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HomeMy WebLinkAboutSDP200900036 Review Comments 2009-06-03Page 1 of 1 Philip Custer From: Philip Custer Sent: Wednesday, June 03, 2009 10:52 AM To:Fitzgerald Barnes; Joe Werres; Lisa Glass; Joe Letteri; ' Notte, Skip'; 'Wagner, Kenneth' Cc:Elizabeth Marotta; Andrew Lowe Subject: RE: Engineering review of Monticello High School Turf Replacement Project Good morning, The sets of plans submitted yesterday have received site and WPO plan approval. I have given four copies of the plans to the county erosion and sediment control inspector. To set up a pre- construction conference and obtain a grading permit, please contact Kenny Thacker at (434)- 296 -5832 x3390 or Andy Lowe at x3245. Thanks, Phil From: Philip Custer Sent: Friday, May 29, 2009 4:43 PM To: Fitzgerald Barnes; Joe Werres; Lisa Glass; Joe Letteri; Notte, Skip; Wagner, Kenneth Cc: Amy Pflaum; Glenn Brooks; Elizabeth Marotta Subject: Engineering review of Monticello High School Turf Replacement Project Good afternoon, Attached is the latest engineering review comment letter for the Monticello High School Turf Replacement Project SDP- 2009 -00036 and WPO- 2009 - 00021). The only outstanding engineering issue is the Stormwater metering and water quality monitoring compromise discussed on the meeting held on 5/18. In the comment letter, a note has been provided that should be included in the plan set. The details of the monitoring and water quality sampling should be coordinated with engineering review before the plan is approved. Please submit 4 copies of the plan to engineering review so that they can be passed off to the erosion control inspector (all "reference only" sheets do not need to be included in the submitted sheet set). The project planner will need additional copies of the set at the time of site plan approval, once all engineering comments have been addressed. Please contact me should you have any questions. Thanks, Phil 6/3/2009 a�•_�� 4180 Innslake Drive 804 290 7957•80n 90 7928 fax Dewberry® Glen Allen,Virginia 23060-3344 www.dewberry.com June 2,2009 Mr. Philip Custer Civil Engineer County of Albemarle Community Development Department Zoning and Current Development 401 McIntire Road Charlottesville,VA 22902 Re: SDP-2009-00036,Monticello High School Minor Amendment WPO-2009-00021,Monticello High School SWM.and ESC Plans Dear Mr. Custer: Please find enclosed four sets of plans and drainage computations for your review and approval. A summary of the comments and responses from the second submission,that were to be incorporated, can be found below. A. Minor Amendment comments (SDP-2009-00036): 4. The tops of the 6 drainage structures appear to be proposed at an elevation well below the grade of the turf, assuming 1.5%slopes from the track and crown of the field. (Rev. 1) The detail provided by Joe Werres drawn by General Sports Venue has been approved and will be stapled to the site plan set. B. Stormwater Management comments (WPO-2009-00021): 1. For water quality analyses,the County uses a composition spreadsheet based on the Simple Method to assess whether water quality measures are needed and what removal rate facilities should be designed for. My analysis of the watershed delineated by the applicant indicates that a facility with a 50%removal rate is required. The water quality volume is 4145cf. (Rev. 1)At the meeting held on May 18th, it was our understanding that the applicant offered to perform water quality sampling as well as flow metering to address water quality concerns. Please provide the following note on sheets C1A and CHB: As a condition of WPO plan approval for this project,the applicant commits to flow metering and water quality monitoring. A flow meter will be installed on one of the loin.underdrain outlet pipes at a midfield stormwater structure. The frequency and location of the water quality sampling should be determined by a qualified individual with experience in water quality analysis. A report shall be submitted to the Community Development office every three months after the construction of the field for a period of one year. The report must include all raw data collected to date and a summary prepared by a qualified individual. The report must also include rainfall data from the nearest NOAA rain gauge. Dewberry: Per Joe Werres,the following note was added to plan sheets CIA and CHB. "Owner to provide water quality testing at the existing storm water management facility forebay." Dewberry&Davis, Inc. Mr.Philip Custer June 2,2009 ww` Page 2 of 2 2. The applicant has indicated that water quality treatment will be provided through infiltration practices and extended detention. However,the blue book notes that infiltration practices should only be designed when the infiltration rate of the in-situ soil is between 0.52 in/hr and 8.0 in/hr. The geotechnical field tests submitted by the applicant show that only one boring possesses a rate in this range. So, it appears infiltration is not a viable option. Also, it does not appear a drawdown calculation for an extended detention basin was provided. [VSMH 5- 6.2] Engineering review recommends designing a biofilter meeting the current regulations (for a 50%removal rate, a footprint of 2.5%of the equivalent impervious area would be needed). There appears to be sufficient room for a 2500sf biofilter at the northwest corner of the track. Engineering would permit the facility to be constructed a year after the installation of the field if a flow meter was installed on the outlet pipe and a report was prepared evaluating the hydrologic characteristics of the turf field. If the data found from the flow metering shows a significant reduction in runoff,the construction of the biofilter may not be necessary(to be determined by the engineering review group). This would also help provide solid background information for the county review department when future grass to artificial turf field enhancement projects are submitted in the years to follow. (Rev. 1)See previous comment. Dewberry: Per Joe Werres,the following note was added to plan sheets CIA and C11B. "Owner to provide water quality testing at the existing storm water management facility forebay." C.Erosion and Sediment Control comments(WPO-2009-00021): All comments have been addressed. If you require any additional information,please feel free to contact me. Sincerely !/ ,F / Dewberry Da -i ,In,. r , Ro•ert►. Notte,P.E. Projec Manager, Senior Associate cc: Joe Werres, ACPS Project Manager Dewberry® 'Now' ‘itiroe tit' Dewberry Innslake Drive 804 290 7957•804 290 7928 fax Dewberry Glen Allen,Virginia 23060-3344 www.dewberry.com May 26,2009 11Y-1 Mr. Philip Custer Civil Engineer County of Albemarle Community Development Department Zoning and Current Development 401 McIntire Road Charlottesville,VA 22902 Re: SDP-2009-00036,Monticello High School Minor Amendment WPO-2009-00021,Monticello High School SWM and ESC Plans Dear Mr. Custer: Please find enclosed two sets of plans and drainage computations for your review and approval. A summary of the comments and responses from the first submission, that were to be incorporated,can be found below. A. Minor Amendment comments (SDP-2009-00036): 1. Please provide the date and source of the topography. Dewberry: The topography for the project area is provided by Dewberry Survey(April 2009). The topography for the area shown outside the project area is as-built data provided by Albemarle County Public Schools(October 1996). This is stated on Sheet OA under the"General Notes"section(Notes 1 and 9)and on Sheet CHB under the "Notes" section (Note 3). 2. Please provide in the set the County's General Construction Notes which can be found in the latest edition of the design manual,available online. Dewberry: The County's General Construction Notes are provided on Sheet OA under the"General Notes" section(Notes 14-22). 3. Are the 6 drainage structures around the field going to be converted to manholes? If so,please specify the tops as VDOT Standard MH-1. Dewberry: The 6 drainage structures around the field are being converted as discussed at the meeting held on 5/18/09. The three structures along the east sideline of the field carrying VDOT drainage, and the structure at midfield along the west sideline,shall be converted to accessible MH-1 tops. The two structures at the corners along the west sideline of the field,which are maintained by Monticello High School,shall have the tops lowered and be non-accessible. This is noted on Sheet CHB of the plan set. 4. The tops of the 6 drainage structures appear to be proposed at an elevation well below the grade of the turf, assuming 1.5%slopes from the track and crown of the field. Dewberry: Per our meeting held on 5/18/09,the two existing inlets on the corners of the Dewberry&Davis, Inc. • west sideline wine buried below the geotextile fabric,which will put the solid structure top elevation 0.8'below the proposed turf surface. There will be no access to these two structures. The proposed rim elevation of the three existing inlets along the east sideline and the structure at midfield along the west sideline will also be buried below the proposed turf surface but access to these structures will be provided. A note has been provided on Sheet C11B that states this. 5. Please provide greater detail in the section showing the trench and underdrain area. For instance: the slope of the compacted earth soil under the gravel layer and elevations of the bottom of trench and the beginning of the 1.5% slope. Dewberry: A note has been added to the"Typical Sideline Field Section at 10-inch Pipe Connection"Detail on Sheet CHB stating that"The 2.5" synthetic turf surface,2" finished stone(#8),4"base stone(#57),and the compacted subgrade are to be sloped at a 1.5% slope from the centerline of the field and from the edge of the track to the proposed trench along the sidelines". The elevation of the bottom of the proposed trench is now called out on this detail as 485.09. B. Stormwater Management comments (WPO-2009-00021): 1. For water quality analyses,the County uses a composition spreadsheet based on the Simple Method to assess whether water quality measures are needed and what removal rate facilities should be designed for. My analysis of the watershed delineated by the applicant indicates that a facility with a 50%removal rate is required. The water quality volume is 4145cf. Per our meeting held on 5/18/09, a flow meter will be installed at the outlet pipe after construction is complete. The results will be evaluated and a report will be prepared that compares the theoretical pre-existing conditions to the proposed conditions in order to show how water quality is being addressed by means of reduced outflow. It was agreed that the results from the flow meter tests will not warrant additional future measures to be constructed on site to address the turf field water quality requirements. 2. The applicant has indicated that water quality treatment will be provided through infiltration practices and extended detention. However,the blue book notes that infiltration practices should only be designed when the infiltration rate of the in-situ soil is between 0.52 in/hr and 8.0 in/hr. The geotechnical field tests submitted by the applicant show that only one boring possesses a rate in this range. So, it appears infiltration is not a viable option. Also, it does not appear a drawdown calculation for an extended detention basin was provided. [VSMH 5- 6.2] Engineering review recommends designing a biofilter meeting the current regulations (for a 50%removal rate,a footprint of 2.5%of the equivalent impervious area would be needed). There appears to be sufficient room for a 2500sf biofilter at the northwest corner of the track. Engineering would permit the facility to be constructed a year after the installation of the field if a flow meter was installed on the outlet pipe and a report was prepared evaluating the hydrologic characteristics of the turf field. If the data found from the flow metering shows a significant reduction in runoff, the construction of the biofilter may not be necessary(to be determined by the engineering review group). This would also help provide solid background information for the county review department when future grass to artificial turf field enhancement projects are submitted in the years to follow. Dewberry: Per our meeting held on 5/18/09,a flow meter will be installed at the outlet Dewberry° pipe after construction is complete. The results will be evaluated and a report will be prepared that compares the theoretical pre-existing conditions to the proposed conditions in order to show how water quality is being addressed by means of reduced outflow. It was agreed that the results from the flow meter tests will not warrant additional future measures to be constructed on site to address the turf field water quality requirements. 3. It is critical to the project meeting the detention requirements that the elevations used in the routing are constructed as proposed on site. Typically,when a pipe is laid in the trench at a certain slope,we find that the trench is also sloped at that percentage because it is easier for a contractor to build. Please provide more notations through out the plan and details that the bottom of the trench is to remain flat at the 485 elevation. Dewberry: A note has been added to the"Typical Sideline Field Section at 10-inch Pipe Connection"Detail on Sheet CHB stating that"The bottom of the trench along the sidelines is to remain flat at a consistent elevation(Elv.485.09). The bottom of the trench will slope up at 1.5% after the trench turns 90 degrees and is routed perpendicular to the sidelines towards the field goal posts. C.Erosion and Sediment Control comments (WPO-2009-00021): 1. Please provide in the set the County's General Construction Notes for Erosion and Sediment Control Plans which can be found in the latest edition of the design manual, available online. Dewberry: The County's General Construction Notes for Erosion and Sediment Control Plans are provided on Sheet CIA under the"General Erosion and Sediment Control Notes"section (Notes 1-20). 2. Please provide Dust Control symbols(DC)on the plan as well as a location for a soil stockpile. Dewberry: The Dust Control symbol is now provided in the plans and in the legend for the Virginia Uniform Coding System for Erosion and Sediment Control Practices on Sheet C11A. A soil stockpile location is not part of these plans. Note#5 on Sheet CHB states that"Contractor is responsible for disposal of all excavated soil at an approved off-site location. It is the contractor's responsibility to obtain and present all necessary documentation for this location to local and state agencies prior to construction. These plans do not identify this location". There is,however,a contractor laydown/storage area as well as a contractor parking and mess consolidation area identified on these plans on Sheet C11A. 3. What is the reason for phased construction of the turf? Is the goal to have half the field available for use during construction? If so,please provide another CE and access path for Phase I. If not,please remove the phasing lines. Dewberry: The reasoning behind the phasing of construction is to limit the project area that is denuded of vegetation to less than 1 acre at any given time. The total disturbed area for this project is about 1.8 acres which is why two phases were specified. For this reason the phasing of the project will remain. This was the method used for a similar project done at the University of Virginia. The entire field will be unavailable for use throughout construction,and an additional construction entrance will not be necessary. I Dewberry® .4.400 4. Please stipulate in the construction sequence that the trench and underdrain at the perimeter of the site should only be installed after the majority of the field is graded and graveled. If the trench and underdrain are installed in the first stages of construction prior to the majority of the earthwork, a significant amount of sediment will likely choke up the soil(limiting infiltration)and be lost through the pipe system. Dewberry: The recommendation above is now shown in the Sequence of Construction (Note 5)on Sheet C11A. 5. Please provide a soil boundary map with labels in the plan set. Dewberry: A Soil Boundary Map with labels is now provided on Sheet C24A. 6. Please provide an adequate channel analysis of the downstream storm sewer network to the pond forebay. (MS-19) Dewberry: An adequate outfall analysis is now provided in the Stormwater Management Analysis booklet. The existing 42"RCP that outfalls into the stormwater management forebay is adequately sized to handle the approximate 47 acre drainage area that is routed to it. Sincerely, Dewb• Davis,Inc. a I /11F r WI Robe • . otte, ' . . Seni it Associate Dewberry® J F 1 llfll98c IRGII` COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 - 4126 Project:SDP - 2009 - 00036, Monticello High School Minor Amendment WPO- 2009 - 00021, Monticello High School SWM and ESC Plans Plan preparer:Skip Notte, Dewberry and Davis, Inc. Owner or rep.:Joe Werres, ACPS Office of Facilities Development Date received:4 May 2009 (plan signed 1 May 2009) Date of Comment: 14 May 2009 Engineer:Phil Custer The minor site amendment, SWM, and ESC plans for the Monticello High School Turf Replacement project, received on 4 May 2009, have been reviewed. The plans cannot be approved as submitted and will require the following changes /corrections prior to fmal approval. A. Minor Amendment comments (SDP 2009 - 00036): 1. Please provide the date and source of the topography. 2. Please provide in the set the County's General Construction Notes which can be found in the latest edition of the design manual, available online. 3. Are the 6 drainage structures around the field going to be converted to manholes? If so, please specify the tops as VDOT Standard MH -1. 4. The tops of the 6 drainage structures appear to be proposed at an elevation well below the grade of the turf, assuming 1.5% slopes from the track and crown of the field. 5. Please provide greater detail in the section showing the trench and underdrain area. For instance: the slope of the compacted earth soil under the gravel layer and elevations of the bottom of trench and the beginning of the 1.5% slope. B. Stormwater Management comments (WPO- 2009 - 00021): 1. For water quality analyses, the County uses a composition spreadsheet based on the Simple Method to assess whether water quality measures are needed and what removal rate facilities should be designed for. My analysis of the watershed delineated by the applicant indicates that a facility with a 50% removal rate is required. The water quality volume is 4145cf. 2. The applicant has indicated that water quality treatment will be provided through infiltration practices and extended detention. However, the blue book notes that infiltration practices should only be designed when the infiltration rate of the in -situ soil is between 0.52 in/hr and 8.0 in/hr. The geotechnical field tests submitted by the applicant show that only one boring possesses a rate in this range. So, it appears infiltration is not a viable option. Also, it does not appear a drawdown calculation for an extended detention basin was provided. [VSMH 5- 6.2] Engineering review recommends designing a biofilter meeting the current regulations for a 50% removal rate, a footprint of 2.5% of the equivalent impervious area would be needed). There appears to be sufficient room for a 2500sf biofilter at the northwest corner of the track. Engineering would permit the facility to be constructed a year after the installation of the field if a flow meter was installed on the outlet pipe and areport was prepared evaluating the hydrologic characteristics of the turf field. If the data found from the flow metering shows a significant reduction in runoff, the construction of the biofilter may not be necessary (to be determined by the engineering review group). This would also help provide solid background information for the county review department when future grass to artificial turf field enhancement projects are submitted in the years to follow. 3. It is critical to the project meeting the detention requirements that the elevations used in the routing are constructed as proposed on site. Typically, when a pipe is laid in the trench at a certain slope, we find that the trench is also sloped at that percentage because it is easier for a contractor to build. Please provide more notations through out the plan and details that the bottom of the trench is to remain flat at the 485 elevation. C. Erosion and Sediment Control comments (WPO- 2009 - 00021): 1. Please provide in the set the County's General Construction Notes for Erosion and Sediment Control Plans which can be found in the latest edition of the design manual, available online. 2. Please provide Dust Control symbols (DC) on the plan as well as a location for a soil stockpile. 3. What is the reason for phased construction of the turf? Is the goal to have half the field available for use during construction? If so, please provide another CE and access path for Phase I. If not, please remove the phasing lines. 4. Please stipulate in the construction sequence that the trench and underdrain at the perimeter of the site should only be installed after the majority of the field is graded and graveled. If the trench and underdrain are installed in the first stages of construction prior to the majority . of the earthwork, a significant amount of sediment will likely choke up the soil (limiting infiltration) and be lost through the pipe system. 5. Please provide a soil boundary map with labels in the plan set. 6. Please provide an adequate channel analysis of the downstream storm sewer network to the pond forebay. (MS -19) Please contact me at (434)296 -5832 ext. 3072 should you have any questions. Application #:SDP200900036 Short Review Cm-talents Project Name:Monticello High School Stadium Turf Replacement - Minor Minor Amendment Date Completed:05/13/2009 Reviewer:Elizabeth Marotta CommDev- Current Development Review Status:No Objection Reviews Comments: No objection pending Engineering review. Date Completed:05/29/2009 Reviewer:Philip Custer Engineer Z &CD Review Status:Requested Changes Reviews Comments: Needs SWM plan and study approved. Page: 1.00 County of Albemarle Printed On: Wednesday, June 03, 2009 I Alin L >RGIN P COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 -4126 Project:SDP - 2009 - 00036, Monticello High School Minor Amendment WPO- 2009 - 00021, Monticello High School SWM and ESC Plans Plan preparer:Skip Notte, Dewberry and Davis, Inc. Owner or rep.:Joe Werres, ACPS Office of Facilities Development Date received:Rev. 1) 26 May 2009 (plan signed 22 May 2009) 4 May 2009 (plan signed 1 May 2009) Date of Comment: Rev. 1) 29 May 2009 14 May 2009 Engineer:Phil Custer The minor site amendment, SWM, and ESC plans for the Monticello High School Turf Replacement project, received on 26 May 2009, have been reviewed. The plans cannot be approved as submitted and will require the following changes /corrections prior to fmal approval. A. Minor Amendment comments (SDP 2009 - 00036): 4. The tops of the 6 drainage structures appear to be proposed at an elevation well below the grade of the turf, assuming 1.5% slopes from the track and crown of the field. Rev. 1) The detail provided by Joe Werres drawn by General Sports Venue has been approved and will be stapled to the site plan set B. Stormwater Management comments (WPO- 2009 - 00021): 1. For water quality analyses, the County uses a composition spreadsheet based on the Simple Method to assess whether water quality measures are needed and what removal rate facilities should be designed for. My analysis of the watershed delineated by the applicant indicates that a facility with a 50% removal rate is required. The water quality volume is 4145cf. Rev. 1) At the meeting held on May 18 it was our understanding that the applicant offered to perform water quality sampling as well as flow metering to address water quality concerns. Please provide the following note on sheets CIA and CI1B: As a condition of WPO plan approval for this project, the applicant commits to flow metering and water quality monitoring. A flow meter will be installed on one of the loin. underdrain outlet pipes at a midfield stormwater structure. The frequency and location of the water quality sampling should be determined by a qualified individual with experience in water quality analysis. A report shall be submitted to the Community Development office every three months after the construction of the field for a period of one year. The report must include all raw data collected to date and a summary prepared by a qualified individual. The report must also include rainfall data from the nearest NOAA rain gauge. 2. The applicant has indicated that water quality treatment will be provided through infiltration practices and extended detention. However, the blue book notes that infiltration practices should only be designed when the infiltration rate of the in -situ soil is between 0.52 in/hr and 8.0 in/hr. The g chnical field tests submitted by the applicant show that only one boring possesses a rate in this range. So, it appears infiltration is not a viable option. Also, it does not appear a drawdown calculation for an extended detention basin was provided. [VSMH 5- 6.2] Engineering review recommends designing a biofilter meeting the current regulations for a 50% removal rate, a footprint of 2.5% of the equivalent impervious area would be needed). There appears to be sufficient room for a 2500sf biofilter at the northwest corner of the track. Engineering would permit the facility to be constructed a year after the installation of the field if a flow meter was installed on the outlet pipe and a report was prepared evaluating the hydrologic characteristics of the turf field. If the data found from the flow metering shows a significant reduction in runoff, the construction of the biofilter may not be necessary (to be determined by the engineering review group). This would also help provide solid background information for the county review department when future grass to artificial turf field enhancement projects are submitted in the years to follow. Rev. 1) See previous comment. C. Erosion and Sediment Control comments (WPO- 2009 - 00021): All comments have been addressed. Please contact me at (434)296 -5832 ext. 3072 should you have any questions.