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Ms. Katie Larsen <br />4/13/2020 <br />Page 4 <br />Nadeau Acres Engineering Review <br /> <br /> <br />Storm adjusted further back. Note that 20 feet from overhead power is not possible given the <br />maintenance access location and the need to revise a storm manhole to a catch basin manhole for <br />drainage purposes. <br />We are still concerned that the storm sewer is too close to the proposed structures for Lots 6 & 7 of <br />Block 2. <br />5. The north arrow is incorrect and wetlands on the figures should be labeled or noted in the legends <br />on Stormwater Management Plan Figures 2 and 3 and Storm Sewer Catchment Figure 4. <br />North arrow revised. Wetland line added to legend. <br />6. Show Proposed HydroCAD Pond “CB50” on Figure 3. <br />CB50 added. <br />7. Proposed HydroCAD Pond P300 stage storage invert (911.0) does not match bottom contour <br />shown on grading plan. (914) <br />HydroCAD model updated to match grading plan. <br />8. Ponds modeled in HydroCAD for backyard drainage swales and depressions (P300, P30A, P30B, and <br />CB50) should be modeled as a catch basin in HydroCAD (“pond with insignificant storage”). If they are <br />modeled as ponds, they will need to be evaluated to meet freeboard requirements for detention basins <br />(2’ of freeboard from the low entry in the 100-year storm event). <br />Revised to ponds with insignificant storage. Note that CB 122/123 was modeled as ponds to <br />determine by-pass flow (if any) to see if these would be directed towards a different pond/wetland or <br />offsite. <br />9. Plunge Pool Energy Dissipator grading requires revision. The bottom of the plunge pool grading of <br />891.5 has no width in the middle of it and grading is not feasible. Recommend at least 4-feet bottom <br />width to avoid erosion of slopes of pool. Confirm riprap size used at riprap check and overflow. <br />Recommend a detail or notes regarding width and depth of riprap check and overflow, and note on <br />how riprap size was determined. <br />10. Drainage Area S-10 is shown to flow to W-10. S-10 includes area east of Lots 12-20 of Block 4. <br />Confirm the drainage path for flow to pass from south to north under proposed Red Oak Lane. <br />11. Roadway profile and storm sewer – the road profile shall be a minimum of 1% grade. Adjust road <br />profile grade to move low points from intersections, Josephine and Red Oak. Storm sewer roadway <br />catch basins are spaced too far apart, 350 ft min. please extend storm sewer and add catch basins. <br />12. For the downstream ditches / outlets please provide a baseline data report <br />- Survey the bottom of the ditches. <br />- Provide a ditch cross section every 200’ or where it is observed to have a change in section. <br />- Shoot culverts and provide information on type, elevation and condition, document % full of water. <br /> <br />• Water Supply <br />There is existing 16-inch diameter ductile iron pipe (DIP) watermain along 20th Av enue (CSAH 54) east <br />of the site and along Birch Street (CSAH 34) south of the site. <br /> <br />The City of Lino Lakes Comprehensive Plan does not designate any trunk watermain going through this <br />site. This has been revised with the latest water system plan. <br /> <br />The applicant is proposing an 8-inch diameter DIP watermain to serve the entire development. The <br />watermain will extend and loop from the east (North Pointe) along Red Oak Lane and from the south <br />(Birch Street). <br /> <br />Comments: <br />1. The watermain along Red Oak Lane shall be 12-inch diameter DIP. Trunk watermain credits will <br />apply. <br />Revised. <br />This is to be updated to a 16 inch DIP trunk watermain along Red Oak and Josephine. Trunk <br />water credits will apply. <br />2. A hydrant shall be installed by the lift station at the north end of Heritage Avenue. <br />Revised. Note that hydrant elevation may need to be revised when Heritage Avenue extends to the <br />north. <br />Please put a temporary hydrant at the north end of Heritage Avenue. <br />3. Applicant shall add a temporary hydrant at the dead end of Red Oak Lane. <br />Revised. Temporary hydrants added to site plans. <br />4. The City of Lino Lakes should consider installing water service stubs to serve the possible <br />future development at 6687 20th Avenue (26-31-22-14-002). It is anticipated that this parcel will develop into five lots that have access off of Red Oak Lane.