03.LaMettry - Summary - 061815Project: LaMettry's Chanhassen
Location: Chanhassen, MN
Prepared for: Rick LaMettry
Prepared by: Sathre-Bergquist, Inc.
Date: June 18, 2015
Volume Control Required 8,273 Cubic Feet
Volume Control Provided 8,522 Cubic Feet
TSS TP
Proposed Load Reduction 65.5%
2-yr (cfs) 10-yr (cfs) 100-yr (cfs)
Pre-Development Rate 2.62 15.77 60.47
Original Post-Development Rate 2.67 16.56 57.08 Not all rates are met due to Altas 14.
Proposed Post-Development Rate 2.29 15.71 57.22 All rates met compared to pre-development.
Report Summary
This site is an extension of the Aududon Motorplex site. This proposed development was included the original stormwater management plan for Audubon Motorplex dated
October, 2006. Since then, stormwater requirements have changed. Primarily the addition of Volume Control and Atlas 14 rainfall intensities for rate control. I have
incorporated Altas 14 into this design. Underground stormwater chambers will be used to meet the additional volume and rate control. After runoff exits the underground
chambers, it will continue downstream to the stormwater pond designed for this overall development.
HydroCAD was used to model rate control for this project. Atlas 14 has been applied to this project, so rates are not equal to original approvals.
Volume Retention
Deadstorage in the underground stormwater chambers will provide the abstraction volume for infiltration. See the Volume Control spreadsheet for details.
Quality Control
The NURP and Pondnet design from the original stormwater report was updated for the Quality Control portion for this project.
Rate Control