HomeMy WebLinkAboutWPO201300021 Review Comments As-Built Reviews 2018-07-23COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902-4596
Phone (434) 296-5832 Fax (434) 972-4126
BISWM — Bond Inspection Storm Water Management Review
Project: Old Trail Village Block 15 and Phase II, Block 12 (Block 12, WP0201300021)
Plan preparer: Jimmy Taggart, PE; Bill Ledbetter —Roudabush, Gale & Associates, Inc.
[BLedbetter(cr�,roudabush.com; JTaggartgroudabush.com ]
914 Monticello Road, Charlottesville, VA 22902
Owner or rep.: March Mountain Properties LLC [1005 Heathercroft Circle, Suite 100]
Dave Brockman, dave(&oldtrailvillage.com
Received date: 10 Jul 2018
Date of comments: 23 Jul 2018
Reviewer: John Anderson
Amendment to WP0201500066 — WP0201300021
Albemarle County Record Drawing Requirements (As -built) for VSMP review. This correspondence is preliminary to
SWM facility inspection. Engineering plans to inspect this facility by 27-July, and send follow-up correspondence.
Sheet 1
With respect to 15 listed items (Record Drawing Requirements), please also ref. Amendment to WP0201500066,
Approved 12/l/17:
1. Item 6: Since landscaping is scheduled for Fall 2018, Albemarle is unable to reduce bond amount for plants. As -
built showing installed location of plants is required.
2. Item 8: See sheet 4BB comments, below.
3. Item 10: (Minor) —Revise text to read deed book.
4. Item 11: (Discussed with County Engineer) Provide permanent safety fence, 6' height, per VESCH Std. & Spec.
3.01, per approved Amendment to WP0201500066, 9 /9A. Approximately 720' linear feet is required to protect
the public against potential hazard. NWSE=642.5, bottom of wet pond elevation=635.86 (wet pond depth
varies 6.5-7'). Ref. Design Criteria and Construction Specifications (VESCH 3.01). Provide gated access to
SWM Facility. Post signs noting potential hazard (3.01, p. III-2, Design Criteria 4). Note: Sheet 4AA shows As -
built gravel pedestrian trail skirting the wet pond. This trail (not shown on approved SWM Plan) magnifies risk.
5. Item 12: Compaction - Approved WP02015000666, sheet 9, Earth Fill Note 4 requires density test (Min. density
=95% of maximum dry density); provide report. F&R Fill Monitoring report d. 6/8/18 indicates no density tests
taken. Propose a test method to substantiate density of constructed —16' high earthen embankment.
6. Third bullet: Sheet 9 of approved Amendment to WP0201500066 requires 10' Berm Min. Width. Label Berm
Min. Width on sheet 4AA (variable width is insufficient; please label Min. field measured width).
7. Item 14: Compaction reports are required to verify that fill compaction in dams. Although geotech observational
reports are included, there are no compaction reports apart from visual observation reports. Compaction reports
are required to reduce the SWM bond for this facility. (Also discussed with County Engineer.)
Sheet 4AA
8. Label OP1, OP2, OP3.
9. Show /label 70 L.F. of wood post guard rail. Ref. sheet 9, Amendment to WP0201500066 (detail, sheet 8).
Engineering Review Comments
Page 2 of 2
Sheet 4BB
10. Install StormRax riser cap, per detail sheet 10, approved Amendment to WPO201500066, per discussion with
County Inspector /Engineering.
11. Install orifice debris cages, per Note, 4BB.
12. Label As -built slope (pitch, 3:1, etc.) upslope of forebay.
13. Wet Pond and Total Basin As -built stage -storage report appear to contain duplicate elevation entries (642.00,
Wet pond; 644.00, Total Basin) with inconsistent column values for Area. Please revise tables.
14. Provide As -built dimensions for installed riprap. Confirm design dimensions meet design shown at approved
sheet 10 (OP I, OP2, OP3). Recommend copy OP I, OP2, OP3 graphics to As -built. Label As -built riprap outlet
protection (dimensions).
15. Since volume of Wet Pond is 84% of design, and 89% of required (due to rock), provide original PE -seal
signature on computations that verify that despite significant deviation from design, the as -built condition is
equivalent to (or better than) design.
16. Design Parameter Outlet #5 (Grass Emergency Spillway) Inv. Elev. (644.94') does not match profile Inv. Elev.
(648.05'); revise, and perform routing, as needed.
17. Design parameters report total discharge=187.57 cfs; outlet #1 discharge=133.64 cfs. Label Design Parameter
Data (1-, 2-, 10-, 25-yr, etc. routing), so these discharge values have context.
18. Provide routing output for Q10-yempre4post-deve1opment events, for comparison with reported pre -development Qto_,�
=28.81, and post -development Q,o_,, =18.23 cfs.
Please feel free to call if any questions.
Thank you 434.872-4501 —x3069
WPO201500066—WPO201600021 BISWM As -built 072318