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Home My WebLink AboutSUB202100195 Correspondence 2021-12-23® ROUDABUSH, GALE & ASSOCIATES, INC. ENGINEERS, SURVEYORS AND LAND PLANNERS e December 15"', 2021 Attn: David James. Albemarle County Community Development 401 McIntire Road, North Wing Charlottesville, VA 22902 Project: Belvedere Phase 5B — Road and Drainage Plan Dear David, Please find attached the revised plans. The plans have been revised to address the comments in received from Albemarle County Community Development dated December 6, 2021. 1. An amendment will need to be made for Belvedere Phase 5 WPO and approved prior to this road plan approval to address the SWM issue with the proposed removal/grading of level spreader or with the Dunlora Farm WPO approval prior to this road plan approval. Response: Acknowledged. 2. Easement plat will need to be approved prior to road plan approval. Response: Acknowledged. 3. Correct the scale shown for all plan view sheets (i.e. 1"=50' appears incorrect). Response: The scale shown for all plan and profile views is correct. 4. Sheet 5: Add `No Parking' signs to Miranda Crossing & speed limit sign. Response: No Parking and Speed Limit Signs have been added to Miranda Crossing. 5. Sheet 6: Provide spot shot between 444' contours at intersection or connect them into a single contour. Response: The contour lines at the intersection have been fixed. 6. Correct the slope in lot yards to be 3:1 or flatter. ROUDABUSH, GALE & ASSOCIATES, O/NEERS. SURVEYORS AND LAND PLANNERS INC.*A r Response: All slopes are now 3:1 or flatter. 7. Where grading on slopes is over 3:1 provide low -maintenance ground cover (not grass). Response: All slopes greater than 3:1 have been removed from the project site. The steepest slopes are now 3:1. 8. The slope off of Fowler St adj. in lot 48 and "Dunlora Farm" area will need to be broken up with a reverse slope bench and surface water diversion. See 18-30.7.5.C. Response: The slopes off of lot 48 have been adjusted to now longer show the grading in Dunlora Farm - Phase 1. 9. Round off grading in steep slopes. See 18-30.7.5.B. Response: The grading in the steep sloped have been rounded off. 10. There are long channels that form at the back of the lots and will need to be lined and protected. Provide channel design and lining requirements. Response: It appears your comment is in regards to lots 49-56. Channel calculations have been provided on this comment response letter. No channel lining has been provided. 11. There are long channels that form at the edge of proposed slope that will need to be lined and protected. Provide channel design and lining requirements. Response: It appears your comment is in regards to the edge of property where Belvedere Phase 5B will connect with Dunlora Farm Phase 1. Blanket matting has been called for along these proposed slopes. 12. Provide half -clogged design for STM 45 (DI-1) following VDOT Design Manual. Response: Half -clogged design for STM 45 has been provided with this comment response letter. 13. Show roof drains and where they outlet. Response: A note has been added on Sheet 6 stating all units shall have splash blocks to ensure sheet flow and the yard will be graded to prevent concentrated flow from leaving the lot. ROUDABUSH, GALE & ASSOCIATES, GINEERS, SURVEYORS AND LAND PLANNERS INC.*f F 14. Sheet 7: Show easement for STM 30 to outfall. Response: The easement has been provided for STM 30 to the outfall. 15. Sheet 10: The maximum pipe slope is 16% [ACDSM, p.14]. Slopes in excess of 16% need for anchor blocks (every other pipe joint at a minimum). Response: The pipe slope has been changed to 15.87%. 16. Sheet 10: Pipe from 46 to 35 will need another manhole (max. pipe length is 50' for 12") or increase diameter to 15". Response: The pipe diameter has been increased to 15". 17. VDOT to approve of 12" dia, pipe in their ROW; Otherwise, provide 15". Response: Acknowledged. VDOT has made no comments regarding the 12" diameter pipes in their comment letter. 18. Velocity is excessive from the outfall from STM 30. Reduce to 10-fps or less. Response: The velocity from the outfall from STM 30 has been reduced to 7.57 fdsec. 19. Provide min. scour velocity of 3-fps in pipes from STM 47 to 35. Response: All storm pipes now have a minimum velocity of 3 ft/sec. 20. Add note or callout to include IS-1 in structures where drop is 4' or greater and at flow intersections. Response: No storm structures have a drop that is 4' or greater. All storm structures located at flow intersections now have IS-1 called for (MH 32, 33, and 35). Thank you for taking the time to review these plans and trust the above adequately addresses your comments. However, please let me know if you have any questions or require any additional information. Chapter 9 - Storm Drains Appendix 9C-13 Performance Curve DI-1 in a Sump p 9 5.1 LL LL 1.6 W 0 0.° Depth -0.35" - 0. 1 milli r II�,■■■■■I1I1I1I1!oil lld�■■■!•-m P■■■��III�■■■■III A111111 BONN MI 1 I 5 10 50 100 010=3ds DISCHARGE (CFS) Source: VDOT Transportation Research Council publication "HYDRAULIC EFFICIENCY OF GRATE INLET'. 1988 1 or 1 VDOT Drainage Manual Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Wednesday, Dec 15 2021 PoA 1 - 2 Yr User -defined Highlighted Invert Elev (ft) = 435.72 Depth (ft) = 0.13 Slope (%) = 4.00 Q (cfs) = 0.870 N-Value = 0.025 Area (sqft) = 0.53 Velocity (ft/s) = 1.64 Calculations Wetted Perim (ft) = 8.15 Compute by: Known Q Grit Depth, Yc (ft) = 0.14 Known Q (cfs) = 0.87 Top Width (ft) = 8.14 EGL (ft) = 0.17 (Sta, El, n)-(Sta, El, n)... ( 0.00, 438.00)-(18.41, 436.00, 0.025)-(26.77, 435.72, 0.025X35.29, 435.98, 0.025}(43.69, 438.00, 0.025}(61.08, 443.54, 0.025) Elev (ft) 444.00 CBI1I11 M4111I] 441.00 440.00 439.00 438.00 437.00 !SY.10If; 435.00 434.00 -5 0 Section Depth (ft) 8.28 7.28 6.28 5.28 4.28 MU 2.28 1.28 0.28 -0.72 -1.72 5 10 15 20 25 30 35 40 45 50 55 60 65 70 Sta (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Wednesday, Dec 15 2021 PoA 1 - 1 OYr User -defined Highlighted Invert Elev (ft) = 435.72 Depth (ft) = 0.17 Slope (%) = 4.00 Q (Cfs) = 1.820 N-Value = 0.025 Area (sqft) = 0.91 Velocity (ft/s) = 2.01 Calculations Wetted Perim (ft) = 10.65 Compute by: Known Q Crit Depth, Yc (ft) = 0.19 Known Q (cfs) = 1.82 Top Width (ft) = 10.65 EGL (ft) = 0.23 (Sta, El, n)-(Sta, El, n)... (0.00, 438.00}(18.41, 436.00, 0.025)-(26.77, 435.72, 0.025}(35.29, 435.98, 0.025}(43.69, 438.00. 0.025}(61.08, 443.54, 0.025) Elev (ft) 444.00 443.00 442.00 441.00 440.00 439.00 438.00 436.00 435.00 434.00 -5 0 Section Depth (ft) 8.28 7.28 6.28 5.28 4.28 Rjok-: 2.28 1.28 0.28 -0.72 -1.72 5 10 15 20 25 30 35 40 45 50 55 60 65 70 Sta (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3DO by Autodesk, Inc. Wednesday, Dec 15 2021 PoA 2 - 2Yr User -defined Highlighted Invert Elev (ft) = 433.56 Depth (ft) = 0.11 Slope (%) = 3.00 Q (cfs) = 1.660 N-Value = 0.025 Area (sqft) = 1.29 Velocity (ft/s) = 1.28 Calculations Wetted Perim (ft) = 23.50 Compute by: Known Q Crit Depth, Yc (ft) = 0.11 Known Q (cfs) = 1.66 Top Width (ft) = 23.50 EGL (ft) = 0.14 (Sta, El, n)-(Sta, El, n)... (0.00, 434.66}(7.48, 434.09, 0.025}(70.14, 433.56, 0.025}(112.14, 434.00, 0.025}(125.30, 434.95, 0.025)-(126.00, 435.00. 0.025) Elev (ft) Section 436.00 435.50 rxl4111111111 434.50 434.00 433.50 433.00 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Depth (ft) 2.44 1.94 1.44 0.94 0.44 M n ca Sta (ft) Channel Report HydraBow Express Extension for Autodesk® Civil 30® by Autodesk, Inc. PoA 2 - 10Yr Wednesday, Dec 152021 User -defined Highlighted Invert Elev (ft) = 433.56 Depth (ft) = 0.14 Slope (%) = 3.00 Q (cfs) = 3.450 N-Value = 0.025 Area (sqft) = 2.09 Velocity (ft/s) = 1.65 Calculations Wetted Perim (ft) = 29.92 Compute by: Known Q Crit Depth, Yc (ft) = 0.15 Known Q (cfs) = 3.45 Top Width (ft) = 29.92 EGL (ft) = 0.18 (Sta, El, n)-(Sta, El, n)... (0.00, 434.66}(7.48, 434.09, 0.02*(70.14, 433.56, 0.025}(112.14, 434.00, 0.025}(125.30, 434.95, 0.025}(126.00, 435.00, 0.025) Elev (ft) Section 436.00 435.50 435.00 434.50 434.00 433.50 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Depth (ft) 2.44 1.94 1.44 0.94 0.44 9K. n ca Sta (ft) ram= .. .... .....� / \ \ \ \ \'y \\ / / \ \\ / I .• d Q . . . . - \ \ / \ . . . . . . .� 11 \\ a / 1 I a / _ 1 I : / \ I III / d. \ // \� \ \ \ �— \ _ - I / \> \ 1\ / \ . . . P / \\ POINT OF ANALYSIS 1 / , . POINT OF ANALYSIS 2 / 11 1°° \ iOf J I I r i II \\ \\ iE \ / — 1 / l 1 ...... \ - \\ \NA ��........ / \ \\ 1 ............. \ / 20 0 20 40 60 SCALE: 1 °=20' - — ° J, U g � m W �o U -° z z u) O o� �Y> J Qa) J U T J = O U Q U m W 0 cn I; 0 ::) Q Q Q JZ vU Z� v, > N W C3 O 0 i N V O a_ W N V �1 Q N W Z > U Q W LLl = U U J a J = U U O aww C)o W ujQ rn U Z d a V 0 w Q 0 O2f w Z 0 Z� ow a r �w o 0 0 V r 0 0 N w O N CD N z syTB Op p,po r r Jimmy L Taggart Lie. No. 2841 a� A�aud12�0/2021 014~ -410MAL Q Z 'W J L J a LU w m w U r a 2 J X Q = U p W z� QzN Q W o } N 0 J LU Cfl Q 06 Q � Q pw �� U. QJ<°O m w ? O Qa cl DESIGNED BY: MSK DRAWN BY: MSK CHECKED BY: ZOO DATE: 12-10-2021 SCALE: JOB: 8438 SUB: 2021-00195 SHEET: OF 12