3821 SHORE AVE 2024-02-28 - Laserfiche WebLink

February 28, 2023 G-5835 3821 —Shore Ave Everett,WA Page 10 Subsurface Drainage Subsurface drains should be installed behind the retaining wall. The drains should consist of a minimum four(4) inch diameter,perforated, rigid PVC drain pipe laid at the bottom of the wall, with the perforations facing downward.The drain pipes should be bedded on, surrounded by,and covered with washed drain rock or gravel. The drain rock and pipe should be wrapped in a layer of non-woven geotextile fabric, such as Mirafi 140N, or equivalent. The drain pipes should be sloped at sufficient gradient to generate flow toward an appropriate stormwater discharge location or collection system. Subsurface drainage recommendations for the retaining wall are illustrated on the attached Plate 4--Ecology Block Rall Drainage. LIMITATIONS The findings and recommendations stated herein are based on field observations, our experience on similar projects and our professional judgment. The recommendations presented herein are our professional opinions derived in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area and within the project schedule and budget constraints. No warranty is expressed or implied. In the event that site conditions are found to differ from those described in this report,we should be notified so that the relevant recommendations in this report can be reevaluated and modified if appropriate. CLOSING We appreciate the opportunity to provide you with geotechnical engineering services for this project. Please do not hesitate to contact us if you have any questions regarding this report. Sincerely, GEO Group Northwest, Inc. ��,\,,AWAS�q�� I � � i w I ,p 20114 Q GISTR � � Dated: 2/28/23 S/ANAL Andrew Hoff, G.I.T. William Chang, P.E. Staff Engineering Geologist. Principal Engineer i r GEO Group Northwest, Inc.