AGENDA DATE: 1/15/2025
TITLE:
Title
Innisfree Village - Private Central Sewerage System and Critical Slopes Waiver (SE2024-34)
BODY
SUBJECT/PROPOSAL/REQUEST: Innisfree Village proposals for (i) a private central sewerage system and (ii) associated critical slopes waiver
ITEM TYPE: Regular Action Item
STAFF CONTACT(S): Richardson, Wall, Herrick, Filardo, Svoboda, Pohl
PRESENTER (S): Frank Pohl
LEGAL REVIEW: Yes
REVIEWED BY: Jeffrey B. Richardson
BACKGROUND: As required by County Code § 16-102, Innisfree Incorporated has notified the Clerk of the Board of Supervisors of its intent to replace an onsite conventional sewage systems with a centralized wastewater treatment and disposal system (Attachment A). County Code §§ 16-104 and 16-105 require the Board to consider and either approve or deny this proposal.
In addition, an associated critical slopes waiver (SE202400034) is requested (Attachment F) to allow the installation of two force mains associated with the central system through critical slopes. The central sewerage system would serve 20 existing and one proposed building (21 total connections) within Innisfree Village, on Parcels 14-3, 14-3A, 14-3B, 14-10, 14-10A, 14-10A1, 14-10A2, 14-10A3, 14-10A4, 14-10C, 14-10F, and 14-10F1, while impacting critical slopes (SE2024-34) on Parcels 14-3, 14-10, and 14-3A. The properties are in the Rural Area 1 comprehensive plan area and a water supply protection area and are not in the ACSA jurisdictional areas.
STRATEGIC PLAN: Safety & Well-Being - Nurture a safe and healthy community.
DISCUSSION: On July 16, 1986, the Board approved Special Use Permit SP-86-25 (with conditions) to allow group residences for handicapped adults, an office addition, a community center, and a machine shed at Innisfree Village, on Parcels 14-3A, 14-10A, 14-10B, 14-10C, and 14-10E, and proposed Parcels 14-10F, 14-10G, and 14-3B. Twenty buildings are currently served by conventional sewage systems. After over 30 years of use, several drainfields have failed and were replaced, and more failures are anticipated in the future. Currently, certain drainfields are not infiltrating as intended and may be contaminating nearby wells. This proposal would allow the replacement and upgrading of the existing systems with a new central sewerage system, which would consist of a gravity main, a centralized wastewater treatment plant, force mains, a drainfield disposal system, and a control system.
This property is not in the ACSA’s Jurisdictional Area for public water and sewer and is currently served by individual water wells and conventional septic tanks, distribution, and drainfield systems.
Section 16-101 of the County Code defines a central sewerage system as a system “designed to serve three or more connections”. Because this system would have more than three connections, it is considered a “central system” requiring Board approval. The owner proposes 21 total individual connections, which includes 20 existing connections and one proposed connection.
Staff reviews these requests for both technical feasibility and conformity with the Comprehensive Plan. Though the Comprehensive Plan discourages central systems in the Rural Area, the County Engineer has reviewed and recommends approval of this proposal, noting the following findings:
1. Existing septic tanks would remain in service and be retrofitted with effluent filters and access risers to enhance pumping. The existing drainfields, however, would be abandoned in place.
2. Redundancy would be provided for the system, including duplex pumps and backup power.
Backup power is currently provided for the residences, water supply wells, etc.
3. The centralized Alternative Onsite Sewage System (AOSS) is considered an advanced treatment system by use of a multi-step biological treatment process. It is designed to meet a Treatment Level 3 (Tl-3) with additional polishing, which exceeds VDH’s highest level of treatment standards.
4. Effluent would be dispersed in a controlled manner to a subsurface dispersal system.
Though the owner could continue to replace drainfields as each drainfield fails, considering the poor soil conditions on the site, this option is not a long-term solution because of the environmental risks and the risk of displacing residents. Therefore, staff believes that there are no viable options other than a central sewerage system.
Staff further believes that allowing the central system would result in fewer impacts and risks to scenic and natural resources. The Virginia Department of Health (VDH) has reviewed and approved the system design and issued a VDH Construction Permit. For these reasons, staff is supportive of the request and recommends approval of the proposed central sewerage system.
Staff recommends that the Board impose conditions of approval requiring that:
1. The central sewerage system must be constructed in accord with the Innisfree Village Wastewater Management System Upgrades plan (Attachment B), the Innsifree Village AOSS Engineering Report (Attachment C), and the VDH Construction Permit (Attachment D), each as submitted;
2. Prior to issuance of any certificate of occupancy for the system, the owner must submit at least the following documentation that the system was constructed in accord with the approved construction permit to the satisfaction of the County Engineer :
a. the Operations and Maintenance agreement between the owner and operator,
b. the final inspection report and completion statement, and
c. the VDH Operation Permit.
3. The owner(s) of Parcel ID numbers 01400-00-00-00200, 01400-00-00-00300, 01400-00-00-003A0, 01400-00-00-003B0, 01400-00-00-00600, 01400-00-00-00900, 01400-00-00-009B0, 01400-00-00-01000, 01400-00-00-010A0, 01400-00-00-010A1, 01400-00-00-010A2, 01400-00-00-010A3, 01400-00-00-010A4, 01400-00-00-010C0, 01400-00-00-010F0, and 01400-00-00-010F1must assume full responsibility for the operation and maintenance of the sewerage system; and
4. If requested by the County Engineer, the owner must annually document compliance with all State operation and maintenance requirements.
In addition, the proposed system would require the installation of a force main on critical slopes in two locations. Therefore, a special exception application to impact critical slopes has also been submitted. Staff also recommends approval of this proposed special exception (Attachment G).
BUDGET IMPACT: Minimal staff time would be required to review final design documents, completion reports, and to verify that ongoing maintenance is being provided.
RECOMMENDATION:
Recommendation
Staff recommends that the Board adopt the attached resolutions approving both:
• the installation of a central sewerage system, subject to the conditions therein (Attachment E), and
• the special exception to allow impacts to critical slopes, subject to the conditions therein (Attachment H).
ATTACHMENTS:
A - Central Sewerage System Owner Request
B - Central Sewerage System Construction Drawings
C - Central Sewerage System Engineering Report
D - Central Sewerage System VDH Construction Permit
E - Central Sewerage System Resolution
F - Critical Slope Waiver Request
G - Critical Slope Waiver Engineering Memo
H - Critical Slope Waiver Resolution
I - Vicinity Map