2-EMC 30% ETrunk TM Report.pdf

1307 N Locust Lane

Provo, Utah 84604 A Professional Limited Liability Company 801-828-7805

East Trunkline and Tickville Reuse Discharge Pipeline 30% Design Report

Eagle Mountain City Wastewater Treatment Facility

August 2026

Background Eagle Mountain City retained JWO Engineering to preliminary design of the proposed East Trunkline and parallel alignment of Tickville Reuse Discharge pipeline to a minimum of 30% design with associated costs. This report will summarize the 30% design objectives and design decisions to this point.

Data Collection, Existing Conditions and Survey JWO Engineering, PLLC compiled existing GIS information and information on existing developments adjacent or along the proposed alignment. The existing conditions at the connection location at the WWTF (Wastewater Treatment Facility) were also evaluated. JWO Engineering, PLLC partnered with Region Engineering and Surveying to obtain aerial imagery and topographic information along the alignment.

Hydraulic Evaluation and System Analysis JWO Engineering, PLLC prepared a spreadsheet and complete hydraulic evaluation of alternative pipe materials and diameters to determine the appropriate size and configuration for the East Sewer Trunkline and the Tickville Discharge Pipeline.

Alignment Alternatives and Selection JWO Engineering, PLLC coordinated with developments along the alignment. Key areas and decisions are listed below:

Ivory Homes During 30% design, it was pointed out that Ivory Homes had approved planning permission for a shopping center that was within the proposed alignment. Ivory Homes was able to provide CAD drawings that included their design and elevations to assist in adjusting the alignments within their planned design. Their plans included significant cuts in elevations on the north side. This was helpful as the alignment needed to go further east which previously meant that depths would exceed 35’ depths. With the adjusted elevations, the depths here are able to be under 25’ of cover at the deepest section.

Ivory Homes did state that the adjacent lot where we the alignment was moved to has not been finalized. The curve of the road may be adjusted. JWO Engineering, PLLC, cautioned that the road design should be finalized as soon as possible to allow the design of the pipelines to continue and still be within the final pavement section. As design of these pipelines continue, Ivory Homes should be reached out to and have planned pavement alignment confirmed.

Flagship Homes Eagle Mountain City notified JWO Engineering, PLLC that Flagship Homes owned the property just east of the WWTF and suggested JWO Engineering, PLLC approach Flagship Homes about coordinating the alignment to come through their development. JWO Engineering, PLLC reached out multiple times over 2 months to see about possibilities but had no response. Eagle Mountain City was notified of this and agreed to follow up with Flagship Homes.

Utility Coordination We coordinated the alignment through blue stakes to identify utility conflicts. Key issues and coordination items are presented below:

Kern River Gas JWO Engineering, PLLC, coordinated with Kern River Gas to obtain requirements to have utilities crossing their easement and pipelines. Crossings need to be perpendicular to their lines. Kern River Gas has two 36” pipelines that run mostly north-south on the east side of Eagle Mountain City.

Crossings need to be beneath the gas lines with 2’ of clearance. The new pipelines will need to cross Kern River Gas 2 times (Sta 192+25 and ~Sta 56+00). An Encroachment Agreement will need to be completed as well; however, this has not been initiated yet due to some anticipated changes in the alignment crossing locations at ~Sta 56+00.

Geotechnical Considerations We reached out to several firms and obtained estimates between $16,000 and over $40,000 to conduct the field study and prepare a geotechnical report for the final design and to give contractors a good feel for the conditions they will encounter during construction of the pipelines.

The conditions are particularly important in the deep areas of the sewer line and at the gas line crossings. The cost for the study could be contracted separately by the city or included in the final design phase of the project.

Environmental and Permit Review We did not identify any environmental or permit issues that are anticipated to occur during the sewer trunkline construction. For the Tickville pipeline, permitting for the discharge is in progress and could impact the ability of the city to discharge flow to Tickville gulch. Other reuse connections to the pipeline would also need to be permitted under a reuse project plan.

Easements Existing property owners along the initial proposed alignment are identified in the CAD file provided with the 30% design. The 30% alignments were adjusted to be within paved sections as much as possible. However, along the east side of Eagle Mountain City the alignments follow a utility corridor that is not planned to be a paved road. Easements will need to obtained for this stretch of the alignment which is approximately 2.7 miles. Additionally, the 30% design alignment at the south end as it turns west to the Eagle Mountain City WWTF will also need an easement for the 1-mile stretch. If an agreement can be made with Flagship Homes to be within paved roads, this easement will not be necessary.

East Trunkline Alignment The recent Master Plan had suggested a probable alignment for the East Trunkline. This alignment was used as a starting point for this 30% design. The alignment was fine tuned to be within public right of way as much as possible and to avoid existing utilities. Utility coordination was initiated with Blue Stakes to get utility contact information and location information. Generally the proposed alignment was followed.

As the proposed alignment moves east, it is fighting the existing grade elevations, meaning it’s going deeper and deeper as it turns east. As the pipeline goes south, it can gradually recover the depth using minimum pipe slopes. The greatest depths (cover over 20’) will be at stations 290+00, 243+00, and between 192+00 and 183+00 (Kern River Gas pipeline crossing).

The East Trunkline will connect to an existing manhole at the north end at the intersection of Old Airport Road and Bismark Peak. At the south end it will connect to an existing manhole at the WWTF that will be replaced. The existing 24” pipeline from this manhole to the WWTF headworks will be upsized to 30” pipe to accommodate the additional trunkline and it’s flows.

Tickville Reuse Discharge Pipeline Alignment The Tickville Reuse Discharge Pipeline will generally follow the East Trunkline alignment to take advantage of construction and easement costs. As the East Trunkline weaves through Eagle Quest development and the roads are not as wide, the Tickville Reuse Discharge Pipeline will stay on the outside of the development. This is possible as the reuse line is not gravity dependent and will not need to be as deep.

Air Release valves will be placed along the alignment to help remove any trapped air in the pipeline, particularly at any high points in elevation.

The reuse line will continue past the trunkline connection point on Old Airport Road, going north until reaching the Tickville Gulch. Improvements will need to be designed and constructed to prevent erosion as it discharged to the natural channel. The reuse line begins at the WWTF, entering at the south end of the WWTF and will require a pump station design and construction to help push the water up to Tickville Gulch. The pump station was not included in this project design.

Opinion of Probable Construction Costs (30% Design Level) Cost estimates were forecasted based on the 30% design and are included in the Appendix of this document. Costs for the Tickville Reuse Discharge Pipeline reflect costs as if it was constructed at the same time as the East Trunkline. These costs are additional to the East Trunkline Costs. The opinion for probable construction cost for the East Trunkline in 2026 dollars is $21.5 Million, and the opinion for the Tickville Reuse Discharge Pipeline is an additional $13.8 Million. These costs include connections to the existing WWTF. The Tickville Reuse Discharge Pipeline costs do not include pump station costs as that was not part of this design.

Future Cost Impacts As this design is only 30% actual costs may vary. JWO Engineering, PLLC has identified likely factors that may impact the costs as design continues and are listed below. As design continues to progress, there may be additional factors that impact the costs as design proceeds.

Ivory Homes – alignment adjustment Soil Testing and Sampling Results Additional Pipe Strength for Deeper Sections Trenchless Options Flagship Homes – alignment alternative Obtaining Easements Erosion Prevention at Tickville discharge

Appendix 30% Cost Estimate for East Trunkline & Tickville Reuse Discharge Pipeline (JWO)

30% Cost Estimate for connections (AE2S – included in JWO costs)