HomeMy WebLinkAboutWPO201400101 Correspondence 2015-03-13 Cs J
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March 13, 2015
Ms. Michelle Roberge r
Albemarle County Community Development Department
Division of Current Development
401 McIntire Road, North Wing
Charlottesville, Virginia 22902
RE: Cascadia Subdivision Blocks 1-3- Comment-Response Letter- VSMP WPO201400101
Dear Michelle,
Enclosed please find four(4) sets of the revised VSMP plan. Please note that we have revised the VSMP plan
to address your comments dated January 15, 2015 in accordance with the following:
A. 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.
-I) Include approved E&S and SWM plans of blocks 1-3 for SWPP on-site.
2) Include a section to list qualified personnel and contact info.
3)Verify if site is on 2012 Impaired Waters - 303(d) List.
1/4) State in the spill response section who should be contacted for spills and cleanup.
RESPONSE: The SWPP has been revised to include items 1-2, and 4. This site appears to be on the
2012 Impaired Waters -303(d)List, as Group Code H28R-02, but is still in need of a TMDL study.
B. Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code section 17-404.
1) Include an 11"x 17" Pollution Prevention Plan map showing concrete washout, porta johns, fueling stations,
and trash containers. This will be marked up by the contractor as construction of site progresses.
"RESPONSE: A PPP plan has been provided with the aforementioned criteria.
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This plan
is disapproved, and the reasons are provided in the comments below. The stormwater management plan content
requirements can be found ill County Code section 17-403.
1)The title on the plans should state "VSMP".
RESPONSE: The title of the plans have been revised to state "VSMP"
Page 1 of 4
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Engineering Charlottesville, VA 22911
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2) Please state the limits of disturbance on sheet ES2.
RESPONSE: The limits of disturbance has been provided on sheet ES1 ►r''
3) Please provide a note on the title sheet to clarify that this site is covered by an existing general permit.
Also, state the registration number. It appears the existing permit was granted for Cascadia Blocks 4-7.
RESPONSE: Revised V
4) $6100 was paid to the state for 60.772 acres land disturbance. Please discuss with Todd Shifflett. It appears
you will need to pay $200 for this application since this plan is an amendment to an existing permit.
RESPONSE: Revised. An application along with a check for$200 has been provided with this v
submittal.
- 5) Show anti-seep color on sheet ES6.
RESPONSE: The detail for SB-2 on sheet ES6 is for informational purposes only. The detail states that
the detail is "from approved Cascadia Blocks 4-7 WPO 201300032." Please refer to that plan for a
complete detail of SB-2.
v 6) Provide the detail for Detention Pond 1 and label type.
RESPONSE: Detail and type added to sheet ES8.
7) 'he method for calculating the pond size reduction is incomplete. Please provide calculations. Use SCS
me>hod an not rational method. Also, include drainage area map of the pre conditions for the 20.24 acres. Label
CN, acreage and Tc values on map.
RESPONSE: Hydraulic/Hydrologic calculations have been provided with this submittal for existing
Pond 1.
8) On ES9, please include the impervious core, label type of basin (ie.Retention Basin II), and depth pool zone
chart.
',RESPONSE: The detail for Pond 2 on sheet ES9 is for informational purposes only. The detail states ?,,
that the detail is "from approved Cascadia Blocks 4-7 WPO 201300032." Please refer to that plan for a L
complete detail of Pond 2.
Page 2 of 4
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D. Erosion and Sediment Control Plan (ESCP)
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.
✓ 1) The diversion ► es need to discharge into an outlet protection or to a trap. Shift dd #2 to discharge into outlet
protection. �j ..4-• .{ ..
2) What happened Ito the existing SCC on the northern portion of site to basin 2? Show as being removed on a
demo plan.
' / -' 3) DD #1 poses some issues. First, it is within lots 16-23. It will have to be noted on the plans for lots to be
cleared after the roads have been stabilized and runoff is discharged into stormdrains. Sed`ond, the dd does not
discharge to a stabilized outlet or sediment trap. Third,there is a sharp bend from the SCC to the diversion dike.
1-3 RESPONSE: The diversion dikes have been redesigned with these comments in mind. The SCC and
diversion dike on the northern portion of the site has been added to the plan. Diversion dike#2 has been
redesigned to divert water to two, 30" temporary slope drains. Please refer to sheet ES4 for detailed
sequencing notes for each measure. '
My recommendation is to use the existing sediment trap for 3.8 acres. Place the dd to follow the sanitary sewer
access road. Place a slope drain at the end of the the SCC and allow to discharge into the existing sediment
basin.
4) Existing dd east of basin 2 is in the way when grading for lots 24-29 occur. It should be noted on the plans for
lots to be graded after the adjacent road has been stabilized and runoff can discharge into stormdrains.
RESPONSE: The existing diversion dike is to remain until the road system is stabilized and runoff from
lots 16-23 can be discharged to stormdrains, and the storm drainage system up to 58A is installed.
Please refer to sheet ES4 for more detail. . . 1
v 5) Place inlet protection for 2 inlets at the intersection of Delphi Lane and Delphi Drive.
`d RESPONSE: Revised
6)The diversion across Cascadia will need to be improved or redesigned. Clarify perimeter controls when SCC
(accross Cascadia Drive) is removed. It appears commercial area and lots 112 to 119 cannot be graded until
adjacent road is stabilized, diversions are re-designed, and SCC is removed. Please clarify in sequence of
construction or on plan.
f
RESPONSE: The existing diversion dike, silt fence, and tree protection is to be removed after
completion of stormdrain structures 1-2C, 66 and 65.
Page 3 of 4
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We trust the above adequately addresses your comments. Please let me know if you have any questions or
require additional information.
Very truly yours,
Clint Shifflett, EIT
Attachments
Cc: Keith Lancaster
Page 4 of 4
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June 18, 2015
Ms. Michelle Roberge
Albemarle County Community Development Department
Division of Current Development
401 McIntire Road, North Wing
Charlottesville, Virginia 22902
RE: Cascadia Subdivision Blocks 1-3- Comment-Response Letter- VSMP WP0201400101
Dear Michelle,
Enclosed please find four(4) sets of the revised VSMP plan. Please note that we have revised the VSMP plan
to address your comments dated April 17, 2015 in accordance with the following:
C. Stormwater Management Plan(SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This plan
is disapproved, and the reasons are provided in the comments below. The stormwater management plan content
requirements can be found in County Code section 17-403.
7)The method for calculating the pond size reduction is incomplete. Please provide calculations. Use SCS
method an not rational method. Also, include drainage area map of the pre conditions for the 20.24 acres. Label
CN, acreage and Tc values on map.
[Revision 1]The post-developed map appears to be incorrect. Verify the DA map. It appears to be larger than
what is shown on plans. Also, verify where runoff for the portion of Fontana Drive(adjacent to Frost Montessori
School) is conveyed to. Does a portion go into Pond 1? What is the Tc for pre-developed conditions?The pond
appears to handle water quality criteria,but verify the post-developed drainage area and impervious area.
RESPONSE: As discussed with the county engineers,the drainage area has been revised per field visit
made by Dominion Engineering to verify the existing drainage divides. The time of concentration path is
shown in detail 1 on sheet ES8 of the VSMP plans.The summary of the TR55 time of concentration
calculations for the existing drainage area can be found on sheet 7 in the Hydraulic/Hydrologic
calculations booklet.
C. Stormwater Management Plan(SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This plan
is disapproved, and the reasons are provided in the comments below. The stormwater management plan content
requirements can be found in County Code section 17-403.
1)The title on the plans should state"VSMP".
Page 1 of 2
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434.979.8121 (p)
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D. Erosion and Sediment Control Plan(ESCP)
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.
1)The diversion dikes need to discharge into an outlet protection or to a trap. Shift dd#2 to discharge into outlet
protection.
[Revision 1] Comment not addressed. Show DD discharging the outlet protection. This is near the Delphi Lane
and Delphi Dr intersection.
RESPONSE: The diversion dike has been revised to discharge to the outlet protection.
We trust the above adequately addresses your comments. Please let me know if you have any questions or
require additional information.
Very truly yours,
Clint Shifflett, P.E.
Attachments
Cc: Keith Lancaster
Page 2 of 2
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v y/a • Engineering Charlottesville, VA 22911
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434.979.8121 (p)
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e, DominionEng.com
March 13, 2015
Ms. Michelle Roberge
Albemarle County Community Development Department
Division of Current Development
401 McIntire Road, North Wing
Charlottesville, Virginia 22902
RE: Cascadia Subdivision Blocks 1-3- Comment-Response Letter- VSMP WPO201400101
Dear Michelle,
Enclosed please find four(4) sets of the revised VSMP plan. Please note that we have revised the VSMP plan
to address your comments dated January 15, 2015 in accordance with the following:
A. 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.
'. 1) Include approved E&S and SWM plans of blocks 1-3 for SWPP on-site.
2) Include a section to list qualified personnel and contact info. .° l °t, ` "; .
~ v.3)Verify if site is on 2012 Impaired Waters-303(d) List.
4) State in the spill response section who should be contacted for spills and cleanup.
RESPONSE: The SWPP has been revised to include items 1-2, and 4. This site appears to be on the
012 Impaired Waters -303(d)List, as Group Code H28R-02, but is still in need of a TMDL study.
N, B.Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code section 17-404.
1) Include an 11"x 17" Pollution Prevention Plan map showing concrete washout,porta-johns, fueling stations,
and trash containers. This will be marked up by the contractor as construction of site progresses.
RESPONSE: A PPP plan has been provided with the aforementioned criteria.
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This plan
is disapproved, and the reasons are provided in the comments below. The stormwater management plan content
requirements can be found in County Code section 17-403.
✓1)The title on the plans should state"VSMP".
VRESPONSE: The title of the plans have been revised to state"VSMP"
Page 1 of 4
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�,e��y Dominion 172 South Pantops Drive
, ■ Engineering
Charlottesville, VA 22911
' 434.979.8121 (p)
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✓ 2) Please state the limits of disturbance on sheet ES2.
''RESPONSE: The limits of disturbance has been provided on sheet ES1
V 3)Please provide a note on the title sheet to clarify that this site is covered by an existing general permit.
Also,state the registration number. It appears the existing permit was granted for Cascadia Blocks 4-7.
" RESPONSE: Revised
4) $6100 was paid to the state for 60.772 acres land disturbance. Please discuss with Todd Shifflett. It appears
you will need to pay $200 for this application since this plan is an amendment to an existing permit.
�.. RESPONSE: Revised. An application along with a check for$200 has been provided with this
submittal.
I 5) Show anti-seep color on sheet ES6.
RESPONSE: The detail for SB-2 on sheet ES6 is for informational purposes only. The detail states that
the detail is "from approved Cascadia Blocks 4-7 WPO 201300032." Please refer to that plan for a
(' complete detail of SB-2.
1"6) Provide the detail for Detention Pond 1 and label type. ,
V RESPONSE: Detail and type added to sheet ES8.
7)The method for calculating the pond size reduction is incomplete. Please provide calculations. Use SCS
method an not rational method. Also, include drainage area map of the pre conditions for the 20.24 acres. Label
CN, acreage and Tc values on map.
RESPONSE: Hydraulic/Hydrologic calculations have been provided with this submittal for existing
"" Pond 1.
8)On ES9, please include the impervious core, label type of basin (ie.Retention Basin II), and depth pool zone
chart.
RESPONSE: The detail for Pond 2 on sheet ES9 is for informational purposes only. The detail states
that the detail is "from approved Cascadia Blocks 4-7 WPO 201300032." Please refer to that plan for a
complete detail of Pond 2.
Page 2 of 4
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,4,4 Dominion 172 South Pantops Drive
v y � ► Engineering Charlottesville, VA 22911
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9ees s DominionEng.com
D.Erosion and Sediment Control Plan(ESCP)
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.
1)The diversion dikes need to discharge into an outlet protection or to a trap. Shift dd#2 to discharge into outlet
protection.
2) What happened to the existing SCC on the northern portion of site to basin 2? Show as being removed on a
demo plan.
L�-3) DD#1 poses some issues. First, it is within lots 16-23. It will have to be noted on the plans for lots to be
cleared after the roads have been stabilized and runoff is discharged into stormdrains. Second,the dd does not
discharge to a stabilized outlet or sediment trap. Third,there is a sharp bend from the SCC to the diversion dike.
1-3 RESPONSE: The diversion dikes have been redesigned with these comments in mind. The SCC and
' diversion dike on the northern portion of the site has been added to the plan. Diversion dike#2 has been
redesigned to divert water to two,30"temporary slope drains. Please refer to sheet ES4 for detailed
sequencing notes for each measure.
My recommendation is to use the existing sediment trap for 3.8 acres. Place the dd to follow the sanitary sewer
access road. Place a slope drain at the end of the the SCC and allow to discharge into the existing sediment
basin.
4) Existing dd east of basin 2 is in the way when grading for lots 24-29 occur. It should be noted on the plans for
lots to be graded after the adjacent road has been stabilized and runoff can discharge into stormdrains.
RESPONSE: The existing diversion dike is to remain until the road system is stabilized and runoff from
lots 16-23 can be discharged to stormdrains, and the storm drainage system up to 58A is installed.
Please refer to sheet ES4 for more detail.
v 5)Place inlet protection for 2 inlets at the intersection of Delphi Lane and Delphi Drive.
RESPONSE: Revised
6)The diversion across Cascadia will need to be improved or redesigned. Clarify perimeter controls when SCC
(accross Cascadia Drive) is removed. It appears commercial area and lots 112 to 119 cannot be graded until
adjacent road is stabilized, diversions are re-designed, and SCC is removed. Please clarify in sequence of
construction or on plan.
RESPONSE: The existing diversion dike,silt fence, and tree protection is to be removed after
completion of stormdrain structures 1-2C, 66 and 65.
`.-`
Page 3 of 4
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pe ' Dominion 172 South Pantops Drive
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:90 s DominionEng.com
We trust the above adequately addresses your comments. Please let me know if you have any questions or
require additional information.
Very truly yours,
Clint Shifflett, EIT
Attachments
Cc: Keith Lancaster
Page 4 of 4
NumW 111.1
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. Engineering Charlottesville, VA 22911
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August 10, 2015
Mr. John Anderson
Albemarle County Community Development Department
Division of Current Development
401 McIntire Road, North Wing
Charlottesville, Virginia 22902
RE: Cascadia Subdivision Blocks 1-3- Comment-Response Letter- VSMP WP0201400101
Dear John,
Enclosed please find two (2) sets of the revised VSMP plan. Please note that we have revised the VSMP plan
to address Michelle's comments dated July 10, 2015 in accordance with the following:
A. Stormwater Pollution Prevention Plan(SWPPP)
There are no remaining comments.
B.Pollution Prevention Plan(PPP)
There are no remaining comments.
C. Stormwater Management Plan(SWMP)
7) [Revision 2] Comment partially addressed. See sheet ES8. It should be noted on sheet ES8 that the existing
pond 1 size is being revised. Show the plan view on sheet ES8 with the proposed grading. Also,the new
elevation for the 2 yr, 10 yr and 100 yr storms should be shown to reflect the calculations.
RESPONSE: A note has been added noting that existing Pondl is to be partially filled in. The 2, 10,and
100 year storm event water surface elevations have been added to the plan view on sheet ES8 as well.
D. Erosion and Sediment Control Plan(ESCP)
3) [Revision 2] In light of the interim plan revisions it appears comment 2-3 are still not addressed. Please note
that E&S measures from the approved block 4-7 plan, interim plan(showing relocated ditch, revisions to
sediment basin near stockpile, and relocating culvert out of stream), and blocks 1-3 plan should clearly reflect
the phasing/transitions between each plan. For example,when is sediment basin 4 from blocks 4-7 removed?
This plan just shows an SCC to Pond 2.
RESPONSE: The locations of existing sediment basin 4 and the existing sediment trap adjacent to SB-2
have been added to the plans. Notes have been added to give detailed instructions for when the existing
E&SC measures from Blocks 4-7 are to be removed.
Page 1 of 2
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°7 . Engineering Charlottesville, VA 22911
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6) [Revision 2] Comment partially addressed. It is noted in the response letter that the existing diversion dike,
silt fence and tree protection is to be removed after completion of STR 1-2C, 66-65. Please look into Cascadia
Drive construction again as it appears there will be sediment laden runoff near culvert labeled 65 that will flow
into the relocated ditch.
RESPONSE: Culvert inlet protection is provided for structures 66,and 2C,as well as outlet protection
for structure 65. In addition to these measures,silt fence has been added on either side of Cascadia Drive.
A note has been added to sheets ES4 and ES5,that the existing diversion dike is to remain in place until
structures 1-2C,and 65-66 are in place.
We trust the above adequately addresses your comments. Please let me know if you have any questions or
require additional information. We have attached Michelle's original comment letter dated 7/10/15 for reference.
Very truly yours,
Mi -tee l Myers, P.E.
Attachments
Cc: Keith Lancaster
Page 2 of 2