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1a. Sewer System Summary PointsKalispell Sanitary Seaver System October 28, 2013 Workshop Presentation -Summary Points 1. Introduction • The sewer model was last updated in 2007-2008. • In order to address some of the assumptions, and get a good handle on existing flows, the model needed to be updated.. 2. Map Title: 2013 Sewer Model Results • The results shown on the map in the yellow tags are given in terms of ERU's. o The first number is the ERU's remaining under existing peak hour flow conditions. o The second number, in parentheses, is the ERU's remaining under peak hour infill conditions. 3. ERU Definition ■ A single family household is 1 ERU or 1 equivalent residential unit. ■ 1 ERU produces 265 gal of sewage a day, or 0.184 gal/min. ■ As Engineers, we always try to design for the worst case scenerios. In sewer design, we use Peak Hour Flow. ■ Peak Hour Flow is determined by multiplying the average flow by a peaking factor. • The peaking factor for Kalispell is 3.05 ■ The Peak Hour Flow for 1 ERU is the average flow (0. 184 gpm) times the peaking factor of 3.05 or 0.56 gpm. ■ This is what Kalispell Design Standards specify and what the sewer model uses. 4. ERU Example ■ According to our impact fee calculations, equivalent units for a hotel room can be calculated by 0.25 ERU's per room. ■ A hotel with 100 rooms would produce as much sewage as 25 ERU's or 25 single family households. • The Peak Hour Flow from the hotel is then calculated as 0.56 x 25 ERU's = 14 gpm 5. ERU Yellow Tag • The first number in the yellow tag is ERU's remaining under Existing Peak Hour Flaw conditions. • The second number in the yellow tag is ERU's remaining under Infill Peak Hour Flow conditions Page 1of8 Kalispell Sanitary Sewer System October 28, 2013 Workshop Presentation -Summary Points 6. Existing Peak Hour Flow Conditions • This cross section represents peak flow in a sewer main. • The pink portion represents Existing flow at peak hour. • The design capacity for the sewer main is 85% full. • Under existing peak hour flow conditions, the white space represents remaining capacity or the number of ERU's that could be added to the main before the main is at design capacity. • Remaining ERU's (white portion) is the first number in the yellow tag. Remaining ERU s Full Existing ?, Infill Flow Conditions • This cross section represents flow under infill pear hour modeled flow conditions. The blue represents infill peak hour modeled flows. • The design capacity for the sewer main is 85% full. • The white space between the infill flows and the design capacity line is the remaining ERU's under infill conditions. This is the 2nd number in parentheses in the yellow tag. • Infill flows are model generated pear hour flows coming into the sewer system from all existing areas served by sewer. These flows are based on land zoning and assumed population densities. • The model doesn't see houses to calculate infill flows. It sees the number and sizes and types of lots and assumes at some point, all lots served by sewer will eventually connect. • Due to these assumptions, infill flow conditions are more of a problem identifying tool and planning tool than a governing tool. This is the Fred namber in the rag Remaining T.RU's iia''.0 i ui! 8. Allocated Flows • Allocated flows are flows from developments that the City has promised to reserve. • These flows are allocated through the MFE process. Further description in #22. Existing Page 2of8 Kalispell Sanitary Serer System October 28, 2013 Workshop Presentation -Summary Points 9. MFE Explanation • MFE or Municipal Facilities Exclusion process is DEQ's checklist completed by the design engineer and signed off by the municipality's engineer. • The MFE advises DEQ that the municipality is reviewing plans and specifications to verify that they meet DEQ's and the City's minimum design standards. • There is also a signature line for the municipality that tells DEQ that adequate water and sewer service is available to the development. • This is typically the last thing completed during the City's review process and is a requirement prior to construction. 10. Surcharge Areas - 2013 Sewer Model Results • Surcharging areas are shown on the legend by the very wide yellow line. • Surcharge means the pipe can't Garry the flows trying to come through it. Surcharging lines inhibit the flow of wastewater and cause backups in the main, manholes, and service lines. Backups can cause sewage to be exposed in the streets/alleys and the residential/commercial services generating health, safety, and liability issues. • Except for a couple of areas we were already aware of and identified in the Sewer CIP, there are no surcharging areas under existing flow conditions. • The surcharges shown on the map only occur under infill conditions. Infill flows are Existing flows + Allocated flows + Assumed flows. 11. Critical Surcharge Area -South Meridian Tag 912(-1,305)ERU This is a critical surcharge area. Under existing conditions, there are 912 ERU's remaining. However, under infill conditions, we have a large negative number meaning there are 1,305 more ERU's of flow trying to come through this main than there is capacity for. 12. Trunk Mains — Line A The legend also identifies the 5 main trunk lines in the sanitary sewer system. Line A is the main trunk line. It serves most of the west side the City and all areas north of Grandview. All of the other trunk lines dump into Line A at some point. 13. Lines B -- E • Line B is the purple colored line that collects sewage in the East side of Kalispell. • Line C also collects sewage in East Kalispell and the areas by Woodland Park. ■ Line D collects the City subdivisions by Village Greens and Glacier commons and ends at Lift Station 9 which pumps into Line E. • Line E starts at the north end of North Main, crosses Hwy 93 by the mall, and runs down 5t' Ave W until it connects to Line A south of the highschool at the intersection of 9 to Street W and 5 h Ave . W. • The legend identifies all of the sewer mains by size. Page 3of8 Kalispell Sanitary Sewer System October 28, 2013 Workshop Presentation -Summary Points • The line styles vary from green to yellow to red, with thinner lines for smaller diameters and thicker lines for larger diameters. • The legend also identifies minimum design capacity in terms of ERU's for each diameter. 14. Sewer Mains by Type • Kalispell maintains o PVC. This is the current type of pipe specified in our Design and Construction Standards. • o vitrified Clay Pipe (VCP) mains. o Reinforced Concrete Pipe (RCP). o Asbestos Cement Pipe (AQ. 15. Lift Stations • Kalispell manages and maintains 40 Sanitary Sewer System. • Crews do preventative maintenance on every lift station at least once a week. • In 2013, the City has spent about $15,000 replacing or rebuilding lift station pumps and motors. Currently working on replacement of $17,000 pump and motor at Triple Creek Lift Station (LS 29). • Our larger pumps can cost as much as $30 - $40 thousand each. 16. Main Issues -Line A • Line A is the only trunk line with surcharging areas under infill conditions. • 9h St w and 5 Ave w (star location) is a significant point on Line A. North of this point there are surcharging areas on the main, but to the south has adequate capacities under infill conditions. • At this point, we currently have capacity for an additional 11,712 ERU's and under infill conditions, there are 9,668 ERU's remaining. 17. Line A Management Areas — refer to Line A Development Summary Diagram ■ The area served by line A (north of star) is broken into two management areas. • The northern portion is shown in green and the southern portion is shown in yellow. • These management areas are split by Grandview Lift Station • The approval of the Grandview Lift Station upgrade was granted upon 4 specific conditions set by DEQ. Page 4 of 8 Kalispell Sanitary Sewer System October 28, 2013 Workshop Presentation -Summary Paints 18. Grandview Lift Station Conditions • At the time of the upgrade, the remaining capacity downstream of Grandview Lift Station was determined to be 860 gpm, which is what the lift station was designed to pump at and is the flow rate the conditions are based on. ■ Condition 1 requires that at 80% of 860 gpm, or 670 gpm of peak inflow, the City will begin to design the West Side Interceptor • Condition 2 requires at 90% inflow capacity, the City will secure funding for the West Side Interceptor. ■ Condition 3 requires at 95 % inflow capacity, the City should begin construction of the West Side Interceptor. • The fourth and final condition requires that at 100% capacity, if the West Side Interceptor isn't complete, the City will stop issuing new connections. * Current Sewer Capacities at Grandview Lift Station are: DEQ Set Peak Inflow Current Peak Inflow Remaining Capacity gpm ERU m % ERU 860 2263 416 48% 1168 19. Grandview Service Area Developments • The area subject to the conditions on Grandview include developments like Silverbrook, West View Estates, Hutton Ranch and the Flathead Valley Community College. • We also have some more recent developments like Glacier Eye and Spring Prairie Phase 3 which includes the new Cabel as . • This area also includes rather large developments waiting for the economy upturn, like Bloomstone, Starling, Glacier Town Center, and Stillwater 180. 20. South of Grandview • South of the Grandview Lift Station, we have several housing developments that aren't yet built out. These include Mountain Vista, Spring Creek, Aspen Creek, and Diamond Ridge. • There are also newer developments like the Central Kitchen, and the Prestige Assisted Living Expansion. ■ Potential new developments that would like to be served by the City are Fox Trotter, Meridian Apartments, and Willow Creek. • Interest for new development is what caused us to raise our first warning sign for sewer capacity. 21. Warning Signs • Actually, according to the model, we have lots of warning signs: •► Willow Creek, Starling, the next phases of Bloomstone, the next Phases of Silverbrook, all of Stillwater 180, all of the old Glacier Town Center, new developments in section 36 of the DNRC land, Fox Trotter, and Meridian Apartments. Page 5 of 8 Kalispell Sanitary Sewer System October 28, 2013 Workshop Presentation -Summary Points 22. Critical Paint - South Meridian Tag 912(-1,305)ERU * This is the limiting Critical Point on Line A. ■ Currently, we have 912 ERU's at this location, but under infill conditions the main would be surcharging. ■ Due to the assumptions under infill conditions, we can't use them to govern. ■ We need to use the existing Bows or the 912 ERU's to determine how much is already allocated and how many unallocated ERU's are remaining. 23. Critical Point Calculations ■ To determine what we have left in the bank to distribute for new developments, we can take the 912 remaining ERU's and subtract the 556 ERU's allocated north of Grandview and also subtract the 332 ERU's allocated south of Grandview, which leaves 24 ERU's still unallocated. Development North of Grandview MFE Total ERU Used ERU Remaining ERU 5ilverbrook-phase 1 yes 285 32 253 tlff8ing -- phase :?. no a 0 0 West View Estates yes 112 19 93 Hilton Homewood suites yes 40 40 0 Hutton Ranch yes 5 DNRC yes 10 10 0 Spring Prairie yes 0 0 20 Bloomstone-phase 1 yes 185 0 185 911 Center yes 1 1 0 Total Estimated Allocated ERUs Remaining 556 Development South of Grandview MFE ! Remaining ERU Mountain Vista Yes 29 Spring Creek Estates Yes 107 Aspen Creek Yes 69 Diamond Ridge Yes 19 Northland Yes 67 Lone Pine Trails Yes 13 West wood Yes 22 Empire Estates Yes 3 Blue Heron Yes 3 Critical Point 912 Development North of Grandview -556 Development south of Grandview -332 24 Total Estimated Allocated ERUs Remaining 332 ERUs Remaining at Existing Peak Flows Unallocated ERUs Page 6of8 Kalispell Sanitary Sewer System October 28, 2013 Workshop Presentation -Summary Points 24. west Side Interceptor Phases * The last items still remaining to be explained in the legend are Phases 1, 2, and 3 of the west Side Interceptor. • We just calculated how many ERU's remain at the critical point. • Now we can apply the same calculation at our star location (91h St W and 5 Ave W) downstream. At this point, we still have 10,824 ERU's remaining unallocated. • This number represents growth potential and can be the connection for the 1 'f Phase of the WSI. • Phase I would be a force main and would include a new lift station. ■ Phase 2 would pick up all of the flows from the developments on 3 Mile Drive. • Phase 3 would pick up all of the flows north of Reserve Drive. 25. WSI Phase Review • Phase I o Doesn't solve any current capacity problem for Trunk Line A o Is Developer driven. Most economical and feasible way for willow Creek to be serviced by sanitary sewer. o Could be partial funded by developer. o Logical 1 s' step. o Engineers cost estimate is approximately 1 million dollars. o Is a phase of the Spring Creek Interceptor as outlined in the 2007 Facility Plan Update. • Phase 2 o Big step to relieve capacity issues in Trunk line A for everything south of Three Mile Drive. o would receive all the flows from development on Three Mile Drive. o Referred to as Spring Creek Interceptor and Three Mile Drive Interceptor portions of the Westside Interceptor in the 2007 Facility Plan Update. 2013 cost estimates for the two sections is 6.5 million dollars. o Cost estimate involve construction cost scenarios before Hwy By-pass construction. After bypass construction is complete costs will increase. • Phase 3 o Reroutes all flows north of Reserve Drive. o Allows growth to continue north of Grandview Lift Station. o Allows large development like Starling to connect to sewer. o Completes first three phases of WSI. o Referred to as Stillwater Interceptor portions of the westside Interceptor in the 2007 Facility Plan Update. 2013 cost estimates for this sections is 6.1 million dollars. Page 7 of 8 Kalispell Sanitary Sewer System October 28, 2013 Workshop Presentation -Summary Points 26. What's the Next Step • Grandview Lift Station CURRENTLY has capacity remaining before the Nest Side Interceptor is required. See table in #19. However, downstream Line A trunk main capacities limit flow coming into Grandview Lift Station. • Trunk Line A CURRENTLY has adequate capacities for existing peak flows. o However, if allocated capacities are reserved as required, only 24 ERU's remain in Line A north of 9"1 Street. • How do we proceed with new developments wanting to build in the City like Meridian Apartments, Fox Trotter, and areas by the new Glacier Eye Clinic? o only proceed with approvals until allocated flow (24 ER.Us) is utilized? o Start with Phase land 2 of WSI? 27. Hove Does the City Fund the Sewer Extensions • SRF Loan? • Developer Extension (Latecomer Agreement) ? • Impact Fees? • Special Improvement District? • Combination of funding sources? 28. Staff Recommendations Participate in Phase 1 of the West Side Interceptor by upsizing the force plain and lift station to accommodate flows from Phases 2 and 3 • Submit request for proposals (RFP's) to qualified engineering firms for planning of Phases 1, 2 and 3 and design of Phases 1 and 2 of the WSI. • Secure funding for Phases I and 2. Participate in funding of Phase I with developers. • Start construction of Phases I and 2, as funding become available. • Secure funding for Phase 3 and construct Phase 3 based on DEQ's conditions for Grandview Lift Station capacities. 29. Staff reeds Direction • Willow Creek o Does the city want to participate in the project (WSI Phase 1) by upsizing sewer force main and the lift station for the future flows for the West Side Interceptor? • West Side Interceptor o Direction for PWs to send out RFP's to qualified engineering firms for planning and design of phases. • Remaining Unallocated Sewer Capacity o only 24 ERU's remaining o Who gets them? First come first serve? ■ Policy determination on how to distribute remaining ERU's. • other ideas? Page 8of8