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2.14.18 - City of Edmonds Response, Maintenance Bond Requirements.pdf1 - OLM was originally provided a city prepared memorandum. I will call this memorandum 1.0. We bid and started work off the details in this memorandum. During a site inspection, the city workers were using the original landscape plan as a basis for inspection. After the onsite inspection, OLM received a second memorandum I am calling 2.0. My question is what set of plans and or memorandums are we to work from? You should use the most recent approved plans, which clearly show vegetation to be installed and raingarden requirements. The initial memorandum provided Feb 18, 2016 was the basis for our inspection for release of the maintenance bond. However, that was two years ago and additional vegetation has perished. In order for us to sign off on the maintenance bond the site needs to match/meet the requirements established. Both memorandums have the common goal of working raingardens, bio-swales and intact vegetation. With that said, the planting of the required vegetation should wait till spring. 2- Is gravel acceptable as a bed mulch? PCC can provide explanation on why this was chosen. Gravel generally is comprised of a combination of mid, small and minus size materials, which can impede the infiltration of water into soils as it would do in nature. Gravel could be defined as impervious by the Department of Ecology, especially if the soils are compacted. if we are discussing washed round rock with no minus then the following applies: Walgreens (permit BLD20120925) - Round rock is not acceptable as a bed mulch when compost amended soils are required. This applies to the new construction site of Walgreens and the associated vegetation required to be installed around the site. Compost amended soils per the handout, E72C Compost Amended Soils, will need to be installed. Round rock may be installed on top of the required compost amended soils only within the landscape only areas (where ground cover is not a requirement). It will not be allowed within raingardens or within the bio- swale except in the spillway. PCC Market (landscape islands and perimeter landscaping) — Washed round rock installed within the island landscape beds would not trigger any stormwater concerns as long as the organic rich soils are not stripped from the landscape. That being said, there are concerns that the proposed washed rock within the landscape strip adjacent to 1001h Ave S. will find its way into the traveled street. The city requires that soils not exceed a 2:1 slope at the back of the sidewalk, which would apply to the proposed washed rock as well. The proposed rock will need to tuck into the soils where they meet the back of the sidewalk. Please recall that organic reach soils should not be stripped of the site. It may be necessary that the soils beneath the proposed rock be compost amended prior to rock placement along 100th Ave West. 3- Is rock acceptable as a spillway entryway into the rain gardens, and is rock acceptable to be used to slow the water flow in areas where rapid water flow might erode and undermine hardscapes such as walkways, parking stalls etc.? Rock is acceptable at a spillway entrance (if vegetation is not established) in an effort to stop erosion of soils, which will also help with the undermining of hardscapes. 4- There is irrigation damage that still needs work, we are having a hard time locating the POC, where and how do we locate the water source for Starbucks so we can do the repairs? The approved city plans do not seem to match what OLM is finding onsite. The water service line feeding the site (within the city right of way) can be located by calling 811 or specifically reaching out to the city's Public Works — Water Division. Beyond that, the city does not track the location of irrigation systems on private property. 5- OLM installed Typar fabric as a separator between the rock areas and the subsurface. Typar was chosen because it is porous allowing air, water and nutrients through to the roots of the plants to promote healthy soil conditions yet provide a separation so the rock does not become absorbed by the soils. In the rain gardens, the fabric is only installed in the rock areas. The planting only areas do not have fabric. Fabric or rock is not permitted within the raingardens. The raingardens, beside the spillway entrance shall all be vegetated. 6- During the inspection, the city employee performing the inspection was counting plantings without taking into account growth, this is especially important in the ground cover calculations as the design of the ground cover is to cover the ground. Where 20 smaller plants once existed a few ago we now have one larger mass of the specified ground cover plant. We need clarification on replacements. Staff realizes that over time the existing vegetation, particularly groundcover, has spread out and thus may not appear to include the same number of plants that were initially planted as they have blended together. However, the existing plants do not currently appear to be providing 75% ground cover within three years as required by ECDC 20.13.020.H. In particular, there are sparse areas along Edmonds Way, along the eastern property boundary as well as in some of the ends of the parking islands. Staff was informed in the field that some of the missing plants have not yet been replaced within the planter beds in the event that the rock will be placed in order to avoid any damage to any new plantings. Refer to staffs letter dated December 22, 2017 with more specific comments on where the landscaping is lacking. 7- Can we update the permit drawings to the new planting schematic? If you would like to propose revisions to the approved landscape plan within non -rain garden areas, you may apply for a landscape plan revision through the Planning Division. The fee for such application is currently $285. Any proposed changes will need to be consistent with the applicable landscape requirements of ECDC Chapter 20.13. 8- In the Engineering Inspection correction notice provided by Chris Rivera he notes in item 8 that "Rock added to the bio-retention swale (between sidewalk and parking lot) at the spillways will need to be reduced. Such that the rock is placed at most to the center of the swale (not extending full width ". Per Alan Robertson (original contractor) and per the ILPD engineering report dated 2014-2-5 this swale is only a means of conveyance and not intended to be a bio retention swale. Item #8 in Mr. Rivera's correction notice is confusing. Clarification is requested. The rock installed within the bio-retention swale is only to serve as erosion control for the spillways from the parking lot. The bio-retention swale, beside acting as a conveyance for stormwater (received from the parking lot) toward the west raingarden, also helps with the infiltration of stormwater. The excess rock installed at the spillways hamper the infiltration of stormwater into the soils.