TOWN OF OSOYOOS WATER SYSTEM MASTER PLAN PART 3 IRRIGATION SYSTEMS 8 & 9 UPGRADING PLAN

Transcription

1 TOWN OF OSOYOOS WATER SYSTEM MASTER PLAN PART 3 IRRIGATION SYSTEMS 8 & 9 UPGRADING PLAN Prepared by: TRUE Consulting Group Our Ref: August 2008

2 TABLE OF CONTENTS Page SECTION 10.0 IRRIGATION SYSTEMS 8 AND 9 UPGRADING OBJECTIVES...1 SECTION 11.0 OVERVIEW OF UPGRADING OPTIONS General Filtration and Disinfection Point of Use Treatment Systems Twin Domestic Distribution System Comparative Assessment of Options...8 SECTION 12.0 TWIN DOMESTIC SYSTEM DESIGN CRITERIA Level of Service Water Demand Water Meters...16 SECTION 13.0 TWIN DOMESTIC DISTRIUBTION SYSTEM RURAL LEVEL OF SERVICE Overall System Description Water Supply and Storage Irrigation System 8 Service Area Irrigation System 9 Service Area Capital Cost Estimates...26 SECTION 14.0 TWIN DOMESTIC DISTRIUBTION SYSTEM MUNICIPAL LEVEL OF SERVICE Overall Description Water Supply and Storage Irrigation System 8 Service Area Irrigation System 9 Service Area Capital Cost Estimates...33

3 SECTION 10.0 IRRIGATION SYSTEMS 8 AND 9 UPGRADING OBJECTIVES Previous sections of this Water Master Plan provide a detailed assessment of Irrigations Systems 8 and 9 focusing on compliance with Interior Health Authority Drinking Water Objectives. Systems 8 and 9 are supplied by a common water distribution system domestic and irrigation water in the rural areas north and south of the Town of Osoyoos on the west side of Osoyoos Lake. The service areas of Systems 8 and 9 are illustrated in Figure From separate intakes in Osoyoos Lake, Osoyoos Lake water is chlorinated and pumped into water distribution systems. Available water quantity is not an issue with Systems 8 and 9. For surface water sources used for domestic (drinking water) purposes, IHA Drinking Water objectives require: 4 log reduction of viruses. This objective is usually achieved by chlorination and maintaining a 0.5 mg/l free chlorine residual after 20 minutes of contact time. While chlorination is provided at both the System 8 and 9 intakes, chlorine contact time to the first domestic connection is estimated to be in the range of 2 to 3 minutes under maximum day demand conditions. 3 log removal of giardia and cryptosporidium. Compliance with the 3 log requirement for giardia and cryptosporidium removal and/or inactivation generally requires filtration for water derived from surface water sources. Neither of the System 8 or System 9 water systems are filtered. 2 treatment barriers. For surface water sources, 2 treatment barriers usually comprises filtration and chlorination. Where the surface water source is of high quality and has low contamination risks, ultraviolet disinfection (UV) may be an acceptable second barrier. <1 NTU turbidity. Consistent compliance with the IHA standard of <1 NTU turbidity for surface water sources generally requires filtration. 0 Fecal Coliform or EColi bacteria. This requirement is generally achieved for surface water sources, by filtration and chlorination The principal upgrading objective for Systems 8 and 9 is source treatment to achieve compliance with Interior Health drinking water quality objectives for the 450 domestic connections serviced by Systems 8 and 9. Specifically related to compliance, IHA has: Water System Master Plan Page 1

4 in its operating permits issued for the Town s water systems, described requirements for the Town to provide a long term plan for source, treatment and distribution system improvements to achieve compliance with the treatment objectives. by letter dated October 01, 2007, required the Town to provide evidence that adequate chlorine contact time was being achieved during the irrigation season or place the systems on a boil water notice. Chlorine contact times are not adequate in Systems 8 and 9 during the irrigation season therefore Systems 8 and 9 have (2008) been placed on a boil water notice for the irrigation season (mid April to early October). Until upgrading is completed, the Boil Water Notice for the Systems 8 and 9 service area will be an annual requirement during the irrigation season. by letter dated December 07, 2007, advised the Town that the proposed development at Willow Beach should be considered for service by System 8 by the Town and the potential opportunity to accelerate, with developer contributions, upgrading of System 8 to achieve compliance. Consistent with the requirements of Interior Health, this section of the Water Master Plan assesses options and presents a plan for upgrading of Systems 8 and 9 to achieve compliance. Also as suggested by IHA, this section assesses upgrading of System 8 to provide a municipal level of service which would enable the Town to provide service to new development with focus on the Willow Beach development proposal. Water System Master Plan Page 2

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6 SECTION 11.0 OVERVIEW OF UPGRADING OPTIONS 11.1 General Concurrent with the Town of Osoyoos assuming ownership of Irrigation Systems 8 and 9 from SOLID, the Town of Oliver assumed ownership from SOLID of irrigation systems 1, 2, 4, 5, 6 and 7. With the exception of Systems 2 and 5, the Town of Oliver operated irrigation systems are combined irrigation/domestic systems with water supplied from a surface water source and treatment consisting of chlorination with contact time substantially less than 20 minutes during the irrigation season. The Town of Oliver has proceeded with a phased plan to provide a Twin domestic system supplied by groundwater sources to achieve compliance. This plan has been approved by regulatory agencies and the Town of Oliver has been successful securing grants from senior government to assist with its implementation of the Twinning program. Recognizing the similarity of Irrigation Systems 8 and 9 to the irrigation systems operated by the Town of Oliver, the alternative of a Twin domestic system supplied by groundwater was identified from the outset as the preferred approach to achieve compliance. In overview detail, it is however appropriate to review the options available to the Town of Osoyoos to achieve compliance to confirm that Twin domestic systems is the least cost and preferred option Filtration and Disinfection Compliance with the IHA drinking water objectives could be achieved by constructing filtration at both the Systems 8 and 9 intakes into Osoyoos Lake. Filtration would be followed by chlorination and contact time to achieve a 4 log reduction of viruses. Conceptually, the filtration and disinfection option would comprise: two separate filtration plants, one at the System 8 pumphouse and one at the System 9 pumphouse. These plants would be sized for the peak pumping rate, 40 ML/day at System 8 and 45 ML/day at System 9. chlorine contact chambers at each pumphouse sized for a minimum of 20 minutes of contact time at peak pumping rates. At each location the chlorine contact chambers would have a capacity of about 800 cubic meters. a second set of pumps would be necessary at each location to deliver water from the chlorine contact chamber to the distribution system. Water System Master Plan Page 4

7 Factors which contribute to the concept of filtration and disinfection not being a practical option include: system capital costs. Assuming conventional filtration would be provided, the treatment plant capital costs were estimated to be of the order of $40.00 Million based on comparison to a plant under construction (2007) in Summerland at a cost of $20.00 Million + having a capacity of 74 ML/day. no available sites for a water treatment plant and the challenge of residual management at the System 8 intake with the closest municipal sewer being more than 3 km to the south. The System 9 intake/pumphouse is located in a residential neighbourhood with no site being available in relative close proximity. operating costs at the cost to the agricultural industry for irrigation water. It is estimated that less than 5% of the total annual water quantity supply by Systems 8 and 9 (approximately 11,000 ML annually) is used for domestic purposes including lawn and garden irrigation. Using an operating cost of $60 per ML prepared for a conventional filtration plant under construction (2008) in Kamloops, annual operating costs for filtration including chemicals, electrical energy, materials replacement, operators and administration, suggest that operating costs would be of the order of $660,000 annually. the cost of filtered and disinfected water for irrigation purposes would be cost prohibitive to the agricultural industry. The average irrigation water use in the System 8 and 9 service area is estimated to be 1.2m or about 5 ML/acre. The operating cost to provide 5 ML/acre for filtration and disinfection would be about $300 per acre which compares to the present irrigation tax (usage) rate of $ per acre. The costs to the agricultural industry would have to increase by at least 300% to about $450 per acre per year if conventional filtration were provided Point of Use Treatment Systems IHA drinking water quality objectives could theoretically be complied with by the installation of a treatment plant in each home serviced by Systems 8 and 9. There are a variety of single family residential unit size treatment plants available and the selection of a preferred type or technology would have to be based on performance tests of several alternatives. Conceptually, the point of use option would involve: Water System Master Plan Page 5

8 supply and installation of each of the 450 domestic connections in the System 8 and 9 service area of a point of use water treatment plant. the point of use water treatment plants would be owned, operated and maintained by the Town of Osoyoos. For up to 500 point of use water treatment plants with each unit anticipated to require a minimum of one service call per year, operating requirements are likely to require 2 full time staff members. Factors which affect the feasibility of the point of use treatment plant option include: the capital costs will be of the order of $5.00 Million including an engineering and contingency allowance and an assumed average supply cost of $10,000 based on a process comprising granular activated carbon (GAC) filtration, ultrafiltration using membranes and UV disinfection. operation and maintenance costs for each unit for GAC replacement annually, membrane replacement every five years and UV bulb replacement annually is estimated to represent an annual cost of about $500 per unit. the Town may have to hire up to two full time staff to operate and maintain the Point of Use systems and be on call on a 24 hour a day basis to respond to emergencies. Operation and maintenance costs for staff will likely represent an annual cost to the Town of about $140,000 annually or about $300 per year per installed unit. the Town will be subject to responding to service situations resulting from inappropriate use of the treatment units. The costs associated with addressing these type of calls is not quantifiable. whether or not POU treatment plants would be a long term solution for compliance acceptable to IHA is to be determined. POU treatment plants are identified as an acceptable option for small systems of less than 500 users. the POU option would not be consistent with the opportunity to service new development with the objective of securing capital cost contributions to assist with the implementation of a compliance plan. To May 2008, there has been no experience whereby a water purveyor has utilized point of use individual water treatment plants on a scale comparable to Systems 8 and 9 for compliance with Interior Health criteria. Water System Master Plan Page 6

9 11.4 Twin Domestic Water Distribution System Conceptually, the Twin domestic water distribution system option comprises the construction of separate domestic water distribution throughout the service areas of Systems 8 and 9. The Twin domestic system would be supplied from the Town s municipal water system and compliance thereby achieved. Existing Systems 8 and 9 remain in service only as irrigation water supply systems. For long range capital budget planning purposes an order of magnitude capital cost estimate of $11.0 Million was prepared in November Advantages associated with the Twin domestic water system option are: the Twin system is not anticipated to result in significantly increased operation and maintenance costs. Electrical energy costs associated with the booster station supplying the Twin system should be offset by reduced electrical energy costs for the irrigation intakes. the Twin system offers the opportunity to provide a level of fire protection throughout the service area of Systems 8 and 9. In the summer months Systems 8 and 9 are operated as pressurized systems therefore do not have a fire protection capability. the Twin system option would enable the Town to consider service to new development as suggested by Interior Health. when the construction of the Twin domestic distribution system is complete and all domestic services supplied from the Twin system, chlorination at the Systems 8 and 9 pumphouses could be discontinued. As it relates to the irrigation system chlorination systems, annual cost savings are estimated to be $25,000 and would include: chlorine purchase costs (13.7 tones 2007) +$15,000 chlorine system operation and maintenance est. +$5,000 chlorine residual measurements throughout the irrigation systems service area est. +$5,000 Discontinuation of chlorination at the Systems 8 and 9 pumphouses would enable the Town to avoid future costs for compliance with increasingly stringent operation and safety standards for chlorination systems. Water System Master Plan Page 7

10 11.5 Comparative Assessment of Options Options reviewed in overview detail for compliance with Interior Health Drinking Water Objectives are summarized as follows. Option Order of Magnitude Capital Cost Increase in Annual Operation and Maintenance Cost Filtration and Disinfection $40.0 Million $660,000 Point of Use Treatment Systems $5.0 Million $400,000 Twin Domestic Distribution System $11.0 Million $0 Filtration and disinfection is not a feasible option on the basis of the estimated $40.00M capital cost and operating costs which would result in prohibitive user charges to the agricultural industry. The point of use option has a lower capital cost that the Twin domestic system option, however a significantly higher annual operation and maintenance cost. If the $400,000 annual operation and maintenance cost associated with the POU option is converted to an equivalent capital cost, the equivalent capital cost of the POU and Twin system option would be comparable. As discussed in Sections 11.3 and 11.4, the Twin domestic system option has the following advantages as compared to the Point of Use treatment option: the Twin system option provides the opportunity to provide a level of fire protection in the service area of Systems 8 and 9. the Twin system represents an option approved by regulatory agencies. There is no experience with POU treatment systems on the scale of 450 connections for Systems 8 and 9. the Twin system option has a design lifetime of the order of 100 years. The functional lifetime of POU treatment systems is uncertain and likely in the range of 10 to 15 years. the Twin system option provides the Town the opportunity to assess service to new development with the objective of securing capital contributions to the system construction. the Twin system option would enable the Town, at some future date to discontinue chlorination at the Systems 8 and 9 pumphouses. Water System Master Plan Page 8

11 While the comparison of options is presented in overview detail, the option of Twin domestic distribution systems to achieve IHA compliance for the Systems 8 and 9 service area is identified as the preferred option. Water System Master Plan Page 9

12 SECTION 12.0 TWIN DOMESTIC SYSTEM DESIGN CRITERIA 12.1 Level of Service The principal objective of the proposed Twin Domestic water distribution system is the provision of domestic water to residents in the service area of irrigation systems 8 and 9 of a quality fully complying with Interior Health s treatment standards. An important secondary functional objective of any community water system is the provision of a water supply for fire protection purposes. As it relates to the conceptual planning of the twin domestic water systems, options for the fire protection capability of the proposed distribution system are: design twin domestic system for domestic service only. In this case, some level of fire flow would be available from the primary supply mains only, i.e. proposed primary supply main along H97 in System 8 and proposed primary supply main on 107 th Street in System 9. With the exception of areas immediately adjacent to these primary supply mains, all other areas within Systems 8 and 9 would not have distribution mains having a capacity to provide fire flow in an amount ratable by the Insurance Industry. If the twin distribution system is sized for domestic service only, primary supply mains would range in size from 100mm to 200mm and distribution mains would generally be 50mm to 100mm. design twin domestic water system with a fire protection capability consistent with Design Guidelines for Rural Residential Community Water Systems as prepared by the Ministry of Environment. The design fire flow as specified in these guidelines is 30 L/sec (500 USgpm) for a duration of one hour. RDOS subdivision and development servicing bylaw no. 2000, 2007 specifies a fire flow of 38 L/sec in rural areas with predominantly residential zoning and where fire fighting equipment is limited. Consistent with a rural water standard, the twin domestic distribution system would be sized to provide a fire flow of 30 L/sec within 150m of all residences in the service area of System 8 and 9. The distribution system would in this case comprise looped 150mm mains with comparatively short laterals of smaller diameter mains, typically 50mm to service properties within 150m of the looped 150mm distribution system. design twin domestic water system to provide a fire protection capability consistent with accepted municipal water system standards. The Fire Underwriters Survey (FUS) publishes a guideline titled Water Supply for Public Fire Protection which is widely accepted as a guideline for municipal water Water System Master Plan Page 10

13 systems. For residential areas, the FUS guideline suggests a minimum fire flow of 60 L/sec (1000 USgpm) for a duration of 1½ hours. This municipal fire flow standard would require a looped water distribution system principally comprising 200mm watermains and, with the exception of short service lines, a minimum distribution main size of 150mm. For the preliminary design of the twin domestic water systems in the Irrigation System 8 and 9 service area, a design fire flow of 30 L/sec consistent with rural community water system design guidelines is considered appropriate. The exceptions are urban density developments along 87 th Street in System 8 and on the 85 th, 87 th and 91 st Streets between 12 th Avenue and 26 th Avenue in System 9 (refer to Figures 12.1 and 12.2) which are suggested to be serviced by an extension of the Town s municipal water system and thereby provided fire protection consistent with municipal standards, i.e. minimum fire flow of 60 L/sec. Sizing the twin domestic water systems without a fire protection capability is not considered appropriate recognizing the number of properties to be serviced (approximately 440), and recognizing that the area is currently provided fire protection by the Town of Osoyoos fire department. Utilizing a municipal standard for the complete service area is also not considered appropriate recognizing the costs associated with larger sized distribution mains and quality concerns that may arise related to long water residence times in these mains. The RDOS is processing two significant development proposals within or adjacent to the service area of Irrigation System 8. The proposed Willow Beach development is located at the north end of Osoyoos Lake and comprises 1088 residential units at a multifamily density. The second development proposal, Reflection Point, is located on the Osoyoos Lakeshore at the east end of 120 th Avenue and comprises 37 residential lots. To service these developments, the Twin domestic water distribution would have to be designed for a fire flow capability consistent with municipal standards. A second preliminary design for the System 8 Twin system has been prepared based on a municipal level of fire protection service to the proposed Willow Beach development. For this option, it is assumed that the design fire flow is 150 L/sec (2400 USgpm) for a duration of two hours. With the Willow Beach development being located at the extreme north end of System No. 8, system design to provide a municipal standard fire flow to this development results in this municipal standard being provided everywhere within the System 8 service area. Water System Master Plan Page 11

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16 12.2 Water Demands For the purposes of estimating water demands of the Twin water system, it is assumed, as a fundamental design criteria, that existing irrigation systems servicing properties in the System 8 and 9 service area will be utilized to the greatest extent practical to supply lawn, garden and agricultural irrigation demands. Lawn and garden irrigation represents the largest usage component of the Town s municipal water system. With the supply to the Twin systems intended to be provided from the Town s municipal system and recognizing that the supply capacity of the Town s municipal system is limited as described in previous sections of this report, it is essential that usage from the Town s municipal sources for irrigation from the Twin system be limited to the greatest extent practical. On this basis, it is proposed: where a service from Irrigation System 8 and 9 will, following Twinning, continue to be available to a property, this service will remain functional for irrigation purposes. In this case, properties will have two services, one domestic for in house uses and one for irrigation purposes. the Twin system will connect to existing mains with the result that properties will have a single service for all uses, only where there is a concentration of typical urban density lots. Twining in existing urban density neighbourhoods is not proposed because there are options to reduce lawn and garden irrigation and twinning in these areas would significantly increase overall project costs. all new development will be serviced by both the Twin system and the existing irrigation system, i.e. dual water system. New development will therefore not represent an additional lawn and garden irrigation water demand on the Town s municipal system through the Twin system. For purposes of sizing the proposed Twin water system, the important design criteria is the maximum day water demand. The maximum day water demand of the Town s municipal water system is 3900 L/capita per day which includes a lawn and garden irrigation component. This demand criteria is applicable to single family residential properties to be serviced by a single service by the Twin system. There is little or no historical data which can be used to estimate maximum day demands for in house use (i.e. no lawn and garden irrigation component). Without historical data, domestic only demands are assumed to be 600 L/day under maximum day demand conditions. Water System Master Plan Page 14

17 On the basis of the assumed maximum day demand criteria for each type of service, the estimated existing maximum day demands for the proposed Twin domestic distribution system is: System 8 Service Area: Single Services (combined domestic/irrigation) 36 lots x 2.2 people/lot x 3900 L/capita = ML/day Dual Services (separate irrigation/domestic) 165 lots x 2.2 people/lot x 600 L/capita = ML/day Total System ML/day (100 USgpm) System 9 Service Area: Single Services (combined domestic/irrigation) 104 lots x 2.2 people/lot x 3900 L/capita = ML/day Dual Services (separate irrigation/domestic) 134 lots x 2.2 people/lot x 600 L/capita = ML/day Total System ML/day (190 USgpm) Total Systems 9 and ML/day (290 USgpm) The Twin system represents an additional demand under maximum day demand conditions of 1.59 ML/day or about an 8% increase in the current municipal system maximum day demand of 20 ML/day. Source upgrading and/or demand management has to be undertaken concurrently with the proposed Twin system if the Twin system is to be supplied by the municipal system. The impacts of new development representing additional demands on the municipal system water sources under maximum day demand conditions will be minimized with the adoption of the recommended dual water system standard. Build out domestic demands of proposed development in the System 8 service area are derived following. Willow Beach 1088 units x 2.2 people/unit x 600 L/capita = 1.43 ML/day 104 th Avenue (Reflection Point) 37 lots x 2.2 people/lot x 600 L/capita = 0.05 ML/day Total System ML/day (270 USgpm) Water System Master Plan Page 15

18 These two developments would represent an increase of the number of connections serviced by the Twin system from 439 to 1564 (350% increase) but the corresponding maximum day water demand increase is limited to 100% Water Meters Demand management will be essential to extending the service capacity of the Town s municipal system water sources. A universal metering program for the municipal system service area has been adopted in principle by the Town. Consistent with the Town s universal meter program for the municipal system, it is proposed that meters be installed concurrent with the Twin system construction on all domestic water services in the System 8 and 9 service area. The metering policy proposed for the System 8 and 9 service area would be as follows: all meter installations for existing services would be a component of the overall project cost. Meter supply and installation would not therefore be a direct cost to the property owner. for all properties to be provided a single combined irrigation/domestic service, the water meter would be installed in the residence in accordance with Town standards. If the homeowner s irrigation system is connected to the water service between the property line and the house, the homeowner at his cost will be responsible for the costs to relocate the irrigation take off to a point downstream of the meter. for all properties to be provided dual services, one domestic from the Twin system and one irrigation from either Irrigation System No. 8 or 9, a pit style meter will be supplied and installed by the Town on the domestic service as close as practical to the property line. This meter will be connected to the homeowners existing domestic service. The existing irrigation service will remain unmetered until the point in time that the Town implements a metering program for agricultural irrigation services. all new connections to both the Twin system and existing irrigation system will be metered without cost to the Town. Some examples of new services are as follows: the owner of a 3.0 ha agricultural property applies for a domestic service from the Twin system for a 4 unit tourist accommodation development. This service would be metered by a pit style meter at property line as a condition of connection approval. Water System Master Plan Page 16

19 as part of a comprehensive development, water service will be provided to a multistory 60 unit strata development. This building would require 2 meters, one domestic from the Twin system and one irrigation from the irrigation system. Both meters would be supplied and installed by the developer in accordance with Town Standards. a 10 lot strata single family residential development is proposed. In this case the developer would be required to construct a dual water distribution, an extension of the Twin system for domestic service and fire protection and an extension of the irrigation system to provide an irrigation service to each lot. The irrigation services would be metered by pit style meters inside property lines constructed as a component of the development services and domestic meters inside each residence constructed when the house construction proceeds. Implementing the proposed metering policy for the Twin system and irrigation system will be complicated by the fact that the Twin system service area is for the most part in RDOS Electoral Area A and the Town does not therefore have building permit jurisdiction. A protocol whereby all building permit applications are referred by the RDOS to the Town for review of water meter design compliance with Town Standards will be essential. Without this protocol, there is the risk of unanticipated use from the Twin system and resultant risks of compromising the adequacy of the municipal system source capacity. The recommended metering policy for the Twin domestic water system represents the potential of significant reduction of the maximum day demands derived in Section Assessments comparing before and after metering water consumption data typically report reductions in average annual water in the range of 20 to 25%. It is accepted that metering will reduce the maximum day demand however percent reductions are more difficult to quantify recognizing that water meters are typically read on a quarterly basis. For purposes of calculating water demands of the Twin system from the Town s municipal system, it is assumed that metering of all Twin system services will achieve a 15% reduction of the maximum day demands. This assumption is considered to be conservative. Table 12.1 summarizes estimated maximum day demands of the Twin system with metering. Water System Master Plan Page 17

20 Table 12.1 System 8 and 9 Twin Domestic Water Distribution System Maximum Day Demands System 8 Service Area: Single Services 36 lots x 2.2 people/lot x 3900 L/capita x 85% = 0.26 ML/day Dual Services 165 lots x 2.2 people/lot x 600 L/capita x 85%= 0.18 ML/day Total System ML/day (85 USgpm) System 9 Service Area Single Services 104 lots x 2.2 people/lot x 3900 L/capita x 85% = 0.76 ML/day Dual Services 134 lots x 2.2 people/lot x 600 L/capita x 85%= 0.15 ML/day Total System ML/day (160 USgpm) Total Systems 8 and ML/day (245 USgpm) Water System Master Plan Page 18

21 SECTION 13.0 TWIN DOMESTIC DISTRIBUTION SYSTEM RURAL LEVEL OF SERVICE 13.1 Overall System Description Conceptually, the Twin domestic water distribution system project is envisioned as two phases, the System 8 service area and the System 9 service area. The System 8 service area is represented by all areas not serviced by the Town s municipal water system and within the Water District boundary on and north of 74 th Avenue. The System 9 service area is represented by all areas not serviced by the Town s municipal water system and within the Water District boundaries south of 74 th Avenue. Whether the System 8 service area is Phase 1 and the System 9 service area is Phase 2 will be a decision of Town Council. The experience of the Town of Oliver with a similar twinning project is that senior governments are more prepared to consider financial assistance if the project is undertaken on a phased basis. For purposes of this report, it is assumed that the System 8 service area would be Phase 1 because: while the total number of services in each system is relatively the same (201, System 8 and 238, System 9), there are a fewer number of single services in the System 8 service area. The Twin system into System 8 therefore represents a significantly lower maximum day water demand on the Town s municipal system. the Town has received two major applications for water service in the System 8 service area (Willow Beach and Reflection Point). If the Town agrees to service one or both of these developments, service will be from the Twin system. As a component of the first phase of the Twinning implementation, supply works will have to be constructed. These supply works are described in Section 13.2 and would be sized for both the System 8 and 9 service area Water Supply and Storage Recognizing that 74 th Avenue is reasonably central to both the System 8 and 9 service areas, supply works to provide a rural level of service are proposed to be constructed in this area where the Town currently has the municipal 340 water reservoir, the irrigation system 8/9 balancing reservoir, the 402 municipal booster station and the 402/340 pressure reducing station. All of this existing supply infrastructure makes the Water System Master Plan Page 19

22 construction of supply infrastructure for the Twin domestic system relatively straightforward. Referring to Figure 13.1, the components of the proposed water supply works comprise: a 650m 3 (170,000 USgallon) cast in place concrete water reservoir with an operating full water elevation of 360m. This operating full water level is about 20m higher than the Town s municipal reservoir and is determined by maintaining a minimum service pressure of 275 kpa (40 psi) to all services in the Twin system 8 and 9 service area. The highest elevations in the service area are within System 8 north of 346 th Avenue. The reservoir capacity is determined on the basis of: Fire Storage 60 L/sec for 1.5 hours = 324m 3 Balancing Storage m 3 /conn. = 327m 3 Total Storage = 650m 3 While the design fire flow is 30 L/sec for 1 hour, large segments of the System 8 and 9 service area will, because of their proximity to the source of supply, have a fire flow capability consistent with municipal standards. Sizing the proposed Twin reservoir for a municipal residential fire flow is therefore considered appropriate. Balancing storage is considered essential recognizing the system is designed to supply in house water demands and in house water demands typically peak in the early morning and early evening. Balancing storage is calculated as 15% of the municipal maximum per capita demand of 3900 L/capita with a 15% reduction factor for metering. The reservoir location is approximate and would be finalized to minimize conflicts with an adjacent fairway of the golf course. a booster station to supply the Twin Reservoir from the 400mm municipal system water supply main. The location of this booster station is shown schematically on the east side of the abandoned irrigation canal. This location has advantages of straightforward access from 74 th Avenue and minimizes conflicts with a future road and the Osoyoos Golf Course. Water System Master Plan Page 20

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24 approximately 250m of 250mm water supply main from the Twin system booster station to the Twin reservoir and a connection to the existing 250mm AC Twin system supply main on 74 th Avenue. The 402 pressure reducing station constructed in 2008 would remain in service as an alternative or standby source of supply from the municipal system to the Twin system. In the event of an extended interruption in electrical service or a major fire flow event, the pressure reducing station would supply to the Twin system from the municipal system 402 pressure zone Irrigation System 8 Service Area The proposed Twin domestic distribution system within the System 8 service area is illustrated in Figure In general, a parallel domestic water distribution line is proposed everywhere there is an existing irrigation. Referring to Figure 13.2, components of the proposed Twin domestic distribution system are: a 250mm PVC primary distribution in the H97 corridor starting from a connection to existing at the H3 H97 intersection and extending north about 4 km to the intersection of H97 and 103 rd Street (location of 8A irrigation booster station). This main is intended to be located in either the west or east boulevard of H97. The appropriate boulevard would be determined in the course of detailed design and would consider available area, restoration requirements, conflicts with existing services, particularly the existing irrigation system, overhead utility conflicts, etc. to the greatest extent practical utilizing local roads, looped distribution mains are proposed with the objective of minimizing stagnation that is associated with dead end unlooped mains. Distribution system loops include: 150mm distribution main east of Highway 97 on 108 th Avenue to 87 th Street, north on 87 th Street to 122 nd Avenue and then west on 122 nd Avenue to H mm distribution main west of H97 on 146 th Avenue to the Old Canal Right of Way, and north within existing irrigation rights of way to the intersection of H97 and 103 rd Street. 150mm distribution main east of H97 at 148 th Avenue to 89 th Street and north on 89 th Street to a connection on H97 at 168 th Avenue. Water System Master Plan Page 22

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26 connections to existing water distribution mains on 87 th Street north of the cemetery. The five existing service properties on 87 th Street would therefore have a single connection for domestic and irrigation use from the Twin system. To the greatest extent practical distribution mains are proposed to be located in road boulevard areas to minimize pavement restoration requirements. Gate valves would be provided at intersecting mains and blow offs installed at the end of unlooped mains consistent with accepted waterworks design standards. The Twin water distribution system as illustrated in Figure 13.2 has the capacity to provide a fire flow of 30 L/sec with a residual pressure of 750 kpa (20 psi) under maximum day demand conditions to the extreme north end of the service area. At the southern end of the Twin system service area available fire flows will be substantially higher in the 60 to 80 L/sec range. Within the System 8 service area, the single family residential neighbourhood on 87 th Street north of 92 nd Street including 104 th Avenue and 98 th Avenue is proposed to be serviced by the municipal water system. A 250mm extension of the municipal water system is proposed from 92 nd Avenue. In the course of detailed design, the location and number of active irrigation services in this neighbourhood would be addressed to determine whether the irrigation system could be abandoned in whole or partially. There is the option in this neighbourhood to leave the irrigation system in service and provide dual services (one domestic and one irrigation) to all serviced lots Irrigation System 9 Service Area The proposed Twin domestic distribution system within the System 9 service area is illustrated in Figure The area east of Highway 97 is proposed to be serviced by the Town s municipal water system and, as described in Section 12.1, provided a municipal level of fire protection consistent with the single family residential land use in the area. The area east of Highway 97 is proposed to be serviced by a 250mm PVC supply main in the Highway 97 corridor starting on Nighthawk Drive north of Hummingbird Lane and extending approximately 3km south to 12 th Avenue. In this area east of Highway 97, Irrigation System No. 9 would remain functional on local roads and Highway No. 97 where there are irrigation services to agricultural properties. Proposed water distribution mains would connect to existing distribution mains where existing services are to single family residential properties only. Examples in this regard are 91 st Street and 85 th Street accessed from 12 th Avenue. Both of these streets service single family land use only therefore a separate Twin distribution main is not proposed on these streets. Water System Master Plan Page 24

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28 The System 9 service area located west of Highway 97 is proposed to be serviced from the Twin domestic reservoir as described in Section Conceptually, the supply main to service the area west of Highway No. 97 is illustrated as: 250mm main within the H97 right of way from 74 th to 62 nd Avenue. 200mm main extending south from 62 nd Avenue at H97 on 107 th Street. As described previously for the System 8 service area, the objective will be to locate proposed Twin domestic distribution mains in the road boulevard areas to minimize pavement restoration requirements. Generally, it is anticipated that the Twin domestic distribution main will be located on the opposite side of the road from the existing irrigation supply main Capital Cost Estimate A preliminary capital cost estimate for the Twin water distribution system in the System 8 service area is presented in Table 13.1 and for the System 9 service area in Table As described in Section 13.3, the assumption has been made that the Twin domestic systems would be constructed in phases with the System 8 service being Phase 1. Supply components at a total estimated cost of $820,000 including allowances for engineering and contingencies are included in Table 13.1 for System 8. If the decision were made to advance the System 9 service area as Phase 1, the total estimated cost of the supply components would be subtracted from the System 8 cost (Table 13.1) and added to the System 9 costs (Table 13.2). Assumptions utilized in the preparation of the preliminary capital cost estimates as presented in Tables 13.1 and 13.2 are presented following: all proposed watermains are assumed to be located in existing public road rights of way, existing statutory rights of way or land owned by the Town. There has been no consideration of locating watermains within to be acquired statutory rights of way over private property. Water System Master Plan Page 26

29 Table 13.1 Twin Domestic Distribution System System #8 Service Area (Rural Service Standard) - Capital Cost Estimate ITEM UNIT OF ESTIMATED UNIT TOTAL NO. DESCRIPTION MEASURE. QUANTITY PRICE PRICE 1.0 Water Distribution Main mm (10 in.) m ,028, mm (8 in.) m , mm (6 in.) m , mm (4 in.) m , mm (2 in.) m , Subtotal 2,290, Water Main Fittings 2.1 Bends ea , End Caps ea , Tees ea. 28 1, , Valves - 300mm (12 in.) ea. 1 4, , mm (10in.) ea. 16 2, , mm (8 in.) ea. 7 1, , mm (6in.) ea , mm (4 in.) ea mm (2in.) ea , Standpipe Assemblies ea. 12 2, , Subtotal 169, Water Services mm PEX Service Line - Corp. & Curb Stops ea , mm service (@ 12m) m , Water Meters - Urban (in house) ea , Rural (pit type) ea , , Subtotal 514, Pavement Repair 4.1 Highway 97 - Main Lines m , Local Roads - Trench Crossings m , Main Lines m , Subtotal 1,146, Appurtenances and Miscellaneous 5.1 Connections and Disconnections ea. 5 4, , Main and Service Crossings (Hwy. 97) - Bored Main Crossing ea. 9 18, , Bored Service Crossing m , Boulevard Reseeding L.S. 15, , Subtotal 259, Booster Pump Station Zone to 360 Twin Zone 6.1 Supply / Install Pumps ea. 3 20, , Discharge Piping and Fittings L.S. 30, , Enclosure Building L.S. 60, , Electrical and Controls L.S. 60, , Subtotal 210, Twin Pressure Zone Reservoir m 3 Reservoir (Cast in Place Concrete) L.S. 350, , Valve Chamber L.S. 25, , mm Supply Main m , Tie to existing 250mm L.S. 2, , Electrical and Controls L.S. 15, , Subtotal 445, TOTAL CONSTRUCTION 5,035, Engineering and Contingencies (25%) 1,254, TOTAL c/w Rounding 6,290, Last Update - May 14, 2008

30 Table 13.2 Twin Domestic Distribution System System #9 Service Area - Capital Cost Estimate ITEM UNIT OF ESTIMATED UNIT TOTAL NO. DESCRIPTION MEASURE. QUANTITY PRICE PRICE 1.0 Water Distribution Main mm (10 in.) m , mm (8 in.) m , mm (6 in.) m , mm (2 in.) m , Subtotal 1,869, Water Main Fittings 2.1 Bends ea , End Caps ea , Tees ea. 21 1, , Valves - 250mm (10in.) ea. 8 2, , mm (8 in.) ea. 13 1, , mm (6in.) ea , mm (2in.) ea , Standpipe Assemblies ea. 10 2, , Subtotal 121, Water Services mm PEX Service Line - Corp. & Curb Stops ea , mm service m , Water Meters - Urban (in house) ea , Rural (pit type) ea , , Subtotal 502, Pavement Repair 4.1 Highway 97 - Main Lines m , Local Roads - Trench Crossings m , Main Lines m , Subtotal 657, Appurtenances and Miscellaneous 5.1 Connections and Disconnections ea. 15 4, , Main and Service Crossings (Hwy. 97) - Bored Service Crossing m , Boulevard Reseeding L.S. 15, , Subtotal 90, TOTAL CONSTRUCTION 3,241, Engineering and Contingencies (25%) 809, TOTAL c/w Rounding 4,050, Last Update - May 14, 2008

31 the capital cost estimates include provisions for pavement surface restoration on Highway No. 97 to the white shoulder line. Experience in the Oliver rural area with a similar twinning project in 2007 suggests that it is not reasonable to assume that construction can be undertaken in the H97 corridor without provisions for pavement restoration. Typically the Ministry of Transportation prefer that any cuts of the existing pavement surface be made along the white shoulder line. the capital cost estimates generally include provisions for restoration of one half the pavement surface of a local road where the right of way is 15m wide or less and where topographic and/or conflicts with other utilities are likely to result in the watermain being located within the existing pavement surface. except in areas of a single family residential density, where the Twin system or an extension of the municipal system will connect to an existing distribution main, the capital cost estimates include provisions for a 20mm (3/4 inch) domestic water service to each benefiting parcel including a water meter on connections to existing servicing piping at property line. all crossings of H97 are assumed to be constructed by boring or equivalent methods. During detailed design, opportunities may be identified for reducing the number of bored crossings by using existing casings under the Highway containing irrigation services or mains. The total estimated construction cost of the Twin systems in the System 8 and 9 service area not including allowances for engineering and contingencies is estimated to be $8.30 million of which pavement restoration provisions represent $1.80 million or 22% of the total project cost. An important aspect of the detailed design will be delineation of boulevard alignment opportunities with the objective of reducing pavement restoration requirements to the greatest extent practical. Water System Master Plan Page 29

32 SECTION 14.0 TWIN DOMESTIC DISTRIBUTION SYSTEM MUNICIPAL LEVEL OF SERVICE 14.1 Overall Description As referenced in Section 12.1, the Town has received service applications from Willow Beach and Reflection Point within the service area of System No. 8. Both service applications represent new development which will require a municipal level of service from a fire protection perspective to comply with RDOS development servicing standards. Consideration therefore has been given to the concept of the Twin system in the System 8 service area being designed for a municipal level of service. New development opportunities in the System 9 service area appear to be constrained by Agricultural Land Reserve. To May 2008, the Town has not received any application to service new development in the System 9 service area. As described in Section 13.4, the portion of the System 9 service area located east of H97 is proposed to be serviced by an extension of the Town s municipal water system, therefore water service should not be a constraint to new future development in this area providing new development is at a single family residential density consistent with available fire flow. The option of a municipal level of service is therefore limited to the System 8 service area Water Supply and Storage To provide a municipal level of service to the Willow Beach development comprising 1088 units, a reservoir is, for hydraulic considerations, appropriately located near the Willow Beach development. It is not practical to convey through pipelines the assumed required fire flow of 150 L/sec (2400 USgpm) from supply works west of 74 th Avenue, as described in Section 13.2, 6 km to the north to Willow Beach. For a municipal level of service within the System 8 service area, the proposed supply works revise as described following and as illustrated in Figure the water storage reservoir for balancing and fire storage would be located on the Osoyoos West Bench north of the Town s landfill. The Town currently has a statutory right of way over crown land at this location for the System 8A reservoir. The existing right of way is adequate in size for the proposed Twin Water System Master Plan Page 30