Memorandum

City of Lawrence

Public Works

TO:	David P. Cronin, P.E., City Engineer
FROM:	Matt Bond, P.E., Stormwater Engineer
CC:	Charles Soules, P.E., Director of Public Works
DATE:	August 27, 2015
RE:	23rd Street & Ousdahl Road - Project PW1134 - Additional Surveying & Engineering Services for stormwater and geometric design improvements.

Project Background

The intersection of 23^rd Street and Ousdahl Road experiences flash flooding during heavy storm events and is frequently inundated and impassable to vehicular traffic (see attached map). This area was identified as Project No. 8 in the 1996 Stormwater Master Plan. The existing storm sewer infrastructure currently provides capacity for a 2-year or less storm event which results in localized street flooding. In other words there is a greater than 50-percent chance of this type of storm event occurring in any given year. At its October 8, 2013 meeting the City Commission approved an engineering services agreement with BG Consultants in the amount of $89,702.00 for the design of stormwater and geometric improvement plans for the intersection (see attached project map).

Project Description

The original project included the design of a storm sewer system from the west property line of Schwegler School to W. 24th Street, 600' east and west along 23^rd Street from Ousdahl Road, a stormwater detention basin located on the southwest corner of the Schwegler School property and geometric improvements for Ousdahl Road at 23^rd Street.

During BG Consultants initial hydrologic & hydraulic analysis and a corresponding visual investigation of the existing storm sewer network it was determined that it would be prudent to include the storm sewer network from W. 24th Street to Naismith Creek in the analysis. This will require the collection of additional survey information. The overall original project length was approximately 3000 linear feet. The additional survey and design work will add another 800 linear feet of storm sewer to the project.

Project Funding

Engineering services will be funded by the Stormwater Utility Fund.

Action Request

If appropriate, Public Works staff requests the City Commission authorize the Interim City Manager to sign Supplement No. 1 with BG Consultants for engineering services for the design of stormwater and geometric improvement plans in the amount of $22,250.00.