we did not want to unnecessarily disturb an already delicate area.” Application of the seed through hydroseeding was also rejected. “The Shred-Vac is very efficient and doesn’t require the use of any water,” he adds. “By shooting the seed as a dry mixture, we basically eliminate a whole step in the seed distribution process; namely the procurement of water and the subsequent agitation process.”
Once the choice of seed was made, the task of getting those plants to thrive was the next objective. “The first factor I looked at was the composition of the soil,” recalls Hogan. “I took soil samples from the project site, compared them with samples from adjoining areas, discovered what was missing, and then began developing a way to make up the difference.” For Hogan, a key factor to success was the use of compost to replace nutrients in the soil combined with ground covering to protect the soil surface, reduce evaporation, and create a more aesthetically pleasing area. “Typically, straw is the ground covering of choice in this business,” he says. “But pine needles have been the natural ground covering in this area for eons and have proven to work very well in my experience.” Likewise, more recent landfill diversion requirements regarding greenwaste have pushed for the discovery of new uses for this abundant material.
There are numerous benefits to using the native pine needles. First, because the soil ecosystem is a complex environment made up of a host of elements, including microbes and fungi, the pine-needle mulch is better able to mimic the makeup of the native soil cover. Second, the abundance of pine needles in this region makes for efficiency of acquisition and transport. Third, using the pine needles instead of landfilling the material saves on dumping fees. Finally, because the pine-needle mulch lasts up to seven years—compared to straw that lasts from one to three years—there is also the potential for long-term cost savings.
Application of the mulch was once again accomplished through the use of the Shred-Vac material spreader. The machine, which is either top-loaded or uses vacuum to gather materials, is mounted on a 5- x 12-ft. trailer equipped with hitches at both ends. It can be loaded and distribute materials from four sides. “This machine is perfect for this application,” states Hogan. “There is no other technology available that’s able to distribute the materials despite the abundance of sticks, rocks, and pine cones found in the pine needles.” The Shred-Vac is equipped with a hammer mill that makes quick work of these foreign objects. “Also,” he continues, “the machine works very quickly and is able to shoot dry materials, so we don’t need to add and mix water.”
The entire slope was finished within 10 working days, including a few days of wet weather when work was put on hold, and given recent progress, this project seems to be working out as planned. By knowing the various factors at play in his work environment and understanding how they might affect the way he does his job, Hogan managed to beat deadlines, keep costs down, and get the job done right.
When the Going Gets Tough…Get a Helicopter
Extreme topography can often be the most important factor at a job site. The following account describes how some savvy professionals not only successfully completed a project located in virtually inaccessible terrain, but also developed a whole new application method that the industry is sure to see more of in the near future.
A Superfund site, the purpose of the Bunker Hill Revegetation Project in Kellogg, ID, was to alleviate the effects of years of mining and related activities that chemically scorched a large area around the mining operations. The 1,050-ac. site, characterized by 2,000 vertical ft. and slopes ranging from 1:1 to 2:1, was a graphic eyesore and the source of serious erosion that was polluting nearby waterways with chemically saturated sediment.
“The biggest challenge of this project was the sheer size and inaccessibility,” points out Shane Waechter, president of Tri-State Hydroseeding Inc. in Kingston, ID. “Because there are no real roads, only small terraces, we had to figure out a way to get the materials on the ground efficiently.” Waechter took into account all of the relevant factors that might affect the success of the project and developed a unique strategy for getting the job done quickly and cheaply.
Erickson Air-Crane Company of Central Point, OR, became involved in the project when it became clear that traditional application methods would not work on such a large and remote site. After some brainstorming, it was decided that the technology normally employed by Erickson to deliver fire-retardant materials to large wildfires would also work for erosion control applications. Once the 2,000-gal. tanks were adapted to distribute a denser mixture of mulch, seed, and tackifier, the rest was up to the pilots. “We left a lot of the placement decisions to the pilots,” adds Waechter. “But the atomization of the material that occurs as it falls through the air ensured even coverage wherever we made the drops.”
In terms of cost, the use of helicopters on this type of project saved both time and money. “A job this size with such limited access would have taken months to years to complete using traditional application methods,” says Waechter. “Also, the potential danger in sending men and machines up that hill without any roads was another cost consideration. One injured man or wrecked truck can easily offset any profit.” Another factor was the weather. “If we were to drag this project over several months, we’d risk inclement weather affecting the work we’d done.”
While the choice of application method was the primary hurdle on this project, there were other factors that influenced the mode of application and the choice of materials. “Because various chemicals had saturated the soil and affected the natural composition of the soil, we had to first apply something to counteract this effect,” Waechter explains. An application of lime, delivered by helicopter, was chosen to neutralize the pH of the chemically sodden soil. Next, an application of seed and tackifier was added to bond the lime and keep it on the hill in case of severe weather events. “We used soft white winter wheat seed because of how rapidly it takes, along with tackifier to make sure everything stayed in place.”
Some work still remains, but the first applications were accomplished in a matter of days. “We started on June 21 of this year and had to be done by July 30,” Waechter recalls. “We finished on July 2.” He reports good results so far and expects the project to be a total success.
According to Waechter, the key to success is an open mind and a willingness to try new things. “It’s important to look at the big picture and not be above trying new things. Also, don’t let ’em tell you it can’t be done, because you don’t know until you try.”
Working With What You Have
For Bob Jerszyck, owner of Bob Jerszyck Landscapes in Worcester, MA, all of the above factors influence the choice of materials and the application method he employs on a particular job. Beyond that, however, a host of other factors, including the future uses of the site and the proximity to other uses, comes into the decision-making process.
At the Emerald Hills Housing Development Project in Hopkinton, MA, the requirement of several 4- to 5-ac. retention ponds and the proximity to a large housing development influenced Jerszyck’s approach to the project. “In this case, we decided that the use of wildflowers would be the best choice,” says Jerszyck. “If the area were to be maintained, we would usually use a blend of bluegrass and creeping fescue. However, in a natural area like this, we use the wildflowers because they are more durable and because of the proximity to the housing there was also the aesthetic element to consider.”
Jerszyck’s application method of choice is hydroseeding. “We generally hydroseed without question. The factors that would make us consider a drop-seed application is access to the job site and access to water.” According to Jerszyck, however, this is rarely a problem on his projects.
In addition to applying seed, Jerszyck installs both silt fence and hay bales at most sites to ensure that the soil stays on-site in the event of unexpected rains. There are often local regulations that govern renegade soil and the amount of time a site may be left uncovered. “Contractors often face fines if soil travels off-site or even if a site is left uncovered past the requisite time,” he explains. Local environmental regulations may even govern the use of certain materials and the choice of application method. “It is important to know the rules of the area you are working in to avoid unnecessary fines.”
The way that certain materials might interact with the equipment and the environment is another important consideration for Jerszyck. At the Deer Run Housing Project in Rutland, MA, the angle of the slopes and the potential for spring rains suggested that tackifier in the hydroseeding slurry would be required. “Normally, I avoid using tackifier if possible,” Jerszyck remarks. “Tackifier tends to plug up the hoses and is extremely slippery once it is on the ground.” Also, because a sidewalk bordered the slopes on this particular project, hay bales and silt fencing were not options. “We had to use the tackifier because of the nature of the project. It’s not my favorite material, but you do what is required to get the job done right.”Jerszyck also recommends being creative in order to keep costs down. “We have used tree logs and stumps for riprap when no rocks were available. The stumps had to be removed anyway, and the landfill won’t take them because of diversion requirements.” He has also applied his creative mind to accessing job sites. “We have used everything from frontloaders to Bobcats to snowshoes and a toboggan to get materials to the job site. Being successful requires efficiency, and that often means using what you have available and making it work.”