HomeMy WebLinkAboutWPO201700027 Review Comments Stormwater Management Plan 2017-10-19COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902-4596
Phone (434) 296-5832 Fax (434) 972-4126
Project title:
Project file number:
Plan preparer:
Owner or rep.:
Date Received:
Rev. 1 Date Received:
Rev. 2 Date Received:
Date of comments:
Rev. 1 Comments:
Rev. 2: Comments:
Reviewer:
Ryan,
Brookhill Stormwater Master Plan & Overlot Grading Plan
WP0201700027
Bohler Engineering — Ryan Yauger [ryauger@bohlereng.com]
Riverbend Development — Alan Taylor [alan@riverbenddev.com]
14 March 2017
01 Aug 2017
28 Sept 2017
26 May 2017
08 Sept 2017
19 Oct 2017
Frank Pohl & Emily Cox
Please see comments below regarding the first submission of the overlot grading plan and
stormwater master plan for the Brookhill Development.
Overlot Grading Plan
1. Please provide this graphic in color. Rev. 1: Comment addressed.
2. Please provide a legend. Rev. 1: Comment addressed.
3. Ensure that the following items are shown on the plan:
• preserved slopes (County GIS and approved ZMA 2015-007)
• managed slopes (County GIS and approved ZMA 2015-007)
• greenway (Approved ZMA 2015-007)
• open space (Approved ZMA 2015-007)
• proposed block lines (Approved ZMA 2015-007 — or as you intend to develop/submit
plans)
• proposed buffers (Approved ZMA 2015-007 — Code of Development section 2.4.2)
• cemetery locations (per Code of Development Section 2.13)
• wetland locations (as approved by the Army Corps of Engineers)
• woodland campsite area to be preserved (per Code of Development Section 2.13)
Rev. 1: Comment addressed.
4. Provide the section divide lines. Section labels are provided, but their limits are unclear. Rev. 1:
Comment addressed.
5. Clearly depict impacts to the proposed greenway, preserved slopes and buffers. These impacts
should match the approved ZMA 2015-007. Rev. 1: Please provide a symbol/hatch in the legend
for these disturbances. Rev. 2: Please show a different hatch for each impact. (steep slopes
should be a different color than greenway impacts)
Engineering Review Comments
Page 2 of 5
6. The 100 -yr flood plain line does not appear to match the line shown on the approved ZMA,
which includes the updated floodplain study. Please confirm and ensure the correct line is
shown. Rev. 1: Comment addressed.
7. Please show and label the floodway with the elevation. Rev. 1: This was not evident on the plan.
Ensure it is shown. Rev. 2: Comment addressed.
8. A retaining wall appears to be located near the preserved historic site. Please confirm it is
outside of all required buffers per the Code of Development and approved ZMA. Rev. 1:
Comment addressed. Ensure it is outside of the 20' buffer required around the perimeter of the
historic site. Rev. 2: Comment addressed.
9. Grading is proposed adjacent to the roadways. Please confirm that all buffer requirements in the
Code of Development Section 2.4.2 are met. Particularly, existing buffers along Route 29 and
Polo Grounds Road are to remain undisturbed. Rev. 1: Comment addressed.
10. Please note the roadway network requirements on page 11 of the code of development
regarding the use of cul-de-sacs. This will be further evaluated with each plan submission. Rev. 1:
Comment addressed.
11. Rev. 1: Please clarify the lines for Block 3. Rev. 2: Comment addressed. Block lines match the
ZMA.
12. Rev. 1: As discussed in the meeting, remove all improvements and only show the proposed
grading as this is an overlot grading plan. Rev. 2: Comment addressed.
13. Rev. 1: In the meeting, it was mentioned that a stream delineation was completed, therefore
changing the location of the 100' buffer. Please provide this new line/stream & buffer location
on this plan. Rev. 2: Please provide the date/source of this survey.
14. Rev. 1: Please provide a symbol/hatch for the wetland in the legend. Rev. 2: Comment
addressed.
15. Rev. 2: Provide source of topography on the plan sheet.
16. Rev. 2: Check legend properly shows everything on the sheet. Be sure to include existing and
proposed topography lines, remove use label, pond id, etc.
17. Rev. 2: Please show the section lines. Block lines are shown.
18. Rev. 2: Please label Greenway as Greenway (Stream Buffer).
Stormwater Master Plan Report
1. [Appendix] Please insert and reference the approved plan from ZMA 2015-007. Rev. 1: Comment
addressed.
2. [Appendix] Please rename the tab titles from "Section" (i.e. Al). It is very confusing since the
project itself is also broken into sections. Rev. 1: Comment addressed.
3. [General] Please outline/show phasing as stated in the Code of Development, Section 2.5 (page
23). Rev. 1: Comment addressed.
4. [Appendix 132] Please include the overlot grading plan illustrating these areas (not just a table).
Rev. 1: Comment addressed.
5. [Page 1] Please change the sentence in the 2nd to last paragraph which states that deviations will
be approved on a section by section basis. Plans will be reviewed on a block -by -block basis (or
however you intend to submit plans?). Rev. 1: Comment addressed.
6. [Page 1] Please emphasize in the last paragraph that each concentrated discharge/outfall of
stormwater will be evaluated individually to meet 9VAC25-870-66. Only the water quality
Engineering Review Comments
Page 3 of 5
aspects of this project will be cumulative and will meet 9VAC25-870-63. Rev. 1: Comment
addressed.
7. [General] Wherever possible, please reference the applicable sections of the regulations. For
example, although it is widely known what "energy balance" means, it is not specifically stated in
the regulations anywhere. Rev. 1: Comment addressed.
8. [General] Suggest creating a glossary. "Energy Balance" would be a good example, where if
defined in the glossary, it could be used in the text. Rev. 1: Comment addressed.
9. [Page 2] In paragraph 3, it states that phosphorus removal will be analyzed based on section.
Again, please change this text to be block by block (or however you intend to submit plans?).
Rev. 1: Comment addressed.
10. [Page 3 — Stream Buffer Areas] Please note that the only impacts allowed to the stream buffer
areas are those shown on the approved ZMA 2015-0007. Also, note that Page 18 of the Code of
Development states that SWM facilities and E&S Facilities shall be located OUTSIDE of the
stream buffer and greenway. They are allowed in open space. Rev. 1: Comment addressed.
11. [General] Please include Section 2.6 from the Code of Development (page 23) within this master
plan. Suggest including it in the introduction. Ensure that this stormwater master plan meets all
of the restrictions as outlined in that code of development section. Rev. 1: Comment addressed.
12. [Page 3 — Floodplain] There is a CLOMR for the impacts to the floodplain. Please obtain a copy
and correct the text in this section. Rev. 1: Please leave spot to insert this in the appendix. Rev.
2: Please reference the CLOMR and appendix in the text in this section.
13. [Page 3 — SWM Strategy] Again, please emphasize that each concentrated outfall will be
analyzed to meet regulations for water quantity. Water quality can be cumulative and will be
evaluated with each plan that is submitted (block by block?). Rev. 1: Comment addressed.
14. [Page 4 — Water Quantity] — Please add to the first sentence "for each concentrated outfall". Rev.
1: Comment addressed.
15. [General] Please include the blocks within each Section. For example, on Page 4, Section 1
heading, please also include the blocks. Rev. 1: Comment addressed.
16. [Page 4] In the first paragraph under Section 1, the last sentence references "preceding tables",
however there were no preceding tables (following tables?). Rev. 1: Comment addressed.
17. [Page 5] Section 2 says it is mostly single family; however, there appears to be a large building
and parking lot in this section. Please clarify. Ensure that all descriptions in the report match
what is shown on the plan. Rev. 1: Comment addressed.
18. [Pages 6 & 7] These sections reference POls that are not shown on map A5 (they are all As or Bs,
etc.). Please clarify. Rev. 1: Comment addressed.
19. [Page 8] Please state the total removal required for the development as well as the total
achieved in the text. Do not force someone to reference table B1. Rev. 1: Comment addressed.
20. [Page 9 — nutrient offset credits] Please state the maximum amount of offsite credits allowed to
be purchased for the entire project (25%). Rev. 1: Comment addressed. Please note that with the
proposed 43 Ib/yr being purchased, you are right at the 25% limit.
21. [Page 9 — nutrient credits] Please note that per VAC 870-69-C, credits must be purchased prior to
approval of each plan or phase. Rev. 1: Comment addressed.
22. [Water Quality — general] Although it is understood that the locations and types may change,
please provide and label all proposed SWM facilities on this plan. Currently only the detention
Engineering Review Comments
Page 4 of 5
ponds are shown on A5 and A6. Each facility should have a label/designation and should be
referenced on the maps and in the text. Rev. 1: Comment addressed.
23. [Figure A5]
a. Please provide Figure A5, post -development overall drainage, in color.
b. Please provide a legend.
c. Please show and label all SWM facilities on this map (not just ponds).
d. Please show the following on this map: sections, blocks, floodplain, steep slopes,
greenway, open space, buffers, cemeteries, etc. (everything that is shown on the overlot
grading plan and approved ZMA).
e. Please fix the labels on this map. The POI callouts should point to the POI outfall
location. The areas look more like drainage areas.
f. Please review/confirm all drainage areas. For example, the roadway elevation on the SE
portion of POI 11 is 390, and the pond elevation is 395. This does not appear correct.
Rev. 1: Comment addressed.
24. [Figure A6 - Notes] Change the term ponds to say "SWM facilities". Rev. 1: Comment addressed.
25. [Appendix 132] Drainage area E summary was not provided. Rev. 1: Comment addressed.
26. [Appendix 133] The water quantity summary does not include 13A, 13B, etc. Please clarify. Please
add columns to show the Section and Block Ws. Rev. 1: Comment addressed.
27. [Appendix 131] Please manually enter or type SECTION 1, SECTION 2, etc. so it is clear what
Drainage Area A, B, C, etc. are referring to. Rev. 1: Comment addressed.
28. Please create a water quality summary sheet similar to the quantity sheet. This will be used to
track overall phosphorus removal through the entire project. See attached Excel tracking
spreadsheet for an example. Rev. 1: This tracking sheet should be filled out for the proposed
conditions with this master plan. It can mirror your VRRM spreadsheet and should be broken
down by section. Also, please add columns for the type of facility and the % off site credits. See
attached spreadsheet for guideline. Rev. 2: The final column should represent the allowable
25% of offsite nutrient credits. It should be a percentage of the total nutrient credits required
and the total being purchased.
29. Rev. 1: [page 3] Remove the sentence that says,"a brief summary... section", as the following
section is calculation and drainage, not a summary. Rev. 2: Comment addressed.
30. Rev. 1: [Page 5] POI 8 and 9 are not going to ponds, they are proposing sheet flow. Please correct
the text in the channel and flood protection sections on this page. Rev. 2: Comment addressed.
31. Rev. 1: Please note that for developments such as Section 2, where more than 1 block is going to
be treated by a single pond, the block with the pond must be constructed first. (blocks 9 and 10
are going to be treated by a pond in block 11). Please add a note outlining this requirement in
the master plan. There are other sections that are affected, section 2 was just an example. Rev.
2: Comment addressed.
32. Rev 1: [page 9] The exhibits for the ponds in section 1 show a total drainage area of 62.55AC,
however, the VRRM only accounts for 30 AC (15 imp and 15 turf), is there 30 AC forest & open
space? Please clarify. This applies to all sections. Rev. 2: Comment addressed.
33. Rev. 1: [page 10] Please correct Sections 3 and 4. The text is the same for both. Also, please
check the VRRRM tables provided for these sections and update the pond exhibits (phosphorus
removal). Rev. 2: Comment addressed.
34. Rev 1: [appendix A.51 Provide a larger size or color if possible. It is very hard to read at 11x17.
Engineering Review Comments
Page 5 of 5
35. Rev. 1: [overlot grading] Be sure to insert the final approved overlot grading plan in the
appendix. Rev. 2: Comment still valid.
36. Rev 1: [land cover summary] please add the sum of total impervious area to each section. Rev. 2:
Comment addressed.
37. Rev 1: [quantity compliance summary] please check POls 4, 7, 8 & 9. They appear to be listed
differently than outlined in the text. Rev. 2: Comment addressed.
38. Rev 2: [Appendix B] Please label the Sections on the VRRM table to clearly identify DA A =
Section 1, etc.
39. Rev 2: [Page 3] Please add a note with the date/source of the stream delineation that was
used to identify the exact location of the stream buffer/greenway.
If you have any questions or concerns, please contact me either by email (ecox@albemarle.org) or by
phone at 434-296-5832 ext. 3565.
Sincerely,
Emily Cox, P.E.
Civil Engineer II
COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902-4596
Phone (434) 296-5832 Fax (434) 972-4126
Project title: Brookhill Stormwater Master Plan & Overlot Grading Plan
Project file number: WP0201700027
Plan preparer: Bohler Engineering — Ryan Yauger [ryauger@bohlereng.com]
Owner or rep.: Riverbend Development — Alan Taylor [alan@riverbenddev.com]
Date Received: 14 March 2017
Rev. 1 Date Received: 01 Aug 2017
Date of comments: 26 May 2017
Rev. 1 Comments: 08 Sept 2017
Reviewer: Frank Pohl & Emily Cox
Ryan,
Please see comments below regarding the first submission of the overlot grading plan and
stormwater master plan for the Brookhill Development.
Overlot Grading Plan
1. Please provide this graphic in color. Rev. 1: Comment addressed.
2. Please provide a legend. Rev. 1: Comment addressed.
3. Ensure that the following items are shown on the plan:
• preserved slopes (County GIS and approved ZMA 2015-007)
• managed slopes (County GIS and approved ZMA 2015-007)
• greenway (Approved ZMA 2015-007)
• open space (Approved ZMA 2015-007)
• proposed block lines (Approved ZMA 2015-007 — or as you intend to develop/submit
plans)
• proposed buffers (Approved ZMA 2015-007 — Code of Development section 2.4.2)
• cemetery locations (per Code of Development Section 2.13)
• wetland locations (as approved by the Army Corps of Engineers)
• woodland campsite area to be preserved (per Code of Development Section 2.13)
Rev. 1: Comment addressed.
4. Provide the section divide lines. Section labels are provided, but their limits are unclear. Rev. 1:
Comment addressed.
5. Clearly depict impacts to the proposed greenway, preserved slopes and buffers. These impacts
should match the approved ZMA 2015-007. Rev. 1: Please provide a symbol/hatch in the legend
for these disturbances.
6. The 100 -yr flood plain line does not appear to match the line shown on the approved ZMA,
which includes the updated floodplain study. Please confirm and ensure the correct line is
shown. Rev. 1: Comment addressed.
7. Please show and label the floodway with the elevation. Rev. 1: This was not evident on the plan.
Ensure it is shown.
Engineering Review Comments
Page 2 of 4
8. A retaining wall appears to be located near the preserved historic site. Please confirm it is
outside of all required buffers per the Code of Development and approved ZMA. Rev. 1:
Comment addressed. Ensure it is outside of the 20' buffer required around the perimeter of
the historic site.
9. Grading is proposed adjacent to the roadways. Please confirm that all buffer requirements in the
Code of Development Section 2.4.2 are met. Particularly, existing buffers along Route 29 and
Polo Grounds Road are to remain undisturbed. Rev. 1: Comment addressed.
10. Please note the roadway network requirements on page 11 of the code of development
regarding the use of cul-de-sacs. This will be further evaluated with each plan submission. Rev.
1: Comment addressed.
11. Rev. 1: Please clarify the lines for Block 3.
12. Rev. 1: As discussed in the meeting, remove all improvements and only show the proposed
grading as this is an overlot grading plan.
13. Rev. 1: In the meeting, it was mentioned that a stream delineation was completed, therefore
changing the location of the 100' buffer. Please provide this new line/stream & buffer location
on this plan.
14. Rev. 1: Please provide a symbol/hatch for the wetland in the legend.
Stormwater Master Plan Report
1. [Appendix] Please insert and reference the approved plan from ZMA 2015-007. Rev. 1: Comment
addressed.
2. [Appendix] Please rename the tab titles from "Section" (i.e. Al). It is very confusing since the
project itself is also broken into sections. Rev. 1: Comment addressed.
3. [General] Please outline/show phasing as stated in the Code of Development, Section 2.5 (page
23). Rev. 1: Comment addressed.
4. [Appendix 132] Please include the overlot grading plan illustrating these areas (not just a table).
Rev. 1: Comment addressed.
5. [Page 1] Please change the sentence in the 2nd to last paragraph which states that deviations will
be approved on a section by section basis. Plans will be reviewed on a block -by -block basis (or
however you intend to submit plans?). Rev. 1: Comment addressed.
6. [Page 1] Please emphasize in the last paragraph that each concentrated discharge/outfall of
stormwater will be evaluated individually to meet 9VAC25-870-66. Only the water quality
aspects of this project will be cumulative and will meet 9VAC25-870-63. Rev. 1: Comment
addressed.
7. [General] Wherever possible, please reference the applicable sections of the regulations. For
example, although it is widely known what "energy balance" means, it is not specifically stated in
the regulations anywhere. Rev. 1: Comment addressed.
8. [General] Suggest creating a glossary. "Energy Balance" would be a good example, where if
defined in the glossary, it could be used in the text. Rev. 1: Comment addressed.
9. [Page 2] In paragraph 3, it states that phosphorus removal will be analyzed based on section.
Again, please change this text to be block by block (or however you intend to submit plans?).
Rev. 1: Comment addressed.
10. [Page 3 — Stream Buffer Areas] Please note that the only impacts allowed to the stream buffer
areas are those shown on the approved ZMA 2015-0007. Also, note that Page 18 of the Code of
Engineering Review Comments
Page 3 of 4
Development states that SWM facilities and E&S Facilities shall be located OUTSIDE of the
stream buffer and greenway. They are allowed in open space. Rev. 1: Comment addressed.
11. [General] Please include Section 2.6 from the Code of Development (page 23) within this master
plan. Suggest including it in the introduction. Ensure that this stormwater master plan meets all
of the restrictions as outlined in that code of development section. Rev. 1: Comment addressed.
12. [Page 3 — Floodplain] There is a CLOMR for the impacts to the floodplain. Please obtain a copy
and correct the text in this section. Rev. 1: Please leave spot to insert this in the appendix.
13. [Page 3 — SWM Strategy] Again, please emphasize that each concentrated outfall will be
analyzed to meet regulations for water quantity. Water quality can be cumulative and will be
evaluated with each plan that is submitted (block by block?). Rev. 1: Comment addressed.
14. [Page 4 — Water Quantity] — Please add to the first sentence "for each concentrated outfall".
Rev. 1: Comment addressed.
15. [General] Please include the blocks within each Section. For example, on Page 4, Section 1
heading, please also include the blocks. Rev. 1: Comment addressed.
16. [Page 4] In the first paragraph under Section 1, the last sentence references "preceding tables",
however there were no preceding tables (following tables?). Rev. 1: Comment addressed.
17. [Page 5] Section 2 says it is mostly single family; however, there appears to be a large building
and parking lot in this section. Please clarify. Ensure that all descriptions in the report match
what is shown on the plan. Rev. 1: Comment addressed.
18. [Pages 6 & 7] These sections reference POls that are not shown on map A5 (they are all As or Bs,
etc.). Please clarify. Rev. 1: Comment addressed.
19. [Page 8] Please state the total removal required for the development as well as the total
achieved in the text. Do not force someone to reference table 131. Rev. 1: Comment addressed.
20. [Page 9 — nutrient offset credits] Please state the maximum amount of offsite credits allowed to
be purchased for the entire project (25%). Rev. 1: Comment addressed. Please note that with
the proposed 43 Ib/yr being purchased, you are right at the 25% limit.
21. [Page 9 — nutrient credits] Please note that per VAC 870-69-C, credits must be purchased prior to
approval of each plan or phase. Rev. 1: Comment addressed.
22. [Water Quality — general] Although it is understood that the locations and types may change,
please provide and label all proposed SWM facilities on this plan. Currently only the detention
ponds are shown on A5 and A6. Each facility should have a label/designation and should be
referenced on the maps and in the text. Rev. 1: Comment addressed.
23. [Figure A5]
a. Please provide Figure A5, post -development overall drainage, in color.
b. Please provide a legend.
c. Please show and label all SWM facilities on this map (not just ponds).
d. Please show the following on this map: sections, blocks, floodplain, steep slopes,
greenway, open space, buffers, cemeteries, etc. (everything that is shown on the overlot
grading plan and approved ZMA).
e. Please fix the labels on this map. The POI callouts should point to the POI outfall
location. The areas look more like drainage areas.
f. Please review/confirm all drainage areas. For example, the roadway elevation on the SE
portion of POI 11 is 390, and the pond elevation is 395. This does not appear correct.
Rev. 1: Comment addressed.
Engineering Review Comments
Page 4 of 4
24. [Figure A6 - Notes] Change the term ponds to say "SWM facilities". Rev. 1: Comment addressed.
25. [Appendix 132] Drainage area E summary was not provided. Rev. 1: Comment addressed.
26. [Appendix 133] The water quantity summary does not include 13A, 13B, etc. Please clarify. Please
add columns to show the Section and Block #'s. Rev. 1: Comment addressed.
27. [Appendix 131] Please manually enter or type SECTION 1, SECTION 2, etc. so it is clear what
Drainage Area A, B, C, etc. are referring to. Rev. 1: Comment addressed.
28. Please create a water quality summary sheet similar to the quantity sheet. This will be used to
track overall phosphorus removal through the entire project. See attached Excel tracking
spreadsheet for an example. Rev. 1: This tracking sheet should be filled out for the proposed
conditions with this master plan. It can mirror your VRRM spreadsheet and should be broken
down by section. Also, please add columns for the type of facility and the % off site credits.
See attached spreadsheet for guideline.
29. Rev. 1: [page 3] Remove the sentance that says,"a brief summary... section", as the following
section is calculation and drainage, not a summary.
30. Rev. 1: [Page 5] POI 8 and 9 are not going to ponds, they are proposing sheet flow. Please
correct the text in the channel and flood protection sections on this page.
31. Rev. 1: Please note that for developments such as Section 2, where more than 1 block is going
to be treated by a single pond, the block with the pond must be constructed first. (blocks 9 and
10 are going to be treated by a pond in block 11). Please add a note outlining this requirement
in the master plan. There are other sections that are affected, section 2 was just an example.
32. Rev 1: [page 9] The exhibits for the ponds in section 1 show a total drainage area of 62.55AC,
however, the VRRM only accounts for 30 AC (15 imp and 15 turf), is there 30 AC forest & open
space? Please clarify. This applies to all sections.
33. Rev. 1: [page 10] Please correct Sections 3 and 4. The text is the same for both. Also, please
check the VRRRM tables provided for these sections and update the pond exhibits
(phosphorus removal).
34. Rev 1: [appendix A.5] Provide a larger size or color if possible. It is very hard to read at 11x17.
35. Rev. 1: [overlot grading] Be sure to insert the final approved overlot grading plan in the
appendix.
36. Rev 1: [land cover summary] please add the sum of total impervious area to each section.
37. Rev 1: [quantity compliance summary] please check POls 4, 7, 8 & 9. They appear to be listed
differently than outlined in the text.
If you have any questions or concerns, please contact me either by email (ecox@albemarle.org) or by
phone at 434-296-5832 ext. 3565.
Sincerely,
Emily Cox, P.E.
Civil Engineer II
Phoshorus Removal Phoshorus Removal
Type of facility & level proposed w/master plan achieved w/ approved Offsite Credits % of offsite
Block (s) SWM Facility ID of design (Ib/yr) plan (Ib/yr) Approved WPO Plan # Purchased (Ib/yr) credits purchsed
SECTION 1
TOTAL
Phoshorus Removal Phoshorus Removal
Type of facility & level proposed w/master plan achieved w/ approved Offsite Credits % of offsite
Block (s) SWM Facility ID of design (Ib/yr) plan (Ib/yr) Approved WPO Plan # Purchased (Ib/yr) credits purchsed
SECTION 2
TOTAL
COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902-4596
Phone (434) 296-5832 Fax (434) 972-4126
Project title:
Brookhill Stormwater Master Plan & Overlot Grading Plan
Project file number:
WP0201700027
Plan preparer:
Bohler Engineering — Ryan Yauger [ryauger@bohlereng.com]
Owner or rep.:
Riverbend Development — Alan Taylor [alan@riverbenddev.com]
Date Received:
14 March 2017
Date of comments:
26 May 2017
Reviewer:
Frank Pohl & Emily Cox
Ryan,
Please see comments below regarding the first submission of the overlot grading plan and
stormwater master plan for the Brookhill Development.
Overlot Grading Plan
1. Please provide this graphic in color.
2. Please provide a legend.
3. Ensure that the following items are shown on the plan:
• preserved slopes (County GIS and approved ZMA 2015-007)
• managed slopes (County GIS and approved ZMA 2015-007)
• greenway (Approved ZMA 2015-007)
• open space (Approved ZMA 2015-007)
• proposed block lines (Approved ZMA 2015-007 — or as you intend to develop/submit
plans)
• proposed buffers (Approved ZMA 2015-007 — Code of Development section 2.4.2)
• cemetery locations (per Code of Development Section 2.13)
• wetland locations (as approved by the Army Corps of Engineers)
• woodland campsite area to be preserved (per Code of Development Section 2.13)
4. Provide the section divide lines. Section labels are provided, but their limits are unclear.
5. Clearly depict impacts to the proposed greenway, preserved slopes and buffers. These impacts
should match the approved ZMA 2015-007.
6. The 100 -yr flood plain line does not appear to match the line shown on the approved ZMA,
which includes the updated floodplain study. Please confirm and ensure the correct line is
shown.
7. Please show and label the floodway with the elevation.
8. A retaining wall appears to be located near the preserved historic site. Please confirm it is
outside of all required buffers per the Code of Development and approved ZMA.
9. Grading is proposed adjacent to the roadways. Please confirm that all buffer requirements in the
Code of Development Section 2.4.2 are met. Particularly, existing buffers along Route 29 and
Polo Grounds Road are to remain undisturbed.
Engineering Review Comments
Page 2 of 3
10. Please note the roadway network requirements on page 11 of the code of development
regarding the use of cul-de-sacs. This will be further evaluated with each plan submission.
Stormwater Master Plan Report
1. [Appendix] Please insert and reference the approved plan from ZMA 2015-007.
2. [Appendix] Please rename the tab titles from "Section" (i.e. Al). It is very confusing since the
project itself is also broken into sections.
3. [General] Please outline/show phasing as stated in the Code of Development, Section 2.5 (page
23).
4. [Appendix 132] Please include the overlot grading plan illustrating these areas (not just a table).
5. [Page 1] Please change the sentence in the 2nd to last paragraph which states that deviations will
be approved on a section by section basis. Plans will be reviewed on a block -by -block basis (or
however you intend to submit plans?).
6. [Page 1] Please emphasize in the last paragraph that each concentrated discharge/outfall of
stormwater will be evaluated individually to meet 9VAC25-870-66. Only the water quality
aspects of this project will be cumulative and will meet 9VAC25-870-63.
7. [General] Wherever possible, please reference the applicable sections of the regulations. For
example, although it is widely known what "energy balance" means, it is not specifically stated in
the regulations anywhere.
8. [General] Suggest creating a glossary. "Energy Balance" would be a good example, where if
defined in the glossary, it could be used in the text.
9. [Page 2] In paragraph 3, it states that phosphorus removal will be analyzed based on section.
Again, please change this text to be block by block (or however you intend to submit plans?).
10. [Page 3 — Stream Buffer Areas] Please note that the only impacts allowed to the stream buffer
areas are those shown on the approved ZMA 2015-0007. Also, note that Page 18 of the Code of
Development states that SWM facilities and E&S Facilities shall be located OUTSIDE of the
stream buffer and greenway. They are allowed in open space.
11. [General] Please include Section 2.6 from the Code of Development (page 23) within this master
plan. Suggest including it in the introduction. Ensure that this stormwater master plan meets all
of the restrictions as outlined in that code of development section.
12. [Page 3 — Floodplain] There is a CLOMR for the impacts to the floodplain. Please obtain a copy
and correct the text in this section.
13. [Page 3 — SWM Strategy] Again, please emphasize that each concentrated outfall will be
analyzed to meet regulations for water quantity. Water quality can be cumulative and will be
evaluated with each plan that is submitted (block by block?).
14. [Page 4 — Water Quantity] — Please add to the first sentence "for each concentrated outfall".
15. [General] Please include the blocks within each Section. For example, on Page 4, Section 1
heading, please also include the blocks.
16. [Page 4] In the first paragraph under Section 1, the last sentence references "preceding tables",
however there were no preceding tables (following tables?).
17. [Page 5] Section 2 says it is mostly single family; however, there appears to be a large building
and parking lot in this section. Please clarify. Ensure that all descriptions in the report match
what is shown on the plan.
18. [Pages 6 & 7] These sections reference POls that are not shown on map A5 (they are all As or Bs,
etc.). Please clarify.
Engineering Review Comments
Page 3 of 3
19. [Page 8] Please state the total removal required for the development as well as the total
achieved in the text. Do not force someone to reference table B1.
20. [Page 9 — nutrient offset credits] Please state the maximum amount of offsite credits allowed to
be purchased for the entire project (25%).
21. [Page 9 — nutrient credits] Please note that per VAC 870-69-C, credits must be purchased prior to
approval of each plan or phase.
22. [Water Quality — general] Although it is understood that the locations and types may change,
please provide and label all proposed SWM facilities on this plan. Currently only the detention
ponds are shown on A5 and A6. Each facility should have a label/designation and should be
referenced on the maps and in the text.
23. [Figure A5]
• Please provide Figure A5, post -development overall drainage, in color.
• Please provide a legend.
• Please show and label all SWM facilities on this map (not just ponds).
• Please show the following on this map: sections, blocks, floodplain, steep slopes,
greenway, open space, buffers, cemeteries, etc. (everything that is shown on the overlot
grading plan and approved ZMA).
• Please fix the labels on this map. The POI callouts should point to the POI outfall
location. The areas look more like drainage areas.
• Please review/confirm all drainage areas. For example, the roadway elevation on the SE
portion of POI 11 is 390, and the pond elevation is 395. This does not appear correct.
26. [Figure A6 - Notes] Change the term ponds to say "SWM facilities".
27. [Appendix 132] Drainage area E summary was not provided.
28. [Appendix 133] The water quantity summary does not include 13A, 13B, etc. Please clarify. Please
add columns to show the Section and Block #'s.
29. [Appendix 131] Please manually enter or type SECTION 1, SECTION 2, etc. so it is clear what
Drainage Area A, B, C, etc. are referring to.
30. Please create a water quality summary sheet similar to the quantity sheet. This will be used to
track overall phosphorus removal through the entire project. See attached Excel tracking
spreadsheet for an example.
If you have any questions or concerns, please contact me either by email (ecox@albemarle.org) or by
phone at 434-296-5832 ext. 3565.
Sincerely,
Emily Cox, P.E.
Civil Engineer II
Phoshorus Removal
proposed w/master plan
Section Block SWM Facility ID (Ib/yr)
Phoshorus Removal
achieved w/ approved
plan (Ib/yr)
Offsite Credits
Plan # Purchased (Ib/yr)