Landscape Architect Articles

From Polluted to Pristine08-11-11 | News

From Polluted to Pristine

By John Hidalgo, RLA, Willdan Engineering

This 7.8 acre Maywood, California site was a polluted waste area, until Wildan Engineering converted it into a pristine community park over the course of four years. The contractor planted the ''Triple Crown'' Tall Fescue Blend turf using the hydroseeding method. The trees shown are Tipu Trees and shown on the right are California Sycamores. The trees were planted by hand.

This Maywood, California project challenged Willdan Engineering to convert 7.8 acres into a community park, while also accomplishing an environmental restoration and hazardous waste clean-up. When Willdan began, the site was a contaminated site laced with hazardous waste bi-products left behind by manufacturing companies.

Willdan also installed Miracle Recreation Equipment Company playground equipment. The playground safety surfacing was specified using engineered playground wood fiber supplied by Artesia Sawdust. The contractor laid 400 cubic yards of this material by hand. Willdan used a backhoe for excavating the palm tree planting holes, and cranes and flatbed trucks were used for transporting, loading and unloading. The palms shown include Date Palms and California Fan Palms.

The stone veneer was a 12x4-inch thick ''Santa Fe Copper'' from Sepulveda Building Materials. Willdan Engineering constructed the bridge's core structure from 8x8x16-inch CMU block with steel reinforcement. The bridge's finished surface was paved with 4-inch-thick P.C.C., and the bridge's railing was custom-designed and built from galvanized steel pipes. The area's plant materials consist of a 1-gallon Berkeley Sedge, 5-gallon Allen Chickering Sage red Fairy Duster, as well as 5-gallon Yankee Point California Wild Lilac.

The goal of the project was to develop an aesthetically pleasing open park adjacent to the world famous L.A. River with the intention of providing pleasurable activities such as picnicking and recreation for the surrounding communities. The park also features a demonstration garden emphasizing the California Native planting palette for the purpose of community education. However, the project's underlying purpose was to serve as a mitigation measure to clean up the contaminated site.

From the initial design meeting to construction completion, the project took four years to complete. The project utilized 50-plus workers from various trades, including landscape contractors, paving contractors, electricians, plumbers, building contractors and environmental mitigation services.

As significant excavation was required, the contractor used heavy construction equipment, such as a backhoe, an earthmover, grader, skip loader, and a flatbed truck.

The park's entire irrigation system runs on an automated system with central control capability, including water saving accessories. The irrigation sprinklers consist of pop-up sprays, pop-up rotors and pop-up bubblers. Irrigation sprinklers and related equipment are Hunter and Rain Bird.

The trees shown are Tipu Tree, Jacaranda and California Sycarmore, and came from 24-inch box containers. All trees specified for this park were planted by hand, with the help of a backhoe for excavating the planting holes. More than 300 trees were specified for this park project and it took two weeks to complete the tree planting alone. Soil preparation for all planting areas, including the turf lawn areas was based on the Soil Laboratory's imported Class A soil analysis of agricultural suitability and recommendations for soil amendments. In addition, planting tablets, soil conditioners and commercial fertilizers were also used as supplements for shrubs and trees.

From Polluted To Pristine

More than 3,600 cubic yard of excavated contaminated material on-site was treated and reused, while 1,500 cubic yard of excavated contaminated material on-site was removed off-site.

The contractor imported 16,700 cubic yard of Class-A topsoil. More than 2,500 square feet of concrete was used alone in the paved walkway areas.

For the riparian California native demonstration gardens, the contractor installed 12,700 square feet of Firestone EPDM membrane liner. The project also boasts 65,000 square feet of decorative colored and stamped concrete pavement.

The Riparian Demonstration Garden was designed and built as a part of the project, and its purpose was to help educate park users about the environmental benefits of planting California Native plants. The construction of this riparian garden took approximately four weeks to constructed, including planting and irrigation system installation. Underneath the river-rock shown is a layer of waterproof poly membrane used as an underlying for drainage and soil contamination abatement. Trees shown in this picture are California Sycamores planted by hand from 24-inch box size containers.

The hardscape was constructed as 4-inch-thick integral color P.C.C. with a stamped pattern that utilized the dry-shake method (2 colors ?EUR??,,????'?????<

New Plant Life

Nine thousand 5- and 1-gallon size shrubs were planted, along with 17 15-foot palm trees, and more than 300 other trees, ranging from 24-inch and 36-inch box size.

For the grass area, the contractor hydroseeded more than 181,400 square feet of turf lawn. For irrigation, the contractor installed a complete fully automated irrigation system with central control, which features Ran Bird, Hunter, Superior and Hammond product.

Plant materials were primarily drought tolerant California friendly species, made up of more than 30-percent California Native species.

For The Kids

For the kids, the contractor installed two full-size children playground areas with play equipment. Also installed were two prefabricated concrete restroom assemblies, six prefabricated picnic shelters with amenities, a basketball court, handball court and two community art exhibit locations. The playground equipment and site amenities came from Miracle Recreation Equipment, Patterson Williams and Most Dependable Fountains.

The contractor also installed a completely new park electrical and lighting system. The lighting system uses KW Industries, Hubble, Spalding, Kim Lighting and Kenall product.

Challenges Faced

According to the contractor, the site's steep grade, bad weather, and tight timeframe were the most challenging aspects of the project. Also cited were the major challenges of coordination of environmental site mitigation with the Environmental Protection Agency (EPA) and coordination with other governing agencies involved and overseeing the construction of the project.

Maintenance

The Construction Contractor, PIMA Corp. was commissioned to maintain the landscaping and irrigation system for 90-days after the completion of construction. Following that, maintenance was taken over by the City of Maywood, Parks & Recreation Department. The general maintenance includes lawn mowing, tree and shrub pruning, repairing and replacing dead plant materials, planting-area weeding and scheduled fertilizing; and irrigation system maintenance.