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HomeMy WebLinkAbout2012_06_25_Meeting Minutes_v1 PSOMAS 1075 Creekside Ridge Drive, Suite 200 • Roseville, CA 95678 • Tele: (916) 788-8122 • Fax: (916) 788-0600 MEETING MINUTES 06-Ker-178 PM R6.7 /T9.2 6TYL010100 File No. 390 MEETING TYPE: Drainage Coordination Meeting SUBJECT: Thomas Road Improvement Program Morning Drive/SR 178 Interchange Project Drainage Analysis and Design DATE OF MEETING: Monday, June 25, 2012 TIME: 1:30 p.m. LOCATION: City of Bakersfield Public Works Department Conference Room Conference Room 1501 Truxtun Avenue, Bakersfield, CA 93301 ATTENDEES: Name Organization Telephone E-mail Address Manny Behl City of Bakersfield 661-326-3576 mbehl@bakersfieldcity.us Jim Holladay City of Bakersfield 661-326-3590 jhollada@bakersfieldcity.us Brian Wright Psomas 916-788-8122 bwright@psomas.com John Oliver Psomas 916-788-8122 joliver@psomas.com ITEM NO. RESP PERSON TOPIC DISCUSSED ACTION ITEM 1 PROJECT OVERVIEW 1.1 Brian Psomas began with an overview of the project: The Project is currently in the final design phase with the 95% submittal due at the end of July. The City set the right of way after the 30% submittal and is currently in the acquisition process. The Draft Drainage Report was submitted in April 2012. 1.2 Manny Unfortunately it appears as though Public Works did not receive a copy of the report until May and are currently reviewing the report. Psomas provided a hard copy of the Drainage Report to the City at the meeting. Morning Drive/SR 178 Interchange Project June 25, 2012, 1:30 PM Page 2 1075 Creekside Ridge Drive, Suite 200 • Roseville, CA 95678 • Tele: (916) 788-8122 • Fax: (916) 788-0600 ITEM NO. RESP PERSON TOPIC DISCUSSED ACTION ITEM 1.3 Brian Changes since the Preliminary Design Phase: · The drainage concept is the same, however more geotechnical infiltration testing indicated a much slower infiltration rate than what was previously reported. The result is that the infiltration basins are now converted to detention basins. · The project includes two detention basins (Basins #1 and #2) within Caltrans right of way and one retention basin (Basin #3) within City right of way. 1.4 Manny The City asked if they could get a copy of the infiltration test results. Psomas provided a copy of the geotechnical report to the City at the meeting. 1.5 Manny The City requires testing in each of the basin locations. The boring depths should be 3 times the ponded depth. 1.6 Brian Additional infiltration testing is to be completed on the western side of Basin #2 and in the new location for Basin #3. 2 DRAINAGE DESIGN 2.1 Brian Psomas had sent a Technical Memorandum to the City on 6/19/12 summarizing the drainage criteria and challenges with the proposed design mainly as a result of the infiltration test results. 2.2 Brian The following criteria were used in the drainage design: Design Storm: The design storm is the 100-yr 24-hr storm event per agreement between Caltrans and the City. Drainage and Water Quality Requirements: There are several requirements that we are trying to meet in terms of storm drain management and water quality management, including: • Treating 90% of the total WQV and maximum drawdown time of 96 hours. • No increase in total peak discharge into Shalimar and Breckenridge Drainage Basin Plans. • No increase in total runoff volume as a result of the project. 2.3 John In order to meet the Caltrans drawdown time of 96 hrs for the WQV we have included 4” perforations in the corrugated metal pipe riser. This increases the total runoff volume for the project. 2.4 Jim/ Manny The City will accept an increase in total runoff volume provided the 4” perforations are set at an elevation that will retain all water for the 5 yr storm event. Psomas to adjust 4” perforations to accommodate the 5yr storm event. 2.5 Manny Basins should have a 12 ft access road around the Psomas to adjust Basin #3 Morning Drive/SR 178 Interchange Project June 25, 2012, 1:30 PM Page 3 1075 Creekside Ridge Drive, Suite 200 • Roseville, CA 95678 • Tele: (916) 788-8122 • Fax: (916) 788-0600 ITEM NO. RESP PERSON TOPIC DISCUSSED ACTION ITEM perimeter and 2:1 max slopes. from 4:1 to 3:1 slopes to increase the bottom area of the basin. 2.6 Brian/ John Was the 60” pipe and Breckenridge Trapezoidal Chanel designed to handle all the runoff from the Breckenridge Plan shed area to the NW of this location? 2.7 Jim/ Manny The City confirmed that this system which was recently completed as part of the Ball Park project was designed to handle the runoff from the Breckenridge Plan shed area to the NW of this location. 2.8 Jim The Breckenridge and Shalimar plans generally have no outfalls. Instead, runoff is routed to basins where it diminishes via infiltration and evaporation. 3 OTHER ITEMS 3.1 Jim/ Manny The City no longer uses the Dynamic Vortech separator. The City does not require us to place this before the outfall of Basin #3. The basin itself will function as the water quality treatment BMP. 3.2 Brian Does the City only have the Type B manhole detail? Manny to provide additional manhole details. 3.3 Jim At the intersection with Panorama Drive, the manhole should include a 36” pipe east, a 30” pipe north, an 18“ pipe west. Note: These minutes are preparer's understanding of items discussed at the meeting. If discrepancies are noted, please contact the preparer within three days of receipt. Prepared by: Brian Wright Distribution: File 390 Jason Lemons, TYLin Masis Kayaian, Caltrans Attendee List