SWA000022__14 Comment Response Letter_20201001

Comments from June 24, 2020 email
- Prior Comment laiii — Documentation showing Mr. Kardos' affiliation with "EPCON Layers Road,
LLC" was not provided with the submittal.
Response: Certificate of Incumbency is included with the submittal documents.
- Prior Comment 1bii2 — Based on the provided stage -storage tables, the wet ponds are not
correctly sized.
o Wet Pond 1&2:
■ The volume of the main pool should not include any portion of the sediment
storage area.
Response: Volume has been removed from the below normal pool
volume.
■ The average depth is not calculated correctly (Wet Pond MDC 2).
Response: The average depth has been recalculated using equation 2
■ The volume of the forebay should not include any portion of the sediment
storage area.
Response: Volume has been removed from the below normal pool
volume.
■ The volume of the forebay appears to be larger than 20% of the main pool
volume (Wet pond MDC 5a).
Response: Line 33 of the EZ form has been changed to "No". The
basins were designed and approved in 2014, when the 15-20% was not
a requirement. The former DEQ manual requested "Approximately
20%" volume in the forebays. Wet Basin 1 & 2 provides over 20% of
the below normal pool volume providing extra settling opportunities
for the basin.
The drawdown time for the design volume appears to be more than 5 days (Wet
Pond MDC 7).
Response: Per the previous supplemental sheets, drawdown was
calculated as Volume provided divided by flow rate of orifice. Basin 1
& 2 have a provided volume of 50,708 cubic feet and the orifice
releases water at 0.14 cfs, making the drawdown time 4.19 days.
The pond appears to short-circuit (Wet Pond MDC 4).
Response: The pond will not short circuit as the inflow pipes will all
enter forebay features before travelling approximately halfway across
the main pool to get to the outlet.
o Wet Pond 3
■ The volume of the main pool should not include any portion of the sediment
storage area.
Response: Volume has been removed from the below normal pool
volume.
The average depth is not calculated correctly and appears to be less than 3 ft
(Wet Pond MDC 2).
Response: The average depth has been recalculated using equation 2
The volume of the forebay should not include any portion of the sediment
storage area.

Response: Volume has been removed from the below normal pool
volume.
The volume of the forebay appears to be larger than 20% of the main pool
volume (Wet pond MDC 5a).
Response: Line 33 of the EZ form has been changed to "No". The
basins were designed and approved in 2014, when the 15-20% was not
a requirement. The former DEQ manual requested "Approximately
20W volume in the forebays. Wet Basin 3 provides over 20% of the
below normal pool volume providing extra settling opportunities for
the basn.
The drawdown time for the design volume appears to be more than 5 days (Wet
Pond MDC 7).
Response: Per the previous supplemental sheets, drawdown was
calculated as Volume provided divided by flow rate of orifice. Basin 3
has a provided volume of 12,423 cubic feet and the orifice releases
water at 0.03 cfs, making the drawdown time 4.79 days.
Prior Comment 1bii3 — Line 27 was not filled out for the "Drainage Area 1&2 Column".
Response: Line 27 has been filled in
Prior Comment 1f — A revised As -Built Permittee Certification was not provided.
o Prior Comment lfii — The SCMs are not located on single family lots (This needs to be
corrected).
Response: Addressed per previous discussions
o Prior Comment 1fiii2 — Documentation showing that the O&M Agreement has been
recorded with the register of deeds was not provided (There was no response to this
comment in the response letter).
Response: Addressed per previous discussions
Prior Comment 3aiv —The percent impervious of the project site, as shown in Section IV, 8 of
the Application (32.9%), does not match the value as shown in the Supplement-EZ Form (46%).
Response: The percent impervious of the project site has been updated to be 33.97%
on both the Section IV, 8 of the Application and the Supplement-EZ Form.
Prior Comment 4 —The "Check here if this is part of a Fast -Track As -Built Package Submittal"
boxes were not checked off on the Designer Certifications.
Response: Box has been checked with the resubmittal
Prior Comment 5 — The correction mentioned in the response to this item was not carried out
throughout the submittal information.
o For Drainage Area 1&2 on the Wet Pond Sheet of the Supplement-EZ Form,
■ Line 22 indicates that the bottom of the vegetated shelf is at elevation 634.0.
■ Line 24 indicates that the top of the vegetated shelf is at elevation 635.0.
■ Line 46 indicates that the width of the vegetated shelf is 8 ft
■ Line 47 indicates that the slope of the vegetated shelf is 10:1
■ These can't all simultaneously be true.
Response: Line 47 has been updated to reflect the steepest slope.