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E3. Resolution 5701 - West Side Intercept10 11 �:iTr��� ��i `i 1 {��' 4� '`�� �' _ _ �4G��11tC`��i { �11 . PUBLIC WORK. EPARTMENT 201 Ist Avenue East PO Pox 1997 Kalispell, NIP 59903 Phone: 406-758- 7720 .fax: 406- 758- 7831 www.kalispell.com Ipublic_works MEMORANDUM DATE: January 14, 2015 TO: Doug Russell —City Manager 9K Susie Turner —Public Works Director, City Engineer FROM: Keith Haskins —Senior Civil Engineer ill SUBJECT: Resolution No. 5701 MEETING: January 20, 2015 Background: In 2008, the need for a West Side Interceptor was identified in the Sewer Facility Plan Update as a solution to the growth occurring on the north and west sides of Kalispell. In 2009, the City received a deviation from the Montana Department of Environmental Quality (MDEQ) to approve Municipal Facility Exclusions (MFEs) beyond the capacity of Grandview Lift Station. The MDEQ deviation was granted contingent upon the following triggers: Grandview Lift Station — Maximum Pumping Capacity Set at 860 gpm When sewer inflows reach: I . 80% of the pumping capacity, the City must begin the design of the West Side Interceptor. 2. 90% of the pumping capacity, the City must secure funding for the construction of the West Side Interceptor. 3. 95% of the pumping capacity, the City must start construction of the West Side Interceptor. 4, 100% of the pumping capacity, the City must stop issuing building permits until completion of the West Side Interceptor. In 2012, the City's Sanitary Sewer Model was updated to reflect changes since its previous update in 2008, including the addition of several subdivisions which were constructed after 2008. When the 2012 sewer model update was completed, a significant bottleneck was identified in sanitary sewer Trunk Line A north of 70' Street West and east of South Meridian Road. At the time, only 24 Equivalent Residential Units (ERUs) of unallocated flow capacity remained in the line. Public Works was asked to look for any feasible projects to reduce or redirect flows in Line A. The available capacity in Line A dropped to 10 ERUs of capacity before the City moved forward with a project to synchronize three lift stations on Three Mile Drive. At completion of the Lift Station Synchronization Project, 155 ERUs of capacity was available in Line A. Currently, there is 146 ERUs of unallocated capacity remaining. With no options remaining to postpone the design and construction of the Nest Side Interceptor (WSI), the City Council approved staff s recommendation to select an engineer for design. Robert Peccia and Associates were selected and have now completed the preferred route assessment for the WSI. The preferred WSI route is estimated to cost approximately 14 million dollars and will include highway crossings, a rail road crossing, land purchases, easement negotiations, a large lift station, sewer force mains, and large diameter sewer gravity main construction. This large project is going to require both time and money to design and construct. In the meantime, planning for new development continues upstream of the bottleneck in Line A. Right now, a planned commercial subdivision site south of Costco is expected to require over 50 ERUs of sanitary sewer capacity and an apartment development on North Meridian is expected to require another 50 ERUs of sewer capacity. These two developments alone, if they come to fruition, will reduce available capacities in Line A to approximately 50 ERUs of unallocated capacity for all other developable areas north of the bottleneck. The City cannot approve MFEs beyond unallocated capacities in Line A. And, with the first phase of construction of the west Side Interceptor tentatively scheduled to begin in Fiscal Year 1711 S, new development sewer allocations may exceed available capacities. For this reason, the Department of Public Works has applied for a deviation to the MFE process which would allow the City to approve new developments beyond unallocated capacities. Attached for reference is the Deviation letter submitted to MDEQ. After incorporating the capacity created by the Lift Station Synchronization Project with the most recent sewer flow metering completed near the bottleneck location on Line A, the existing peak hour sewer flows are calculated to make up only 54% of the design capacity of the pipe. The remaining pipe capacity is 46%, of which 39% of the pipe capacity is allocated to undeveloped lots in upstream subdivisions and developments, and 7% is unallocated. The MDEQ has tentatively approved the deviation which will allow the City to manage flows from new developments north of the Line A bottleneck based on pipe capacity, providing the City commits to the 'Vest Side Interceptor via the following triggers: 1. when measured flows reach 70% of the pipe capacity at the bottleneck location in Line A, the City will complete any remaining portions of design for the west Side Interceptor. 2. when measured flows reach 75% of the pipe capacity at the bottleneck location in Line A, the City will secure funding for the construction of the west Side Interceptor. 3. when measured flows reach 80% of the pipe capacity at the bottleneck location in Line A, the City will begin construction of the west Side Interceptor. 4. when measured flows reach 85% of the pipe capacity at the bottleneck location in Line A, the City will stop issuing building permits for areas upstream of the bottleneck. 5. These conditions will not override or void conditions previously placed on Grandview Lift Station. With the deviation, the City can manage the 46% (1,033 ERUs) of pipe capacity remaining beyond existing flows. At a 2% growth rate, and assuming half of all new growth will occur north of the bottleneck in Line A, the remaining capacity is expected to last through the year 2019. Action Requested: Approve Resolution No. 5701, a resolution of intent to augment the City of Kalispell sanitary sewer collection utility by constructing a west Side Sanitary Sewer Interceptor (WSI). Fiscal Effects: None at this time. The WSI is anticipated to primarily be funded through the sanitary sewer collection impact fund. Alternatives: As suggested by City Council. Attachments: 1. Resolution 5701 with Exhibit "A" 2. Trunk Line A Municipal Facility Exclusion Deviation (12-18-14) A RESOLUTION OF INTENTION TO AUGMENT THE CITY OF KALISPELL SANITARY SEWER COLLECTION UTILITY BY CONSTRUCTING A WEST SIDE SANITARY SEWER INTERCEPTOR. WHEREAS, the City of Kalispell owns, maintains and operates a sanitary sewer collection utility that conveys sewage to a waste water treatment facility; and WHEREAS, the City of Kalispell is near allocated capacities in the existing sanitary sewer collection system for areas currently served by sanitary sewer collector known and designated as "Trunk Line A"; and WHEREAS, Montana law, at §76-4-127 MCA, requires municipalities through a process known as Municipal Facilities Exclusion (MFE) to certify that adequate municipal facilities for the disposal of sewage are available to new subdivisions prior to final plat approval; and WHEREAS, it is projected that commercial and residential development will continue to expand in the northern and western portions of the City served by sanitary sewer Trunk Line A; and WHEREAS, the City has exhausted all other feasible options to create additional capacities in sanitary sewer Trunk Line A; and WHEREAS, a project to provide the necessary additional capacity for sanitary sewer conveyance in the northern and western portions of the City, known as the ,'Lest Side Sewer Interceptor, has been investigated, including the complete outlining of a preferred route assessment consisting of preliminary engineering calculations, sanitary sewer modeling, environmental impacts, project costs and potential funding sources for the design and construction of the project; and WHEREAS, the deviation granted to the City to allow approval of new sanitary sewer collection flow allocations beyond the remaining capacities of Line A requires the commitment of the City for management of flows in Line A and the design, funding and construction of the West Side Interceptor based upon measured pipe flows. NOW THEREFORE, BE IT RESOLVED BY THE CITY COUNCIL OF THE CITY OF KALISPELL, MONTANA: SECTION 1. The City of Kalispell is committed to design. and construct the West Side Interceptor at or near the preferred route as outlined in the Preferred Route Assessment —West Side Interceptor as prepared by Robert Peccia and Page 1 of 3 Resolution 5701, West Side Interceptor Associates and made available at the office of the Department of Public Works. SECTION 2. This commitment is founded upon the understanding between the City and the Montana Department of Environmental Quality that the completion of the West Side Interceptor project from the intersection of 5th Avenue West and I oth Street West to sanitary sewer Lift Station 36, north of Reserve Drive will satisfy the deviation and associated trigger conditions set forth in Exhibit "A" to the Municipal Facilities Exclusion process on Lift Station 3 at Grandview Drive as well as the deviation and associated trigger conditions set forth in Exhibit "A" to the Municipal Facilities Exclusion process for Trunk Line A south of Grandview Lift Station. Exhibit "A" is attached hereto and incorporated fully herein by this reference. SECTION 3. Any loan to pay required project costs for the West Side Interceptor will first and primarily be paid for out of the sanitary sewer collection portion of Sanitary Sewer Impact Fees. PASSED AND APPROVED BY THE CITY COUNCIL AND SIGNED BY THE MAYOR OF THE CITY OF KALISPELL THIS 20TH DAY OF JANUARY, 2015. Mark Johnson Mayor ATTEST: Aimee Brunckhorst, CMC City Clerk Page 2 of 3 Resolution 5701, West Side Interceptor EXHIBIT "A" Grandview Lift Station Deviation — Maximum Pumping Capacity Set at 860 gpm When sewer inflows reach: • 80% of the pumping capacity, the City must begin the design of the West Side Interceptor. • 90% of the pumping capacity, the City must secure funding for the construction of the West Side Interceptor. • 95% of the pumping capacity, the City must start construction of the West Side Interceptor. • 100% of the pumping capacity, the City must stop issuing building permits until completion of the West Side Interceptor. Trunk Line A Deviation • When measured flows reach 70% of the pipe capacity at the bottleneck location in Line A, the City will complete any remaining portions of design for the West Side Interceptor. • When measured flows reach 75% of the pipe capacity at the bottleneck location in Line A. the City will secure funding for the construction of the West Side Interceptor. • When measured flows reach 80% of the pipe capacity at the bottleneck location in Line A, the City will begin construction of the West Side Interceptor. • When measured flows reach 85% of the pipe capacity at the bottleneck location in Line A, the City will stop issuing building permits for areas upstream of the bottleneck. • These conditions will not override or void conditions previously placed on Grandview Lift Station. Page 3 of 3 December 18, 2014 Emily Gillespie, P.E. Public Water Supply and Subdivisions Bureau 655 Timberwolf, Suite #3 Kalispell, MT 59901 RE: Trunk Line A Municipal Facility Exclusion Deviation Dear Ms. Gillespie, The purpose of this letter is to request a deviation to Circular DEQ-2 Standard 20.14, the corresponding Municipal Facilities Exclusion (MFE) approval process, and provide the City's justification for management of sewer capacities south of Grandview Lift Station on Trunk Line A (please see Figure 2). The City is approaching the capacity allocations in a lower section of Line A and has exhausted all known possibilities to increase available capacities, including the recent synchronization of three Lift Stations on Three Mile Drive. With no feasible alternatives remaining to reduce pipe flows in Line A, the City is working towards the design and construction of a West Side Interceptor. The City requests a deviation be granted for the MFE sewer capacity determination on Line A in consideration of the City's commitment to management of flow in Line A and the design and construction of the West Side Interceptor. This letter will provide you with a short history of Line A, the results of recent sewer system modeling, the long-term solution provided by the West Side Interceptor, the preferred routing for the West Side Interceptor, the tentative schedule for design and construction of the West Side Interceptor, and the proposed design and construction triggers for the West Side Interceptor to allow City management of remaining sewage capacities in Line A. History of Line A Line A is the main Trunk Line in Kalispell, extending south from its connection with Grandview Lift Station to the Kalispell Wastewater Treatment Plant (WWTP) (see Figure 2). All other trunk lines in the City connect to Line A. The pipe sizes increase from 8" on the northern end of Line A up to 36" prior to the WWTP. Much of Line A is original piping, approaching 100 years of active use. In 2008, the Sanitary Sewer Facility Plan Update completed by HDR Inc., recognized a need for a sewer interceptor to allow continued growth on the north and west sides of Kalispell. In 2009, Grandview Lift Station was upsized and a deviation to the MFE process was approved by MDEQ for properties north of Grandview Lift Station. The deviation to the MFE process allowed City management of remaining sewer capacities by utilizing triggers based on flows into Grandview Lift Station to initiate the design and construction of the West Side Interceptor. 201 1 ` A ven u e East, P. 0. Box 199 7, Kalispell, MT 59903 —Ph on e (406) 758- 7720 -- Fax (406) 758- 7831 www.kalispell.com Following is a summary of the triggers established as part of the deviation: Grandview Lift Station — Maximum Pumping Capacity Set at 860 gpm When sewer inflows reach: ■ 80% of the pumping capacity, the City must begin the design of the west Side Interceptor. • 90% of the pumping capacity, the City must secure funding for the construction of the West Side Interceptor. 95% of the pumping capacity, the City must start construction of the west Side Interceptor. • 100% of the pumping capacity, the City must stop issuing building permits until completion of the west Side Interceptor. With these conditions in place on the Grandview Lift Station, flows into the lift station could basically double before any work on the West Side Interceptor would be required. Shortly after the lift station upgrade and MDEQ deviation, the growth in Kalispell slowed down considerably due to the economic recession. In turn, the City's focus with Capital Improvement Projects changed from Capital Improvement Projects for growth to Capital Improvement Projects for operation and maintenance of aging infrastructure. Recent Sewer Modeling Results In 2012, development began to increase again in Kalispell, prompting the Public works Department to update the sanitary sewer model. Due to their history with the City's sewer model, HDR Inc. completed the update. The update included any new subdivisions approved and constructed between. the years 2008 and 2012. Additionally, City crews conducted sewer flow metering in key locations and provided lift station flow data to HDR to assist in calibrating the model. When the model was completed and calibrated, a bottleneck in the Line A was identified, having only 24 Equivalent Residential Units (ERUs) of unallocated capacity remaining. Currently, approximately 60% of this capacity is made of actual measureable flow, and about 39% of the capacity is taken up by flow allocated to future development (unbuilt lots in upstream subdivisions). This bottleneck is shown on Figure 2, and is located in the first alley east of South Meridian, north of 7th Street East. once identified, the City evaluated the sanitary sewer system to identify any means for providing additional capacity to Line A. As a short term solution, the City synchronized three lift stations from developments on Three Mile Drive. Before the synchronization project, all three lift stations could run at once, causing a surge in sewage flows. After the project was completed, anytime the largest lift station pumped, the other two smaller lift stations were postponed until the largest lift station finished pumping. This reduced the downstream surge by nearly 390 gpm, adding 155 Equivalent Residential Units of additional capacity in Line A. Currently, the remaining capacity at this point in Line A is 149 ERUs. At the current development rate, this remaining capacity is estimated to last approximately two years. Page 2 of 7 West Side Interceptor (WSI) Ultimately, the City recognizes the WSI as the necessary long term solution for sewage capacities in Line A (see Figure 3). The WSI would provide a means to reduce gravity sewage flows in Line A by redirecting the flows to the WSI at key locations. With the first phase of construction, flows from developments on the western portions of Three Mile Drive will be routed to the WSI. Future phases would extend the interceptor further to the north, eventually intercepting flows from Lift Station 36. The WSI will reconnect to Line A at a section of 30" main with ample remaining capacity. As the service area continues to develop, southern portions of the West Side Interceptor and current Line A south of the 30" connection will need to be improved, but these improvements are not projected to be necessary for 30 to 60 years. WSI Preferred Routing The City selected Robert Peccia and Associates (RPA) as the engineer of record for the planning, design and construction of the WSI. As their first task, RPA developed recommendations for the routing of the WSI. This task also included: determining a service area based on City planning boundaries and zoning projections; sizing an interceptor for the service area through sewer system modeling; evaluating preliminary environmental impacts for the recommended route; easement and property purchase estimates; and design and construction cost estimates for the recommended route. RPA estimates $14 million in property purchases, design, and construction costs to complete the WSI as shown in Figure 3. Please also refer to Figure 3 for the service area and recommended route. Tentative Design and Construction Schedule Design and construction of the WSI can be completed using the collection portion of City Sewer Impact Fees. The City projects approximately $1.25 million in impact fee revenue available for the project by the end of Fiscal Year 14/15 (FY 14/15). With these funds, the City plans on constructing a casing underneath the Kalispell Bypass just south of Highway 2 in FY 14/15. Additionally, the City will sign a task order for RPA to complete all necessary surveying on Phase 1 of the WSI to secure the land purchases and easements required for the recommended route. Figure 1 - Tentative Timeline for Design and Construction of the West Side Interceptor Page 3 of 7 In FY 1511 6, the City plans on purchasing the required properties and easements to secure these routes as well as having RPA design the South Meridian Lift Station. In FY 1 d117, RPA should be able to complete the design of the WSI. After the route is secured and the design is complete, the City would begin the construction of the WSI based on available funding. Funding the construction of the WSI is anticipated to be completed through the use of one or more State Revolving Fund loan(s). Loan payments are anticipated to be paid through applicable sewer impact fee revenue. Proposed Design and Construction Trimiers The City of Kalispell has demonstrated a clear commitment to the West Side Interceptor project. This fiscal year, the City of Kalispell has paid over $150,000 for RPA to complete the tasks required for the WSI preferred route assessment and casing design under the Kalispell bypass. Additionally, the City will pay for the construction of the casing pipe for the interceptor under the bypass this fiscal year. This cost is currently estimated at $250,000. In consideration of the City's clear financial commitment to the West Side Interceptor, but also recognizing the financial burden involved to construct the entire project and the time required to secure a route and design the project, the City requests a deviation to Circular DEQ-2 Standard 20.14 and the corresponding MFE process for determination of available sewer capacity. To ensure proper efforts are made towards the standard provisions for sanitary sewer capacity as typically required through. the MFE process, the following conditional triggers would be applied, similar to the current conditions on Grandview Lift Station: l . When measured flows reach 70% of the pipe capacity at the bottleneck location in Line A, the City will complete any remaining portions of design for the West Side Interceptor. 2. When measured flows reach 75% of the pipe capacity at the bottleneck location in Line A, the City will secure funding for the construction of the West Side Interceptor. 3. When measured flows reach 80% of the pipe capacity at the bottleneck location in Line A, the City will begin construction of the West Side Interceptor. 4. When measured flows reach 85% of the pipe capacity at the bottleneck location in Line A, the City will stop issuing building permits for areas upstream of the bottleneck. 5. These conditions will not override or void conditions previously placed on Grandview Lift Station. Flows will be measured in the pipe at the upstream manhole closest to the identified bottleneck. Flows will be monitored for a 2 week interval using the City of Kalispell metering equipment. The City recommends completing flow metering during the month of June, which is recognized as the rainy month for Kalispell, when inflow and infiltration are typically at their peaks. When trigger number 3 is reached, the City will perform 2 week flow metering at the bottleneck location biannually, once in June and again in December. A summary of flow metering results will be provided to MDEQ for review after completion of all annual or biannual metering. Page 4 of 7 Conclusion Kalispell Public Works Department proactively operates and manages the sanitary sewer collection system. Proactive management and operation requires looking into the future, as demonstrated by the completion of the 2008 Facility Plan Update and 2012 system wide sewer modeling update. In order to address continued growth beyond currently allocated sewer capacities in Line A, the City is moving forward with the design and construction of the West Side Interceptor project. Although, portions of design and construction are currently underway, the City requests a deviation to the MFE approval process for Line A south of Grandview Lift Station to allow for proper planning and funding of the project. To ensure allocated capacities are protected, the City will proceed with design and construction as required in the aforementioned conditional triggers. I greatly appreciate your consideration for a deviation to the MFE sewer capacity methodology on Trunk Line A. Please feel free to contact me with questions or for further clarifications. Sincerely, Keith Haskins, PE Senior Civil Engineer 406-75 8-7727 Page 5 of 7 ^'tom_ y '\ i■ � -{ram r ■ y • � f7 -iV� w 1VA all ra y, _.. lop Ar f y 1 It� � 1T � . �� � ■ -1� i r+ A .. •. � out-. ■Nqbrit V`_ +4�'� r � . tiR t �ii�.I� •� a i-. y -'a'e„ _. - tom. _ � • IP '�•7. III 'I ; iw tis•. -y. • r ,'�`[•1r r J;ft .■• '1r - ■ �I '�Jr r h 1�. - }' �r •. for _�jp i•�,� �-.�. - 1 r - • - "■ • r * +� �1 r c6 r CowleGo � II � • x � a } . � 'fix' �1 - 6 i _fie/� 1p - ., � � f • - ti � .. _art• _ - � ■� 1 �� ■■e:S� � � ■� � • .±fir �' �--` �r•-..� ..:, ; ..• � 1 �- ����--� �wr j, s ►. >i. 12 ■ � , �+ : �o.' . 'F - ;fir: �" •;,�. 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