WQ0019907_More Information (Requested)_20230427

ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGERS, JR.
Director
DAVID MOHR— CHIEF OPERATING OFFICER
ONSLOW WATER AND SEWER AUTHORITY
228 GEORGETOWN ROAD
JACKSONVILLE, NORTH CAROLINA 28540
Dear Mr. Mohr:
NORTH CAROLINA
Environmental Quality
April 27, 2023
Subject: Application No. WQ0019907
Additional Information Request
Southeast Regional WWTP
High -Rate Infiltration System
DWI Project: SRP-W-ARP-0189
Onslow County
Division of Water Resources' Central and Regional staff, and Division of Water Infrastructure staff,
have reviewed the application package received January 27, 2023. However, additional information is
required before the review may be completed. Please address the items on the attached pages no later than
the close of business on May 29, 2023.
Please be aware that you are responsible for meeting all requirements set forth in North Carolina
rules and regulations. Any oversights that occurred in the review of the subject application package are
still the Applicant's responsibility. In addition, any omissions made in responding to the outstanding items
in Sections A through T, or failure to provide the additional information on or before the above requested
date may result in your application being returned as incomplete pursuant to 15A NCAC 02T .0107(e)(2).
Please reference the subject application number when providing the requested information. All
revised and/or additional documentation shall be signed, sealed and dated (where needed), with an
electronic response submitted to my attention at: hiips://edocs.deg.nc.gov/Forms/NonDischarge-Branch-
Submittal-Form-Ver2.
If you have any questions regarding this request, please contact me at [phone] or
[e-mail]. Thank you for your cooperation.
Sincerely,
Erick Saunders, Engineer
Division of Water Resources
cc: Wilmington Regional Office, Water Quality Regional Operations Section (Electronic Copy)
Carl Scharfe, PE — The Wooten Company (Electronic Copy)
Bryan Lievre — Division of Water Infrastructure (Electronic Copy)
Laserfiche File (Electronic Copy)
D E Q�� North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 1 1617 Mail Service Center I Raleigh, North Carolina 27699-1617
NORM CAROLINA -
oePemmeatoie�o�me�iQuar\ /� 919.707.9000

Mr. David Mohr
April 27, 2023
Page 2of11
A. Cover Letter:
1. No comments.
B. Proiect Narrative:
It is mentioned several times in the narrative that treated effluent from this facility can be piped to
the Summerhouse WWTP reclaimed water pump station, permitted under WQ0029945, for
disposal at the Summerhouse facility's infiltration basins. However, the treatment standards
required to dispose of effluent to these basins in Permit No. WQ0029945 are more stringent for
certain parameters than the effluent quality than what is being proposed in Table 2 of the Narrative
and Item VI. I. of the High -Rate Infiltration System Application Form (FORM: HRIS 06-16). This
includes the following parameters:
a. Total Phosphorus (as P) — 2 mg/L Monthly Average limit in WQ0029945, 3 mg/L Monthly
average proposed in this application.
b. Turbidity, HCH Turbidimeter — 10 NTU Daily Maximum limit in WQ0029945, no limit
proposed in this application.
Any effluent that is to be sent to the infiltration basins at Summerhouse will be required to meet
the limits established in Attachment A of Permit No. WQ0029945. Please provide an explanation
for how effluent from this facility will be monitored so that only treated effluent that meets the
standards established in Permit No. WQ0029945 will be sent to Summerhouse.
2. On Page 9 of the project narrative, it is indicated that the branch line to the Storage Pond with be
used for excessive flow events or temporary wastewater treatment plant upsets. If this is used for
both storage and upset conditions, provide an explanation for how operations will be conducted to
ensure that off quality water entering this structure is not entering the disposal system as a bypass
in violation of 15A NCAC 02T .0705(i).
3. The narrative did not include an explanation for how the existing storage lagoon will be repurposed
into a holding pond, including work undertaken to close it out of the old Holly Ridge facility and
to connect it to the new effluent pump station. Please provide an excerpt in the narrative for how
this work will be conducted and how it will be phased into the new facility.
4. This project includes a proposal of a groundwater lowering system that will drain water from the
site and discharge it to "an existing ditch system that drains to the forested wetlands areas on the
eastern site of the property parcel" which ultimately discharges to King's Creek. However, the
application does not provide the flow path of this water to King's Creek and does not address the
hydrologic or water quality impacts of introducing this additional water to the ditch system and
downstream jurisdictional features.
An analysis shall be performed to determine the downstream hydraulic and water quality effects of
introducing the surface discharge of the groundwater lowering system. This analysis shall delineate
the flow path of the discharged water from each of the three discharge locations to King's Creek,
identifying any properties downstream of the route and any engineered features, such as culverts,
which would not have been designed for the additional flow, and a discussion of the effects of
constituents like nutrients, iron, pH, BOD, and turbidity in the receiving water bodies. It shall also

Mr. David Mohr
April 27, 2023
Page 3of11
discuss the impact of the lowered groundwater into a jurisdictional wetland to ensure it does not
violate wetland standards in accordance with 15A NCAC 02B .0231.
As proposed, the surface discharge of the lowered groundwater from this facility to the forested
wetlands to the east of the property may be an addition of pollutants from the basin disposal system
into a jurisdictional water requiring a permit under the Clean Water Act (CWA) under new
guidance from the Supreme Court of the United States' (SCOTUS) decision in the County of Maui
vs. Hawaii Wildlife Fund case (hereby referred to as the Maui Case). The CWA forbids any addition
of any pollutant from any point source into jurisdictional surface waters without an appropriate
permit from the Environmental Protection Agency (EPA). The SCOTUS's decision in the Maui
Case clarifies that a permit is required when there is an addition of any pollutant through a direct
discharge from a point source into navigable waters or when there is a functional equivalent of a
direct discharge (hereby referred to as a "functional equivalent"). Several factors were provided in
the decision to determine of whether a particular discharge would be considered a functional
equivalent, including:
"(1) transit time, (2) distance traveled, (3) the nature of the material through which the pollutant
travels, (4) the extent to which the pollutant is diluted or chemically changed as it travels, (5)
the amount of pollutant entering the navigable waters relative to the amount of the pollutant
that leaves the point source, (6) the manner by or area in which the pollutant enters the
navigable waters, (7) the degree to which the pollution (at that point) has maintained its specific
identity"
Based on the proximity of the groundwater lowering system to the infiltration basins, the discharge
of lowered groundwater surrounding these basins may cause an addition of pollutants into
jurisdictional surface water features as a functional equivalent of a direct discharge. An NPDES
permit shall be obtained for the direct discharge of this water unless it is explicitly demonstrated
this would not lead to a functional equivalent of a direct discharge. This demonstration shall include
a delineation of the nearest jurisdictional surface water with an analysis utilizing the above factors
to evaluate the pollutant transport from the basins to these waters.
C. Application Fee:
1. No comments.
D. Hi2h Rate Infiltration System Application (FORM: HRIS 06-16):
1. Item IVA. of the application requests the status of permits/certifications applicable to the subject
facility, most of which did not include a "Date Submitted", "Date Approved", and
Permit/Certification Number". Please provide a status update for all the permit/certification
applications.
Table IVA. does not clarify where in the project areas require "Nationwide 12 / Section 404"
permits/certifications. The project narrative mentions a loss of wetlands required for the
construction of the access road to the upstream and downstream sampling points for the
groundwater discharge points. However, there are other areas in the application that may impact
wetlands, like the "Connection Point for Contracts 1 & 2" detail on Sheet C 105 of the Contract 2
plans and the wetland feature being removed for Basins 18, 19 and 22 depicted in Contract 3 plans.
Please provide clarification as to whether these areas require any federal or state
permits/certifications for impacting wetlands.

Mr. David Mohr
April 27, 2023
Page 4of11
It is explained in the answers for VL6.and VL9. in Section VI that the existing holding pond's liner
will be inspected to ensure it is in good condition. Please provide an explanation for how this
inspection will be performed.
4. Item VIL2. of the HRIS 06-16 form indicates that there is no artificial drainage within 200 feet of
the structure, but the applicant is intending on complying with 15A NCAC 02T .0706(b) to reduce
the setback from groundwater lowering drainage systems to 100 feet. Please revise.
5. How were the infiltrative surface areas in VIL9.b. calculated for each basin? These values are larger
than the freeboard elevation water surface area which is typically used as the infiltrative surface
area.
E. Property Ownership Documentation:
1. No comments.
F. Soil Evaluation:
1. In accordance with the Soil Scientist Evaluation Policy, a saturated hydraulic conductivity K.t)
and drainage coefficient shall be recommended for use in the water balance based on a
comprehensive site evaluation, a review of data, minor amounts of contrasting soils, and the nature
of the wastewater to be applied. A recommendation for these values shall be provided to support
the values that are used in the water balance.
G. Agronomist Evaluation:
1. N/A.
H. Hydrogeologic Report:
Some parts of the hydrogeologic report, particularly the figures and tables in Appendices A and B,
were low resolution and difficult to interpret. Please submit these legible versions of Appendix A
and Appendix B.
2. In Section 1.7 of the report, it mentions that Section II is the analysis of soils and geology of the
Shalotte Site. Please revise this section.
3. The nomenclature for basins in Section 2.3 appears to be incorrect for certain fields. For instance,
for the descriptions of Basins 15 and 16, it states that "aquifer matrix conditions found as Basin 14
was best defined by...". Similarly, the excerpt for Basin 23 references Basin 19. Please review this
field names in this section for accuracy, and clarify whether this is a typo, or if conditions for Basin
14 are used to be representative of Basins 15 and 16.
4. How were the aquifer thicknesses determined in the hydraulic conductivity and specific yield
calculations performed at each aquifer test sites in Section 4.2?
5. How were the recharge and evaporation values of 0.011 feet per day and 0.008 feet per day used in
the MODFLOW model determined? Were these values applied over the full model extent?

Mr. David Mohr
April 27, 2023
Page 5of11
The Solute Transport in Section 4.4 provides a solute transport model for the 20-year loading of
Total Nitrogen at 7 milligrams per liter. This also states that "a majority of the modeled nitrogen is
controlled with the groundwater control drains at 100 feet", but it is unclear what criteria was used
to make this determination, as there doesn't appear to be an analysis of the Total Nitrogen entering
the groundwater lowering system. Please provide an in-depth explanation of the solute transport
model's results in Figures 9A through 9F.
The Solute Transport in Section 4.4 was only performed for Total Nitrogen, but there are other
parameters of interest that should be modeled to evaluate the solute transport coming from the
basins to the groundwater lowering system located outside the compliance boundary. These
parameters should also include Total Phosphorus and Ammonia.
Figures 7A through 7C depict the drawdown or "negative mound" caused by the groundwater
lowering system to provide a mounding analysis. Based on the results, there are certain values that
are negative, indicating a positive mounding based on the daily loading models, though it is hard
to interpret whether this negative value would mean direct contact of the groundwater table into
the basin. Please clarify these results in relation to the bottom of the basins.
9. The Evaluation of Permeability report completed by GeoTechnologies, Inc. was sealed, but not
signed and dated by the Engineer. This document shall be signed and dated by the sealing engineer.
10. The Evaluation of Permeability report completed by GeoTechnologies, Inc. was performed to
determine the highest level of compacting to be used while still providing permeability compatible
with what was used in the designed flow models. Was a slope stability analysis performed to
determine if the compaction levels found in the subsequent Compaction Analysis performed by
Edward Andrews were adequate to prevent failure of the slopes?
I. Water Balance:
1. In the water balance in Table 11 of the Hydrogeologic Report, how was the Ksat of 14 inches per
hour and the drainage coefficient of 0.04 determined? Section 2.2 — Soil Descriptions in the
Hydrogeologic Report states that the hydraulic conductivity of identified restrictive horizons were
not analyzed.
The water balance in Table 11 of the Hydrogeologic Report does not appear to account for
precipitation input for the top of dam elevations or the existing holding lagoon that will be included
in this project. Precipitation along the berm slopes above the designed full basin level will enter the
system and shall be included in the water balance. These precipitation input areas will be different
than the "Spray Irrigation Area" acreage listed in the provided water balance, with some areas being
substantially larger. For instance, in Item VIL9.b of the HRIS 06-16 form, Basin 14 is designed
with 7.4 feet of freeboard with an infiltrative surface area of 23,911 square feet (W) while the top
of dam area is 44,725 fe. Adjusting the calculations to represent the top of dam area will almost
double the amount of precipitation input in Basin 14 than what was calculated using the basin's
infiltration area in the provided water balance. Please revise the water balance and incorporate
precipitation inputs representative of the surface area contributing runoff and precipitation input
into each basin.
L Engineering Plans — Contract 2:
1. The hydraulic profile on Sheet C004 does not include the existing holding pond. Please include this
in the profile to include the basin's connection to the effluent pump station and drain lines.

Mr. David Mohr
April 27, 2023
Page 6 of 11
On Sheet C101, anything east of the chain link fence is reported to fall under Contract 3, including
the "10" Gravity Return Line from Holding Pond". However, on Sheet C107 of the Contract 3
plans, it is stated that the modifications to the existing storage pond are listed to be performed under
Contract 2. It does not appear that the modifications to the pond, including the installation of the
drain line and pinch valve mentioned on Page 9 of 13 in the Project Narrative, are included in either
contract. Please provide updated plans, in either Contract 2 or 3, detailing modifications for the
existing holding pond, including required demolition to existing facilities, tie in and installation of
the drain line, profile views of the piping, and details of any relevant appurtenances such as the
pinch valve.
3. On Sheet C101 there is a line from the existing pond labeled as `10" Gravity Return Line from
Holding Pond'. On Sheet C220 of the Contact 3 Plans, the return line from this pond is labeled ` 12"
Holding Pond Return Line'. Please clarify the dimensions of this holding pond return line and
update the plans.
4. Detail 3 — Connection Point for Contracts 1 & 2 on Sheet C 105 of the Contract 2 depicts the influent
force main and the return line to Summerhouse PS crossing through a wetland boundary.
Documentation shall be provided to certify that this work has a 401/404 wetland
permit/certification, or a justification explaining why this certification is not required. If tunneled
or direct bored, a note shall be made on the plans detailing the method of installation.
5. There are several sections on Sheets M200 and M201 which have cross section callouts that are
either not depicted or refer to the wrong detail or page. For example, the Top Plan - New Headworks
on Sheet M200 and Top Plan — Proposed Headworks on Sheet M201 have section callouts C —
M201 and D — M202, neither of which are depicted. Additionally, Section detail B on Sheet M201
is also labeled B — M200, but the callouts that refer to this section are labeled B — M201 in the plan
view. Please revise and update the plans to correct the section callouts.
6. The notes in Detail B — M200 on Sheet M201 are cutoff on the lefthand side of the page. Please
revise and update the plans for clarity.
7. The cross-section callouts on the Plan view for the New SBR Building No. 2 on M405 through
M407 appear to be incorrect. For instance, section callout A — M404 points to a section view of
SBR Building No. 1 on Sheet M404 instead of SBR Building No. 2. Section A — M405. Please
revise and update the plans to correct the section callouts.
8. Plan Sheet M700 identifies a 10" WAS line from the Digesters to Sludge Building No. 2, but the
same line appears to be identified as a 12" line in Plan Sheet M701. Please clarify the dimensions
of this line and update the plans.
J. En2ineerinE Plans — Contract 3:
During a site visit, Wilmington Regional Office staff observed the existing drainage way east of
Basins 3, 4, and 7 near monitoring well MW-3 as depicted on Sheet C200 and believe this to a
surface water requiring a 200-foot setback to infiltration basins in accordance with 15A NCAC 02T
.0706(a) rather than a ditch as it is currently listed, which would only have a 50-foot setback. The
Wilmington Regional Office shall be contacted to perform an official waterbody determination for
this feature to determine the appropriate setbacks. If it is considered a surface water, the plans and
all appropriate documents shall be updated with these updated setbacks accounted for.
2. Sheet C100 details a wetland to be remediated within the existing Spray Field Zone 1 footprint,
which is shown in the footprint of Basins 18, 19, and 22 on Sheet C200. Documentation shall be

Mr. David Mohr
April 27, 2023
Page 7of11
provided to verify that the removal of this wetland is properly certified, or a justification shall be
provided verifying that this feature is not a jurisdictional wetland. A Jurisdictional Determination
by the U.S. Army Corp of Engineers shall be provided to verify if a certification is not required.
3. The monitoring well depth on Detail 1 of Sheet C200 is shown to be 45.5 feet, much deeper than
the provided water table at the site. Monitoring wells should be installed such that the water level
in the well is never above or below the screened portion of the well. Please revise the monitoring
well detail to reflect the well dimensions for this site.
4. The infiltration basin sections for certain basins on Sheets C300 through C305, such as Basin 20,
included groundwater lowering pipe elevations above the bottom elevation of the ponds. This
promotes lateral transport of the infiltrated wastewater from the basins to the lowering pipe, with
variable groundwater depth. Has a slope stability analysis been performed for the basin side walls
to account for this?
K. Specifications — Contract 2:
1. Specifications shall be provided in either Contract 2 or Contract 3 detailing procedures for the
repurposing of the existing holding pond for use as a holding pond. This shall include updating the
Summary of Work to include for how and when this structure will be switched from utilization in
current to the new mode of operations and include any specific site construction requirements and
associated equipment required for this work.
L. Specifications — Contract 3:
Section 02300 - Earthwork includes general specifications for the earthwork associated with the
installation of the basins; however, during construction special considerations to ensure
construction activities do not impact the infiltration capacity of the basins are required. The
specifications for the earthwork activities within the infiltration basins shall require 100' of
horizontal native material be maintained between the basin wall (NOT including the engineered
sand fill) and the proposed groundwater lowering system, provisions to minimize the impacts of
construction activities on the infiltrative surfaces of the basins, and specific material and installation
requirements for the select engineered sand fill side slopes and vertical cuts detailed in each basin
depicted on Sheets C300 through C305 of the Contract 3 Plans. Section 02300 of the specifications
shall be updated to include these requirements to ensure that the prescribed structural integrity and
design capacity are achieved during basin construction.
M. En2ineerin Calculations:
In accordance with 15A NCAC 02T .0704(c)(3), engineering calculations shall include hydraulic
and pollutant loading for each treatment unit. Pollutant loadings shall be provided for each
treatment unit.
In accordance with 15A NCAC 02T .0704(c)(3), buoyancy calculations shall be provided for
treatment units. Buoyancy calculations shall be provided for below ground, including but not
limited to the pump stations being proposed.
3. The peaking factor used for the design criteria of the system in the Introduction section of the
calculations package is 2.5, which would mean a peak daily flow of 3.75 MGD at the fully expanded
1.5 MGD proposed for this system. However, the design proposal documents by Evoqua Water
Technologies for the Sequencing Batch Reactor and Automatic Backwash Disc Filters in Appendix

Mr. David Mohr
April 27, 2023
Page 8of11
A use a peak flowrate of 3.00 MGD at an average flowrate of 1.5 MGD. Please clarify the
discrepancy between these peaking factors and note that these units could be a limiting unit when
this system is expanded in the future to 1.5 MGD.
4. Please provide manufacturer's information to verify that the filter screen's rated capacity is 4 MGD
as mentioned in Table 3.
5. The SBR Effluent Parameters in Item C on Page 3 of 10 of the Preliminary Proposal for the SBR
unit list the design effluent concentration of 8 mg/L for Total Nitrogen, which does not meet the
requirements of 7 mg/L to reduce the setbacks to groundwater lowering drainage systems in
accordance with 15A NCAC 02T .0706(b). Please provide an explanation for how this treatment
standard will be met at this facility, which shall include pollutant loading calculations in accordance
with 15A NCAC 02T .0704(c)(3).
N. Site Map:
1. No comments.
O. Power Reliability:
1. No comments.
P. Operation & Maintenance Plan:
1. No comments.
Q. Residuals Management Plan:
1. No comments.
R. Additional Documentation:
➢ Certificate of Public Convenience and Necessity:
1. N/A
➢ Existing Permit:
1. No comments.
➢ Final Environmental Document:
1. N/A
➢ Floodway Regulation Compliance:
1. No comments.
➢ Operational Agreements:

Mr. David Mohr
April 27, 2023
Page 9of11
1. N/A
➢ Threatened or Endangered Aquatic Species Documentation:
1. No comments.
➢ Wastewater Chemical Analysis:
1. N/A
S. Recommendations: (Response not required)
It is proposed on Page 8 of 13 of the Project Narrative that the sampling location for monitoring
and compliance be set for each field at the field's groundwater discharge points. Please note that if
this used for groundwater monitoring purposes, these groundwater discharge points would be
located outside of the field's compliance boundary, as subsurface groundwater lowering drainage
systems are prohibited within the compliance boundary in accordance with 15A NCAC 02T
.0705(y). Monitoring the groundwater lowering effluent outside the compliance boundary could be
immediately subject to corrective action requirements listed in 15A NCAC 02L .0106(e) if there is
an exceedance of groundwater standards.
2. On page 9 of the Project Narrative, it states that all existing temporary wells and monitoring wells
will be removed or destroyed during construction of the new infiltration basins. Please note that it
will be a condition of the permit to have these wells properly abandoned by a certified well driller
in accordance with 15A NCAC 02C.
T. Questions from Division of Water Infrastructure (DWI) Staff:
1. Review of Contract 2
A. General Review
1. Please provide copies of all necessary permits including but not limited to the Non -Discharge
Permit for the proposed wastewater treatment plant, sewer extension, encroachment permit(s),
easements, well construction, etc.
2. Please provide a Bid Bond per Section I. of the Bid Design Document Submittal Checklist.
3. It should be noted that the design flow seems to vary, with peak flows from 3.0 million gallons
per day (MGD) to 4.0 MGD. This design parameter should be consistent throughout the
documents provided.
4. Items provided for review included Project Manuals for the Sequencing Batch Reactor (SBR)
Equipment and the Wastewater Treatment Plant (WWTP), in addition to other items. The manual
for the WWTP also included items specified within the SBR manual. It is understood that the
purpose of the SBR manual is to enable the option to gain bids for the equipment separately.
However, please understand that if this process is utilized, this must be accomplished in a more
seamless manner. For example, if the same equipment is specified within each document, then
the bids should not be provided as lump sum, as it will not be possible to remove equipment from
the WWTF bid if it has already been purchased through the SBR bid. Furthermore, if the
equipment is purchased through the SBR bidding process, then the WWTF manual should specify
the exact model/make for each piece of equipment.

Mr. David Mohr
April 27, 2023
Page 10 of 11
5. Please be informed that the Representative Wastewater Flow Projections Data provided along
with the application in electronic format does not comply with estimating future demand in
accordance with 15A NCAC 2T .0114.
B. Review of Calculations
1. Please provide justification for use of 2.5 as PF, taking into consideration hourly fluctuations.
2. As mentioned during a telephone conversation between David Mohr (ONWASA) and Bryan
Lievre (DWI) on April 4, 2023, please provide pump capacities from Summerhouse and Holly
Ridge Pump Stations to the new SE WWTF Influent PS.
3. Please provide solids removal estimates for the headworks structures.
4. Table 1 of the Engineering Calculations provides an Average Daily Flow (ADF) of 1.5 MGD and
a Peak Hourly Flow (PDF) of 3.75 MGD. The manufacturer provided information for the
Sequencing Batch Reactor and Tertiary Disc Filters provided within this report utilize an ADF of
1.50 MGD and a PHF of 3.00 MGD. If the design is to be based on, in part, a PHF of 3.00 MGD,
please be informed that these structures may become the limiting design criteria and thus require
upgrading, in the event expansion is desired in the future.
5. Please discuss the intended standard operation of the influent and effluent pump stations with
respect to the status of the slide gates which separate flow from the two compartments of each
wet well as well as the operation of the respective pumps. Also discuss the intended operation
while sending flow to the EQ Basin and Summerhouse Pump Station for each of the two pump
stations mentioned above.
6. The Engineering Calculations utilize a Design MLSS at Top Water Level (TWL) of 2,400 mg/L
for the Sequencing Batch Reactors. This value seems low in comparison to other permitted
designed systems. Please provide justification for this value.
C. Review of Plans
1. The cover sheet of the plans does not contain the Division Project Number SRP-W-ARP-0189.
2. Plan Sheets C101, M250 and M600 identify a 10" gravity return line leading from a Holding
Pond to the Influent and Effluent Pump Stations. Based on information provided in Contract 3, it
appears as though the existing 13.30 MG Storage Pond located on the Holly Ridge irrigation
parcel is proposed to be used as a potential temporary Holding Pond in the event additional
storage is needed (with an influent to the pond tapped off the 16" line prior to entering the
proposed WWTF). Please identify what controls are installed or proposed to limit flow from the
pond to each of the pump stations and provide plan and profile views of the line from the pond to
the pump stations or intended inlet and effluent invert elevations for the piping.
3. Plan Sheet M700 identifies a 10" WAS line from the Digesters to Sludge Building No. 2, but the
same line appears to be identified as a 12" line in Plan Sheet M701. Please revise or explain.
D. Review of Specifications
1. Part 1.02 A. 7. of Section 11071 Specifies an Element Size of 0.25" x 0.75" x 0.13" SSTL316 for
the bar screen, but Part 2.02 A. 1. refers to an Element Size of 0.025" x 0.75" x 0.13". Please
revise the suspected incorrect value.
2. Section 11150 of the Technical Specifications provides a Peak Daily Flow of 3.0 MGD for the
SBR Influent Characteristics, which does not agree with the Calculations Peak Daily Flow of 3.75
MGD (Table 1). Also, the temperature range (of 12°C to 20°C) in Section 11150 of the

Mr. David Mohr
April 27, 2023
Page 11 of 11
Technical Specification does not match the calculations (15°C to 27°C). Please revise or
explain.
2. Review of Contract 3
A. General Review
1. Please provide a Bid Bond per Section I. of the Bid Design Document Submittal Checklist.
2. Please provide copies of all necessary permits including but not limited to the Non -Discharge
Permit for the proposed wastewater treatment plant, sewer extension, encroachment permit(s),
easements, well construction, etc.
3. Please provide the backfill material for Pump Station 3-2 in Section X.4 of the Attachment for
Part X of the High -Rate Infiltration Systems Form: HRIS 06-16.
4. Prior to construction surficial clay, peat, or organic layers, either Bt, Bh or depositional clay, silty
or otherwise restricted layers will need to be excavated, removed, and stabilized to reduce the risk
of plugging the sand matrix of the surficial aquifer. What methods/procedures will be in place
and who will be responsible for this inspection to ensure the sand matrix is not compromised in
this manner?
B. Review of Calculations
1. Please explain how the pumping rates of 500 gpm for the groundwater lowering pump stations
were determined.
2. For each field, the force mains from the pump stations will be combined and then discharge the
groundwater to a single point (three discharge points, one for each field). The latitude and
longitude of these stations, as well as the discharge points, are provided in the table below. The
three discharge points will include a shallow swale and end rip rap section to dissipate the
velocity of the discharge. The water will flow overland to the existing ditch system that drains the
forested wetland areas on the eastern side of the property parcel. This ditch ultimately discharges
to King's Creek, which is classified as tidal Salt Water, Swamp, and High Quality Water (SC;
Sw; HQW). Please address the hydrologic or water quality and quantity impacts of introducing
this additional water to the ditch system and the downstream features.
C. Review of Plans
1. The cover sheet of the plans does not contain the Division Project Number SRP-W-ARP-0189.
D. Review of Specifications
1. No comments.