Appendix M. Hydraulic Transient Analysis

Transcription

1 Water Storage and Distribution Master Plan City of Barrie October 2013 Final Appendix M Hydraulic Transient Analysis Project Number: TP Appendices

2 Wednesday October 9th, 2013 Paul Smeltzer AMEC 3215 North Service Road Burlington, ON L7N 3G2 Re: Dear Mr. Smeltzer, GENIVAR Inc. (GENIVAR) is pleased to present the results of our System-Wide Transient Analysis of the Barrie water system. The analysis is an assessment of transient pressures experienced in the Barrie water system under a global power failure and recommendations on mitigating and removing their impact on the system. We trust this meet your requirements at this time. If you have any further questions, please do not hesitate to call. Yours truly, GENIVAR Inc. Jean-Luc Daviau, M.A.Sc., P.Eng Project Manager Arash Alkozai Hydraulic Modeller /aa 600 Cochrane Drive, 5th Floor, Markham, Ontario L3R 5K3 Telephone: Fax:

3 Table of Contents Transmittal Letter Table of Contents 1. INTRODUCTION BARRIE WATER NETWORK MODEL DEVELOPMENT TRANSIENT ANALYSIS Peak Hour Scenario Zone Zone 2N Zone 3N Zone 2S Zone 3S Min Hour Scenario Zone Zone 2N Zone 3N Zone 2S Zone 3S CONCLUSION AND RECOMMENDATIONS List of Tables Table 1: Top Water Level (m) in each of the pressure zones in Barrie... 2 Table 2: Water Supply Facilities... 3 Table 3: Water Storage Facilities... 4 List of Figures Figure 1: The City of Barrie Water System consisting of Zones 1, 2N, 3N, 2S, and 3S Figure 2: Color-coded map of Transmission and distribution pipes in Barrie Figure 3: Maximum Transient Pressures in Zone 1 under Peak Hour Scenario Figure 4: Minimum Transient Pressures in Zone 1 under Peak Hour Scenario Figure 5: Maximum and Minimum pressure envelops from Well #22 to Anne Res under Peak Hour Figure 6: Maximum and Minimum pressure envelops from Well W_Tiffin to Anne Res under Peak Hour. 8 Figure 7: Maximum and Minimum pressure envelops from Well W_Perry to Anne Res under Peak Hour. 9 Figure 8: Maximum and Minimum pressure envelops from Well Herr to Anne Res under Peak Hour Figure 9: Maximum and Minimum pressure envelops from Well Anne to Anne Res under Peak Hour Figure 10: Maximum and Minimum pressure envelops from Well Wood to Anne Res under Peak Hour. 10 Figure 11: Maximum Transient Pressures in Zone 2N under Peak Hour Scenario Figure 12: Maximum Transient Pressures in Zone 2N under Peak Hour Scenario Figure 13: Maximum and Minimum pressure envelops from Well P_Anne to Bayfield Res under Peak Hour Figure 14: Maximum and Minimum pressure envelops from Well JSON to Bayfield Res under Peak Hour.13 Figure 15: Maximum and Minimum pressure envelops from Well Bwood to Bayfield Res under Peak Hour Figure 16: Maximum and Minimum pressure envelops from BPS Res1-7 to Bayfield Res under Peak Hour GENIVAR i

4 Table of Contents Figure 17: Maximum and Minimum pressure envelops from Codring BPS to Bayfield Res under Peak Hour Figure 18: Maximum and Minimum pressure envelops from Res 1-7 to Cording BPS under Peak Hour. 15 Figure 19: Maximum Transient Pressures in Zone 3N under Peak Hour Scenario Figure 20: Maximum Transient Pressures in Zone 3N under Peak Hour Scenario Figure 21: Maximum and Minimum pressure envelops from Leacock BPS to Ferndale Res under Peak Hour Figure 22: Maximum and Minimum pressure envelops from Anne Res to Leacock BPS under Peak Hour.18 Figure 23: Maximum Transient Pressures in Zone 2S under Peak Hour Scenario Figure 24: Maximum Transient Pressures in Zone 2S under Peak Hour Scenario Figure 25: Maximum and Minimum pressure envelops from the Treatment Plant to Harvie Res under Peak Hour Figure 26: Maximum and Minimum pressure envelops from Well #17_#18 to Harvie Res under Peak Hour Figure 27: Maximum Transient Pressures in Zone 3S under Peak Hour Scenario Figure 28: Maximum Transient Pressures in Zone 3S under Peak Hour Scenario Figure 29: Maximum and Minimum pressure envelops from BigBay BPS to Zone 3S Res. under Peak Hour Figure 30: Maximum and Minimum pressure envelops from Harvie Res to BigBay BPS under Peak Hour.24 Figure 31: Maximum and Minimum pressure envelops from 3S BPS to Zone 3S Res under Peak Hour. 25 Figure 32: Maximum Transient Pressures in Zone 1 under Minimum Hour Scenario Figure 33: Maximum Transient Pressures in Zone 1 under Minimum Hour Scenario Figure 34: Maximum and Minimum pressure envelops from Well #22 to Anne Res under Min Hour Figure 35: Maximum and Minimum pressure envelops from Well W_Tiffin to Anne Res under Min Hour.27 Figure 36: Maximum and Minimum pressure envelops from Well W_Perry to Anne Res under Min Hour.28 Figure 37: Maximum and Minimum pressure envelops from Well Herr to Anne Res under Min Hour Figure 38: Maximum and Minimum pressure envelops from Well Anne to Anne Res under Min Hour Figure 39: Maximum Transient Pressures in Zone 2N under Minimum Hour Scenario Figure 40: Maximum Transient Pressures in Zone 2N under Minimum Hour Scenario Figure 41: Maximum and Minimum pressure envelops from Well P_Anne to Bayfield Res under Min Hour Figure 42: Maximum and Minimum pressure envelops from Well JSON to Bayfield Res under Min Hour.31 Figure 43: Maximum and Minimum pressure envelops from Well Bwood to Bayfield Res under Min Hour.32 Figure 44: Maximum and Minimum pressure envelops from BPS Res1-7 to Bayfield Res under Min Hour.32 Figure 45: Maximum and Minimum pressure envelops from Codring BPS to Bayfield Res under Min Hour Figure 46: Maximum and Minimum pressure envelops from Res 1-7 to Cording BPS under Min Hour Figure 47: Maximum Transient Pressures in Zone 2N under Minimum Hour Scenario Figure 48: Maximum Transient Pressures in Zone 3N under Minimum Hour Scenario Figure 49: Maximum and Minimum pressure envelops from Leacock BPS to Ferndale Res under Min Hour Figure 50: Maximum and Minimum pressure envelops from Anne Res to Leacock BPS under Min Hour.35 Figure 51: Maximum Transient Pressures in Zone 2S under Minimum Hour Scenario Figure 52: Maximum Transient Pressures in Zone 2S under Minimum Hour Scenario Figure 53: Maximum and Minimum pressure envelops from the Treatment Plant to Harvie Res under Min Hour Figure 54: Maximum and Minimum pressure envelops from Well #17_#18 to Harvie Res under Min Hour.37 Figure 55: Maximum Transient Pressures in Zone 3S under Minimum Hour Scenario Figure 56: Maximum Transient Pressures in Zone 3S under Minimum Hour Scenario Figure 57: Maximum and Minimum pressure envelops from BigBay BPS to Zone 3S Res under Min Hour.39 Figure 58: Maximum and Minimum pressure envelops from Harvie Res to BigBay BPS under Min Hour.39 Figure 59: Maximum and Minimum pressure envelops from 3S BPS to Zone 3S Res under Min Hour GENIVAR ii

5 1. Introduction GENIVAR Inc. was retained by AMEC to conduct a system wide transient analysis of the water network in the City of Barrie. The analysis is part of an assessment of the City s water network to service future populations up to the planning horizon of The analysis will consider existing transient mitigating appurtenance of the water network and recommend any necessary protection for future scenarios. 2. Barrie Water Network The City of Barrie water supply is a multi-zonal network consisting of both surface water and ground water supply. Until recently, groundwater was the only source of supply. In recent years the City has added a surface water treatment plant to supplement the groundwater supply. The City s water network consists of zones 1 2N, 3N, 2S, and 3S as shown in Figure 1. Figure 1: The City of Barrie Water System consisting of Zones 1, 2N, 3N, 2S, and 3S. GENIVAR 1

6 Zones 1, 2N, and 3N are supplied by groundwater while Zone 2S is supplied primarily by the surface water treatment plant and Zone 3S is boosted from 2S. The Top Water Level (TWL) for each of the zones is shown in Table 1. Table 1: Top Water Level (m) in each of the pressure zones in Barrie Zone TWL (m) N N S S Pipe sizes in the network range from 50 mm to 1,200 mm. A color-coded map of pipe diameters in the network is shown in Figure 2. Figure 2: Color-coded map of Transmission and distribution pipes in Barrie. GENIVAR 2

7 As can be seen, the Barrie water system has a well interconnected network of transmission pipes mainly connecting the supply facilities to storage tanks in the network. Table 2 and 3 summarize the supply facilities and storage available in each zone. It should be noted that the table represents 2031 conditions after zones have been re-aligned. Table 2: Water Supply Facilities Zone Water Supply Facilities 1 P_BAYVIEWPARK_1 1 W-WOOD_1 1 W_20_1 1 W_ANNE_1 1 W_CENT1_1 1 W_CENT2_1 1 W_HER1_1 1 W_HER2_1 1 W_JOHN_1 1 W_PERRY_1 1 W_TIFFIN_1 1 W_WELL#19_1 1 W_WELL#21_1 1 W_WELL#22_1 2N P_ANNE_2N 2N P_CODRING_2N 2N RES1-7-2N 2N W_BWOOD_2N 2N W_JSON1_2N 2S P_INNISFIL_2S 2S SWTP 2S W_17_2S 2S W_18_2S 2S W_HUR_2S 3N P_LEACOCK_3N 3S 3SBPS 3S P_BIGBAY_3S GENIVAR 3

8 Table 3: Water Storage Facilities Zone Reservoir TWL (m) 1 RES R_ANNE_ N R_BAYFIELD_2N S R_HARVIE_2S N R_FERNDALE_3N S R_MAP_3S Model Development The Barrie water model was imported into Bentley s Hammer to conduct the transient analysis. Hammer is a software that was originally developed by Environmental Hydraulics Group (EHG) which is now part of GENIVAR. Two separate demand scenarios were created for the analysis: Minimum Hour (Min Hr) and Peak Hour (Pk Hr). It is expected that the most sever transients occur during periods of low demand where the majority of flows are concentrated in the transmission pipes and dissipative forces are minimal or during the highest demand period where the most number of pumps are operating. The analysis was conducted for the year 2031 where the flows in the system are the highest and infrastructure upgrades (new pipes, zonal realignment, etc.) are in place. 4. Transient Analysis The transient scenarios modeled consist of simulating steady state conditions in the network for a period of five (5) seconds followed by a sudden power failure affecting all the pumps that were ON during steady state conditions. The power failure turns off power to the pumps and they start to spin slower with each turn (depending on the pump inertia) until they fully stop. Transients can originate from a variety of sources. However power failures provide a realistic approach to evaluating transient pressures experienced in a system. The immediate impact of power failure is a low pressure wave (downsurge) that originates from the pump station and travels to the rest of the network. The downsurge gets reflected as a high pressure wave (upsurge) coming back towards the pump station and the rest of the network. This process continues until the waves are dissipated through friction losses or through reliefs provided by surge valves. Depending on the location, the impact of the pressure waves could result in low pressures or high pressures. GENIVAR 4

9 The results presented provide an overview of the maximum and minimum transient pressures experienced in the zones as a result of a global power failure. The results also show the maximum and minimum head profiles experienced along some of the major transmission mains in the system. Pipes in the water network are designed to withstand steady state pressures of 100 psi (690 kpa). The majority of them also have at least a 40% surge allowance for a total of 140 psi (965 kpa). Pressures above this particularly in the distribution system is a concern since it can lead to pipe breaks, or leaks. Pipes are also designed to take short-lived vacuum pressures. However, vacuum pressures increase the risk of groundwater or solid intrusion through the pipe joints and in rare cases to pipe collapse. 4.1 Peak Hour Scenario The peak demand scenario was simulated with a global power failure and the maximum and minimum pressures experienced in the network for Zone 1 are shown in Figures 3 and 4. The results are separated for each of the pressure zones in the network Zone 1 Maximum Pressures: The maximum pressures experienced in Zone 1 under transient conditions is below 140 psi with the majority of the Zone experiencing pressures between 80 psi (550 kpa) to 100 psi (690 kpa) as shown in Figure 3. Areas experiencing high pressures are near the discharge of pumping stations and near the base of the zone where steady state pressures are typically high. Minimum Pressures: The minimum pressures in Zone 1 under the simulated scenario are shown in Figure 4. The results show that some areas of the zone do experience vacuum pressures particularly near the pressure zone boundaries. The majority of the zone however experience minimum pressures in the range of 40 psi (275 kpa) to 60 psi (415 kpa). There are also significant portions of the zone that experiences pressures less than 20 psi. These are short-lived and not expected to impact supplied pressures substantially. Transmission Profiles: Pressure profiles are provided from the groundwater wells to the storage reservoirs in Zone 1. The profiles are shown in Figures 5 to 10. Well#22 to Anne Reservoir (Figure 5): The pressure envelops along this transmission main shows that a short portion of the pipeline will undergo short-lived vacuum pressures near its discharge point into the reservoir. The pressure wave reflecting from the reservoir is mostly dissipated and the upsurge along the main is not much above what it experiences under steady state. W_Tiffin to Anne Reservoir (Figure 6): The pressure envelop along this main also shows shortlived vacuum pressures near its high point. The upsurge return wave is mainly dissipated and is only 5-8 psi (35 kpa 55 kpa) greater than steady state conditions. GENIVAR 5

10 W_Perry to Anne Reservoir (Figure 7): The pressure envelop along this main also shows a short vacuum near the reservoir but about a 10 psi (70 kpa) upsurge that is dissipated along its return. Herr to Anne Reservoir (Figure 8): The is a long transmission pipe from the well to the reservoir. The pressure profile shows localized upsurge pressures where other transmission mains join. Similar to the other profiles in Zone1, there is a few hundred meters of pipe that experiences short-lived vacuum pressures near the reservoir. The upsurge is between 5 30 psi (35 kpa 205 kpa) above steady state conditions. Anne to Anne Reservoir (Figure 9): The pressure envelope shows vacuum pressures near the reservoir with a psi (70 kpa 105 kpa) upsurge. The surge pressures are quickly dissipated in the network. Wood to Anne Reservoir(Figure 10): The pressure envelope is similar to other profiles in Zone 1. A short section of the main experiences vacuum pressures with an upsurge pressure of psi (70 kpa 105 kpa) that is mainly dissipated by the time it returns to its origin. The results on Zone 1 show that the transient pressures experienced are mild with no significant downsurge or upsurge pressures experienced. The pressures are moderated by Anne Reservoir and the well-looped network. The ground profiles along the transmission mains are also gently rising slopes that are favorable from a transient perspective. GENIVAR 6

11 Figure 3: Maximum Transient Pressures in Zone 1 under Peak Hour Scenario. Figure 4: Minimum Transient Pressures in Zone 1 under Peak Hour Scenario. GENIVAR 7

12 Figure 5: Maximum and Minimum pressure envelops from Well #22 to Anne Res under Peak Hour. Figure 6: Maximum and Minimum pressure envelops from Well W_Tiffin to Anne Res under Peak Hour. GENIVAR 8

13 Figure 7: Maximum and Minimum pressure envelops from Well W_Perry to Anne Res under Peak Hour. Figure 8: Maximum and Minimum pressure envelops from Well Herr to Anne Res under Peak Hour. GENIVAR 9

14 Figure 9: Maximum and Minimum pressure envelops from Well Anne to Anne Res under Peak Hour. Figure 10: Maximum and Minimum pressure envelops from Well Wood to Anne Res under Peak Hour. GENIVAR 10

15 4.1.2 Zone 2N Maximum Pressures: The maximum transient pressures experienced in Zone 2N are below 140 psi (965 kpa) as shown in Figure 11. The majority of the zone will experience surge pressures between psi (555 kpa 690 kpa). Some areas (particularly adjacent to Zone 1) will experience pressures between psi (690 kpa 830 kpa). Minimum Pressures: Most of the zone will have minimum pressures above vacuum pressure as shown in Figure 12. The minimum pressure in the majority of the zone will range between psi (275 kpa 415 kpa). Some areas with low steady state pressures will experience pressures below 20 psi (140 kpa). However this is short lived as the surge pressures are quickly dissipated in the network. Transmission Profiles: Transmission profiles are provided from the groundwater wells and booster stations to the Bayfield Reservoir. P_Anne to Bayfield Reservoir (Figure 13): The maximum and minimum pressure envelops along this transmission main show a pressure drop of about 50 psi (345 kpa) during the initial downsurge. However, the pressures remain above vacuum throughout the length of the watermain and surge is quickly relieved by the suction and discharge side reservoirs. JSON to Bayfield Reservoir (Figure 14): The maximum and minimum pressure envelops along this watermain also show a 50 psi (345 kpa) downsurge, however pressures remain above vacuum all throughout the pipeline. The surge is quickly dissipated and the returning upsurge is minimal. Bwood to Bayfield Reservoir (Figure 15): The pressure envelop along this main is similar to other profiles in Zone 2N and shows the pipeline pressure stays above vacuum and the upsurge is minimal. Res-1-7 to Bayfield Reservoir (Figure 16): The transmission main does not experience vacuum pressures and the upsurge pressure is lower than the initial stead state pressure. The pressure wave is dissipated through the network and relief is provided by the suction and discharge side reservoirs. Codring Discharge and Suction (Figures 17 and 18): The pressure profiles on the discharge and suction sides of Codring booster station show that there is an initial downsurge of 50 psi (345 kpa) at the discharge side while the suction side experiences an upsurge of 30 psi (205 kpa). The surge pressures are quickly dissipated and return wave is minimal. Relief is provided by the storage reservoirs on the suction and discharge side. GENIVAR 11

16 Figure 11: Maximum Transient Pressures in Zone 2N under Peak Hour Scenario. Figure 12: Maximum Transient Pressures in Zone 2N under Peak Hour Scenario. GENIVAR 12

17 Figure 13: Maximum and Minimum pressure envelops from Well P_Anne to Bayfield Res under Peak Hour. Figure 14: Maximum and Minimum pressure envelops from Well JSON to Bayfield Res under Peak Hour. GENIVAR 13

18 Figure 15: Maximum and Minimum pressure envelops from Well Bwood to Bayfield Res under Peak Hour. Figure 16: Maximum and Minimum pressure envelops from BPS Res1-7 to Bayfield Res under Peak Hour. GENIVAR 14

19 Figure 17: Maximum and Minimum pressure envelops from Codring BPS to Bayfield Res under Peak Hour. Figure 18: Maximum and Minimum pressure envelops from Res 1-7 to Cording BPS under Peak Hour. GENIVAR 15

20 4.1.3 Zone 3N Maximum Pressures (Figure 19): The maximum transient pressures experienced in Zone 3N are below 140 psi (965 kpa). The majority of maximum transient pressures in the zone range between 60 to 100 psi (415 kpa 690 kpa). The maximum pressures are experienced near the discharge of the booster station that supplies the zone. Minimum Pressures (Figure 20): The minimum transient pressures experienced in the zone range between 20 to 60 psi ( kpa). Pressure in the entire zone stays above vacuum pressure during the down surge. Transmission Profiles: Reservoir. Transmission profiles are provided from the booster station to the Ferndale Leacock Booster to Ferndale Reservoir: The pressure envelope on the discharge and suction side of Leacock PS is shown in Figures 21 and 22. The discharge side pressure envelop shows that there is a 50 psi (345 kpa) drop in pressure during the initial down surge at the station. However, the reflected upsurge is minimal and dissipates quickly. The suction side upsurge pressure is also about 50 psi (345 kpa) above steady state. This leads to a short-lived vacuum pressure throughout the suction pipeline (from Anne Reservoir to Leacock PS). However, this is quickly relieved by the storage reservoir and pressure is restored. The upsurge pressure experienced on the suction side is significant. However, given the low steady state pressure, the overall pressure is still well below 140 psi (965 kpa) limit for most pipelines. GENIVAR 16

21 Figure 19: Maximum Transient Pressures in Zone 3N under Peak Hour Scenario. Figure 20: Maximum Transient Pressures in Zone 3N under Peak Hour Scenario. GENIVAR 17

22 Figure 21: Maximum and Minimum pressure envelops from Leacock BPS to Ferndale Res under Peak Hour. Figure 22: Maximum and Minimum pressure envelops from Anne Res to Leacock BPS under Peak Hour. GENIVAR 18

23 4.1.4 Zone 2S Maximum Pressures (Figure 23): The maximum transient pressures in Zone 2S varies significantly depending on the location. Some areas near Wells #17 and #18 (currently Zone 1 wells but will be transferred into 2S) experience pressures between psi. Other high pressure areas are limited to the areas near the boundary with Zone 1 (low lying areas). However, the majority of the zone experiences pressures between psi. Minimum Pressures: Some areas of the Zone will go into vacuum pressures as shown in Figure 24. A significant portion of the Zone will experience pressures below 20 psi and the rest of the district will have minimum pressures varying between 40 to 60 psi. The low pressures are short lived as relief is provided from Harvie reservoir. Transmission Profiles: Transmission profiles are provided from the Plant, and ground water wells to the Harvie Reservoir. Plant to Harvie Reservoir: The maximum and minimum pressure envelops from the plant to Harvie Reservoir is shown in Figure 25. The minimum envelop shows that there is about a 70 psi downsurge associated with the power failure at plant leading to vacuum pressures in about a 1 km of the pipeline. The upsurge from Harvie reservoir is minimal and only 20 psi greater than the steady state pressures and the surge is quickly dissipated in the network. Well #17_#18 to Harvie Reservoir: The maximum and minimum pressure envelops from groundwater wells #17 and #18 are shown in Figure 26. The results show that about 2.5 km of this pipeline will have full vacuum pressures under a power failure scenario. Because this pipeline has few connections along its path, little relief is provided by the network. The resulting upsurge from Harvie Reservoir is about 30 psi above steady state pressures. However the surge waves are quickly dissipated by friction and relieved by the reservoir. GENIVAR 19

24 Figure 23: Maximum Transient Pressures in Zone 2S under Peak Hour Scenario. Figure 24: Maximum Transient Pressures in Zone 2S under Peak Hour Scenario. GENIVAR 20

25 Figure 25: Maximum and Minimum pressure envelops from the Treatment Plant to Harvie Res under Peak Hour. Figure 26: Maximum and Minimum pressure envelops from Well #17_#18 to Harvie Res under Peak Hour. GENIVAR 21

26 4.1.5 Zone 3S Maximum Pressures (Figure 27): The maximum transient pressure in some of the low lying areas of Zone 3S range between psi. However, the majority of the maximum transient pressures in the zone range between 60 to 80 psi. Minimum Pressures (Figure 28): Some areas of the Zone experience minimum transient pressures less than 20 psi. However, this is short lived and the pressure is restored by the reservoir. Transmission Profiles: Transmission profiles are provided from the booster pumping stations to the Zone 3S Reservoir. Big Bay BPS (Figures 29 and 30): The maximum and minimum pressure envelops show that the maximum pressure envelop does not rise above steady state pressures. There is a 60 psi drop under the downsurge, however the pressure stays well above vacuum. On the suction side of BigBay BPS, the initial upsurge is 30 psi higher than steady state pressures. However, the steady state pressure is low and thus even with the upsurge, the pressures are well below 140 psi. The suction pipe also goes into short lived vacuum but is relieved quickly by the Harvie reservoir. 3SBPS (Figure 31): The maximum and minimum pressure envelops show that maximum pressures do not go above steady state while minimum pressures stay well above vacuum. GENIVAR 22

27 Figure 27: Maximum Transient Pressures in Zone 3S under Peak Hour Scenario. Figure 28: Maximum Transient Pressures in Zone 3S under Peak Hour Scenario. GENIVAR 23

28 Figure 29: Maximum and Minimum pressure envelops from BigBay BPS to Zone 3S Res. under Peak Hour Figure 30: Maximum and Minimum pressure envelops from Harvie Res to BigBay BPS under Peak Hour. GENIVAR 24

29 Figure 31: Maximum and Minimum pressure envelops from 3S BPS to Zone 3S Res under Peak Hour. 4.2 Min Hour Scenario The results for the Min Hour Scenario power failure is shown in Figures 32 to 59. The results are very similar to the peak hour scenario results. The majority of transient pressures experienced are mild and significant upsurge and downsurge events are short lived. High and low pressures are a concern in Wells #17 and #18. The suction sides of booster stations also show greater pressures than steady state and go into momentary vacuums. But the pressures are quickly restored by the presence of reservoirs. GENIVAR 25

30 4.2.1 Zone 1 Figure 32: Maximum Transient Pressures in Zone 1 under Minimum Hour Scenario. Figure 33: Maximum Transient Pressures in Zone 1 under Minimum Hour Scenario. GENIVAR 26

31 Figure 34: Maximum and Minimum pressure envelops from Well #22 to Anne Res under Min Hour. Figure 35: Maximum and Minimum pressure envelops from Well W_Tiffin to Anne Res under Min Hour. GENIVAR 27

32 Figure 36: Maximum and Minimum pressure envelops from Well W_Perry to Anne Res under Min Hour. Figure 37: Maximum and Minimum pressure envelops from Well Herr to Anne Res under Min Hour. GENIVAR 28

33 Figure 38: Maximum and Minimum pressure envelops from Well Anne to Anne Res under Min Hour. GENIVAR 29

34 4.2.2 Zone 2N Figure 39: Maximum Transient Pressures in Zone 2N under Minimum Hour Scenario. Figure 40: Maximum Transient Pressures in Zone 2N under Minimum Hour Scenario. GENIVAR 30

35 Figure 41: Maximum and Minimum pressure envelops from Well P_Anne to Bayfield Res under Min Hour. Figure 42: Maximum and Minimum pressure envelops from Well JSON to Bayfield Res under Min Hour. GENIVAR 31

36 Figure 43: Maximum and Minimum pressure envelops from Well Bwood to Bayfield Res under Min Hour. Figure 44: Maximum and Minimum pressure envelops from BPS Res1-7 to Bayfield Res under Min Hour. GENIVAR 32

37 Figure 45: Maximum and Minimum pressure envelops from Codring BPS to Bayfield Res under Min Hour. Figure 46: Maximum and Minimum pressure envelops from Res 1-7 to Cording BPS under Min Hour. GENIVAR 33

38 4.2.3 Zone 3N Figure 47: Maximum Transient Pressures in Zone 2N under Minimum Hour Scenario. Figure 48: Maximum Transient Pressures in Zone 3N under Minimum Hour Scenario. GENIVAR 34

39 Figure 49: Maximum and Minimum pressure envelops from Leacock BPS to Ferndale Res under Min Hour. Figure 50: Maximum and Minimum pressure envelops from Anne Res to Leacock BPS under Min Hour. GENIVAR 35

40 4.2.4 Zone 2S Figure 51: Maximum Transient Pressures in Zone 2S under Minimum Hour Scenario. Figure 52: Maximum Transient Pressures in Zone 2S under Minimum Hour Scenario. GENIVAR 36

41 Figure 53: Maximum and Minimum pressure envelops from the Treatment Plant to Harvie Res under Min Hour. Figure 54: Maximum and Minimum pressure envelops from Well #17_#18 to Harvie Res under Min Hour. GENIVAR 37

42 4.2.5 Zone 3S Figure 55: Maximum Transient Pressures in Zone 3S under Minimum Hour Scenario. Figure 56: Maximum Transient Pressures in Zone 3S under Minimum Hour Scenario. GENIVAR 38

43 Figure 57: Maximum and Minimum pressure envelops from BigBay BPS to Zone 3S Res under Min Hour. Figure 58: Maximum and Minimum pressure envelops from Harvie Res to BigBay BPS under Min Hour. GENIVAR 39

44 Figure 59: Maximum and Minimum pressure envelops from 3S BPS to Zone 3S Res under Min Hour. 5. Conclusion and Recommendations A Transient Analysis of the Barrie water system was conducted to assess the risk of transients in the network. The analysis consisted of using the City s developed water model in Bentley s Hammer and developing Transient scenarios. The model consisted of all zones in the water system and had the built infrastructure and demands for Two separate global power failure scenarios were developed to assess the transient pressures under maximum and minimum flows. The results show that the City s water network experiences mild transient pressures due to a number of factors. Maximum transient pressures does not get above 140 psi (965 kpa) for the majority of the system and minimum transient pressures are mainly above vacuum. Areas that do experience vacuum pressures have short-lived negative pressures that quickly stabilize back to positive. The factors that contribute to Barrie s water network having a mild response to transients are: Storage Reservoirs: The City s water network has floating storage available in each of the zones. The storage is well connected to the rest of the zone through transmission mains. Pressure transients are moderated by the reservoirs and relief is provided quickly to areas that have an imbalance. GENIVAR 40

45 Ground Elevations: The pipe profiles shows in the Figures illustrate that the majority of transmission mains have gently rising profiles that are well suited to prevent transient issues such as column separation. Transmission Network: The City s transmission network is well-looped and interconnected. This allows for quick dissipation of surge waves within the network. As the results illustrate, in most cases after the initial significant downsurge, the reflected upsurge is minimal and by the time the reflected wave returns to the supply source, it is dissipated. There are however a few areas of concern that need to be visited in further detail. Wells #17 and #18: These two wells are Zone 1 wells that are to be transferred to Zone 2S in the future where it will pump directly to Harvie Res. as shown in Figures 26 and 54. The ground profile for the transmission from the wells to the reservoir shows that the ground elevation rises above the height of the discharge reservoir at its midway point. Under typical operations, the high point will have a pressure of psi ( kpa). However, if the wells are turned off the reservoir does not have the hydraulic gradeline to maintain a positive pressure throughout the pipeline. This will lead to column separation at the high parts of the pipeline and upon restart of the pumps, it will lead to high pressures that can be damaging to the pipeline and well pumps. The results of the power failure also shows that a large parts of the transmission main go into full vacuum under a down surge. This can be rectified by installing Combination Air Valves (CAVs) at the high points of the pipeline. Similarly soft-starters can be installed at the pumps to reduce surges during pump starts. Suction side of Booster Stations: The results show that significant upsurge and downsurge occurs on the suction side of booster pumps. In many cases where the suction side is next to a reservoir, the surge is quickly dampened. However, in Cording BPS, Leacock BPS and BigBay BPS, the suction pipeline experiences pressure fluctuations that are excessive. These should be further analyzed for individual stations and verified in the field. In cases where the infield pressure monitoring verifies the modeling results, surge relief valves should be installed. Other recommendations are general and are rules of thumb that should be applied to any system to reduce the risk of transients such as: -Soft-starters on pumps -Surge Relief/Anticipation valves at pumping stations -Regular maintenance on Air Valves -After a power failure, at least 5 minutes should be allowed to pass before pump re-start GENIVAR 41

46 -Pressure and flow from each of the supply points should be connected to the SCADA system so they can monitored -Pressure monitoring should be conducted at low and high areas of the zone where the results of transient events are more prominent -PRV valves should be regularly maintained to ensure they are functioning as designed and their setpoints checked in the field -Maintenance work on reservoirs that require shutdown should be modeled to ensure the system is not put on undue levels of risk GENIVAR 42