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HomeMy WebLinkAboutWPO201000011 Review Comments Stormwater Management Plan 2010-04-30ALg�,�� �'IRGINZ� COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 -4126 Project: Treesdale Park; WPO- 2010 - 00011; SDP - 2010 -00013 Plan preparer: Mr. Scott Collins, PE; Collins Engineering Owner or rep.: Albemarle Housing Improvement Program, Inc. Date received: 16 February 2010 (Rev. 1) 22 March 2010 (Rev. 2) 1 April 2010 (Rev. 3) 7 April 2010 Date of Comment: 8 March 2010 (Rev. 1) 30 March 2010 (Rev. 2) 2 April 2010 (Rev. 3) 30 April 2010 Engineer: Phil Custer The third resubmittal of the final site and SWM plans for the Treesdale Park Project has been reviewed. The following comments are provided. A. SDP - 2010 -00013 Final Site Plan Comments 1. This final site plan shows more disturbance to critical slopes than the plan accompanying the critical slopes waiver that was approved by the Planning Commission in the fall of last year. Because of the increase in critical slope disturbance, it is my opinion that a critical slope waiver must again be granted by the Planning Commission. This decision can be overturned by the Chief of Current Development, who is the acting agent of the Zoning Ordinance for this project. (Rev. 1) Engineering review has been verbally informed by the Chief of Current Development that a critical slope waiver is not required at this time. 2. VDOT approval is required. At this time, VDOT approval has not yet been received. (Rev. 1) The county has not received any confirmation from VDOT that the plan can be approved. (Rev. 2) VDOT approval has been received. 3. An area for a bus stop, as required by Proffer 5, must be accounted for in this plan. This bus stop will require the dedication of additional ROW in the future. The placement of Building 1 must consider adjustment of the setbacks because of the future ROW dedication. (Rev. I) Comment has been addressed. 4. All Right of Way needed for this development on TMP 61 -184 must be dedicated before the approval of this final site plan. (Rev. 1) Comment has not been addressed. All public ROW necessary for the Rio Road upgrades and construction of Stonewater Drive to Station 12 +00 must be dedicated prior to approval of the Treesdale site plan. In addition, the private street easement for Stonewater Lane, drainage easements, and temporary construction easements needed to complete all this work must be provided by the owner of TMP 61 -184 before approval of the Treesdale site plan. Please see comment B.1. (Rev. 2) Engineering understands that the applicant will be submitting a plat from TMP 61 -184 in the near future that will address all the necessary requirements. The plat should include: -the dedication of all ROW for Rio Road improvements; -the dedication of Stonewater Drive to the intersection with Stonewater Lane; -the creation of the private street easement to Treesdale Park (Stonewater Lane) from Stonewater; -the public drainage easements (with deeds) for pipes 525, 544, S46, S19, and S21 of the Stonewater set and 7, 5, 4C, 4A, and 3 of the Treesdale set; and -all necessary construction easements to install these improvements (a general note on the plat referencing the Treesdale site plan will suffice). (Rev. 3) The offsite easement plat (SUB- 2010 - 00045) is currently under review. This plat and deeds of easement must be recorded prior to site plan approval. The construction and permanent (drainage and greenway) easements on TMP 61 -184 must be recorded before this final site plan is approved. (Rev. 1) Comment has not been addressed. The applicant has provided an amendment to the agreement between Rio and AHIP, but this document only references a IOft construction easement. Permanent greenway and public drainage easements are required prior to site plan approval. (Rev. 2) See previous comment. (Rev. 3) The offsite easement plat (SUB - 2010 - 00045) is currently under review. This plat and deeds of easement must be recorded prior to site plan approval. 6. The construction and permanent easements on TMP 61A -A must be recorded before this final site plan is approved. (Rev. 1) If these easements are already recorded, please provide the Deedbook and Page number within the set. (The offsite property in question is actually 61A -3 -A, not 61A -A.) (Rev. 2) The current proposed alignment of the sanitary sewer line is not within the existing easement. This offsite easement plat must be updated prior to site plan approval or another alignment of this sewer main must be designed and approved by ACSA. (Please see accompanying pdfs.) (Rev. 3) ACSA approval of the change to the sewer alignment has not yet been received. The sewer line appears to be only 5 -6ft off the edge of the existing easement. Please also label the deedbook and page number for the existing easement in the site plan. 7. The boundary line adjustment combining all parcels into one must be recorded prior to approval of this final site plan. (Rev. 1) Engineering review understands this plat has already been approved and is currently in the process of being recorded. Please provide the county with a receipt of recordation once the plat is recorded at the courthouse. (Rev. 2) Comment has been addressed. Streams and wetlands are located within the limits of construction. Please provide an approval letter from the Army Corps of Engineers. If the applicant contends that streams or wetlands will not be impacted, please provide a letter from the Army Corps of Engineers that confirms this statement. (Rev. 1) Please remove the grading of the stormwater maintenance path from the wetland area. Engineering will confirm that all ESC disturbances are outside of the jurisdictional areas once the ESC plan is reviewed. (Rev. 2) Comment remains unchanged. The stormwater access path must be shown in this set and the grading should be adjusted so as not to disturb the wetlands. (Rev. 3) Comment has been addressed. 9. Please show all of the existing easements recorded with SUB - 2008 -00253 on the plat with the deed book and page number listed. [18- 32.6.6] (Rev. 1) Comment has been addressed. 10. Please add more TOW/BOW spot elevations on the retaining wall along Rio Road and remove the note referencing a height of 7ft. (Rev. 1) Comment has been addressed. 11. Please specify the two terminals of the guardrail along Rio Rd. (Rev. 1) Comment has been addressed. 12. The layback angle of the segmental retaining wall used should be considered in the layout of the site plan. For every 5.3 vertical feet, the wall loses lft horizontally. For the series of walls on the west side of the property, the lost space will likely not be an issue. However, the slope of the retaining wall should be considered for the wall along Rio Rd. Please show the true thickness of this wall, from the face at the bottom and from the back edge at the top. This will likely necessitate moving the wall closer to the building in order to maintain the 2ft spacing between back of wall and the guardrail posts as specified in the detail is sheet S -4. (Rev. 1) The detail provided by the applicant on sheet S -5 does not match the dimension of the design on Sheet S -1. Please modify Sheet S -1 to match the section detail. (For instance, the ROW is shown as being 12.33ft off the back of curb in the detail, but on sheet S -1 it is shown as ]]ft. Also, the 1 ft clearance provided from the ROW to the back wall segment on the detail does not seem to be afforded on Sheet S -1. (Rev. 2) In plan view, move the wall 1.5ft towards the building. The current distance from the face of the wall to the back of the guardrail is two feet. The detail for the Anchor wall system requires a minimum of 3.33ft. (Rev. 3) The plan is currently acceptable. 13. For the wall along the Right of Way of Rio Road please provide a specific section detail dimensioning the length of the geogrid system and show how the geogrid is built around the guardrail. Please also show the ROW line in the section detail. (Rev. 1) The detail provided by the applicant on sheet S -5 does not match the dimension of the design on Sheet S -1. Please modify Sheet S -1 to match the section detail. (For instance, the ROW is shown as being 12.33ft off the back of curb in the detail, but on sheet S -1 it is shown as 11 ft. Also, the ]ft clearance provided from the ROW to the back wall segment on the detail does not seem to be afforded on Sheet S -1. (Rev. 2) In plan view, move the wall 1.5ft towards the building. The current distance from the face of the wall to the back of the guardrail is two feet. The detail for the Anchor wall system requires a minimum of 3.33ft. (Rev. 3) The plan is currently acceptable. 14. The guardrail along Rio Road should be maintained by VDOT. The retaining wall along the ROW may need to be maintained by VDOT. Ultimately, the decision regarding maintenance of the guardrail and wall will be made by VDOT. The applicant should be made aware that the ROW line could need to be shifted farther into the site. (Rev. 1) Since this comment letter was transmitted, VDOT has stated that the ROW should be placed ]ft behind the back of the guardrail. Please refer to the previous comments. (Rev. 2) VDOT approval has been received. 15. All drainage pipes carrying water from the VDOT right of way must have drainage easements dedicated to public use before the issuance of the first Certificate of Occupancy. The easements dedicated to public use should be clearly differentiated from the other drainage easements shown on the plan. The easements that must be dedicated to public use are over pipes 1, 2A, 2C, 3, 5, 7, 9, 11, 21, 23, 25, 27, 29, 31, and 33. Any portion of the drainage easements located on TMP 61- 184 must be recorded before site plan approval. (Rev. 1) Drainage easements are not needed on the remainder of the pipes. If they are to remain on the plan, please designate them separately from the public easements. The drainage easement offsite must be recorded with a deed of easement prior to site plan approval. (Rev. 2) The private and public drainage easements do not appear to be clearly designated. Please seethe accompanying pdf. The offsite drainage easements must be recorded prior to site plan approval. (Rev. 3) The offsite drainage easements are currently being reviewed by SUB - 2010 - 00045. This plat and deeds of easement must be recorded prior to site plan approval. 16. Please provide a note on the cover sheet below the sheet index stating that the ROW dedication, public drainage easements, and RWSA easement must be recorded prior to the issuance of the first Certificate of Occupancy. (Rev. 1) Comment has been addressed. 17. Please remove all significant trees from the public drainage easements. (Rev. 1) All large trees have been removed from the public drainage. However, the easement is now encompassing much of the retaining wall southwest of building 4. Please adjust the easement so that the footer of the retaining wall is outside of the public drainage easement. The pipe must be within the inner third of the easement, so it appears the pipe must be shifted slightly as well. (Rev. 2) Comment has been addressed. 18. The entrance has a slope steeper than 4% on the exit from the site. Please reduce this slope to 4% or flatter. (Rev. I) Comment has been addressed. 19. The speed limit on this section of Rio Road is 35mph. For this reason, the sight distance triangles must be adjusted. (Rev. 1) Comment has not been addressed. The sight distance line looking south is still drawn to 305ft as opposed to 390ft. (Rev. 2) Comment has been addressed. Because of the limited entrance, adequate sight distance does not need to be established to the south. 20. Please provide overland flow relief for inlets 12 and 16 so that structures will not be flooded in case of inlet failure. [DM 18- 32.6.6.s] (Rev. I) Comment has been addressed. 21. Please show the crossing of a sewer lateral and fire line for drainage pipe 25. (Rev. 1) Comment has been addressed. 22. In the calculations, a few of the pipes do not appear to be flowing under open channel flow hydraulics. Please adjust the design of these pipes. (Rev. 1) Comment has been addressed. 23. Please provide a channel design, with ditch lining, for the stream reconstruction after Pipe 3 is placed. (Rev. 1) A channel is still being disrupted with the storm sewer system installation and must be replaced. A simple dimension callout and lining specification in the storm sewer profile will suffice. (Rev. 2) Comment has been addressed. 24. The drainage area map doesn't match up with the design of the roofdrain system. Please update the map and calculations accordingly. (Rev. I) Comment has been addressed. 25. Many of the drainage areas in the plan that are >90% pavement should have a time of concentration of 5 minutes. For instance, drainage areas for inlets 32 and 26 should have a time of concentration of 5 minutes. Please update the map and calculations accordingly. (Rev. 1) Comment has been addressed. 26. (Rev. 1) The ROW line north of the site entrance must be placed l ft off of the sidewalk. (Rev. 2) Since VDOT has approved the plan, this comment has been withdrawn. 27. (Rev. 1) Please shift the easement over pipe 29 to the south so it does not encroach on the building footprint. (Rev. 2) Comment has been addressed. 28. (Rev. 1) Safety slabs are needed in structures 6 and 8. (Rev. 2) Comment has been addressed. 29. (Rev. 3) Please remove the "Area Reserved to Accommodate Additional Parking as Required" from the recreational space on all sheets where it is shown. No future development will be allowed in this area without approval from the Planning Department or Board of Supervisors depending on the proposal. B. SDP - 2010 -00013 Road Plan Comments 1. The barricade on Treesdale Way must be removed. Engineering review will not approve a plan for this development that lacks safe movements from and onto northbound Rio Rd. In order to receive engineering approval, Treesdale must either provide a full intersection on site (which may not be allowed by Planning /Zoning because of the approved ZMA), construct the necessary road improvements proposed in the Stonewater construction set, or wait until these improvements are built or bonded by the Stonewater Developer before getting a Certificate of Occupancy. If the applicant wishes to construct these improvements, the necessary road plans should be included in this set and also accounted for in the Treesdale ESC plan. All necessary offsite easements and ROW dedication must also be provided prior to site plan approval. (Rev. 1) The last option listed in my comment above was incorrect. The certificate of occupancy stage is not an appropriate time to confirm that all road improvements are completed. The Treesdale site plan must show all necessary road improvements that must be constructed in order for the site to be fully functional. Because the Right- In/Right -Out cannot serve as the sole entrance for the project, the site plan must show all of the Rio Road improvements shown in the Stonewater Plan as well as Stonewater Drive to Station 12 +00 and Stonewater Lane to the property line. All ROW dedication and easements (access, drainage, construction, etc.) must also be platted prior to Treesdale site plan approval. (Rev. 2) The submitted plan does not contain the information requested above. This afternoon, I met with Glenn, Amy, and Bill to further discuss what elements of the Stonewater construction plans would need to be included in the Treesdale site plan. The option discussed at the meeting on Thursday was to include the entire Stonewater construction set within the Treesdale site plan. It looks as though this would be an acceptable option, as long as the ESC plans were merged. When the time comes to receive a grading permit, two separate checks can be given to the county but the permit will require both owners' signatures. An alternative to the scenario above, is that the applicant include the road plans for Stonewater in the Treesdale set and places a phase line as shown below. The ESC plan in the Treesdale set would then be updated to protect only Phase "Z ", primarily a sediment trap and level spreader below structure S45 would be needed. Silt fence and diversions would also likely be needed here. Engineering will allow the drainage from structure S45 to temporarily release overland to the existing stream as long as level spreader is provided in the ESC plan. (Rev. 3) The Stonewater Road and ESC plans have been added to the Treesdale set of plans. The county is currently reviewing the offsite easement plat (SUB- 2010 - 00045). This plat and deeds of easement must be recorded prior to site plan approval. 2. The applicant has labeled the travelways within the plan as private roads. In looking through the preliminary site plan file, it appears that these travelways were not approved as private roads. In order to be referred to as a private road, please provide a request per 14 -234. The private roads can be authorized by the Chief of Current Development. The appropriate road standards can also be determined by the Chief of Current Development if approval of the road is granted. A technical review of the road plans will be performed by engineering once the roads are authorized and the standards determined. This request is not needed if the applicant changes all references to "private roads" to "private access easements." Private access easements will be reviewed to the standards outlined in 18 -4.12 and these standards appear to be met as designed. (Rev. 1) Comment has been addressed. 3. In the Treesdale Way section, one of the sidewalks should be specified as 6ft wide. (Rev. l) Comment has not been addressed. Both Treesdale Way and Treesdale Park Court should have one 6ft wide sidewalk in their section detail. (Rev. 2) Comment has been addressed. C. WPO- 2010 -00011 Stormwater Management Plan Comments 1. Per Water Protection Ordinance text amendments that were approved by the Board of Supervisors last year, the WPO application for the Stonewater Development, WPO- 2007 - 00045, has been voided because approval was given to the plans more than 12 months ago. Treesdale must include all of the design graphics and calculations for the shared facility in this set for re- review. The calculations should be updated with the latest proposed hydrologic information. (It looks as though the drainage area to the BMP has gotten larger since the original design and the post - development factored C calculation for Treesdale Park in the Stonewater set were incorrect.) (Rev. 1) The water quality volumes and detention calculations are acceptable. Please include the grading for the stormwater access and greenway path in the plan. Please adjust the grading so that fill for the path is out of the wetland. This work will also need to be considered in the erosion and sediment control plan for Treesdale. (Rev. 2) Comment remains unchanged. The stormwater access path must be shown in this set and the grading should be adjusted so as not to disturb the wetlands. (Rev. 3) Comment has been addressed. 2. Please include a modified simple spreadsheet for the SWM facility. (Rev. I) The Modified simple spreadsheet has been provided. Engineering recognizes that the required removal rate is 53% but will permit the facility for this development to be an enhanced extended detention basin since the proper volumes are provided. 3. Please specify the design of the concrete trash rack on the riser and provide a stage- discharge graph so that routing calculations can be confirmed. (Rev. I) Comment has been addressed. 4. The pond shall not backwater into the drainage system. Please raise the outlet of the drainage system to at least the permanent pool elevation. (Rev. I) Comment has been addressed. 5. Unless the design of the BMP is changing, please replace all references to an "enhanced biofilter facility" to an "enhanced extended detention facility ". (Rev. I) Comment has been addressed. 6. Please provide a planting plan for the Extended Detention Facility. (Rev. 1) The plants proposed in the landscaping plan are acceptable species. However, the number of units appears to be short of general landscaping standards. Each planting should be provided at 18" on center. In the plan, plants are shown between 3ft and Eft away from one another. Engineering review accepts that only half of the wetland area must be planted. (Rev. 2) Engineering review is waiting for information from the applicant regarding the planting plan. Also, the plan does not refer to a size of any of the plantings. Regardless of the decision in reference to the sizing and spacing standards of the plantings, the size should be specified in the Landscape Table on Sheet SWM -2. 1",v. 3) Comment has been addressed. 7. New Stormwater Facility Maintenance Agreements will be needed for both parcels 61 -183 and 61- 184. The new agreements should refer to the "Treesdale Park SWM Plan (WPO- 20 1 0 - 000 1 1)" on page 1 of both documents. (Rev. 1) Comment has not been addressed. (Rev. 2) Comment has not been addressed. A grading permit will not be issued until these agreements are revised. (Rev. 3) Comment has not been addressed. A grading permit will not be issued until these agreements are revised. 8. A new SWM bond will be computed once the WPO plan is ready for approval. (Rev. 1) The SWM bond will be computed at a later date. (Rev. 2) Comment remains unchanged. (Rev. 3) Comment remains unchanged. File: E4_fsp swm _PBC_wpo201000011- sdp201000013 Treesdale.doc