Evergreen Landcare were sub-contracted by Fulton Hogan on the East Taupo Arterial Project from the initial stages of earthworks.
During this time we provided straw mulching, hydroseeding and grassing services as well as final formation, grooming, turf establishment and mowing on roadside swale drains.
The low fertility and easily erodible pumice soils on which the East Taupo Arterial is built, coupled with the proximity of Lake Taupo’s clear waters created unique challenges. While Evergreen’s standard hydroseeding product was used in some areas, the large cuts and fill batters of raw pumice called for use of our more technical hydroseed mulches.
Hydrosoil® was used to establish grasses on areas such as the vertical abutments of the TH2 Gully culvert. It acts as an artificial top-soil, containing grass seed and higher levels of course organic material along with mycorrhizal fungi to promote grass growth and kick-start the natural soil-building processes. On site we applied Hydrosoil® from a hanging frame held up by an excavator onto a vertical terramesh wall.
Bioblanket® is a bonded fibre matrix that provides protection to vulnerable soil surfaces from the effects of water, wind and frost until grasses can become established. Bioblanket® was used to establish a dense grass sward in the 30 kilometres of swale drain.
Siltstop® is a filtration tube product that can be used for temporary or long term control of water runoff and sediment. Due to its portability Siltstop® was used extensively on the Eastern Taupo Arterial to protect germinating seed beds in the roadside swale drains from autumn rain storms.
Due to the large areas of soil that were exposed at one time, the application of straw mulch was critical in order to minimize water-borne sediment movement and comply with environmental consents. Evergreen used tractor-mounted straw blowers to apply a layer of hay over high risk areas.