“ Natures Image is an outstanding firm with an outstanding staff. The quality of their work far exceeds any other native landscape firm. They provide innovative and cost effective solutions for implementing projects and for resolving the difficulties that often arise from environmental conditions at the project sites.”

Mari Schroeder, Project Manager, ECORP

Overview
Big Tujunga Wash Mitigation Bank project encompassed 100 acre site of willow riparian, oak/sycamore woodland and coastal sage scrub terrain overrun with Arundo and other non-native plant species. Los Angeles County Department of Public Works, through Chambers Group, engaged Natures Image as landscape construction specialists for this restoration project. This public works project demanded economical use of public funds and a light footprint that would preserve thriving native species while eliminating exotic species that interlaced it.

The Challenge
A riparian environment running throughout this site was home to several endangered fish species. Project owners were hesitant to allow heavy equipment into the site as they calculated the impact machinery would have crossing the waterways and compressing soil. Without machines performing all work by hand would have caused construction costs to be driven up to unacceptable levels.

The sheer volume of plant debris to be eliminated presented a challenge. Owners did not want any Arundo remains left on the site fearing its resilience, but costs associated with a full-scale removal were prohibitive.

Two one-acre ponds were overgrown with water hyacinth. Specialized equipment for large-scale removal of this infestation was not economical but the abatement was large enough that hand removal would also prove costly. These and many other challenges required innovative and economical solutions.

The Solution
Natures Image modified methods to address the requirements and challenges of this restoration and reduce cost projections. The plan as developed by all team members included removal of non-natives, grinding debris in-place, installing irrigation systems, hand-seeding and seed imprinting followed by a five-year maintenance period to ensure permanent results.

Two innovative tactics were developed to enable the use of the heavy equipment and contain skyrocketing labor costs. First, tractors and trucks were outfitted with oversized tires reducing the pound-per-square-inch impact to that of a human footprint and eliminating any soil compression. Second, platforms were built at key locations so equipment could come in over the waterways with no contact..

Rather than the client incurring the high cost of trucking out all Arundo debris, Natures Image brought in a specialized grinder that reduced the giant reed stalks to compost. Seeding was postponed for a year in favor of spraying the biomass to eliminate any regeneration and allowing it to decay in place.

Natures Image addressed the water hyacinth challenge by custom rigging a small boat to manually remove this exotic. By combining these innovations the client saved over $150,000.

The Results
Measures implemented to protect sensitive fish species and terrain were cost-efficient and effective. Arundo was successfully eliminated from over 25 acres of dense riparian habitat with the grind-in-place reducing total costs by 50%. The fine grind produced by this equipment eliminated the biomass through rapid decay and allowed easy ability to spray any resprouts. The terrain was then ready for seeding within one year and allowed for natural recruitment as well. Existing native plants were preserved and fortified creating a result that pleased project owners, regulators and the local community.