Monitoring Program Terms of Reference REVELSTOKE FLOW MANAGEMENT PLAN

Transcription

1 Columbia River Project Water Use Plan Monitoring Program Terms of Reference REVELSTOKE FLOW MANAGEMENT PLAN CLBMON-17 Middle Columbia River Juvenile Fish Habitat Use Revisions May 12, 2010

2 Revised Terms of Reference for the Columbia River Project Water Use Plan Monitoring Programs Revelstoke Flow Management Plan 1.0 OVERVIEW This document presents Terms of Reference for the effectiveness monitoring programs for the Revelstoke Flow Management Plan (RFMP, Table 1). These programs will monitor outcomes of the recommended operational changes, and provide information on which to base future operating decisions. This document provides detailed Terms of Reference for the following programs: 1) CLBMON-15a & b Middle Columbia River Physical Habitat and Ecological Productivity Monitoring: A 13-year program to monitor physical habitat parameters, periphyton, and benthic invertebrates in the Middle Columbia River to determine linkages between operational changes, physical habitat, and ecological productivity. 2) CLBMON-16 Middle Columbia River Fish Population Indexing Surveys: A 13-year program to monitor abundance and biological characteristics of fish populations in the Middle Columbia River to assess the response of these populations to operational changes at Revelstoke Dam. 3) CLBMON-17 Middle Columbia River Juvenile Fish Habitat Use: A 6-year program to monitor changes in habitat use by juvenile fishes in the Middle Columbia River in response to operational changes at Revelstoke Dam. 4) CLBMON-18 Middle Columbia River Adult Fish Habitat Use: A 6-year program to monitor behavioural (diel and seasonal) and energetic responses of selected adult fish species (bull trout and mountain whitefish) to operational changes at Revelstoke Dam. Table 1 Revelstoke Flow Management Plan Monitoring Program Terms of Reference Resubmission Information Name of Monitoring Program CLBMON-15a Middle Columbia River Physical Habitat Monitoring CLBMON-15b Middle Columbia River Ecological Productivity Monitoring CLBMON-16 Middle Columbia River Fish Population Indexing Surveys CLBMON-17 Middle Columbia River Juvenile Fish Habitat Use CLBMON-18 Middle Columbia River Adult Fish Habitat Use CLBMON-53 Middle Columbia River Juvenile Fish Stranding Assessment Order Clause Fulfilled Schedule C: 4.a Schedule C: 4.a Schedule C: 4.b Schedule C: 4.c Schedule C: 4.d Amended Order, Clause 2 (c) Submitted with this Package Previously Submitted To CWR Submission Dates March 2007, January 2009 March 2007, January 2009 March 2007, January 2009 March 2007 March 2007 No July 2008, February 2009 BC Hydro Page 2

3 The monitoring program will be implemented over a 13-year time span, which exceeds the study duration recommended by the Water Use Plan Consultative Committee by one year. The increased duration is to honour BC Hydro s commitment to the Revelstoke 5 (REV 5) Core Committee to advance implementation of three studies (CLBMON-15a, 15b and 16) to allow for an extra year of baseline data collection. One year was also added to the end of CLBMON-17 and 18, extending them to six year studies from the original five. CLBMON-53 was added to the Order as a result of the REV 5 WUP amendment. 2.0 MONITORING PROGRAM RATIONALE The Columbia River Water Use Plan Consultative Committee (WUP CC) identified the potential impacts of the operation of Arrow Lakes Reservoir (ALR) and Revelstoke Dam on large river fish habitat in the Middle Columbia River as a key environmental concern of the Columbia River Water Use Plan. The quality and quantity of large river habitats in the Middle Columbia are thought to be heavily influenced by the operation of Arrow Lakes Reservoir and flow releases from Revelstoke Dam. The length of flowing river in the Middle Columbia is controlled by the seasonal operating elevation of Arrow Lakes Reservoir (Figure 1). The Arrow Lakes Reservoir normally fills from April to July, inundating the ~50 km length of Middle Columbia River channel and floodplain. At full pool (440 m), ALR backwatering influences the Middle Columbia River as far as the base of Revelstoke Dam. Maximum reservoir elevation and the duration at which it is maintained vary annually based on a complex combination of climate, treaty obligations, and operational needs. Short-term variations in Revelstoke Dam flow releases (including zero discharge events) are thought to influence the quality of fish habitats in the Middle Columbia River. Load following and peaking operations have resulted in patterns of river discharge that vary on a diel, seasonal, and annual basis, with discharges ranging from 0 to 1700 m 3 s -1. Flow releases from Revelstoke Dam generally increase through daylight hours and peak in early evening following peak demands for power. During night time periods, however, generating station output is typically reduced to follow electricity demand and flow releases from Revelstoke Dam frequently cease completely depending the time of year. Periods of zero discharge, which occur mainly during spring (March to May) and fall (September to November), could limit the availability and suitability of large river habitats for fishes. The WUP CC recommended establishment of a year round 142 m 3 s -1 minimum flow release from Revelstoke Dam to enhance large river fish habitats in the Middle Columbia River. Key environmental objectives of the minimum flow release are to: 1) increase productivity of benthic communities, 2) develop habitat conditions that increase the recruitment of juvenile fishes, and 3) maximize the abundance, condition, and growth of adult fishes. In developing the minimum flow recommendation for Revelstoke Dam, it was recognized that there was considerable uncertainty about the environmental benefits of the proposed minimum flow release. This uncertainty was attributed to significant data gaps about the current status of aquatic communities in the Middle Columbia River, and the lack of data on the importance of mainstem large river habitats relative to reservoir and adjacent tributary habitats available to fishes in the Upper Arrow watershed. To help resolve these data gaps, reduce technical uncertainties and assess the effectiveness of the 142 m 3 s -1 minimum flow, the WUP CC recommended an adaptive management program, collectively referred to as the Revelstoke Flow Management Plan (RFMP). BC Hydro Page 3

4 BC Hydro received approval for the construction of a fifth unit (REV 5) at the Revelstoke Generating Station in REV 5 will add 500 MW to the station s generating capacity and its operation will allow for peak discharge of 2124 m 3 s -1, an additional 425 m 3 s -1 over current operations. The in-service date for full operation of REV 5 has been scheduled to coincide with the start of the recommended minimum flow in November Some of the predicted trends with REV 5 operations include: a general increase in the frequency of high flows with corresponding increases in river elevations and velocities immediately downstream of the dam and a general increase in average daily discharge during low demand periods (BC Hydro 2006). BC Hydro received an amended Order that includes recommendations from the REV 5 process for additional monitoring programs and physical works. Some of these changes are included in the individual study Terms of Reference for the RFMP. The RFMP is a 13-year program to monitor the effectiveness of the minimum flow release as recommended by the WUP CC (Tables 1 and 2). The approach of the program is to estimate the responses of key physical and biological variables to operations. These responses will then be interpreted to assess the effects of minimum flow and REV 5 operations on benthic and fish productivities of the Middle Columbia River ecosystem. In the first four years of the program ( ), operation of the dam will not change and monitoring will be conducted to supplement existing data on physical and biological conditions of the Middle Columbia ecosystem under the current operating regime. Operational changes such as the implementation of the minimum flow and full in-service operation of REV 5 will be timed to coincide in late Monitoring programs will continue for a range of three to 10 additional years, depending on specific information requirements. An interim review of the Revelstoke Flow Management Plan (Table 2) will provide an opportunity to examine initial results and, where required, refine the monitoring program to better meet key objectives. To structure these assessments, a simple conceptual diagram was developed to describe how physical factors could influence fish populations in the Middle Columbia River (Figure 2, see also BC Hydro 2005). This diagram outlines linkages among factors that substantially influence physical habitat conditions in the Middle Columbia River (e.g., dam releases, tributary inflows, reservoir operations) and the responses of benthic communities and fish populations. Five integrated monitoring programs were recommended to address key data requirements and uncertainties articulated in the conceptual model regarding impacts of minimum flow releases on the Middle Columbia River ecosystem (BC Hydro 2005). Four programs relate to habitat (CLBMON-15a Physical Habitat Monitoring), benthic community (CLBMON-15b Ecological Productivity) and fish population indicators (CLBMON-16 Fish Population Indexing Surveys and CLBMON-17 Juvenile Habitat Use). An additional monitoring study was recommended to provide a greater understanding of the behavioural and bio-energetic consequences of operations on fish habitat use (CLBMON-18 Adult Habitat Use). This study focuses on specific biological uncertainties associated with the prescribed minimum flow and seeks to answer the following questions: 1) what is the behavioural response (diel and seasonal pattern of habitat use) of adult fishes to minimum flows? and 2) do minimum flows generate bio-energetic benefits (and therefore potential for increased growth) for individual fishes? To integrate the elements of the monitoring program and coordinate the analyses of monitoring data, all programs will be implemented on a common spatial referencing approach (Figure 1). Establishment of a common spatial stratification scheme will facilitate linking key hypotheses, as they relate to the response of ecological indicators to changes in minimum flow releases and REV 5 operations through a logical chain of inference (e.g., physical habitat benthic productivity fish habitat use fish productivity). It will also facilitate documentation of the BC Hydro Page 4

5 influence of Revelstoke Dam releases, tributary inflows/contributions, and Arrow Lakes Reservoir operation on physical and biological components of the ecosystem. The geographic scope of the RFMP is the Middle Columbia River section extending ~30 km from the Akolkolex River to the tailrace of Revelstoke Dam (Reaches 2, 3 and 4; Figure 1). However most programs (with the exception of CLBMON 15a) will prioritize the upper two reaches (3 and 4), which are the portion of the Middle Columbia River most influenced by operational changes. 3.0 REFERENCES BC Hydro Revelstoke Unit 5 Project Environmental Assessment Certificate Application. Volume 1: Supplemental Information Report. BC Hydro Consultative Committee Report: Columbia River Water Use Plan, Volumes 1 and 2. Report prepared for the Columbia River Water Use Plan Consultative Committee by BC Hydro, Burnaby, BC. BC Hydro Page 5

6 Reach 3 Reach 4 Reach 2 Reach 1 Figure 1 Map of the study area for the Revelstoke Flow Management Plan showing the location of the Revelstoke Dam and reach breaks used in the RFMP. BC Hydro Page 6

7 Dam flow release Tributary Inflow Reservoir Elevation Flow Velocity Wetted Area Inundation Frequency Physical Habitat Monitoring Juvenile Habitat Use Adult Habitat Use Benthic productivity Ecological Productivity Monitoring Useable area Energy expenditure Food supply Fish Growth Fish survival Fish abundance Fish Population Indexing Monitoring Figure 2 Conceptual diagram of linkages among physical and biological variables responding to Revelstoke Dam flow releases and Arrow Lakes Reservoir operations on large river habitats in the Middle Columbia River. Associated monitoring programs proposed in the Revelstoke Flow Management Plan are shown in italics. BC Hydro Page 7

8 Addendum #1 May 20, 2010: Middle Columbia River Juvenile Fish Habitat Use (CLBMON-17) 1.0 MONITORING PROGRAM RATIONALE 1.1 Background The Columbia River Water Use Plan Consultative Committee (WUP CC) supported the implementation of a year-round minimum flow release of 142 m 3 s -1 from Revelstoke Dam to enhance fish populations in the Middle Columbia River (BC Hydro 2005a, 2005b). A key environmental objective of the minimum flow release was to increase the recruitment of juvenile life stages of fishes to habitats in the Middle Columbia River. Past inventory studies (RL&L 1991, 1994) and more recent monitoring programs (Golder and Associates Ltd. 2005) of fish populations in the Middle Columbia River below Revelstoke Dam have found that the mainstem river habitats are used primarily by adult life stages, implying that mainstem habitats of the Middle Columbia are unsuitable or unnecessary for juvenile fishes. This monitoring program aims at obtaining a better understanding about how juvenile life stages use the Middle Columbia River habitats and to assess if their pattern of habitat use is influenced by the provision of minimum flow releases. In 2007, BC Hydro received approval for the construction of a fifth unit (REV 5) at the Revelstoke Generating Station. REV 5 will add 500 MW to the station s generating capacity and its operation will allow for peak discharge of 2124 m 3 s -1, an additional 425 m 3 s -1 over current operations. The in service date for full operation of REV 5 has been scheduled to coincide with the start of the minimum flow in November Some of the predicted trends with REV 5 operations include: a general increase in the frequency of high flows with corresponding increases in river elevations and velocities immediately downstream of the dam and a general increase in average daily discharge during low demand periods (BC Hydro 2006). An addendum to the WUP includes the provision to include monitoring of REV 5 operations in these Terms of Reference. Therefore, references to evaluating the minimum flow releases or operational changes should be interpreted as including REV 5 operations. 1.2 Management Questions The key management questions addressed by this monitoring program are: 1) What are the seasonal abundances and distributions of juvenile life stages of fishes in the Middle Columbia River? 2) How do juvenile fishes use the mainstem habitats in Middle Columbia River? 3) What factors affect recruitment of juvenile life stages in the Middle Columbia River? i) Do operational strategies for Revelstoke Dam and Arrow Lakes Reservoir influence the availability of juvenile fishes preferred habitats? ii) Do current operational strategies affect availability of the food base for juvenile fish life stages? iii) Do predators influence juvenile fish recruitment and habitat use in the Middle Columbia River? BC Hydro Page 8

9 1.3 Management Hypotheses Three related hypotheses will be tested for the fish species observed to use the Middle Columbia: Ho 1 : Ho 2 : Ho 3 : Juvenile life stages do not use mainstem habitats in the absence of minimum flow releases. Juvenile life stages do not use mainstem habitats during 142 m 3 s -1 minimum flow releases. The provision of a minimum flow does not affect the average abundance of juvenile life stages in mainstem habitats. 1.4 Key Water Use Decision Affected The key water use decision affected by this monitoring program is the implementation of the 142 m 3 s- 1 minimum flow release from Revelstoke Dam. A key environmental objective of the provision of the minimum flow release is to improve mainstem habitat conditions for juvenile life stages of key Middle Columbia River fish populations. It will also take into account the effects of the addition of a fifth unit at the Revelstoke Dam, which will likely increase average channel velocity under maximum flow conditions by up to 0.7 m/s at the tailrace and by 0.1 m/s near the airport (BC Hydro 2006; see also Background section). Inferences from this study will be interpreted in conjunction with results of the other RFMP monitoring programs (Physical Habitat Monitoring, Ecological Productivity Response, Adult Fish Habitat Use) to provide an overall assessment of the effects of minimum flow releases and REV 5 operations on fish populations. 2.0 MONITORING PROGRAM PROPOSAL 2.1 Objectives and Scope The objectives of this monitoring program are: 1) To provide information on juvenile fishes use of the Middle Columbia River and on the suitability of these habitats to meet critical life history requirements (e.g., rearing) of these fish populations. 2) To assess the effects of the implementation of the 142 m 3 /s minimum flow and REV 5 on the recruitment of juvenile life stages of fishes of the Middle Columbia. The scope of the monitoring program is to: 1) Describe the relative abundance and seasonal distribution of juvenile fishes in the Middle Columbia River; 2) Determine the range of habitats available to juvenile fishes within the study area; 3) Assess changes in habitat use by juvenile fishes in response to implementation of a minimum flow release from Revelstoke Dam and to REV 5 operations. Information will be documented on all captured species. The geographic scope of the monitoring program is the ~11 km long section of the Middle Columbia River from Revelstoke airport to the tailrace of Revelstoke Dam. The BC Hydro Page 9

10 priority area for assessment, where the highest sampling intensity will be focused, is the portion of the Middle Columbia River most influenced by operational changes. 2.2 Approach The general approach to this monitoring program is to develop and implement a systematic sampling program to infer changes in recruitment of juvenile life stages to large river habitats in the Middle Columbia River in response to the minimum flow and to operational changes related to REV 5. Fish sampling will be conducted annually during contrasting habitat conditions: low and high Arrow Reservoir elevations. Given the wide range of habitats, reservoir elevations and flow conditions to be examined, a range of standard sampling approaches will be required in representative habitats within the study area. Sampling will be conducted in mainstem habitats and lowermost reaches of selected fish-bearing tributaries that flow into the Middle Columbia River. Initial results will be used to develop a systematic survey approach to produce repeatable indices of relative abundance of juvenile fishes. 2.3 Methods The following primary tasks are required to complete juvenile habitat use monitoring in the Middle Columbia River: Task 1: Project Management Project coordination involves the general administrative and technical oversight of the program. This will include, but not be limited to: 1) budget management, 2) study team management, 3) logistic coordination, 4) technical oversight in field and analysis components, and 5) facilitation of data transfer among other investigators associated with the RFMP. A safety plan must be developed and submitted to the BC Hydro contact for all aspects of the study involving field work, in accordance with BCH procedures and guidelines. Specific safety training may be required Task 2: Fish Sampling The objective of the fish sampling task is to design and implement a systematic and repeatable approach for estimating and monitoring the relative abundance and documenting biological characteristics of juvenile life stages. The methodology should therefore provide an effective means to detect changes in population characteristics over the course of the program. The intent is to allow unbiased statistical comparisons among habitat types, seasons, and between the current flow regime and the 142 m 3 s -1 minimum flow release operation. Sampling sites should be representative of the area, while including low-angle and steep habitats, as well as habitats from wetted side channels and the lowermost reaches of fish-bearing tributaries. Suitable sampling sites will be assigned a unique, georeferenced identifier to be marked on a set of air photos. Physical data will be recorded at each site to supplement the fish collection data. The sampling strategy will address issues associated with randomization, intensity and distribution of sampling effort, foreseeable limitations on inferences generated from monitoring data, and steps taken to avoid methodological biases in each component of the work. Data analyses should include examination of condition factors (length-weight BC Hydro Page 10

11 relationships), length frequency, and comparisons of fish growth (whenever sample size allows it) among seasons and years. Species richness, abundance and diversity should also be considered Task 3: Data Archiving To facilitate effective management of data from the monitoring program, data will be archived in an MS Access database compatible with other RFMP studies and integrated with that developed in CLBMON Task 4: Reporting A technical report will be completed each year to document methods, results, conclusions, and recommendations. To facilitate effective management of data from the monitoring program, an MS ACCESS data base will be developed and updated on an annual basis. A detailed report will synthesize the data collected over the term of the program at the completion of the monitoring period. Reports will follow the standard format that is being developed for WUP monitoring programs. All reports will be provided in hard copy and as Microsoft Word and Adobe Acrobat (*.pdf) format, and all maps and figures will be provided either as embedded objects in the Word file or as separate files. 2.4 Interpretation of Monitoring Program Results The results from this program will be integrated with the four other monitoring programs of the RFMP (Physical Habitat, Ecological Productivity, Fish Population Indexing Surveys, Adult Habitat Use) and will be used to support inferences about the effects of flow releases from Revelstoke Dam in the Middle Columbia River. Results from the RFMP and associated inferences will be used to establish the long term minimum operating release requirements for the Revelstoke Dam. 2.5 Schedule The proposed duration for this monitoring program is six years, beginning three years prior to the implementation of operational changes. The first two years (2008 & 2009) of the program have already been completed. 2.6 Budget Total Program Cost: $456, REFERENCES BC Hydro Revelstoke Unit 5 Project Environmental Assessment Certificate Application. Volume 1: Supplemental Information Report. BC Hydro. 2005a. Consultative Committee report: Columbia River Water Use Plan, Volumes 1 and 2. Report prepared for the Columbia River Water Use Plan Consultative Committee by BC Hydro, Burnaby, BC. BC Hydro. 2005b. Columbia River Project, Draft Water Use Plan. 38 pp. + appendices BC Hydro Page 11

12 Golder Associates Ltd Large River Fish Indexing Program: Middle Columbia River Phase 4 Investigations. Report prepared for B.C Hydro Power Supply Environmental Services, Burnaby, B.C. Golder Report No F 66p. + 5 app. RL&L Environmental Services Ltd. 1994b. Fish stock and habitat assessments of the Columbia River below Revelstoke Canyon Dam. Report Prepared for BC Hydro, Environmental Resources. RL&L Report No. 340F: 99 p. + app. RL&L Environmental Services Ltd. 1991a. Columbia River fisheries inventory of the Columbia River below Revelstoke Dam, May, 1991 studies. Data Report Prepared for BC Hydro Environmental Resources. 9 p. + 1 app. RL&L Environmental Services Ltd. 1991b. Columbia River - fisheries inventory of the Columbia River below Revelstoke Dam. - October 1991 Study Data Report. Prepared for BC Hydro Environmental Resources. 9 p. + 1 app. BC Hydro Page 12