WQ0045709_Staff Report_20241004

State of North Carolina
Division of Water Resources

Water Quality Regional Operations Section
Staff Report

FORM: WQROSSR 04-14 Page 1 of 3

To: NPDES Unit Non-Discharge Unit Application No.: WQ0045709
Attn: Zachary Mega Facility name: Oaks at Wakefield
WWI

From: Chris Smith
Raleigh Regional Office

Note: This form has been adapted from the non-discharge facility staff report to document the review of both non-
discharge and NPDES permit applications and/or renewals. Please complete all sections as they are applicable.

I. GENERAL AND SITE VISIT INFORMATION
1. Was a site visit conducted? Yes or No
a. Date of site visit: September 26, 2024
b. Site visit conducted by: Chris Smith (RRO) and Caitlin Williams (WSRO)
c. Inspection report attached? Yes or No
d. Person contacted: and their contact information:
e. Driving directions:
2. Discharge Point(s):
Latitude: Longitude:
Latitude: Longitude:
3. Receiving stream or affected surface waters:
Classification:
River Basin and Subbasin No.
Describe receiving stream features and pertinent downstream uses:
II. PROPOSED FACILITIES: NEW APPLICATIONS
1. Facility Classification: (Please attach completed rating sheet to be attached to issued permit)
Proposed flow: 5600 GPD
Current permitted flow: N/A
2. Are the new treatment facilities adequate for the type of waste and disposal system? Yes or No
If no, explain: Unknown
3. Are site conditions (soils, depth to water table, etc) consistent with the submitted reports? Yes No N/A
If no, please explain: See Additional Regional Staff Review Items
4. Do the plans and site map represent the actual site (property lines, wells, etc.)? Yes No N/A
If no, please explain:
5. Is the proposed residuals management plan adequate? Yes No N/A
If no, please explain:
Docusign Envelope ID: B1857BE1-8020-4272-9366-1D8908A10958
FORM: WQROSSR 04-14 Page 2 of 3
6. Are the proposed application rates (e.g., hydraulic, nutrient) acceptable? Yes No N/A
If no, please explain: Unknown
7. Are there any setback conflicts for proposed treatment, storage and disposal sites? Yes or No
If yes, attach a map showing conflict areas.
8. Is the proposed or existing groundwater monitoring program adequate? Yes No N/A
If no, explain and recommend any changes to the groundwater monitoring program:
9. For residuals, will seasonal or other restrictions be required? Yes No N/A
If yes, attach list of sites with restrictions (Certification B)
Describe the residuals handling and utilization scheme:
10. Possible toxic impacts to surface waters:
11. Pretreatment Program (POTWs only):

III. REGIONAL OFFICE RECOMMENDATIONS
1. Do you foresee any problems with issuance/renewal of this permit? Yes or No
If yes, please explain: See Additional Regional Staff Review Items
2. Recommendation: Hold, pending receipt and review of additional information by regional office
Hold, pending review of draft permit by regional office
Issue upon receipt of needed additional information
Issue
Deny (Please state reasons: )
3. Signature of report preparer:
Signature of regional supervisor:
Date:
IV. ADDITIONAL REGIONAL STAFF REVIEW ITEMS

DWR Staff made borings at the 6 Ksat nest sites and the Deep Boring site for the proposed disposal “Yellow Area”
identified on the provided maps and flagged in the field by AWT. At 4 of the 7 locations DWR Staff encountered
auger refusal by hard saprolite or rock at the bottom depth value provided by AWT. These depth values
correspond to the depth of the Ksat tests at these locations. This indicates that the Ksat test borings were sitting
directly on the rock/saprolite when the tests were conducted. AWT Ksat nest profile descriptions did not include
the rock/saprolite layer and instead referred to these depths as part of a C horizon (e.g. C 20-26”+, C 18-24”+)
even though there was an obvious and immediate change to a significantly different material at the lower “bottom”
depth stated for the C horizons. The borings made by DWR Staff were within 1 to 2 feet of apparent, pre-existing
boring holes located at the sites flagged by AWT.

DWR Staff encountered auger refusal at the “Deep Boring” site as well, likely due to the same rock/saprolite layer
observed at the Ksat nest locations. The description provided in this case indicated an R horizon at “36”+”
accompanied by the comment “Total depth is 36 inches to rock.” The site evaluation provided does not explain how
this horizon described as “R” and “rock” differs from the Ksat profile descriptions that describe this same
occurrence as part of the “C” horizon. This further indicates that the Ksat tests were not run at appropriate
depths or were not run in the horizons as described.

The Ksat data provided cannot be accepted as valid the way it has been presented. The Glover Solution regularly
used to process collected data into a value for saturated hydraulic conductivity is recommended when the distance
between the bottom of the hole and any impermeable layer below the hole is greater than or equal to 2 times the
constant water depth in the hole. This condition is not met in the Ksat data provided.

Docusign Envelope ID: B1857BE1-8020-4272-9366-1D8908A10958
10/4/2024
FORM: WQROSSR 04-14 Page 3 of 3
There is mention of Solution USBR 7300-89 Condition I in the Ksat data tables. This condition is described as
existing when the distance from the water surface in the borehole to the water table or an impermeable layer is
greater than or equal to 3 times the depth of the water in the borehole. This is, effectively, the same condition
described by the Glover Solution. This condition is not met in the Ksat data provided.

As stated in the DWR Soil Scientist Evaluation Policy, soil profile descriptions should extend at least 12” below the
horizon in which the test is run. The provided descriptions do not meet this standard.

In the profile descriptions provided the bottom depth of the lowest horizons includes a “+” sign. This incorrect
notation. The end/lowest depth of a horizon observed should be a number indicating where digging/boring stopped
and/or where auger refusal was encountered. Please stop doing this.

There are many large (10”-12” diameter) rocks embedded in the proposed spray field; particularly easily observed
near Ksat nest 3. Their presence was not described or addressed in the application or site description.

Docusign Envelope ID: B1857BE1-8020-4272-9366-1D8908A10958