WQ0018755_Staff Hydrogeologic Review_20210916

DWR
Division of Water Resources
Water Quality Permitting Section
Staff Hydrogeological Report for Permit Renewals
Permit Number: WQ0018755 Region: WiRO Permit Type: RW
Current Permit Expiration Date: 5/4/2025
Date requested for review: 8/24/2021 Date review completed: 9/15/2021
Hydrogeological Investigation Report Reviewer: Poonam Giri
1. Are monitoring well locations known (to six decimal degrees)? ❑Y ON (If no, request coordinates.)
2. Are the details of well construction known (i.e. elevation, depth, screened interval)? ❑Y MN
3. Wells are (check all that apply): ❑ Upgradient © Downgradient
❑Inside Field ❑ Inside RB ❑At RB ®Between RB &CB ❑At CB ❑Outside CB
4. Are wells placed appropriately with respect to the facility (i.e. gradient, review, and compliance
boundary)?
❑Y ®N If no, please explain Both the compliance and review boundaries for the irrigation fields
are at the property line. Effluent quality does not necessitate the installation of monitoring wells
around the irrigation fields at this time. - Monitoring wells MW-2 and MW-3 are between the
compliance and review boundaries for the unlined effluent storage pond. MW-1 is not accurately
known (to 6 decimal degrees) but appears to be outside the compliance boundary. Monitoring wells
are needed at the compliance boundary for the storage pond due to continuous 02L exceedances at the
review boundary.
5. Is the number and/or placement of wells sufficient for determining the compliance?
❑Y NN It is recommended a well is installed upgradient of the storage lagoon, outside of the
footprint of the irrigation area. This will help determine whether the cause of the ammonia in MW-2
and MW-3 is due to the timber forest nearby, or the storage lagoon. A well at the compliance
boundary (downgradient from MW-2) is needed.
6. Have any well construction or abandonment schedules been included in the last permit?
❑Y ©N
Have schedules been completed? ❑Y ❑N
7. Has a review of BIMS groundwater monitoring data been conducted (i.e. GW, NDMR, NDAR
reports)? NY ❑N
8. Are the monitored parameters appropriate for this facility? ®Y ❑N If no, please explain:
Standard parameters are monitored and are sufficient for the treatment system and disposal
method.
Form WQPSND-R 08-21 Page 1 of 3

DWR
Division of Water Resources
Water Quality Permitting Section
Staff Hydrogeological Report for Permit Renewals
9. Are any trends evident in the groundwater monitoring (GW) data? NY ❑N
Provide a summary of any trend(s) determined. Specify the monitoring parameter, affected
well(s), well location with respect to the site, etc.): From 2009 to present, ammonia has been above
the 02L standard in MW-2 and MW-3. Ammonia concentration in both wells has been increasing
over time (see attached graph). It is possible that the ammonia in these wells is due to nearby
agricultural impacts (timber forest). It is also possible that the unlined storage lagoon is contributing
to the ammonia in the groundwater ammonia. These two wells also may not have been well sited.
Notably, the recent upward trend in ammonia, suggests that MW-2 may be failing. It is recommended
that a well contractor re-evaluate the placement and integrity of MW-2.
10. Are there recurring or current violations of 02L groundwater standards at the review
boundary?
NY ❑N
Have wells been installed at the compliance boundary? ❑Y NN
Overall, pH is low (3-6); 02 L exceedances for Ammonia at MW-2 and MW-3; occasional elevated ff,
coliform in groundwater. Installation of a well at the compliance boundary around the storage pond is
necessary.
11. Are there recurring or current violations of 02L groundwater standards at the compliance
boundary? ❑Y ®N
N/A; No wells at the CB.
Has the region taken any action to address violation(s)? ®Y ❑N
The Region is aware of the ammonia exceedances. A NOV was issued 11/30/202 for limit violations
of Ammonia-N and TDS.
12. List any potential concerns with downgradient and/or offsite receptors. Adjacent land is forested
and there do not appear to be any stream or surface water receptors.
13. Has a Comprehensive Site Assessment (CSA) been conducted? ❑Y ®N
14. Does the facility have a Corrective Action Plan (CAP)? ❑Y ®N
15. Are any changes needed to the current groundwater monitoring plan? ®Y ❑N
No changes are needed for the frequency or parameters monitored, but it is recommended that an
upgradient (Background) well is added. Additionally, installation of a monitoring well at the compliance
boundary down gradient from and adjacent to MW-2 & MW-3 due to the exceedance of TDS, and
Ammonia at the review boundary.
16. Are additional wells recommended? ®Y ON If so, where? Installation of a well at the
compliance boundary around the unlined storage pond is necessary. Additionally, it is recommended
Form WQPSND-R 08-21 Page 2 of 3

DWR
Division of Water Resources
Water Quality Permitting Section
Staff Hydrogeological Report for Permit Renewals
that a well is installed upgradient of the pond to determine the source of ammonia in groundwater
near the storage lagoon.
17. Is surface water monitoring recommended? ❑Y ON List parameters of concern and sampling
location.
18. Describe any additional information or items needed to evaluate the groundwater
characteristics of the site: 1. It is recommended that a well contractor re-evaluate the placement and
integrity of MW-2. This well may need to be replaced. 2. The coordinates of MW-1 are not reported
to the required precision and will need to be determined. Coordinates for all wells should be field
verified or requested.
19. Describe any new or modified conditions related to groundwater monitoring or hydrogeologic
issues that should be included in the renewed permit: 1. As there are 02L exceedances for
ammonia, and with the ammonia trending upward through time, if it is determined that the unlined
storage pond is leaking, a liner should be considered.
2. Pursuant to 02L .0106(d)(1), the permittee shall demonstrate, through predictive calculations or
modeling, that natural site conditions, facility design and operational controls will prevent a violation
of standards at the compliance boundary. Alternately, the Permittee may submit a plan for alteration
of existing site conditions, facility design, or operational controls that will prevent a violation at the
compliance boundary.
3. A monitoring well is needed at the compliance boundary by the storage pond to assess compliance.
4. An upgradient monitoring well is needed at the storage lagoon to help determine whether the
nitrogen in groundwater is from the timber forest, or the lagoon.
20. List any other areas of concern or note: Installation of a mechanical screen is not expected to
reduce the nitrogen concentrations of the effluent. It will not address the elevated level of ammonia in
MW-2 and MW-3.
I do not have any concerns with the proposed modification to the treatment system.
21. Recommendation:
®Hold, pending receipt and review of additional information by regional office
El Hold, pending review of draft permit by regional office
❑ Issue upon receipt of needed additional information
❑ Issue
❑Deny (Please state reasons:)Click or tap here to enter text.
Reviewer's Signature
Date: 09/16/2021
Form WQPSND-R 08-21 Page 3 of 3

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