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Home My WebLink AboutWPO202200042 Correspondence 2022-10-266P ROUDABUSH, GALE & ASSOCIATES, INC. P 8 ENGINEERS, SURVEYORS AND LAND PLANNERS September 19, 2022 Mr. David James County of Albemarle, Community Development Department 401 McIntire Road, North Wing Charlottesville, VA 22902 RE: Belvedere Phase 3 Block 10 VSMP March 23, 2021 Comments Dear David: Please find attached the revised plans. The plans have been revised to address the comments received from the County on 23`d March, 2021. Our responses are in red below. Stormwater Pollution Prevention Plan (SWPPP) • The SWPPP content requirements can be found in County Code section 17-405. A SWPPP must contain (1) a PPP, (2) an ESCP, (3) a SWMP, and (4) any TMDL measures necessary. • Update sheets as needed. • Sheets have been updated. Note: Site vicinity map on pg. 4-6 of SWPPP. 2. Pollution Prevention Plan (PPP) • The PPP content requirements can be found in County Code section 17-404. • Provide the PPP exhibit sheet. • PPP information have been provided on Sheets 7, 11, 15, and 19 (phase overview sheets) for each phase of the project. 3. Stormwater Management Plan • VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This plan is denied, and the reasons are provided in the comments below. The stormwater management plan content requirements can be found in County Code section 17- 403. • It should be noted this design represents a complete change in stormwater management strategy to one of grandfathered status. Therefore, comments "a" through " d" are no longer necessarily applicable to the submitted plans. a. Show existing drainage divides. • Drainage divides shown on sheet 3. b. Show pre -development DA map. • Shown on sheet 3 c. 9VAC25-870-69.B.3. • Off -site compliance is no longer applicable as this site is considered "grandfathered" under 9VAC25-870-48.A.1 • (i): Provide some alternative site designs. Provide one that may meet the minimum 75% TP reduction. • (ii): Identify bmps used in your alternative designs. • (iii): What are the bmps that will/won't work for this site? • (iv): The current design which doesn't provide any on -site treatment. • Also consider ESD, LID, reducing impervious cover, Forest/OS area options. 6P ROUDABUSH, GALE & ASSOCIATES, INC. P 8 ENGINEERS, SURVEYORS AND LAND PLANNERS d. Provide a copy of the VRRM (email if fine). • See note under "c." above e. Channel protection criteria has not been adequately addressed (see comment 6). • This has been addressed in a summary claim of the "grandfathered" status per 9VAC25- 870-48-A.1 f. 1% LOA: Show the site's contributing DA versus the total watershed at LOA point. • "Drainage Area Comparison" exhibit shown on page 26. g. Sheet25: • Show c/I of channel you're discharging into. • C/L shown on page 26. • Show your LOA point. • Shown on page 26. • If your point of discharge is at a natural channel than Energy Balance must be met. {9VAC25-870-66.B.3.) When stormwater from a development is discharged to a natural stormwater conveyance system. Then your analysis stops there. • See narrative provided on page 26. h. Backyards where runoff is not detained with splash blocks: Some of these areas will not sheet flow due to grading (any slopes over 7°/u). • Provide yard drainage, alt. design. • Note requiring splash blocks for all units included on sheet 26 of this plan below narrative. i. SWM agreement & nutrient credit purchase requirement prior to plan approval. • Acknowledged 4. Erosion and Sediment Control Plan a. Virginia Code §62.1-44.15:55 requires the VESCP authority to approve or disapprove an ESCP. This plan is disapproved, and the reasons are provided in the comments below. The erosion control plan content requirements can be found in County Code section 17-402. b. Plan shows disturbance in the preserved slopes that are not currently permitted. • The limit of disturbance is dictated by the rezoning plan. The exact location of that limits line was the subject of extensive meetings between our office and planning/zoning staff. It is our belief that we have honored the agreed -upon line. c. Sheet 2: Mention that ST IA, 4A, 7A & diversions must be in place before removing ST 1, 4, 7 & diversions. • Included in "Sequence of Construction" narrative on sheet 2. d. E&SC sheets: • Provide the elevation for each proposed contour. • Provided • Provide CRS symbols for phase 2. • Provided • Add DC & CRS to the legend. • Provided • Is SSE being used everywhere? I can't tell the difference b/w SF & SSE used. • Linetype has been differentiated between SF and SSF on applicable E&SC sheets. This is reflected in the E&SC legend. 5. Sheet 10: Rename STl to ST1A, ST4 to ST4A, ST7 to ST7A for clarity. a. Acknowledged 6P ROUDABUSH, GALE & ASSOCIATES, INC. P 8 ENGINEERS, SURVEYORS AND LAND PLANNERS 6. Phase 4 sheets: a. Indicate graded slopes over 3:1. • Acknowledged b. Proposed slopes steeper than 3:1 have low maintenance (not grass) ground cover specified on the plan. • Noted on plans where applicable. 7. Sheet 22: a. Rename traps, keep phase labels. • Acknowledged b. Rename DIP titles to IP. • Acknowledged 8. Sheet 22/23: a. Remove detail of stone CE. Provide paved CE, wash rack detail (ACDSM, p. 8). • Acknowledged b. Provide SSF detail. • Acknowledged c. Provide CRS detail. • Acknowledged d. Provide OP sizing information. • Acknowledged 9. Provide a profile of the stream crossing and cross-section. Provide what ESC measures will be needed there. a. Profile of stream crossing shown on sheet 18; temporary stream crossing detail shown on sheet 10 w/ necessary E&SC measures. 10. Continue and show the improvements to the outfall. l ) 'l \t/ Stream crossing Matchline V r a l �- t r� 0 ` a. Improvements all the way to the outfall shown on sheets 10, 14, 18, 22. 11. Concentrated discharge from pipes require outlet protection: a. Provide for pipe end that's discharging to river. b. Provide detail & size the riprap. c. Outlet protection provided (shown in insets sheets 18 & 22). Detail and talcs shown on sheet 23. ROUDABUSH, GALE & ASSOCIATES, INC. ENGINEERS, SURVEYORS AND LAND PLANNERS 8 P 12. Provide estimate of cut & fill. Where will excess cut material go? a. Estimate has been provided on 19. Any excess available, including topsoil, will first be utilized on site, then any remainder shall be stockpiled for other Belvedere projects unless permitted otherwise. Thank you for taking the time to review these plans. We hope the revised plans adequately address your comments. If you have any questions or concerns, please email Alexander Flint at aflint@roudabush.com. Best Regards, Alexander Flint