Physical Works Terms of Reference

Transcription

1 Peace Project Water Use Plan Physical Works Terms of Reference District of Mackenzie Effluent Discharge Feasibility and Design Study GMSWORKS #28a 23 November 2009

2 Terms of Reference for the Peace Water Use Plan District of Mackenzie Effluent Discharge Feasibility and Design Study 1.0 Introduction The Peace Water Use Plan water use planning process was initiated in February 2001 and completed in May The Peace WUP Committee (the Committee) Report of December 2003 recommended an operating regime for the Williston Reservoir that allows for drawdown to 2147 (652.3 m). The committee also recommended conducting an engineering feasibility and preliminary design study to investigate long term solutions to water supply, effluent dilution and log supply problems associated with lower reservoir levels. In response to an Order (File No /Peace) issued by the Comptroller of Water Rights (CWR) on 09 August, 2007 BC Hydro drafted, but did not submit, a Terms of Reference that addressed Schedule A (1)of that order. Specifically the following, The licensee shall submit within 6 months of the date of this Order, for approval by the Comptroller, terms of reference for an engineering feasibility and design study to determine practical and cost-effective solutions to the following issues associated with lower reservoir levels: a. water supply at Abitibi newsprint and Pope & Talbot pulp mills; b. effluent disposal at Abitibi newsprint mill, Pope & Talbot pulp mill and District of Mackenzie; and c. log supply for Canfor and Abitibi sawmills. Subsequent to the development of those Terms of Reference (TOR) and before they could be submitted to the Comptroller of Water Rights for approval, the forest industry began to recede in BC. Industry in the District of Mackenzie was impacted to the extent that all three forest companies in the area either ceased operations or went bankrupt. That essentially nullified much of the terms of reference as there were no plants operating and a study of the impacts of water levels on the operation could not be completed. In a letter, dated 28 August, 2009, the Comptroller s office redirected BC Hydro to delay submitting the terms of reference for the industry portion of the study and submit a TOR related to the District of Mackenzie s effluent discharge. Submission of terms of reference for the study addressing the District of Mackenzie s effluent discharge is now required by December 1, Terms of reference for the industry portion are now to be submitted by February 12, These Terms of Reference were developed by BC Hydro and by the District of Mackenzie to address the order by the Comptroller of Water Rights. Once developed the TOR underwent a review by First Nations, external stakeholders and government agencies including DFO, and Ministry of Environment. Following these reviews BC Hydro and the District of Mackenzie reviewed the comments received and revised the TOR accordingly. BC Hydro 1

3 As per the requirements of the CWR, the Department of Fisheries and Oceans will be asked to sign-off on the TOR. The DFO letter will be submitted, along with other stakeholder, First Nations and agency comments or letters of acknowledgement to the CWR when the TOR is submitted for approval. Following approval of the TOR by the CWR and subsequent issuance of Leave to Commence with the study, the BC Hydro and the District of Mackenzie (the Team) will develop a Request For Proposals (RFP) for the study that is based on these TOR. The Team will select a consultant (or consultants) to undertake the study and will remain actively involved in monitoring and directing the consultants throughout the course of the study although active project management of the study will fall to the BC Hydro representative. Upon completion of each phase of the study (Feasibility, Preliminary Design and selection of final option(s) for submission to the Committee) the Team will play an active role in inter and intra-phase decisions. 2.0 Description of Project 2.1 Location The headwaters of the Peace, a tributary of the Mackenzie River, are located in north-eastern British Columbia (Figure 1). The Peace is formed by the confluence of the Finlay and Parsnip rivers flowing in opposite directions in the Rocky Mountain Trench. At the confluence the Peace flows east and is the only river to cut through the Rocky Mountains. Once out of the Peace Canyon the river maintains an easterly direction, crossing the B.C./Alberta border. The Peace River is confluent with the Slave River that, in turn, flows north into Great Slave Lake in the Northwest Territories. The Mackenzie River begins at the outlet of Great Slave Lake and flows north to the Arctic Ocean. The town of Mackenzie (pop: <5000) is located at the south end of the Parsnip Reach on the Williston Reservoir. The forest industry has been integral to development in the area and, in the recent past, Mackenzie supported three large integrated forest operations on the reservoir. These operations included a newsprint mill, a bleached Kraft pulp mill, and two sawmills located at Mackenzie and associated timber harvesting operations throughout the reservoir area. Currently, Canfor owns a large capacity sawmill that is operating at less than capacity and has associated timber harvesting operations throughout the reservoir drainage area. These forest operations relied heavily on the reservoir for water supply and effluent dilution. Canfor has used the reservoir for log transport via self-propelled barge, but has no plans for continued use of this barge in the future. As well, the town of Mackenzie relies on the reservoir for effluent dilution. BC Hydro 2

4 Figure 1: Place Names in Peace Water Use Plan 2.2 Existing Works The existing works comprising the Peace project include: W.A.C. Bennett Dam: This dam, commissioned in 1967, is located at head of the Peace Canyon forming Williston Reservoir. The earthfill dam is 2040 m ( ft) in length at the crest and 183 m (600.4 ft) high with a crest elevation of m ( ft) above sea level. Williston Reservoir covers approximately 1773 square kilometres (km 2 ) (684.6 square miles (miles 2 )) at full pool and has an active storage of 393 Million cubic metres (Mm 3 ) (32 Million acre feet (MAF)). The operating range of the reservoir for power generation is between m ( ft) and m ( ft). The spillway has three radial gates and nine sluice gates. The sill elevation for the radial gates is m ( ft) and the sluice gates m (2105 ft). The maximum discharge is 9200 m 3 /s ( ft 3 /s) using the radial and sluice gates. BC Hydro 3

5 Power Intakes: There is one power intake for each unit. They are located on the north side of the dam. Intakes are 3.96 x 5.94 m (13 x 19.5 ft). The sill elevation for intakes 1 to 3 is m ( ft). The sill elevation of intakes 4 to 10 is m ( ft). G.M. Shrum Generating Station: The underground G.M. Shrum Generating Station has 10 units with a total installed capacity of 2730 MW. Once through the turbines, the water is discharged through two manifolds, one for units G1 to G5 and one for G6 to G10, into the upper end of Dinosaur Reservoir. Peace Canyon Dam: This dam is located at the foot of the Peace Canyon forming Dinosaur Reservoir. The Peace Canyon Dam consists of a concrete gravity dam and earthfill saddle dam on the right abutment. The main dam is 325 m ( ft) long and 61 m (200.1 ft) high with a crest elevation of m ( ft) above sea level. The saddle dam is 200 m (656.2 ft) long and 20 m (65.6 ft) high. Dinosaur Reservoir covers approximately 9 km 2 (3.5 miles 2 ) at full pool. It has limited active storage. The shoreline length is 54.4 km (33.8 miles). The normal operating range is between m ( ft) and m ( ft). The spillway has six radial gates. The sill elevation for the radial gates is m ( ft). The maximum discharge is m 3 /s ( ft 3 /s). Power Intake: There is one power intake for each unit. The intakes are 6.7 x 12.4 m (22.0 x 40.7 ft). The sill elevation is m ( ft). Peace Canyon Generating Station: The Peace Canyon Generating Station has four units with a total installed capacity of 700 MW. The water is discharged into the Peace. 3.0 Background While the licenced minimum reservoir level is (642.0 m) the lowest level that the reservoir has ever drawn down to is 2147 (652.3 m). In the upper Parsnip Reach near the town of Mackenzie, the reservoir begins to transition into a river regime below this level. Water levels on Williston Reservoir, below key thresholds, can result in effluent dilution concerns for the District of Mackenzie. There have been a number of engineering studies undertaken since the mid-1990s to investigate water supply and effluent issues related to the Williston Reservoir. Included in this list would be: Design of Raw Water Intake System as Part of Mitigation Facilities for Williston Lake Drawdown prepared for Finlay Forest Industry by Northwest Hydraulics Consultants in October BC Hydro 4

6 Williston Lake Drawdown, Water Supply, Effluent Disposal and Wood Supply Mitigation Measures Overview Report prepared by Western Economic Consulting Ltd, Westmar Consultants Inc., and Holborn Consulting Ltd. In March Williston Lake Drawdown - Contingency Planning Report. Prepared for the Williston Lake Contingency Planning Advisory Group by Western Economic Consulting Ltd, Holborn Consulting Ltd. And Envision Consultants Ltd. In December Finlay Forest Industries Mackenzie Pulp and Paper Mills Groundwater Supply Forecasts. Report to Finlay Forest Industries Ltd. By Thurber Engineering Ltd and Piteau Associates Engineering Ltd. In December Effluent Dispersion Study for the Diffuser Relocation. Prepared for Finlay Forest Industries Ltd. By H.A. Simons Ltd in January The District of Mackenzie discharges effluent into Dahl Lake that is tributary to Williston Reservoir. Water levels below 2150 begin to impact on the sanitary out-fall requirements. Below this elevation the connection becomes restricted and effluent discharges become more concentrated. The Committee recommended conducting an engineering and preliminary design study to investigate long-term solutions to the effluent discharge problems associated with lower reservoir levels. 4.0 Benefits of Study This study will provide the Committee with the information necessary to recommend any changes to the operating regime of Williston Reservoir following the mid-wup review process. Such recommended changes may include a new Initial Minimum Elevation for Williston Reservoir. Conversely, the study may identify cost-effective solutions to Mackenzie s effluent management concerns that do not include modifications to the operation of the reservoir. The specific objective is: To determine whether there are practical, cost-effective effluent disposal solutions (technical or regulatory) for the District of Mackenzie BC Hydro 5

7 5.0 Schedule and Estimated Costs Phase and Description Tasks & Activities Duration Phase 1: Project Initiation Phase 2: Feasibility Study Phase 3: Preliminary Design Phase 4: Reporting to Government Develop draft Terms of Reference (TOR) and circulate to District of Mackenzie for review. Review of TOR by Public, Government regulators and First Nations Finalize TOR; CWR approval of TOR; Issue RFP; Select Consultant in collaboration with District of Mackenzie Consultant Study Program Select feasible options Refine initial options as required. Include initial review of options by MoE Regional Office with respect to Municipal Sewage Regulations Prepare draft report - two rounds of review, including meeting with District of Mackenzie Final report with recommendations Prepare preliminary designs and cost estimates for preferred: Effluent management option(s) Review preliminary results with District of Mackenzie. Review of option by MoE. Prepare design report for: Selected effluent management option Prepare a recommendation to Government for implementing practical, cost-effective project to be submitted to the WUP Committee Formal presentation/submission to Government by the WUP Committee 6 Months 12 months 6 months 6 months Phase 5: Review and Approval? Decision by Government BC Hydro 6

8 6.0 Design and Deliverables The following tables outline one possible scope of work for the feasibility studies and preliminary design. Effluent System Feasibility Study Item Literature Review Description Review studies conducted during the Williston Lake Drawdown Contingency Planning process Review general literature on effluent disposal options including use of wetlands for effluent treatment Review the provincial regulatory requirements and the specific permits. Review federal regulatory requirements under CCME Municipal Wastewater Effluent Strategy. Facility Review Review current water effluent disposal systems for the District of Mackenzie to determine design vs. performance strengths, weaknesses, opportunities. Review current effluent disposal for the district options for change, efficiencies, conservation, partial or total recycling, etc. New Options Preliminary Option Analysis Regulatory analysis do existing permits correctly reflect current or proposed regulatory requirements? Is there any provision within the regulations for accommodating unusual situations? For example, if Williston Reservoir is drawn down for low system inflow (drought) or force majeure conditions resulting in the reservoir being drafted to 2145 (653.8m) to 2135 (650.7m) or lower do the current regulations have a mechanism for allowing the mills to continue operating? What is it? How does it work? If not what are the options? Compare all options on their technical, environmental (including regulatory), social and financial merits. BC Hydro 7

9 Effluent System Preliminary Design Item Preliminary Design Final Report Description For options recommended by BC Hydro and District of Mackenzie, prepare preliminary design and cost estimates. Prepare final report 7.0 Cost Objectives The estimated costs (2009 Dollars) associated with this project is $280,000. BC Hydro 8