Sewer Feasibility Study _ Final Published 080.pdf

Sewer Feasibility Study August 8, 2023

TABLE OF CONTENTS

1.0 Vision and Objective

2.0 Underpinning a Public Sewer Utility

2.1 Cost of Service Study (COSS)

2.2 DCA Guidance and Regulations

2.2.1 Stakeholder Agreement

2.2.2 Capital Improvements Schedule and Rate Study

2.3 Policy Adoption

2.4 Environmental Compliance

3.0 Sewer Flow Projections

4.0 Smart Facility Siting and IJAs

5.0 Modest Means of Entry

5.1 Tri-County South

5.2 Newnan Road West

5.3 North Expressway

6.0 Private/Institutional Development Systems (PIDs)

6.1 Community Services (i.e. “Sun City Peachtree”)

6.2 South Hampton Mobile Home Community

7.0 Base Scenario Flow Segmentation

7.1 Conceptual Sewer Corridor Legs

7.2 Flow Probability Distribution

7.3 Practicality Validation

8.0 Base Scenario Phasing Plan

8.1 Phase I

8.2 Phase II

8.3 Phase III

8.4 Phase IV

9.0 Adaptable Tools

10.0 Summary and Recommendations

10.1 Collaboration and Commissioning Charter

10.2 Fast-Tracking Options

SCHEDULE OF ATTACHMENTS

Attachment 1: Exhibit 1. Overall Map. (Page 19 of 26) Attachment 2: Table 1. Strategic Low Points. (Page 20-21 of 26) Attachment 3: Table 2. Existing Spalding County PIDs. (Page 22 of 26) Attachment 4: Table 3. Flow Projection Sample Worksheet. (Page 23 of 26) Attachment 5: Table 4. Flow Projection Probabilities. (Page 24 of 26) Attachment 6: Figure 1. Full Base Scenario Phasing Concept. (Page 25 of 26) Attachment 7: Workbook 2 – Tables 8.1, 8.2, 8.3, and 8.4. (Page 26 of 26)

APPENDICES

Appendix A. DCA Guidance.

Appendix B. Example language for “minimum bill arrangement”.

Appendix C. EPD Antidegradation Implementation Guidelines.

Appendix D. CNOP Overview.

Appendix E. “Now-and-Next” Workshop Slide Deck.

Appendix F. Treatment and Conveyance Technologies.

Appendix G. Community Subsurface Systems.

1.0 Vision and Objective

From multiple perspectives including land availability, accessibility to transportation thoroughfares, proximity to Atlanta, increasing density in Griffin, and cost of living, Spalding County is ripe for development. The County aspires to facilitate desirable development types in a focused, controlled manner that preserves its rural character and community vision.

Unincorporated Spalding County does not currently have a public sanitary sewer system.

However, public sewerage is essential to achieving the County’s growth vision because it will allow high density development that septic systems cannot support. Moreover, through a strategic offering of public sewer, the County will have a mechanism for controlling the type of growth it invites and where that growth occurs.

Spalding County Water & Sewerage Facilities Authority (SCWSFA) is the entity responsible for public water and sewer in unincorporated Spalding County. Although the County government and SCWSFA have separate roles and responsibilities associated with growth and development within the County, implementation of a strategic sewerage plan and channeling of developer investments requires participation and collaboration between both entities. SCWSFA, with Spalding County government as a fundamental stakeholder and partner, commissioned this Sewer Feasibility Study to provide a “30,000-foot level” evaluation of the financial viability of establishing public sewer service within four (4) separate Target Areas in the County.

This Study seeks to clarify SCWSFA’s and Spalding County’s understanding of the next steps to achieving smart public sewerage and to identify a modest means of entry into the sewer business. This Study is not intended to be a Plan. Rather, it is an examination of viability, yielding a Base Scenario along with an adaptable methodology that SCWSFA and stakeholders can apply as future opportunities and constraints evolve.

SCWSFA, with the support of Spalding County, commissioned Lindsay Engineering & Consulting, LLC (“Lindsay Engineering”) to conduct this Study and summarize its findings and recommendations in this document. Lindsay Engineering’s mission is to empower SCWSFA with an actionable template for achieving remarkable success in its first infrastructure investment.

Success within the first phase of implementation will serve as a crucial proof of viability and a model for expansion into ensuing phases of targeted public sewerage in Spalding County.

2.0 Underpinning a Public Sewer Utility

The Georgia Department of Community Affairs (DCA) publishes best practices pertinent to public utility development that are recommended or, in some cases, mandatory. Highlights of DCA guidance are noted in Section 2.2. Essential policies and protocols (Section 2.3) may be driven by DCA, the Georgia Environmental Protection Division (EPD), or the funding mechanisms and collaboration strategies selected by SCWSFA and its stakeholders.

2.1 Cost of Service Study (COSS)

SCWSFA will need to define a planning-level cost-of-service recuperation strategy. This strategy should be driven by:

▪ Stakeholder Input. For example, use of impact fees or CDBG funding sources necessitates participation by Spalding County government in orchestrating and managing the funding stream. In turn, SCWSFA’s capital plans and associated fee structures can alter the trajectory of growth type, density, and location, and represent a collaboration opportunity for County leadership. Grant funding may be available for qualifying project types, which may also be another shifting factor in SCWSFA’s infrastructure prioritization strategy.

▪ Utility Philosophy. SCWSFA may entertain a system improvement-based strategy (e.g. supported by an impact fee program), a project-based capacity allocation strategy, debt service and rate-funded capital, or any such combination. The optimal mechanisms will reflect SCWSFA’s philosophies on appropriate cost ownership, debt tolerance, and stakeholder reliance.

▪ Holistic Cost Accounting. Beyond capital costs for infrastructure, SCWSFA’s total cost-of-service will include annual operations and maintenance, utility management, and non-construction costs such as legal and engineering for program delivery.

Findings of the COSS will focus SCWSFA’s initial efforts on achieving a “modest means of entry” into public sewerage and inform the next steps of securing funding.

2.2 DCA Guidance and Regulations

New developments impose costs for extension/addition of public utilities such as public safety, water and sewer, and roads. Often, the local government desires those infrastructure costs to be borne by the new developments rather than the existing taxpayers. Development Impact Fees are a quality growth tool explicitly defined under the Georgia Development Impact Fee Act to control land development patterns and recuperate public utility capital costs. The Georgia DCA regulates Impact Fees; a DCA guidance whitepaper is enclosed in Appendix A. Spalding County government may not elect to implement an Impact Fee Program. Regardless, the provisions in the Act and DCA guidance must be understood. The guidance translates into best practices for smart growth that apply irrespective of its funding mechanisms including:

2.2.1 Stakeholder Agreement

Key stakeholders must agree on desired development patterns and service areas.

This Sewer Feasibility Study is a milestone in memorializing those and requires adoption by SCWSFA and Spalding County government for successful implementation. Other stakeholders (school boards, development authorities, watershed committees) must also be active participants in its adoption process to facilitate consensus. The “committee” approach prescribed by DCA may allow various Spalding County stakeholders – in particular, those with the ability to influence implementation of the steps outlined in this Study – to establish a mutual understanding of each other’s constraints and how the parties affect others’ abilities to drive forward the agreed vision. At a minimum, negotiation of a collaboration charter is recommended; this recommendation is developed further within Section 10.

2.2.2 Capital Improvements Schedule and Rate Study

SCWSFA, in collaboration with Spalding County government and other key stakeholders, must develop a multi-year schedule of sewer infrastructure needs;

five (5) years is the DCA minimum. The capital improvements schedule will entail master planning beyond the extent of this Sewer Feasibility Study, building specificity into SCWSFA’s near-term projects, and enabling construction of a detailed rate model. The rate model should refine annual operating and maintenance expense projections, handling of asset depreciation, and delineation of customer classes with associated fee/usage charge structures.

2.3 Policy Adoption

Policies and local government ordinances will be required to define how the wastewater utility will be managed and operated. A Spalding County Sewer Use Ordinance, adopted by the County government, will affect the performance of the utility in terms of maintenance of private systems, illegal connections, and discharge characteristics (industrial elements, grease, etc.). SCWSFA will require standardized specifications and design criteria. Various other agreements and ordinances may be needed to govern impact fees (reference Appendix A) and developer funding mechanisms such as ESCROW agreements or “minimum bill arrangements” (refence Appendix B).

Additionally, workflows and protocols need to be updated and agreed upon by all stakeholders, such that each entity has the appropriate involvement and level of authority in critical processes. These would include processes such as reviewing DRIs, making capacity commitments, allowing private sewer/septic systems, and accepting a development’s closeout punchlist, testing, and as-built documentation. SCWSFA and Spalding County government will be integral partners in adoption of mutually beneficial policies and protocols that preserve SCWSFA’s control of the County’s targeted sewer service areas.

2.4 Environmental Compliance

In anticipation of SCWSFA’s need for disposal of treated wastewater, EPD’s Antidegradation Implementation Guidelines are provided in Appendix C. Land application (LAS) disposal of treated effluent is not subject to antidegradation analysis but requires separate soil sampling, hydraulic and agronomic evaluation of land requirements, and buffer provisions for initial permitting. In the absence of specific projects referenced in a Regional Water Plan, stream discharge (NPDES) permitting follows EPD’s published Antidegradation Report process with assignment of a Wasteload Allocation, public notice and participation requirements, and assessment of economic and social impacts. The LAS option is more land-intensive and generally suitable for discharges below approximately 200,000 gpd; the NPDES option is subject to more stringent permitting and effluent standards. A stream discharge permit in Spalding County will likely require development of a Comprehensive Nutrient Optimization Plan (see Appendix D). SCWSFA’s selection of and success in its chosen permitting pathway will depend on the regulatory climate and socioeconomic rationale. The methodology in this Study is adaptable to either pathway;

LAS is the selected Base Scenario, as the default option pending an approved antidegradation defense for stream discharge. Notably, current Flint River recharge initiatives and influence of the Upper Flint Council and stakeholders could benefit SCWSFA’s permit ambitions.

3.0 Sewer Flow Projections

Preceding SCWSFA’s selection of Lindsay Engineering for this Sewer Feasibility Study, another consultant worked with SCWSFA and numerous Spalding County stakeholders in delineation of four (4) Target Areas for future sewerage potential. The final deliverable of that effort was a Technical Memorandum (TM) entitled Spalding County Sewer Flow Projections (Feb. 22, 2023), hereinafter “Flow Projections TM”, publishing current/overlay and ultimate/expanded boundaries of each Target Area and estimated sewer flows for various planning horizons. The Flow Projections TM calculated a combined “Current Sewer Demand” for the four overlay corridors of over 1.4 MGD, and four expanded boundaries of over 6.6 MGD – the latter equating to more than the City of Griffin’s three wastewater plants, combined. While the general technical methodology behind those projections is understood, building infrastructure for aspirational flow values is not consistent with a conservative, “modest means of entry” that is the SCWSFA’s stated immediate goal.

The methodology in this Sewer Feasibility Study considers the build-out totals in the Flow Projections TM but leverages a more probable current demand scenario, or “Base Scenario”. The foundational premise of this Study is that, if this Study effectively provides SCWSFA with confidence in a Base Scenario’s viability and risk exposure, then SCWSFA can extrapolate outward from that Base Scenario, adapt to shifting stakeholder interests, and implement the Study methodology as a working model for success against an uncertain future.

4.0 Smart Facility Siting and IJAs

“Smart” sewer planning begins with some simple best practices such as identifying strategic locations for infrastructure. The most low-lying locations within a sub-basin can be used to site regional pump stations or treatment facilities, thereby minimizing pumping and associated operating and maintenance (O&M) demands. To the extent reasonable, near-term infrastructure investments can then be phased to be compatible with – or at least not in hindrance to – long-term smart growth, even though the planning horizon for this Study is 20 years.

The City of Griffin is perched at the highest elevation in Spalding County. Grade falls away from the City and towards the County lines at the extremities of each of the four Target Areas, with a major ridgeline running north-to-south approximately coinciding with the Highway 19/41 corridor. Conveyance to the City of Griffin therefore generally implies “pumping uphill”. Setting the long-term sustainability of that concept aside, opportunities do exist for negotiating Intrajurisdictional Agreements (IJAs) with the City of Griffin as well as the City of Hampton, City of Senoia, and other receptive, neighboring public sewer utilities for wastewater treatment. In fact, the antidegradation analysis process requires evaluation of interconnection options with systems within a five-mile radius of a proposed discharge.

Leveraging the advantage of a blank planning canvas for unincorporated Spalding County, a natural, sustainable engineering solution would entail a Spalding County West wastewater treatment/reclamation facility (WRF) in the Upper Flint River Basin and a Spalding County East WRF in the Upper Ocmulgee River Basin.

The recommendations in this Study reflect on the near-term and long-term merit of these opportunities as related to executing a smart sewerage strategy. Sliding scale cost tools and cost “menus” within this Study are adaptable to various scenarios. Thus, initial screening of a choice between conveyance to an IJA for treatment versus self-sufficient reliance on new SCWSFA treatment facilities can be reduced to straightforward comparison of the IJA’s costs and terms versus the cost scale of self-ownership.

Table 1 (Attachment 2, pages 20-21) highlights ten (10) strategic sites (low lying areas) within or proximate to the four Target Areas for potential future regional pump stations or treatment.

Table 1 prioritizes the areas, on a general planning level, for land acquisition based on the criticality of the proposed site infrastructure to the County’s long-term vision and smart sewerage needs. Section 5.0 narratives on the four Target Areas describe the strategy behind the site selections.

5.0 Modest Means of Entry

At SCWSFA’s April 19, 2023 Board Meeting, Lindsay Engineering conducted a “Now-and-Next” Workshop to kick-off the Sewer Feasibility Study. (Appendix E Slide Deck.) Part of the Workshop entailed review of a theoretical scenario for sewering the Tri-County South Target Area. Tri-County South’s overlay district area is the smallest of the four targets and offers the lowest current or planned flow opportunity as forecast in the Flow Projections TM. That theoretical scenario illustrated the magnitude of an infrastructure investment cost for even this smallest zone, emphasizing the significance of collection system components as a percentage of the total cost.

Those Now-and-Next Workshop exercises and SCWSFA feedback focused the trajectory of this Study on achieving a “tipping point” in a fiscally conservative initial sewerage strategy by sustaining a 100,000 gpd modular wastewater treatment/reclamation facility. A modest, accessible means of entry will minimize upfront investment required to capture that demand base. Treatment and conveyance technologies and alternatives, as reviewed in that Workshop, are summarized in Appendix F.

The Base Scenario developed in Section 8.0 focuses on the Arthur K. Bolton (AKB) corridor as the most likely to demonstrate early success in public sewerage. The constraints, challenges, and shortlist viable means of entry strategies for the remaining three Target Areas are summarized hereafter:

▪ 5.1 Tri-County South: The Flow Projections TM 20-year forecast for the overlay district, inclusive of ~8,000 gpd in existing septic flow to be tapped on to public sewer, only totals a dry weather flow of 10,185 gpd. The overlay corridor is comprised of dense, small lots as compared to the other Target Areas. It is the smallest of the four Target Overlay Areas, and complicated by division across a ridge. This planning horizon flow projection is too small for the Tri-County South Overlay to sustainably support modular, decentralized public sewer treatment. This Target Area, containing City of Griffin service area, was originally prioritized when the City of Griffin had a sewer moratorium in effect; over the course of this Study, Griffin’s moratorium lifted, shifting the SCWSFA’s priorities. However, service strategy considerations are presented herein for adaptability to future conditions. The most viable options for public sewerage in Tri-County South include two main pump stations referred to in Table 1 as West TCS Overlay PS and East TCS Overlay PS. Discharge locations will hinge on infrastructure availability at the time the stations are developed but include: (1) pumping to Griffin for treatment; (2) pumping to a future SCWSFA WRF – ideally west, to the proposed Flint WRF; or (3) employing a regional subsurface, chamber type treatment solution (see Appendix G). The subsurface solution would be similar to traditional septic, thus having similar drawbacks to septic, but may be suitable for up to approximately 25,000 gpd. Beyond this capacity, the technology is expensive and land-intensive. Option (2) is preferred for SCWSFA service area from vantagepoints of self-sufficiency and long-term resilience. However, conveyance piping costs weighed against the available, ready customer base may be a barrier to entry. Although the overlay zone was the originally stated priority, SCWSFA may be more likely to demonstrate financial viability in Option (2) if development interest heightens within the expanded boundary, potentially conducive to a strategic pump station site more proximate to the Newnan Road West area. The expanded boundary is relatively undeveloped, in comparison to the overlay, and might afford a more substantial near-term customer base to offset conveyance capital, assuming other factors (e.g. transportation network) render it equally attractive to developers.

▪ 5.2 Newnan Road West: Huckaby is the general reference, in Newnan Road West, to a target mixed-development node situated at the westernmost ridge of the corridor. Huckaby’s is a small, mostly non-residential zoned area, however the majority of Newnan Road West is light residential/agricultural. Rezonings will be needed to achieve increased density. This is the only Target Area that does not have an expanded boundary vision beyond its overlay limits. Newnan Road West ideally straddles the Upper Flint River, offering a strategic future wastewater reclamation and recharge opportunity. However, the challenge in this Target

Area is akin to that described for Tri-County South. The Flow Projections TM 20-year totals assume transition of existing septic demands, which is contingent on failing septic.

Otherwise, the new base flows projected over that horizon total less than 65,000 gpd. A more practical interim solution for this corridor may entail conveyance of the Huckaby node flows to the nearby City of Senoia for treatment under a competitive IJA. Although this doesn’t give SCWSFA near-term self-sustainability, a “Huckaby Ridge Pump Station” (see Table 1) is consistent with long term need for a strategic collection point around Line Creek. Securing land for a future Flint WRF is also recommended.

▪ 5.3 North Expressway: This Target Area has the most complex topography of any of the four.

Highway 19/41 is a significant ridgeline between the County’s drainage basins. The expanded corridor is irregularly shaped and spans several headwaters. The overlay corridor along the highway falls from roughly el. 924 feet at the south limit of the boundary (Griffin area) to approximately el. 916 feet around the north County line (Henry County). Most of this Target Area is residential. The most viable near-term strategy for acquiring a customer base within this corridor likely entails a focus on highway frontage parcels flowing to the “NEx East Pump Station” (see Table 1), with conveyance to the City of Hampton. This option would beneficially retain flows in the Flint Basin; the pumping system could be modified to redirect to Heads Creek in the future, retaining the NEx East PS site. Gravity conveyance to the existing Henry County Water Authority (HCWA) treatment plant situated along Bear Creek at the end of S. Lee Road could develop into an amenable IJA option, subject to conclusions of the City of Hampton’s negotiations with HCWA for transfer of ownership. Other options with similar future ownership uncertainty include combining with the South Hampton Mobile Home Community or pumping to the Sun City Peachtree system (both in the Ocmulgee Basin) as discussed in Section 6.0. Although perhaps less economically viable in the near-term, the expanded North Expressway Target Area presents opportunity for flow transfer across the north-south Hwy 19/41 ridge, west toward Heads Creek, into the Upper Flint Basin. A future Heads Creek Trunk Sewer to the Flint WRF may be re-examined as desired development momentum arises. The headwaters of Heads Creek Reservoir are highlighted in Exhibit 1 and Table 1 as a general location for further strategic review.

The fourth, remaining Target Area - Arthur K. Bolton (AKB) – has consistently been a priority interest for all stakeholders participating in this Sewer Feasibility Study. It is a spotlight for proposed development since recent lifting of the development moratorium in Spalding County (end of May 2023). It is strategically situated across a major receiving water for the Upper Ocmulgee, presenting flexible drainage topography. Besides also being the corridor with the largest overall projected flow prospects, AKB affords a timely opportunity to “tend to SCWSFA’s fences”, implementing an I-75 area sewerage strategy. Therefore, AKB is selected for the Base Scenario of this Study.

6.0 Private/Institutional Development Systems (PIDs)

Privately owned wastewater treatment and discharge systems are permitted by EPD under certain conditions (reference Appendix C), and require agreement of the local government to assume responsibility and ownership of the systems in the event that the private owner disbands, dissolves, or becomes insolvent. There are seven (7) existing PIDs in Spalding County, as shown in Table 2 (Attachment 3, page 22/26). Community Services, LLLP operates under two permits, so it is considered two separate PIDs, even though it covers a single service area. The status of this PID and another significant residential PID are summarized below.

▪ 6.1 Community Services (i.e. “Sun City Peachtree”): Sun City Peachtree (SCP) is not a Target Area within the scope of this Sewer Feasibility Study. However, by virtue of trust indenture responsibilities or via a buy-out, Spalding County may have a future controlling interest in this Private/Institutional Development System (PID), and therefore it cannot be dismissed in planning efforts. The PID is owned by Community Services, LLLP. The PID has a qualified sewer service area separate from the County’s four Target Areas. Its Troublesome Creek treatment facility discharges through three avenues – LAS, reuse (golf course), and NPDES stream outfall. The facility is currently rated (designed) for 275,000 gpd and has a design development for doubling to 0.55 MGD. The PID operator reports a current capacity allocation of 0.95 MGD. The facility permit has various seasonal/discharge location limits, but ultimately affords 1.69 MGD in potential permitted capacity. At the time of this Draft submittal, it is unclear if the PID has a legally binding indenture agreement, consistent with EPD requirements, that ascribes Spalding County trustee responsibility for a 0.95 MGD / 3,000-acre system. Pending further investigation into legal responsibilities, financial solvency of the PID, and service area size/capacity potential, long-term public sewer integration options could include: (1) leveraging the SCP system for available permitted capacity, potentially expanding infrastructure to receive flow from North Expressway East, (2) conveying SCP flows to a strategic, planned site in this Study, namely the Highway 16 WRF described in Section 4.0.

▪ 6.2 South Hampton Mobile Home Community: The South Hampton Mobile Home Community (SHMHC) at the very north extent of Spalding County, east of Highway 19/41, is the second known PID in the SCWSFA service area. The SHMHC treatment facility is currently permitted for a 100,000 gpd stream discharge. PID ownership changed hands in 2016. As of the writing of this Study, the current Michigan-based PID owner is not believed to have a trustee indenture agreement in place in accordance with EPD requirements, and it is uncertain if the original owner had such. The PID’s NPDES permit expiration is July 31, 2023. Due to EPD’s staffing constraints, issuance of the proposed draft permit for a public comment period has been delayed.

These two PIDs serve dense residential development which is generally undesirable within the Target Areas described in this Study or outside the service areas of the PIDs. The SCP PID has a qualified service area, but the remaining five (5) PIDs are not known to have a similar agreement, and the status of their trust indenture agreements is also unknown as of the date of this Study.

While PIDs fulfill a specific need and are warranted under certain circumstances, they are generally contradictory to SCWSFA’s public sewerage initiatives. It is recommended that SCWSFA and Spalding County government closely evaluate these PIDs to understand their status with respect to maintenance, resilience, trustee compliance, service area limits, capacity/rating, and financial solvency. Any future consideration of new/expanded PIDs should be reviewed for consistency with the County’s public sewerage vision and potential opportunity to fulfill the PID proposal as part of the public sewer demand base.

7.0 Base Scenario Flow Segmentation

A pressure sewer solution, as opposed to conventional gravity, is less subject to the constraints of topography. However, respecting gradient conditions in development of a Base Scenario gives SCWSFA maximum flexibility in technology selection and value engineering in subsequent detailed planning and design. Even if a pressurized conveyance solution is implemented, at some point that system must discharge into a gravity collector. The Base Scenario for AKB therefore springboards from Table 1 Strategic Low Points, in keeping with the long-term vision.

7.1 Conceptual Sewer Corridor Legs

Next, directly along the priority Highway 16 alignment, conceptual “Legs” were illustrated segmentally. These each extend from low-lying receiving waters upgradient to the next ridgeline, thus adhering to the logic of leveraging topography in a smart planning pattern.

This exercise resulted in four (4) Legs, traced in different color polylines on Exhibit 1, any one of which could be considered as the full extent of a Base Scenario corridor:

▪ Leg 1 (green): Extending from the ridgeline near Wild Plum Road (i.e. Lakes at Green

Valley) downgradient across Buck Creek, terminating at a low point near the lake features just east of S. Walkers Mill Road.

▪ Leg 2 (yellow): Extending from the end of Leg 1 upgradient to the next ridgeline at High Falls Road.

▪ Leg 3 (blue): Extending from the end of Leg 2, at the High Falls ridgeline, northeast along Hwy 16 to Cabin Creek.

▪ Leg 4 (purple): Extending from the end of Leg 3 at Cabin Creek, upgradient to terminus near the County line, which is also a ridgeline.

Along each of the Legs, a dedicated Parcel Subset was selected for prospective flow contribution in the Base Scenario, thus reducing the near-term assessment to only those parcels best positioned for new/re-development rather than including the full overlay. The Subsets generally consist of those parcels with highway frontage. The total area of AKB’s overlay district is approximately 2,532 acres; the total area of the selected Parcel Subsets is 1,372 acres. By projecting customer connections on roughly half of the already-condensed overlay corridor, this Base Scenario takes a conservative approach.

7.2 Flow Probability Distribution

A range of low-high-probable flows (gpd/acre, extrapolated by parcel acreage) were then assigned to the Parcel Subsets employing simple Criteria itemized below, derived from the density categories and flows in the Flow Projections TM. These Parcel Subsets with attributes, flow projections, and probability distributions are provided in Workbook 1 (containing worksheets for each Leg). A sample worksheet is enclosed as Table 3 (Attachment 4, page 23/26).

▪ Criterium 1: If the parcel is relatively small (<15 acres) and already has a building, it is expected to be a less likely target for re-development than a large parcel containing a building.

o Small parcels under this criterium were assigned an expected Low Flow of 0 gpd/acre, High Flow of 180 gpd/acre (C-1B), and Probable Flow of 30 gpd/acre (low probability distribution, irrespective of Leg).

o For Leg 4, large parcels under this criterium were assigned an expected Low Flow of 0 gpd/acre, High Flow of 194 gpd/acre, and Probable Flow of 75 gpd/acre (normal/average probability distribution). These align with a C-1A (midpoint) or C- 1/C-1C (high) density characteristic.

o For Legs 1, 2, and 3, large parcels under this criterium were assigned the same as Leg 4, except with a Probable Flow of 32 gpd/acre (low probability distribution). The low probability capture on these Legs is designed to account for the Base Scenario, conceptual sewer alignment not extending the length of the Legs.

▪ Criterium 2: Undeveloped parcels are anticipated to be more readily developable (easier to acquire), in general, as compared to lots with buildings. These flow densities are therefore expected to align with a C-2 zoning threshold, selected for consistency with planned light industrial customers.

oParcels fitting this criterium were assigned an expected Low Flow of 0 gpd/acre and High Flow of 242 gpd/acre. For Leg 4, a Probable Flow of 75 gpd/acre was assumed, to reflect a normal/average probability distribution. For Legs 1, 2, and 3, a low probability density of 40 gpd/acre was assumed, again to account for the Base Scenario alignment not extending the full length of the Legs.

o Two exceptions were employed on undeveloped parcel with known prospects:

▪ At the end of Leg 4 (nearest I-75), on an approximately 3-acre parcel, density characterization was input to model a speculative hotel development. This would be a uniquely high-demand customer, categorized with a Low Flow of 260 gpd/acre, High Flow of 1820 gpd/acre, and Probable Flow of 1300 gpd/acre (low probability distribution).

▪ On Leg 3, at an approximately 127-acre parcel, input density was set to a Low Flow of 0 gpd/acre, High Flow of 75 gpd/acre, and Probable Flow of 37 gpd/acre, very similar to other undeveloped parcels under this criterium.

However, it was given a normal/average probability distribution rather than a low probability distribution, due to known developer interest (Tomochichi).

A probability simulation tool (Monte Carlo, Crystal Ball) was used to examine the statistical likelihood of achieving various flow thresholds within each Leg’s Parcel Subset according to the inputs above. Distribution output is presented in Table 4 (Attachment 5, page 24/26), tabulating the probability that a flow will be less than a particular value. For example, the probability model for Leg 4 predicts that the risk of achieving less than 105,744 gpd is less than 20%. (Stated otherwise, the selected criteria result in at least an 80% likelihood of capturing 105,744 gpd or greater.)

7.3 Practicality Validation

As a secondary validation of the flow projections approach, results were benchmarked against characteristic development. For example, the four industrial customers at Lakes of Green Valley, a development consisting of roughly 500 acres, operate at an approximate flow characteristic of 77 gpd/acre. Applying this blanket density across the Parcel Subset area of 1,372 acres yields 104,234 gpd. This benchmark validation provides additional confidence that more than 100,000 gpd is achievable from the condensed parcel selection.

Moreover, it is anticipated that SCWSFA’s initial, modest entry into public sewer will concentrate development on the selected initial service area, potentially amplifying these projections and probabilities.

8.0 Base Scenario Phasing Plan

The “Legs” methodology described in Section 7.0 is a technique for validating flow projections and confidence levels within segmented collection corridors. However, the alignment of a Leg is not necessarily the optimal routing of a conveyance network to serve that focused corridor. To define the Base Scenario, each Leg corridor was developed into a detailed pipe routing concept, distinguishing pressurized mains and gravity sewers in a hybrid solution. These four concepts were aligned in a phased approach as follows. A summary Figure 1 (Attachment 6, page 25/26) illustrates the four phases combined.

8.1 Phase I

Phase I is prioritized because it straddles the strategic low point identified for the proposed Highway 16 WRF. It also has known, desirable development prospects (e.g. a hotel) and extends to the County line, driving a conceptual stake in the SCWSFA service area. Proposed Phase I infrastructure facilitates capture of the “Leg 4” area with the highest flow projections. Most importantly, it includes the treatment facility that enables subsequent phases. All pressure sewer must eventually discharge to gravity; Phase I incorporates a strategic trunk sewer along Cabin Creek to the proposed WRF. The line-item components and planning level construction cost opinions for Phase I are captured in Table 8.1 of the Workbook 2 Base Scenario Summary Estimate (Attachment 7, page 26), indexed to year 2024.

In keeping with the “tipping point” philosophy of economically viable treatment facility sizing and the confidence levels of the flow projection methodology, the Phase I WRF is itemized at 100,000 gpd.

8.2 Phase II

Phase I facilitates extension into Phase II, which is focused along the “Leg 3” zone where the Tomochichi development is proposed. The concept for Phase II includes a combination of strategic low-lying gravity sewer along with pressure sewer in a hybrid solution, similar to the philosophy of Phase I. It also entails an expansion of the Phase I WRF capacity. Phase II line-item components and planning level construction costs are captured in Table 8.2 of the Workbook 2 Base Scenario Summary Estimate.

8.3 Phase III

Phase I also facilitates extension into Phase III, which provides a concept for capturing a prime development area beyond the AKB overlay district but within the Expanded Boundary, along I-75, incorporating the strategic low-lying I-75 Pump Station site. Service to this area may obviate large community septic solutions or encroachment of other systems into SCWSFA’s service delivery area. Phases II and III are interchangeable; they do not have interdependence on each other, and only hinge on establishment of Phase I. Phase III, as with Phase II, entails a 100,000 gpd WRF capacity expansion line-item. Cost projections are captured in Table 8.3 of Workbook 2.

8.4 Phase IV

Phase IV extends to the critical Lakes of Green Valley area and various Leg 1 and Leg 2 parcels well-positioned for development. It relies on completion of Phase I and Phase II (but not Phase III). It does not include a WRF capacity expansion component. However, if it is implemented after the other Phases are well-established, capacity needs to support this extension should be re-evaluated. Phase IV cost projections are provided in Table 8.4.

SCWSFA may elect to proceed initially with only Phase I or to make firm plans to include other Phases of the Base Scenario in the immediate next steps of implementation, subject to the noted constraints.

Workbook 2 also includes a probability analysis for the four Base Scenario Phase costs, as discussed in Section 9 hereafter.

9.0 Adaptable Tools

Because SCWSFA’s future needs are highly uncertain, Lindsay Engineering constructed various Adaptable Tools as part of this Study, for SCWSFA’s future use. These Adaptable Tools were used in development of the Base Scenario just as they would be used in development of any new or altered scenario. They include:

▪ Flow Projection Methodology with Monte Carlo Crystal Ball: As illustrated in Table 4 for Base Scenario confidence levels in anticipated flows, the Monte Carlo simulation is provided as a mechanism for considering the risk of not achieving target flows.

▪ Cost Menu and Models: Workbook 3 is provided as a supplement tool to facilitate future cost estimating needs, indexed to year 2024. It defines level of detail requirements to achieve various estimate accuracy ranges (minimum Class 4 developed in this Study). A historical index is included as the basis for escalating costs from prior years. Three separate tabs in the Workbook provide cost menus or models for Pump Stations, Treatment Facilities, and Pipes that SCWSFA can use to forecast different facility sizes or types. Different methodologies are employed for the three infrastructure elements, but all incorporate benchmarking to actual projects. For example, the Pipe build-up includes 58 line-items for various pipe diameters, materials, and depths, and each of these line-items is comprehensive of holistic construction costs related to bedding traffic control, surface restoration, appurtenances, erosion control, and other provisions listed therein. Similarly, the Pump Station and Treatment Facility tabulations yield selection menus based on capacity metrics.

▪ Costing Confidence Monte Carlo Tool: Workbook 2 includes a probability simulation applied to the Base Scenario, which serves as an adaptable model for application to any future cost opinion. For example, the Cost Distribution probability tabulation shows that, based on the estimating standards employed in the Base Scenario cost opinion, there is a 90% likelihood that Base Scenario Phase I will cost no more than $5,859,927. The Summary total in the Workbook for Phase I (shown on Table 8.1 under Attachment 7) is $5,930,070. Thus, SCWSFA has a tool for assessing cost probabilities and making confidence budget decisions consistent with its risk tolerance, in terms of percentages and cost deltas.

SCWSFA should update and refine these tools over time to incorporate shifting trends and needs.

10.0 Summary and Recommendations

This Sewer Feasibility Study identifies a modest means of entry into public sewer in Spalding County, prioritizing the AKB corridor and developing a strategic AKB Base Scenario phasing plan.

The Base Scenario demonstrates consistency with the County’s vision and forward-thinking, “smart” infrastructure siting. The phased breakdown of the Base Scenario, along with the adaptable construction costing tools and probability distribution methodology, empower SCWSFA to select a sizing and investment level that align with its risk tolerance and resources, examining “What If?” scenarios as they arise.

10.1 Collaboration and Commissioning Charter

The details of this Study may be refined or changed; it should be considered a working document that enables SCWSFA’s next planning steps. However, for the recommendations in this Study to be successfully implemented, it is essential that key foundational elements of this Study be embraced and formally accepted by all influencing stakeholders. These elements include:

▪ Agreement to proceed with a defined Base Scenario. SCWSFA and Spalding County may agree to begin with Phase I under the prescribed Base Scenario, but the parties may elect to proceed promptly with the additional Phases described herein as well.

SCWSFA and the County, with input from stakeholders such as developers and regulators, may also alter the details of the Base Scenario in this Study. For example, a particular development’s appetite for investing in an extension may affect the financial viability of that extension or phase. Regardless, SCWSFA must achieve a consensus on supporting the initial, selected means of entry.

▪ Agreement to partner in policy/protocol development. As discussed in Section 2.3, a variety of new or updated procedures and policies will be critical for successful entry into public sewer in accordance with a shared vision. Defining these specific needs and then building effective policies to support them will require workshop-driven collaboration.

The elements above will emanate from transparent communication between SCWSFA and Spalding County, and hinge on a mutual understanding and appreciation of each entity’s role in the other’s successful execution of the vision. Therefore, it is recommended that SCWSFA and Spalding County leadership mutually agree to develop a Collaboration and Commissioning Charter, through a delegated committee-driven approach, establishing engagement parameters and defining success. The Chartering Committee must meet regularly and engage additional stakeholders as appropriate to the topics at hand.

10.2 Fast-Tracking Options

Government agencies are generally recognized as being meticulous planners. Due diligence is non-negotiable, especially where rate payers are concerned. However, planning can be immobilizing when faced with a highly uncertain and variable future. One of the major challenges of this Study was the lack of constraints or historical trends. Substantial effort was invested into this Study to establish an actionable framework that will allow forward progress in public sewerage despite the myriad of unknowns.

A core conclusion of this Study is that SCWSFA needs proof of success through an initial implementation phase before various details can be effectively planned. It is preemptive to embark on a Sewer Master Plan or Rate Study. Although these steps are crucial for utility management, there is currently no utility data to inform them.

Thus, it is recommended that SCWSFA continue to think like a utility while concurrently moving like a developer.

First, SCWSFA must confirm agreement to establish the Chartering Committee described in Section 10.1 and to then work in committed, good-faith partnership to select the initial investment and structure essential policies. After that is achieved, the most influential next step SCWSFA can take is fast-tracking the selected Base Scenario in the spirit of a “pilot demonstration”.

Options and considerations for tactical fast-tracking include:

▪ Commissioning a first-cut Cost of Service Study (COSS). A preliminary COSS should entail comparison of other utility rate structures and models and ascertaining developer investment thresholds needed to support the selected pilot. In this step, SCWSFA will make core decisions regarding taking on debt – whether it is appropriate, and under what conditions. SCWSFA will also examine “all-in costs” associated with the pilot scope, such as land purchase, consulting, and annual expenses. There is no better tool for future COSS and rate studies than a backward-looking proof of concept.

▪ Prioritizing policy development. The Chartering Committee will unveil a myriad of procedural considerations that may take significant time to address. One of the Committee’s initial demands will be to prioritize these and focus on the elements that have the potential to de-rail the pilot, deferring less urgent elements. Meeting regulatory requirements, for example, is a basic priority. Prescribing limits and mandates on proposed sewer connections is another.

▪ Enlisting developers. Private developers are experts in rapid implementation. By delegating various execution roles to interested developers, SCWSFA can act in a supervisory capacity and focus its resources on responsibilities that cannot be delegated. Developers who align with SCWSFA’s vision and piloting mission can take a leadership role in navigating easement acquisition, producing detailed designs, and constructing infrastructure – all of which are time-intensive processes for government entities. This approach will rely on design criteria, which must be generated on a preliminary level to at least address the pilot scope.

As SCWSFA proceeds in its joint public sewer initiative with Spalding County, this recommended fast-track pilot demonstration will only enhance the clarity of a conventional methodology, yielding lessons-learned as modestly as possible, and infusing proof of success into forward momentum.

Attachment 1: Exhibit 1. Overall Map.

Attachment 2: Table 1. Strategic Low Points. (2 pages)

Target Area Facility Name/Concept Projected Facility / Options / Phasing Relative Priority Capacity Concept (Build-Out) Preliminary Land Requirement

Newnan Road West (1 of 2) Flint WRF Treatment Facility situated for current/future NPDES discharge HIGH (Strategic site on Flint River.) 15 MGD WRF w/Stream Discharge 30 acres (See Note 8)

Newnan Road West (2 of 2) Huckaby Ridge Pump Station

Options (1) PS to convey east, over ridge, to Flint WRF, (2) PS to convey west to COS, which could be permanent solution, or interim solution until Flint WRF is available

HIGH (Strategic siting for priority service area at County Line.) <1 MGD (PS) 1 acre

North Expressway (1 of 2) Heads Creek Strategic Node (see Note 5)

Options (1) Treatment Plant w/current or planned NPDES discharge, (2) No facility - convey to Flint WRF

HIGH (Strategic site on Creek in Flint River Basin.) 6 MGD WRF w/Stream Discharge 30 acres (See Note 7)

North Expressway (2 of 2) NEx East Pump Station (see Note 6)

Options (1) Pump north to COH (unless COH acquires HCWA plant, for gravity option), (2) Pump west across highway to Heads Creek WRF,

(3) Interim WRF is an option, but with low viability, and will substantially increase land requirement

MED (Strategic low point at County Line. Also could be coordinated with water supply extension to COH.)

<1 MGD (PS) 1 acre

Tri-County South (1 of 2) West TCS Overlay Pump Station (see Note 3)

Options (1) PS to convey west to Flint WRF, (2) PS to convey east ultimately to Hwy 16 WRF; (3) PS to convey north to COG

MED (Lower service viability, but very strategic Wasp Creek location at service area boundary).

<1 MGD (PS) 1 acre (see Note 4)

Tri-County South (2 of 2) East TCS Overlay Pump Station

Options (1) PS to convey west to West TCS Overlay PS or WRF, or (2) PS to convey east, ultimately to Hwy 16 WRF, potentially receiving West TCS pumped flow for re-pumping

LOW (Limited sub-basin flow projections.) <1 MGD (PS) 1 acre

AKB (1 of 4) West AKB Pump Station

Options (1) PS to convey east to BCPS, for repumping to Hwy 16 WRF;

(2) PS to convey west to COG (Potato Creek)

MED (In Exp Area, not Overlay.

However, failing septic in High Falls Road area increases priority.)

<1 MGD (PS) 1 acre

AKB (2 of 4) Buck Creek Pump Station (BCPS) Options (1) PS to convey east to Hwy 16 WRF; (2) PS to convey west to COG (Potato Creek)

HIGH (Strategic siting for priority service area.) <1 MGD (PS) 1 acre

AKB (3 of 4) Hwy 16 WRF @ Cabin Creek Treatment Facility situated for current/future NPDES discharge

HIGH (Strategic siting for priority service area.) 15 MGD WRF w/Stream Discharge 30 acres (See Notes 1 and 2)

AKB (4 of 4) I-75 Pump Station Options (1) PS to convey east to BCWSA; (2) PS to convey west to Hwy

16 WRF

HIGH (Strategic siting at limits of service area.) <1 MGD (PS) 1 acre

*Acquire noted land on lowest-lying point of subbasin, but with the usable portion needed well above 100-year floodplain.

Notes:

1. Hwy 16 WRF could ultimately include (1) AKB Expanded of ~6.5 MGD, (2) Tri-Co Expanded of ~3 MGD, (3) east side of N. Expressway Expanded of ~3 MGD, (4) Sun City Peachtree ~1.5 MGD. Planning level build-out of 15

MGD.

2. LAS is likely impractical above 200,000 gpd (and certainly beyond 0.5 MGD). Land requirement is driven by LAS vs. NPDES decision. If LAS is selected, soil testing must be conducted to refine land estimate.

3. Tri-County West Overlay PS is illustrated to capture priority overlay corridor. The "Expanded" Tri-County boundary extends substantially further west and may warrant additional pump station master planning.

4. Tri-County West Overlay PS is illustrated on Wasp Creek at a location that could be strategic for future treatment (interim or permanent). If this option is desirable, a more viable land allotment is 15 acres.

5. Interim NPDES discharge would help with Flint River recharge.