8925 AIRPORT RD MUKILTEO SCHOOL DISTRICT 2018-01-02 MF Import

• overexcavauon and removal of surficial soils in the azea of the horse wrral adjacent to the miagadon azea to mitigate for prior potential nitratelnitrite pollutant entry into the wetlands, • retenuon of existing upland to create an island along the south side of the mitiga6on azea, • initial removal and subsequent control of invasive plant species such as purple loosestrife, reed canazygrass and Himalayan blackberry, • protecfion of downstream watec quality through use and monitoring of approved temporary � erosion and sedimentauon control measures during all construcaon acdvities and • maintenance and preserva6on of wedand funcdonal values of the existing and through retention of minimum 25 foot buffers around retained and created weUands. 3.3 Construction Plan Two miaga6on sub-ueas will be created on the northeastem and southeastern margins of Wefland E, approximately 11,120 and 1,500 square feetrespectively. The Wetland Mitigauon PlanUng Plan (Figure 2, attached) cons6tutes a Construc6on Pian which specifies requirements for excavation, drainage,materials stockpiling, soil replacement, plandng and maintenance of wetland hydrology. Implementation of this plan will require the on-going professional assistance of a weUand biologist who is 1) experienced in management of the creafion of wedands and the relaaonship of the range of weUand plant species to varied hydrologic regimes, 2) abie to adjust construction plans and direct consWction activides on-site in response to specific unforseen site conditions which may be revealed during construction, and most importanfly> 3) supervision of construction to ensure adherence to the intent, goals and specifications of the mi6gation plan. The project biologist may be retained to assist the appiicant and its representa6ve in evaluaaon of contractors, and will make Field changes to the design as required, including authorizing plant subsdtuaons and using contractor-supplied construcflon survey equipment to verify staking of design water level contours prior to planting. A well-coordinated and stepwise program under the overail supervision of the project biologist will be required for successful implementafion of the planned miugation, including the following eight step program: 1) pre-construction mee6ng, 2) staking of e::cava8on, miagation and restoration boundazies, 3)installation of temporary erosion and sedimentation control measures, 4)cleazing and grubbing; grading and over-excavaaon of mitigation area; stockpiling of topsoil and wedand soil materials and contained rootstock and seedstock, 5) replacement of soil materials in appropriate ueas, hand seeding and hydromulching, 6) establishment of hydraulic regime, 7) installation of all plant materials and satisfaction of post-pianting requirements and 8) post-construcflon meeting. In a111ikeGhood,conswction of the mitiga6on/restoration area will begin in the early to late summer of 1994, with site preparation, grading and excavation, soils placement and hydromulching. Mu.h'lteo Sch. Dist. Centra[Faci(iry Finol Miagotion Plan Page 8 Lave!!-Sauer(and &Associates, lne. I�