High Falls and Manitou Falls Hydroelectric Project Description

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2. Project Information

The following section contains information regarding the two projects as proposed in the POD.
2.1 High Falls
2.1.1 Description of Proposed Project
2.1.1.1 General
The proposed project at High Falls would capture the surveyed gross head of 34.9 m plus the raised head-pond level of 1 m for an overall gross head of 35.9 m. The conceptual development incorporates the use of a short overflow weir and two small sluices. The intake is situated on the west shore of the river and feeds a single penstock which bifurcates to feed two horizontal Francis turbines each with an installed capacity of 1.6 MW.

The general arrangement and details of the power facilities and access roads are presented on Drawings 090706-HF-ARD, -PLN, -INT, -HDW, and –PH, found in Appendix A1. The extent of the lands involved in the development is also shown on the drawings. The proposed site development is described in more detail in the following sections.

2.1.1.2 Summary of Hydraulic Characteristics
Estimated existing water levels:

  • maximum headwater level (1:100-yr flood) el 267.705 m
  • normal operating headwater level el 266.7 m
  • normal tailwater level downstream at powerhouse el 230.8 m
  • normal operating gross head 35.9 m
  • estimated net head 34.1 m
  • long-term average flow 13.1 m3/s
  • rated flow 11.0 m3/s
    2.1.1.3 Installed Capacity
    The installed capacity at this site will be two units of 1.6-MW capacity for a total installed capacity of 3.2 MW.
    2.1.1.4 Site Access
    Proposed site access is shown on Drawing 090706-HF-ARD (Appendix A1). Access to the High Falls site will be gained from Kagiano River Road which intersects with Northbrook Road and, prior to the bridge removal over the Pic River, with Lemay Road approximately 2.76 km north of the site as the crow flies. Michal Road turns into Northbrook Road and intersects Caramat Industrial Road 23 km north-northwest of Manitouwadge. There are two possible route alternatives for arrival at a common site access point shown on Drawing 090706-HF-ARD (Appendix A1).

    Alternative A is to enter from Kagiano River Road north of the site 3.5 km off of Lemay Road. This option would require the construction of a bridge over the Pic River and grading/addition of granular material to Kagiano River Road from the proposed laydown area to Lemay Road. Alternatively, access could be gained from Northbrook Road by crossing the Pic River on an existing bridge downstream of the site on Michal Road. This Alternative B would require approximately 22 km of grading/addition of granular materials. For either alternative, the grading/addition of granular materials are estimated to be of a minor nature.

    There are two new access roads proposed at the site at the end of the common road, which is identified on Drawing 090706-HF-ARD (Appendix A1) as the laydown area or the optional 130-m long turn road suggested to eliminate a sharp turning point. The new intake and powerhouse roads have been selected to have a maximum 12% grade. The intake road will utilize a 250-m radius throughout while the powerhouse access road will have one curve of 150-m radius with the remainder being larger. The length of the new intake and powerhouse access roads will each be approximately 0.7 km long.

    2.1.1.5 Headworks Structures
    The river width at the crest of the falls is narrow and will only allow the construction of a 25-m long weir. Field observation suggests that a rock foundation will be available with minimum excavation required. The maximum height of the weir will be approximately 3 m with the majority of the wall being of a lower height. A short gravity wingwall would be required on the south shore to contain the design flood from migrating around the control works.

    Because of the short weir length, additional spill capacity is required to accommodate flood flows. It is proposed that two underwater sluices be provided, each 2.5 m2. A downstream sluice channel will be excavated from the north shoreline directing the sluiced flows back into the river channel above the falls so that the aesthetic appearance of flood flows over the fall will be retained.

    The intake structure will be located on the north side of the river and will incorporate a 2.5-m2 roller gate. The intake will include trashracks for debris and upstream gains for stop-log insertion to service the racks or the gate, if required. A concrete gravity block wall is required between the sluices and the intake structure.

    Drawings 090706-HF-PLN, -INT and –HDW, found in Appendix A1, show the layout and details of the headworks structures.

    2.1.1.6 Conveyance System
    A 2.35-m diameter, approximately 100-m long, penstock will be used to convey water from the intake to the two units in the powerhouse. The first 55 m will be buried and relatively level. Because of the low head, this portion may be of a material other than steel. The remaining 45 m down the steep slope will have anchor blocks and ring girders for support and stability. The thickness will be determined based on the internal pressure from waterhammer or handling. Because two units are proposed in the powerhouse, a bifurcation will be required with inlet valves incorporated on the unit penstocks downstream of the bifurcation to provide isolation for each unit. A plan and profile of the conveyance system is shown on Drawings 090706-HF-PLN and 090706- HF-INT (Appendix A1).
    2.1.1.7 Powerhouse
    The High Falls powerhouse is considered a “compact” design. It is proposed to be located on the downstream side of a rock island on the north side below the falls. This location was chosen to effectively hide the structure from public viewing as much as possible. The use of horizontal Francis units minimizes the amount of excavation required for the foundation. The design incorporates downstream service gains for isolating the draft tube chambers for inspection and maintenance purposes. Currently, an overhead crane is proposed. This could be eliminated if the owner decides that equipment could be dropped through roof hatches resulting in a lower profile superstructure. Drawing 090706-HF-PH (Appendix A1) shows the plan and a transverse cross section of the powerhouse.
    2.1.1.8 Tailrace
    The use of horizontal units reduces the depth of excavation required for the tailrace channel (see powerhouse profile on Drawing 090706-HF-PH in Appendix A1). The channel will follow the current path of a shallow stream on the backside of the “island like” outcrop on which the powerhouse is founded. The channel will be 10 m wide, wider than the current stream bed (see Drawings 090706-HF-PLN and 090706-HF-INT in Appendix A1). Some camouflage will be provided by the rock island outcrop.
    2.1.1.9 Transmission
    Preliminary calculations indicate that the existing 48-kV line connecting the Twin Falls plant to Hydro One’s Manitouwadge transformer station (TS) could carry the energy from both proposed generating stations. Thus, no upgrade to this line is considered necessary at this time. Some equipment upgrades and changes to the protection equipment at the Manitouwadge TS may be required. A system evaluation study will be performed to determine the exact impact of the new proposed stations on the existing transmission line and the equipment in the Manitouwadge TS.

    Connection to the existing Twin Falls transmission line may have potential impacts on the Twin Falls protection equipment. The above-noted system study would also look into this issue.

    A substation will be located near the powerhouse where a transformer would step up the 4.16-kV generator voltage to 48 kV. The transformers will be outdoor, dry type complete with a grounding grid and fencing. Other equipment located in the substation will include lightning arresters, 3-phase high-voltage circuit breaker with interrupters and the necessary protection equipment.

    The proposed transmission line route is shown on Drawing 090706-HMF-DLA (Appendix A1). Because the pole spacing will be limited to approximately 100 m, the line will be approximately 18 km in length to bypass lakes and other obstacles along the proposed route.

    2.1.2 Area of Inundation
    It is expected that very little inundation will occur upstream of the site. Topographic surveys along the reach of river upstream of the falls will be performed as part of the next phase of the engineering of the project. At that time, subsequent studies will be performed to confirm the upstream impact of the proposed development.
    2.1.3 Operating Strategy for Project
    2.1.3.1 Type of Proposed Project
    The proposed High Falls development will be operated as a run-of-river project as the surrounding geology of the Pic River will not support seasonal or daily peaking.
    2.1.3.2 Operating Strategy
    Typically, the plant would be operated as a run-of-river facility, with the output set to obtain highest efficiency. The control structure at the crest of the falls will be utilized to control head-pond levels and provide the flows required for power generation. A minimum compensation flow will pass over/through the weir at all times.

    The proposed operational regime for the facility is based on the natural flow regime of the Pic River, and will approximate the seasonal water level fluctuations that presently occur. During periods of high flow and high head-pond level, the water will flow over the long weir such that the historic high water level is not exceeded (i.e., the estimated maximum elevation of 267.7 m). During periods of low inflow, the weir will revert to flow control to maintain a constant compensation flow over the weir and provide limited opportunities for power production. It is during this period, when inflows into the head pond are below the minimum required for full operation, that the unit will normally be shut off and/or operated for only a few hours per day (depending on head-pond level and/or available flow). The expected maximum and minimum water levels in the head pond are 267.7 m and 266.7 m, respectively, but will be further investigated during subsequent planning/engineering studies. The tailrace water level is expected to be el 230.8 m, and will be verified during the next development stage.

    2.1.4 Water Management Plan
    There is no water management plan (WMP) for the Pic River as there is currently no water power development on the river system. A simplified WMP will be required when the facility is in operation.
    2.2 Manitou Falls
    2.2.1 Description of Proposed Project
    2.2.1.1 General
    The proposed project at Manitou Falls would capture the surveyed gross head of 13.2 m plus the raised head-pond level of 1.1 m for an overall gross head of 14.3. The conceptual development incorporates the use of an overflow weir which transitions into an overflow canal wall. An intake canal conveys water to the powerhouse which is located on the east edge of the rock shelf which forms the falls of the river. The powerhouse incorporates two vertical axis flow turbines each with an installed capacity of 1.4 MW. The development would be characterized as close-coupled where the intake and powerhouse are one structure.

    The general arrangement and details of the power facilities and access roads are presented on Drawings 090706-MF-ARD, -PLAN, -PRO, -SECT and –PH (Appendix A2). The extent of the lands involved in the development is also shown on the drawings. The proposed site development is described in more detail in the following sections.

    2.2.1.2 Summary of Hydraulic Characteristics
    Estimated existing water levels:

  • maximum headwater level (1:100-yr flood) el 215.9 m
  • normal operating headwater level el 214.6 m
  • normal tailwater level downstream at powerhouse el 200.3 m
  • normal operating gross head 14.3 m
  • estimated net head 13.6 m
  • long-term average flow 28.4 m3/s
  • rated flow 24.5 m3/s
    2.2.1.3 Installed Capacity
    The installed capacity at this site will be two units of 1.4-MW capacity for a total installed capacity of 2.8 MW.
    2.2.1.4 Site Access
    Proposed site access is shown on Drawing 090706-MF-ARD (Appendix A2). The proposed development turn-off from the Caramat Industrial Road is approximately 31 km from Manitouwadge. The existing access from Caramat Industrial Road will require right-of-way clearing, the addition of granular material and grading for 5.75 km. Currently, the end of this existing access road joins with an access trail which has been washed out by a local slope failure; this trail will require significant upgrading to provide proper access. The total length of the trail upgrade is 0.45 km. New roads to access the intake and powerhouse areas total 0.35 km.

    The intake and powerhouse access roads have planned 12% maximum slopes with a minimum curve radius of 110 m.

    2.2.1.5 Headworks Structures
    The river width at the crest of the falls is moderately wide which will allow for the construction of the powerhouse on the east edge of the rock shelf forming the falls. A 24-m long concrete weir will be constructed on top of a rock outcrop on the west side of the river. The weir will then undergo a 135-deg bend and continue for 30 m with a maximum height of approximately 3.2 m. The weir takes another 155-deg bend for another 35 m to the powerhouse. This last section of weir also serves as the intake canal wall. Being almost 90 m long, the weir is able to pass the flood flows without any need for sluices. A short gravity wingwall is required on the east shore while a nonoverflow gravity wall is provided to form the west side of the intake canal.

    A small trash sluice is provided immediately upstream of the intake at the end of the last section of the overflow weir. The sluice is 2 m wide and utilizes stop logs to discharge debris from in front of the intake structure.

    A 10-m long training wall is required immediately downstream of the trash sluice to direct water away from the powerhouse structure.

    The structures at the headworks can be seen on Drawings 090706-MF-PLAN, -PRO and –SECT (Appendix A2).

    2.2.1.6 Conveyance System
    Because the development is close-coupled, the intake structure forms part of the powerhouse structure and a separate conveyance system is not required.
    2.2.1.7 Powerhouse
    The Manitou Falls powerhouse is immediately downstream of the intake and is termed closecoupled. Depth of excavation for the powerhouse substructure is significant whereas the vertical axis turbines allow for a compact design in the upstream to downstream direction. The combined intake/powerhouse will require enough concrete for stability purposes as this structure is deemed a water-retaining structure.

    The use of double regulation (wicket gates and blades can both be manipulated) means that the owner may forgo the use of self-closing gates either at the intake or the draft tubes, depending on the amount of risk the owner is willing to tolerate.

    The powerhouse plan and section is shown on Drawing 090706-MF-PH (Appendix A2).

    2.2.1.8 Tailrace
    The tailrace requires a 95-m long by 9.6-m wide channel to develop the full head at the site. A 75-m long training wall is required to separate tailrace flows from natural river flows.
    2.2.1.9 Transmission
    The transmission line was discussed in detail in Section 2.1.1.9 for the High Falls development.

    A similar substation will be located near the powerhouse where a transformer would step up the 4.16-kV generator voltage to 48 kV. The transformers will be outdoor, dry type complete with a grounding grid and fencing. Other equipment located in the substation will include lightning arresters, 3-phase high voltage circuit breaker with interrupters and the necessary protection equipment.

    The proposed transmission line route is shown on Drawing 090706-HMF-DLA (Appendix A2). The length of the Manitou line to the point of common coupling is 0.5 km.

    2.2.1.10 Additional Considerations
    An improvement in the location of the powerhouse may be possible after the results of a more thorough geotechnical program are available. The powerhouse could be moved farther east along the current portage path. This would move the structures more into dry areas for excavation and could also reduce the length and height of walls. It would also have the added benefit of moving the powerhouse farther off the rock outcrop of the falls.

    The banks of the Pic River, upstream and downstream, are composed of loose granular soils and are susceptible to erosion. Rock from the excavations could be used to armor particularly erosion-prone bends.

    2.2.2 Area of Inundation
    It is expected that a minimum amount of inundation will occur upstream of the site, and should not reach the confluence of the White Otter River and the Pic River.

    A topographic survey along the reach of river upstream of the falls has not yet been performed, but will be verified during subsequent studies.

    2.2.3 Operating Strategy for Project
    2.2.3.1 Type of Proposed Project
    The proposed Manitou Falls development will be operated as a run-of-river project as the surrounding geology of the Pic River will not support seasonal or daily peaking.
    2.2.3.2 Operating Strategy
    Typically, the plant would be operated as a run-of-river facility, with the output set to obtain highest efficiency. The control structure at the crest of the falls will be utilized to control head-pond levels and provide the flows required for power generation. A minimum compensation flow will pass over/through the weir at all times.

    The proposed operational regime for the facility is based on the natural flow regime of the Pic River, and will approximate the seasonal water level fluctuations that presently occur. During periods of high flow and high head-pond level, the water will flow over the long weir such that the historic high water level is not exceeded (i.e., the estimated maximum elevation of 215.9 m). During periods of low inflow, the weir will revert to flow control to maintain a constant compensation flow over the weir and provide limited opportunities for power production. It is during this period, when inflows into the head pond are below the minimum required for full operation, that the unit will normally be shut off and/or operated for only a few hours per day (depending on head-pond level and/or available flow). The expected maximum and minimum water levels in the head pond are 215.9 m and 214.6 m, respectively, but will be further investigated during subsequent planning/engineering studies. The tailrace water level is expected to be el 200.3 m, and will be verified during the next development stage.

    2.2.4 Water Management Plan
    There is no WMP for the Pic River as there is currently no water power development on the river system. A simplified WMP will be required for the facility prior to its operation.
    2.3 Project Activities
    2.3.1 Construction Schedule and Activities
    Construction of the proposed facilities is scheduled to take place between 2013 and 2015.
    2.3.2 Operation
    The facilities will operate as run-of-river facilities. Flow up to each facility’s capacity will be run through the powerhouse and turbines and all flows in excess of this amount will be put over the weirs (or through the sluiceways at High Falls). Due to this run-of-river mode of operation, there will be no change in current flow patterns in the Pic River. The facilities will be designed with the capacity to be remotely operated in addition to having on-site controls. Typically, hydroelectric projects are designed for a 50- to 100-yr lifespan. Upgrades and rehabilitation activities may extend that useful life.
    2.3.3 Decommissioning
    There are no present plans for decommissioning of the facilities. The decision on decommissioning (or alternatively upgrading or rehabilitation to extend facility life) would depend on the structural/historic attributes of the facility as well as economic and other considerations at the time.
    2.4 Resource Material Requirements
    2.4.1 Energy and Water Requirements and Sources
    On-site energy requirements during construction are likely to be provided by portable diesel generator. Operational outside energy requirements for the facility will be supplied via a return distribution line from the interconnection point. A back-up diesel generator will likely be installed on site to provide emergency power to the facility during power outages. The proponent will also consider interconnecting to the existing Kagiano Transmission line to supply power during construction as well.

    On-site water requirements for construction are not known at the present time, although it is likely that water will be required during the construction process (i.e., wash water, etc). This water may be supplied from the Pic River via portable pumps. The quantities required are anticipated to be small and will not require a Permit to Take Water (PTTW) from MOE as the taking will be much less than the 50 000 L/d threshold. Construction process water might also be trucked in from outside sources if required.

    Operational water requirements for the facility are not known at this time. Small amounts of cooling water may be withdrawn from the Pic River to cool powerhouse components. A PTTW will be obtained if the amount required exceeds the PTTW threshold. There will not likely be any requirement for potable water at the facilities. Operational water requirements will be determined during the detailed design process.

    2.4.2 Excavation and Quantity of Fill
    Excavation will be required for the overflow weirs, powerhouses and tailraces. The expected quantity of excavated material is unknown at this point. Excavated material will include topsoil, underlying soils and bedrock in terrestrial areas, and channel bed material and bedrock within the riverbed. Existing channel bed material will be reused to the greatest extent possible to re-line the excavated portions of the channel downstream from the facility. Excess material will be stored for future use on roadways and other areas requiring fill or material. Excess material will be disposed of in accordance with local regulations. Solid waste materials requiring off-site disposal will be chemically tested for waste classification purposes in accordance with the Ontario Waste Management Regulation (ON. Reg. 347), as amended by Regulation 558/00, and then disposed of accordingly.

    Some fill materials may be required from commercial sources, but quantities are unknown at this time.

    2.4.3 Toxic/Hazardous Materials
    Fuels, hydraulic fluids and lubricants will be used in equipment during construction and operation of the facilities. The storage facility for these materials will comply with all current regulations and guidelines. The storage of small amounts of hydraulic fluids and lubricants will be in a contained area, well away from the watercourse. It is not anticipated that any explosives will be manufactured on site. Any explosives stored on site (if required) will be contained in a manner compliant with NRCan requirements and industry standards. Transport of explosives will be done in accordance with TC requirements (e.g., Transportation of Dangerous Goods Act).
    2.5 Waste Disposal
    Solid nonhazardous construction waste (e.g., material packaging) generated during the construction process will be removed from the site to an approved disposal location (likely the municipal landfill) or recycling/composting facility if available. Waste debris from clearing activities (e.g., grubbing, non-merchantable timber) will be disposed of in accordance with regulatory requirements. No gaseous wastes other than construction equipment emissions are anticipated. Industrial liquids such as paints, sealants, fuels and lubricating fluids will be stored in a secure containment area and disposed in accordance with provincial liquid waste disposal regulations (e.g., Environmental Protection Act and Ontario Waste Management Regulation 347).


  • High Falls and Manitou Falls Project
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