TO:
Honorable Mayor Powell and Members of the City Council
THROUGH:
David N. Carmany, City Manager
FROM:
Jim Arndt, Public Works Director
Sona Kalapura, Environmental Programs Manager
SUBJECT: Title
Site Design for the Manhattan Beach Strand Ocean-Friendly Garden
RECEIVE AND FILE
Body
____________________________________________________________________
RECOMMENDATION:
Staff recommends that the City Council receive and file this report.
FISCAL IMPLICATIONS: Funding for this project is being provided through a grant from the Department of Water Resources and West Basin Municipal Water District (West Basin) in the amount of $23,000. As a participant in the grant program, the City is expected to assist with site design and soil assessment services ($700), and provide landscape support to prepare and maintain the project site. These costs will be paid for out of the existing maintenance fund. In addition, the City will need to provide signage at the site designating the project as an Ocean Friendly Garden and include logos from the funding partners and participating entities.
BACKGROUND: In July 2011, the City was awarded a grant from the West Basin Ocean Friendly Demonstration Gardens Program. West Basin and the Surfrider Foundation (Surfrider) plan to build ten demonstration gardens throughout the West Basin service area (two in each of the five West Basin Divisions). The site selected for the grant project is located at the northeast Pier Garden, the sloped area between the elevated parking lot and the Manhattan Beach Strand. This area was selected as an ideal location to highlight the main goals of the program, namely to conserve water, reduce dry-weather and storm water runoff, and educate the public on how they can implement ocean friendly landscaping.
DISCUSSION: The City of Manhattan Beach was awarded a grant to turn the existing northeast planter on the Strand into an Ocean Friendly Garden. This new landscape will create a demonstration garden highlighting best management practices that apply conservation, permeability, and retention principles to revive watersheds and oceans to the site.
The Ocean Friendly Demonstration Gardens Program includes the provision of a landscape architect, landscape design, materials, labor, and a licensed landscape contractor to install the garden. The landscape design team, Green Gardens Group (G3), has developed a draft design for the Manhattan Beach Strand Ocean Friendly Garden site. Should City Council approve the site design, West Basin will begin the process to select the landscape contractor to install the garden.
Since the project location is a very visible fixture in Manhattan Beach, the City held a community meeting on August 15th to hear comments on this demonstration garden. Like other sustainable garden projects in the city, this Ocean Friendly Garden proposal has been well received by the community. Several questions relating to the plant species to be used, stabilization of the slope, and maintenance of the site were addressed by the design team at this meeting.
Prior to this community meeting, several Manhattan Beach residents expressed an interest in volunteering to assist with the landscape design development and review process. These volunteers have significant expertise in sustainable landscaping and California native plants that thrive in Manhattan Beach, and have provided valuable insight to the design and plant palette proposed for the site.
Proposed Site Design
For ease of review, the components of the landscape design for the Manhattan Beach Strand Ocean Friendly Garden are summarized in the following categories:
1. Site Design and Preparation
2. Irrigation
3. Maintenance Plan
4. Plant Palette
1. Site Design and Preparation
The site design for the Manhattan Beach Strand Ocean Friendly Garden proposes an aesthetically pleasing layout, including flowering plants with lots of color and texture, and a strong use of California natives. Further, the plant groupings included in the draft design lend to an overall tapestry effect which will dramatically improve the visual appeal of the site, while promoting the principles of water conservation and retention of runoff. Please refer to Attachment A: Draft Site Design for a visual.
Preparation of the site includes:
• removal of existing plant material,
• soil amendments to promote healthy plant growth, and
• grading and slope stabilization.
Removal of Existing Plant Material
The existing plants on the current site will have to be removed in order to grade and remediate the soil prior to installation of the new garden. Aside from the existing species of palm, the remaining plant material can be turned into mulch. In order to adequately prepare the soil, this removal will include the nine small palm trees on the site. None of the palms are over five feet, and they are located haphazardly throughout the sloped planter area, with several leaning out of the slope. Palms can provide nesting habitat for rats, crows and European starlings and are not recommended for use by the landscape designer. In addition, there are over a dozen palm trees near the Pier, and none of those will be removed as part of this project.
Soil Amendments
A soil test was conducted on the site to assess the beneficial biological life present in the soil, e.g., bacteria, protozoa, nematodes, fungi. It was found that there is not enough fungi present to support healthy growth of shrubs and perennials. Further, there are some indications of possible anaerobic conditions in the soil sample, which may be caused by compaction or overwatering. As part of the site design and preparation, the proposal calls for the amendment of the soil with compost, and the application of compost tea, followed by shredded non-aromatic bark mulch to protect the soil.
Grading and Slope Stabilization
The soil of the site is to be graded into subtle mounds and depressions, with plants following the contours and accentuating the grading. Since the project site is fairly steep, one of the goals of the proposal is to illustrate how properties on a hillside can be landscaped sustainably. This will be achieved by creating four infiltration areas throughout the site, and a swale at the top of the existing wall. Some soil removal may be required, with excess soil being transported to the Public Works Yard. The maximum proposed slope is 2:1 (equivalent to 45 degrees), and broken concrete from the City’s current repair projects will be utilized for the infiltration areas to stabilize the slope. Boulders and coir mats will be used for slope stabilization as well.
2. Irrigation
The project design focuses on the conservation of water, energy, and habitat through climate-adapted plants, spaced for mature growth. To support these goals, West Basin will donate a smart controller to assist in the adjustment of irrigation frequency and volume at the site. The project will also utilize surface or sub-surface drip irrigation. The tubing will be buried under the soil, or under mulch, so it will not be visible. By manipulating the grading and creating depressions throughout the site, rainwater will be able to infiltrate locally, for use by plant root systems, as well as percolate into the groundwater in the infiltration areas. As opposed to traditional hillside landscaping where water is directed off the site, no surface runoff is to be directed to impermeable surfaces or piped unfiltered into the ocean.
3. Maintenance Plan
The garden site is a very high-profile location of the well-used Manhattan Beach Strand, and clear direction and provision of information to maintenance crews will be critical for the success of the new garden installation. The timing of certain maintenance tasks for a California native garden is very different from that of the ornamental plantings the maintenance crews are currently tending. To address these concerns, the design team will provide a one-page maintenance plan that summarizes what City staff and volunteers will need to do on a weekly, monthly, quarterly, and annual basis to keep up the new garden. In addition, West Basin will host a demonstration session to show how the plants should be properly maintained.
4. Plant Palette
The Plant Palette is made up of exclusively California Native plants. The plants are native to coastal scrub environments, sandy dune settings, and riparian waterways. Grouping plants from similar natural habitats together, but on separate irrigation zones, will ensure success of the plants. The plants in the garden will provide food and habitat for native butterflies, birds, and bees. Examples of flowering plants included in the design are Island Pink Yarrow and the Beach Primrose - the City’s official flower. For the full listing of plants, please refer to Attachment B: Proposed Plant Palette.
Project Schedule
Should the landscape design be approved by City Council, West Basin expects to review proposals and select a landscape contractor by October 23, 2012. The City is expected to prepare the project site by this date so installation of the garden can begin on October 29, 2012. The installation will take three weeks, and completion of the project is expected by November 16, 2012. Once the garden is completed, there will be a ribbon-cutting ceremony conducted by West Basin for all City Council members and City Staff to attend.
CONCLUSION:
The Strand Ocean Friendly Garden project is another opportunity for the City of Manhattan Beach to utilize grant funding to illustrate the principles of sustainable landscaping to the community. Staff recommends that City Council receive and file the site design for the Manhattan Beach Strand Ocean Friendly Garden project.
Attachments:
Attachment A: Draft Site Design
Attachment B: Proposed Plant Palette
cc: Juan Price, Maintenance Superintendent