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Home My WebLink About9-2-08 Drainage Coordination Meeting Minutes PSOMAS 2295 Gateway Oaks Drive, Suite 250 • Sacramento, CA 95833 • Tele: (916) 929-7100 • Fax: (916) 929-6380 DRAFT MEETING MINUTES 06-Ker-178 PM R6.7 /T9.2 06-0C9400 6BAK040100 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: Tuesday, September 2 , 2008 TIME: 1:30 p.m. LOCATION: Cal Trans District 6 Manchester Office Conference Room 2015 E. Shields Ave, Suite A Fresno, CA 93726 ATTENDEES: Name Organization Telephone E-mail Address Anton Kistmetian Caltrans - Oversight 559-243-3859 Anton.Kismetian@dot.ca.gov Masis Kayaian Caltrans – Hydraulics 559-243-3513 Masis.Kayaian@dot.ca.gov Jeff Whitaker Caltrans-NPDES Storm Water 559-243-3515 Jeffrey.Whitaker@dot.ca.gov Sam Wong Caltrans – Hydraulics 559-243-3507 Sam_Wong@dot.ca.gov Brian Wright Psomas 916-929-7100 bwright@psomas.com Sean Hamblet Psomas 916-929-7100 shamblet@psomas.com Matt Lampa Psomas 916-929-7100 mlampa@psomas.com Morning Drive/SR 178 Interchange Project September 2, 2008, 1:30 PM Page 2 PSOMAS 2295 Gateway Oaks Drive, Suite 250 • Sacramento, CA 95833 • Tele: (916) 929-7100 • Fax: (916) 929-6380 ITEM NO. RESP PERSON TOPIC DISCUSSED OPEN CLOSED STATUS 1.0 PROJECT OVERVIEW 1.1 Brian Caltrans staff was very familiar with the project; only a brief overview stating the location and type of facility was given. 2.0 Existing Drainage 2.1 Sean An exhibit showing existing drainage patterns was presented to the group and existing drainage patterns were described. Northeast quadrant: Runoff from the area to the northeast of the SR 178/Morning Drive intersection flows generally east to the eastern project limit, where it crosses SR 178 and flows to the south. Southeast quadrant: Portions of the adjacent land to the south of SR 178 and east of Morning Drive flow towards SR 178. This runoff flows easterly along SR 178 and eventually to the south into the Breckenridge Drainage Area. West of Morning Drive: The offsite areas west of Morning Drive generally flow to the south into the Shalimar Drainage area. Roadway drainage: Along SR 178 there is an existing high point just west of Morning Drive. East of the high point, the roadway runoff generally flows to the east via a piped drainage network and overside drains. Runoff is eventually routed to the south into the Breckenridge Drainage Area. West of the high point the runoff generally flows to the west via a piped drainage network and eventually to the south into the Shalimar Planned Drainage Area. 2.2 Anton Caltrans noted that recent grading near Mesa Marin Raceway removed natural drainage channel to the south of SR-178 and the only outlet is a 24” pipe draining to the south. Given that two 60-inch cross culverts drain to this 24” pipe, Caltrans has concerns about flooding in this area. 2.3 Sam Caltrans noted that when Breckenridge Basin H was constructed, the City was not issued a Morning Drive/SR 178 Interchange Project September 2, 2008, 1:30 PM Page 3 PSOMAS 2295 Gateway Oaks Drive, Suite 250 • Sacramento, CA 95833 • Tele: (916) 929-7100 • Fax: (916) 929-6380 ITEM NO. RESP PERSON TOPIC DISCUSSED OPEN CLOSED STATUS permit for a drainage crossing on SR 178. The outfall pipe from the detention basin was taken to Caltrans right-of-way and was capped. Caltrans will not allow the crossing until facilities are in place that will convey runoff to the south without the possibility of flooding SR- 178. 2.4 Anton Runoff from the Canyon Hills Assembly of God Church and adjacent parcels is tributary to an existing SR-178 cross culvert. Caltrans and Psomas are in agreement that proposed roadway drainage systems should effectively separate on-site and off-site drainage to the maximum extent possible. Existing drainage patterns for the church and adjacent parcels should be maintained, allowing drainage to continue flowing to the Shalimar Planned Drainage Area 3.0 Proposed Drainage 3.1 Sean Design Assumptions: The proposed drainage infrastructure for the area north of SR 178 and east of Morning Drive noted in the Breckenridge Plan will not be in place upon completion of the project. Offsite runoff from this area will be included when calculating peak flows for cross drainage at the east end of the project. 07/08/08 Psomas to coordinate obtain list of approved treatment BMPs from the City. 3.2 Sean Preliminary Layout: Psomas discussed the overall layout of the drainage system on the project. Roadway drainage to the east of the high point will be routed to a proposed detention/retention pond at the eastern end of the project via a system of pipes and roadside swales. Ultimately, this area will drain to the Breckenridge Drainage Area. Roadway drainage to the west of the high point will be collected in a pipe network and piped to a proposed detention/retention pond at the western end of the project to the south of SR 178. Ultimately, this area will drain to the Shalimar Drainage Area. Existing drainage patterns will be maintained to the maximum extent possible under the proposed project. Morning Drive/SR 178 Interchange Project September 2, 2008, 1:30 PM Page 4 PSOMAS 2295 Gateway Oaks Drive, Suite 250 • Sacramento, CA 95833 • Tele: (916) 929-7100 • Fax: (916) 929-6380 ITEM NO. RESP PERSON TOPIC DISCUSSED OPEN CLOSED STATUS 3.3 Sean City of Bakersfield Input: Psomas summarized the City of Bakersfield retention requirements as determined from a coordination meeting held 07/30/08. Per the City’s guidance, retention shall be provided such that there is no net increase in total runoff from the project. Detention/retention ponds will be sized to store the net increase in runoff volume as a result of the additional impervious area with the proposed project. 3.4 Anton In contrast to the City’s requirement of retaining only the net increase in runoff as a result of the project, Caltrans assumed that retention basins had to retain all on-site runoff for two consecutive 10-year, 24-hour events when preparing the PSR. Caltrans would support less retention and discharge to City drainage facilities provided a written agreement can be obtained from the City. 09/02/08 Psomas to obtain written confirmation from the City of Bakersfield regarding retention requirements. Design Methodology 3.5 Sean Hydrologic Calculations: - The Rational method will be used for hydraulic calculations related to storm drain hydraulics. - The NRCS method will be used for detention routing and, due to the size of the offsite watersheds, will be used to determine peak flows for cross drainage at the east end of the project. Design Frequencies: - The 10 and 100-year events will be used for cross culvert hydraulic calculations. - The 25-year event will be used for roadway drainage calculations. Roadway Drainage Layout: - The drainage layout will be such that existing drainage patterns will be maintained to the maximum extent practicable. - Inlets will be spaced based on HDM spread criteria, which, for this project, will be limited to the shoulder. Pipe Sizing: Will be based on FHWA HEC-22 Morning Drive/SR 178 Interchange Project September 2, 2008, 1:30 PM Page 5 PSOMAS 2295 Gateway Oaks Drive, Suite 250 • Sacramento, CA 95833 • Tele: (916) 929-7100 • Fax: (916) 929-6380 ITEM NO. RESP PERSON TOPIC DISCUSSED OPEN CLOSED STATUS pipe sizing methodology. Water Quality Volume: Will be determined using the CSU Sacramento Basin Sizer software as described in the PPDG. 3.6 Masis District 6 basin sizing and drainage guideline handouts were provided to Psomas. District 6 requires that retention basins drainage be sized to for two consecutive 10-year, 24-hour events. When sizing ponds, infiltration shall not be taken into consideration. These requirements may be modified depending on whether the City will agree to allow discharge to their facilities. 3.7 Anton Proximity to PG&E transmission lines and topography must be considered when designing the proposed retention basin on the western end of the project. PG&E has guidelines regarding the location of basins in relation to transmission lines. 09/02/08 Psomas to coordinate with PG&E guidelines regarding proximity of basins and transmission lines Water Quality 3.8 Jeff Psomas must account for all on-site drainage and specify terminus discharge point. Proposed roadside bio swales and basins fulfill Caltrans water quality requirements. No other concerns or major issues noted at this time regarding water quality 3.9 Anton Water quality requirements will be fulfilled via infiltration basins alone if 100% of drainage is retained in basin. 4.0 Questions and Comments 4.1 Anton Retention basins may also be investigated in pervious areas around interchange ramps to decrease storage volume in downstream basin. Whether or not this will be required will be dependent on whether the City agrees to Caltrans discharge to their drainage systems. 4.2 Anton Prior to submittal of drainage report, Psomas should coordinate and meet with Landscape Architecture and Maintenance to ensure their requirements are met. 09/02/08 Psomas to coordinate and meet with respective entities prior to report submittal 4.3 Brian Psomas asked about existing flooding or Morning Drive/SR 178 Interchange Project September 2, 2008, 1:30 PM Page 6 PSOMAS 2295 Gateway Oaks Drive, Suite 250 • Sacramento, CA 95833 • Tele: (916) 929-7100 • Fax: (916) 929-6380 ITEM NO. RESP PERSON TOPIC DISCUSSED OPEN CLOSED STATUS maintenance related problems on the existing facility at the eastern end of the project. Caltrans stated that they were not aware of any problems since there has not been a large event since the existing channel had been eliminated near the Raceway. 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: Matt Lampa, PE Distribution: File 390 Nick Izadpanah, TRIP Attendee List