Based on the above, it is recommended that Lift Stations #1 and #3 be abandoned and their flows be diverted to the regional Lift Station #8.

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1 Lakeside; Clairmont Heights; Portion of Clairmont currently serviced to Pump Station #2; Crossroads North and Crossroads South portion of flows that are diverted to Lakeside Trunk. It is understood that Aquatera is interested in decommissioning Lift Station #1 and the Northgate Lift Station (Lift Station #3) and diverting the flows to a regional lift station at Lakeside North. The rationale is to simplify operating the wastewater system and to reduce operation and maintenance costs. To assess the impact of a single regional lift station on the ultimate servicing plan, the ultimate design flows to Lift Stations #1, #3 and #8 were reviewed as noted below: LS #1: 13 L/s (services Area 17) LS #3: 180 L/s (services Areas 8, 9 and 16) LS #8: 682 L/s (without LS #1 and #3 flows) LS #8: 875 L/s (with LS #1 and #3 flows) Since Lift Stations #1 and #3 having capacities of 29 L/s and 20 L/s, respectively, keeping the existing lift stations in operation will not significantly reduce the capital or operating costs of the regional lift station. The order of magnitude costs associated with abandoning Lift Stations #1 and #3 and diverting the ultimate design flows to the proposed regional Lift Station #8 include: Diversion sewer from LS #1 (MH 174) to MH 233 $90,000 Oversizing sewer from MH 233 to LS #8 $50,000 Diversion sewer from LS #3 (MH 164) to MH 144 $140,000 Oversizing sewer from MH 144 to LS #8 $30,000 LS #8 incremental cost for LS #1 flows (13 L/s) $50,000 LS #8 incremental cost for LS #3 flows (180 L/s) $250,000 Decommissioning LS #1 and #3 $25,000 (each) Thus the total cost of abandoning Lift Station #1 would be in the order of $200,000, while the cost of abandoning Lift Station #3 would be in the order of $450,000. The comparative order of magnitude costs associated with maintaining Lift Stations #1 and #3 are: Upgrading and rehabilitating LS #1 $200,000 Construct LS #3 with 286 L/s capacity $1,000,000 The cost effectiveness of abandoning Lift Station #1 in favour of the regional lift station is dependent on the upgrading and rehabilitation costs. However, any savings in capital costs associated with maintaining Lift Station #1 in operation would be offset by higher operation and maintenance costs in the long term. Based on the above, it is recommended that Lift Stations #1 and #3 be abandoned and their flows be diverted to the regional Lift Station # Forcemain to Wastewater Lagoon All of the proposed wastewater servicing plans will ultimately discharge to the lagoons north of Township Road 724. Because of the relatively high elevation of the lagoon in comparison to the Creek crossing, all wastewater flows will have to be pumped into the lagoon. Five servicing concepts were considered for the outfall to the lagoon: January, 2007 Page 36

2 Servicing all areas, including the 116 Street North and South, Ferguson Lake and Clairmont West Phase 2 areas, through a common forcemain. In this case, the forcemain on Range Road 63 would extend north of Township Road 724 discharging to the lagoon and Clairmont West Phase 2 would have its own lift station connecting to the common forcemain at Township Road 724. Develop a new lift station south of Township Road 724 between Range Roads 62 and 63 to service the lands immediately to the south and the Ferguson Lake service area via a gravity connection. The area southeast of Township Road 724 and Range Road 62 (Service Area No. 10) could also be serviced by gravity to this lift station. The 116 Street North and South areas would connect to the Clairmont West Phase 2 trunk on Range Road 63. A separate forcemain would be used to connect the Lakeside North Regional Lift Station and Four Mile Corner Lift Station directly to the lagoon. Same as No. 2 above, except that the Four Mile Corner Lift Station forcemain would discharge into the gravity sewer on Township Road 724. Same as No. 2 above, except that the Lakeside North Regional Lift Station forcemain will discharge into a gravity sewer and the Four Mile Corner Lift Station forcemain would discharge into the existing forcemain on Township Road 724 near Range Road 62. Same as No. 2 above except that both the Lakeside North regional forcemain and the Four Mile Corner forcemain would discharge into the gravity sewer. The first alternative was rejected because of the complexity of connecting multiple lift stations to a single forcemain and the increased operational risks. The selection of Alternatives 2, 3, 4 or 5 depends on the detailed design of the Lakeside North Regional Lift Station based on careful consideration of: Capital Costs Annual operation costs An assessment of the forcemain hydraulics and particular the interaction of a shared forcemain between two lift stations (Alternative No. 2) and the impact of a larger forcemain connecting to a small downstream forcemain (Alternative No. 4) For the purposes of this study, alternative 2 is proposed as it defers constructing proposed Lift Station #10 and forcemain to future contours. 8.4 Recommended Ultimate Servicing Concept The recommended ultimate servicing concept is shown in Figure The design flows were modelled using the City of Grande Prairie diurnal curves, where as the pipe system was sized using the Harmon formula which yields more conservative flows. However to have the flexibility in accommodating a range of future residential, commercial and industrial developments, a reduction in the proposed pipe sizing is not recommended. Servicing costs can be minimized by utilizing existing systems as much as possible and by staging the lift station construction. Shareable cost estimates for the major trunk systems and lift stations/forcemains are provided in Appendix A and are summarized in Table January, 2007 Page 37

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5 Table 8.4.2: Ultimate Sanitary Servicing Shareable Cost Summary Trunk Sewers 450 mm Diameter Lift Station #8 Lift Station #8 Forcemain Discharge into 116 Street Trunk Lagoon Rehab Total Cost Construction Cost $15.42 M $3.55 M $5.50 M $15.93 M $4.32 M $44.72 M Engineering and Contingency $5.40 M $1.24 M $1.93 M $5.58 M 0 $14.14 M Total $20.82 M $4.79 M $7.43 M $21.51 M $4.32 M $58.86 M Note: Above costs include only the cost shareable components. Trunk sewers refer to sewers greater or equal to 450 mm diameter and some 375 mm pipe segments which are included to facilitate L.S. 1, 2 and 3 decommissioning. January, 2007 Page 38