11/13/2002 P&Z Packet - Laserfiche WebLink

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Mr. Jim Studenski, P.E. • City of Lino Lakes November 5, 2002 Page 4 • • berm. If this is the case, then easement documents need to be submitted to the City. Also, rip -rap and an 8" PVC. storm outlet pipe along the westerly property line are shown on property that is not on the development site. This would require an easement to be submitted to the City. 3. MH with R -4342 casting and 8" PVC outlet located along the westerly development property line. The 8" PVC is recommended to be changed to a 15" RCP with fixed end section and set at the normal water elevation of 895.7 (instead of 895.00 shown on the plans). That is, the outlet structure and pipe are recommended to be re- designed. 4. Provide stormwater calculations for the 2 -year design rainfall event, the 10 -year design rainfall event and the 100 -year (revised) designed rainfall event. 5. Determine if 4" or 6" perforated draintile (or both) will be used on the project. Either correct the plans and/or re- compute the stormwater runoff /routing calculations to match the sizing. 6. Provide the City Engineer with literature and technical data describing the proposed "4- inch Netlon Advanced turf' and "Netpave 50 backfilled with 3/8" clear- washed dresser trap bit. admix rock" for review. There are concerns about permeability and bituminous component of the Netpave regarding compaction over time. 7. Prior to construction commencement, provide the City Engineer with a completed copy of the MPCA -NPDES permit.. 8. Regarding separation between groundwater elevation and the mostly westerly infiltration basin base or finish elevation. Groundwater elevations have been established by two (2) soil borings as described by a Braun Intertec Report (May 8, 2002). The groundwater elevations were 890.5 and 892.5. These groundwater elevations provide greater than the three (3) foot separation from all of the development site proposed basins or swales base elevations. It is also recommended that nearby private water supply wells be located for adjacent properties to determine the proximity of the water wells to the stormwater system. The location of the adjacent private wells along with well log information needs to be provided to the City Engineer for his review. 9. Pretreatment features, such as basin slope geometry, ponding water depths and detention time, length/width for ponds, swale slope and overflow issues have been addressed on the revised plans. It is recommended that these plan items be accepted as shown.