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0 <br />U <br />C0 <br />Z <br />W <br />m <br />U) <br />z <br />U) <br />J <br />0 <br />a <br />a <br />W <br />Z <br />Z <br />0 <br />0 <br />w <br />U) <br />T <br />W <br />Z <br />W <br />a <br />a <br />Z <br />w <br />x <br />0 <br />ws b <br />Final Technical Memorandum <br />To: Michael Grochala, City of Lino Lakes <br />From: Madison Rogers, WSB <br />Andi Moffatt, WSB <br />Date: April 8, 2020 <br />Re: Stormwater Management — 1-35 Corridor AUAR <br />City of Lino Lake, Minnesota <br />WSB Project No. R-015144-000 <br />INTRODUCTION <br />The original Alternative Urban Areawide Review (AUAR) was completed and approved in <br />September 2005. The AUAR analyzed the stormwater impacts of the three development <br />scenarios. Based on the analysis, a Mitigation Plan was developed. <br />AUAR updates are required every five years from the original date of the approved AUAR. <br />Updates were prepared in 2010 and 2015. Each assumed no change in the proposed <br />development land use scenarios and included discussion of mitigation improvements that had <br />been completed at the time. Since the 2015 AUAR update was prepared, the City has completed <br />an updated Comprehensive Plan. This AUAR Update includes review of three revised scenarios. <br />The information and analysis outlined within this memo is intended to complete a portion of the <br />AUAR Update related to Item # 11.ii — Water Resources — Stormwater related to revising of the <br />three revised scenarios. This memo is intended to update the stormwater analysis provided in the <br />original AUAR where applicable. <br />WATER RESOURCES — STORMWATER <br />ii. Stormwater - Describe the quantity and quality of stormwater runoff at the site prior to <br />and post construction. Include the routes and receiving water bodies for runoff from the <br />site (major downstream water bodies as well as the immediate receiving waters). Discuss <br />any environmental effects from stormwater discharges. Describe stormwater pollution <br />prevention plans including temporary and permanent runoff controls and potential BMP <br />site locations to manage or treat stormwater runoff. Identify specific erosion control, <br />sedimentation control or stabilization measures to address soil limitations during and after <br />project construction. <br />Procedures and Methods Followed <br />The procedures and methods used to estimate the runoff volumes and pollutants loads within the <br />AUAR were based on the Natural Resource Conservation Service (NRCS) runoff curve number <br />method and event mean concentration pollutant values from the Minnesota Stormwater Manual. <br />Any development within the study area will be required to meet the stormwater standards of the <br />City of Lino Lakes and Rice Creek Watershed District (RCWD). These standards include: <br />• Promote volume control and groundwater recharge. <br />• Protect water quality from nutrients, heavy metals, and other urban pollutants. <br />KA015144-000\Admin\DOCSWUAR -Update 2020\Stormwater\MEMO - 040920 - Stormwater AP.docx <br />