01-30-08 Council Agenda - Laserfiche WebLink

Home Browse Search

£IWUHG i ASSN-DIES Tang flaaia Memo TO: Honorable Mayor and City Council Members FROM: Lee Elfering, City Engineer DATE: January 24, 2008 RE: Impervious Surface Percentage To provide further information to the City Council to aid in discussions on maximum impervious surface limits for R1 lots, we were asked to review existing lot conditions. Due to the varying times of development, changes in City ordinances, and original parcel shapes prior to subdivision there is no one area that can be said to be the typical R1 lot within the City. Therefore, multiple small areas were reviewed to provide more accurate information. In total 9 different areas were chosen to try to provide an estimate of the impervious surface percentages for some of the typical R1 lot size and configurations that exist throughout the City. An exhibit is attached that highlights the 9 sample areas used and their location in the City. A spreadsheet is also attached that provides the house number for each address used in the comparison, the lot size, impervious area, and the percentage of impervious surface on the individually lot. In addition, the average impervious surface percentage per area is also provided. Lot impervious percentages varied on individual lots from approximately 10.1% to 51.8% while the average percentage based on the 9 locations varied from 16.6% to 36.1 %. The Ramsey County GIS 2006 aerial was used to determine impervious surface and lot size numbers. An attempt was made to exclude decks that appeared to be wood and allowed water through while concrete decks were accounted for, however; the numbers are estimates. If you have any questions regarding the calculations please call me at (763) 780 -0450 extension 13. 10062 Flanders Court NE — Blaine, MN 55449 — Ph: (763) 780 -0450 Fax (763) 780 -0452 Z: \PROJ \120000E - Little Canada General\2008 \Impervious % Study \Memo - 012408- CC.doc