10/09/2024 PZ Combined Packet - Laserfiche WebLink

Home Search

Ms. Katie Larsen 10/02/2024 Page 2 Spargur Estates Engineering Review •Recommend digging down to permeable soils and installing sand/compost mix to final grade to better promote infiltration and reduce standing water in a rain event 4.Provide ditch High Water Level (HWL) on plans 5.Relocate existing shed outside of 5' easement/setback 6.Relocate existing fire pit outside of 20' distance from property line and 25' distance from structures 7.The current 906.8 'berm' near the southeast corner of Lot 4 would spill over the 906.5 spot elevation on the eastern property line •Raise berm and initial EOF to east to 907.2 (Basin to the east is 'land- locked' and will ultimately flow back to the west) •EOF for basin to the east is towards this development and would be at 907.2 •The highpoint on the east side at the front of Lot 4 would become the secondary EOF for the existing basin to the east when inundated. •Stormwater Management Stormwater management for the site consists of a small read yard depression. However, based on site layout, stormwater management is not required under City ordinance. Comments on the proposed stormwater design are offered below. Pre- and Post- Development Discharge Rates (cfs) Condition 2-Year 10-Year 100-Year 10-Day Snowmelt Existing 0.62 1.70 4.17 Not required Proposed 1.27 2.80 6.43 Not required Comments: 1.There are minor increases in site runoff rates due to the new impervious. However, as stormwater management requirements are not triggered, these increases are not regulated. Runoff to the north and south will be captured by storm sewer routing to City ponds. 2.Sufficient freeboard is available between the depression modeled HWL and the proposed household low floors/low entries. 3.Silt fence or bioroll is recommended around the rear yard depression to maintain infiltration capacity and reduce likelihood of excess ponding in the future. •Water Supply The proposed water will be supplied by four existing 1-inch Type K copper services extended to the lots. Comments: 1.Show the existing well for Lot 1 if present