11102 EVERGREEN WAY 2018-01-01 MF Import

The maximum design depth of flow in the swale should be shown on the swale cross-sectional detail. The swales must be somewhat accessible for maintenance. A gate in the fence along the east side of the upper swale would be appropriate. Given the width of the swales, some type of level spreader ehould be placed at regular intervals alonq the length of each swale to try and prevent water from creating a low-flow channel in the ewale. A succeseful spreader in the past has been a 4 by 6 or 8 board (timber?) imbedded in the bottom of the swale (lonq dimension downwards) and into the banks , (about 2 feet) . The timber must be set absolutely level at � the heiqht of the expected turf in the swale, one every 25- 30 feet is usually appropriate. A detail of the spreader should be included on the plans. The spec. sheet of an acceptable wood preservative is attached. Astpond• The wetpond does not meet the City's requirements for a length to width ratio of 3 : 1. Solid baffles should be used to create an effective length to width ratio greater than 3:1. The standards also call for at least one baffle across the width of the pond - this baffle should not be a completely solid baffle. Baffles must extend vertically from the bottom of the pond to the required wetpond storage elevation. A wooden baffle essentially constructed like a fence in the bottom of the pond has been used successfully in the paat. A plan detail and information on an environmentally safe wood preservative are attached for the applicant�s information. A planting schedule for the treatment area of the wetpond must be approved by the City. The plans should call out the type of vegetation to be planted, the density of the plantings, and the total number of plants needed. Plants auited to the depth of water in the treatment areas should be used, such as hardstem bulrush, yellow iris, and/or cattails. Required density of plantings is a minimum of one per square foot (1.0' O.C. ) in the Silver Lake drainage basin, or one per 2 .25 square feet (1.5' O.C. ) outside of the Silver Lake drainage basin, with plants of the same type planted in groups rather than in a completely random pattern. The pond detail muc�t clearly show the area of the pond to be i planted and a note should reference the planting schedule. The actual contours far the pond and how they relate to the surrounding topography must be shown.