Protecting a site from erosion and restoring the area is always a concern among developers and project managers with most construction projects. This challenge can be amplified by slope, soil and extreme weather conditions, including storms and harsh temperatures.
One project headed by Equitable Gas Company (EQT), headquartered in Pittsburgh, Pennsylvania, faced what would turn out to be a record winter for snow and ice, creating an even higher potential risk of erosion than normal. Even though the project was completed in early fall, project managers were aiming to protect the post-construction site from erosion and restore vegetation before winter temperatures dropped. The team worried that the arrival of winter would prevent seed from germinating and subject the site to winter rain and snow melt, any one of which would have delayed completion until the spring.
Finding the right product
In early fall 2013, EQT (now known as Peoples Natural Gas) completed a 10 mile pipeline project in the hills of Alleghany County, Pennsylvania, and needed to stabilise the site relatively quickly post construction, when all soil-disturbing activities at the site had been completed and the site was ready for final stabilisation.
Project managers working on the EQT pipeline project sought a product that would protect the area from erosion and return the vegetation removed during the construction phase of the project. The challenge they faced was finding a product that could either (1) prevent erosion and quickly re-establish growth or (2) protect the site throughout a harsh winter if growing conditions got too cold in the fall to establish sufficient growth.
After careful research, the production company chose EarthGuard® Fiber Matrix (FM), a cost-effective alternative to rolled erosion control matting or blankets and other spray-on products.
EarthGuard is a soil-stabilising emulsion, specifically formulated to work on the ionic level with soil chemistry to reduce erosion and sediment run-off. It is non-toxic, 100% biodegradable, and conforms to the Pennsylvania Dept. of Environmental Protection ‘Final 2010 Erosion and Sediment Pollution Control Program Manua’l. EarthGuard Fiber Matrix, a product developed by Terra Novo Inc., is a one-step application product that combines the proven erosion-control chemistry of EarthGuard with wood/cellulose fibre. It is applied as an aqueous slurry, either by itself or in combination with seed, using a hydroseeder.
EarthGuard is chemically engineered to be effective at low rates while absorbing the impact of raindrops and providing immediate dust control, erosion control and soil stabilization until permanent vegetation is established or construction has resumed. This means EarthGuard fit the bill for all of EQT’s needs for this pipeline project, and then some.
Preventing erosion and promoting vegetation at an effective cost
Best defined as a stabilised fibre matrix, EarthGuard works in four different manners:
- Throughout its service life, EarthGuard works directly on and continually with soil to prevent the degradation of existing soil structure caused by erosive forces.
- EarthGuard’s long-chained negatively charged particles create a liquid net over the top of soil preventing the soil movement of small particles.
- The product flocculates any sediment that might get dislodged during a rain event to reduce turbidity.
- Fiber used in combination with EarthGuard prevents splash erosion.
As a result, EarthGuard promotes germination by stabilising soil, amendments, and seed while maintaining soil pore space which helps to preserve soil infiltration capacity and the ability of microbes to breath.
These unique attributes are unlike other products, such as bonded fibre matrix (BFM) or fibre reinforced matrix (FRM) which simply dry and harden to blanket a soil layer underneath, often creating a layer so hard and thick that it prevents seed germination and growth.
To be effective, BFMs and FRMs require a 3500 lb/ac application rate on slopes 2:1 or greater. However, at its heaviest recommend application rate, EarthGuard requires at least 500 fewer pounds of fibre per acre. This results in less water required and a reduction in material and application costs.
In the past, on a typical pipeline project, EQT utilised erosion control matting, but after trying EarthGuard they quickly realized the money they saved. Less personnel were required to restore the site, the project was completed quicker and most importantly, the applied cost was significantly less.
On 18th September 2013, Penn Line Service of Scottdale, Penn. sprayed EarthGuard at a rate of nine gallons and 2500 lbs of 70/30 wood/paper fiber per acre over a 10 mile stretch. Other erosion-control products would have required two or three separate multi-directional applications to ensure full coverage. With EarthGuard’s quick, reduced-material application process, coverage of the site was completed in just one application.
By 15th October 2013, full vegetation had been established while withstanding several heavy rain events, all of which pleased inspectors and the site’s project managers, Bruce Allen Inc.
For the EQT pipeline project, EarthGuard Fiber Matrix proved to be the best-suited erosion control and reclamation product to restore the site. Erosion was eliminated in the pipeline’s path, while vegetation was restored to its natural state well before the winter.
Edited from source by Elizabeth Corner
Read the article online at: https://www.hydrocarbonengineering.com/product-news/30052014/product-news-developing-vegetation-for-pipeline-projects/