Columbia Basin Fish and Wildlife Program Columbia Basin Fish and Wildlife Program
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Project Summary

Project 2008-111-00 - Twin Lakes Enhancement
Project Number:
Twin Lakes Enhancement
The Twin Lakes Enhancement Project utilizes liquid oxygen injected into the hypolimnion to oxygenate it and make it available. Since 2009, oxygen has been injected into the hypolimnion of North Twin Lake and the resulting changes in water quality, invertebrate and fish populations and angler success compared South Twin Lake which remained unoxygenated. An oxygenation system for South Twin was constructed in 2011 so that South Twin can be oxygenated if the North Twin system is deemed successful.
Proponent Orgs:
Colville Confederated Tribes (Tribe)
Starting FY:
Ending FY:
Province Subbasin %
Intermountain Columbia Upper 100.00%
RM and E
Focal Species:
Bass, Largemouth
Trout, Brook
Trout, Interior Redband
Trout, Rainbow
Species Benefit:
Anadromous: 0.0%   Resident: 100.0%   Wildlife: 0.0%
BiOp Association:

No photos have been uploaded yet for this Project.

Summary of Budgets

To view all expenditures for all fiscal years, click "Project Exp. by FY"

To see more detailed project budget information, please visit the "Project Budget" page

No Decided Budget Transfers

Pending Budget Decision?  No

Actual Project Cost Share

Current Fiscal Year — 2024
Cost Share Partner Total Proposed Contribution Total Confirmed Contribution
There are no project cost share contributions to show.
Previous Fiscal Years
Fiscal Year Total Contributions % of Budget
2020 (Draft)


The table below contains contracts with the following statuses: Active, Closed, Complete, History, Issued.
* "Total Contracted Amount" column includes contracted amount from both capital and expense components of the contract.
Expense Contracts:
Number Contractor Name Title Status Total Contracted Amount Dates
47609 SOW Colville Confederated Tribes 200811100 EXP TWIN LAKES ENHANCEMENT History $517,602 4/1/2010 - 3/31/2011
52300 SOW Colville Confederated Tribes 2008-111-00 EXP TWIN LAKES ENHANCEMENT History $683,492 4/1/2011 - 3/31/2013
61663 SOW Colville Confederated Tribes 2008-111-00 EXP TWIN LAKES ENHANCEMENT History $232,701 4/1/2013 - 3/31/2014
65574 SOW Colville Confederated Tribes 2008-111-00 EXP TWIN LAKES ENHANCEMENT History $143,928 4/1/2014 - 3/31/2015
68324 SOW Colville Confederated Tribes 2008-111-00 EXP TWIN LAKES ENHANCEMENT History $135,216 4/1/2015 - 3/31/2016
72000 SOW Colville Confederated Tribes 2008-111-00 EXP TWIN LAKES ENHANCEMENT History $148,788 4/1/2016 - 3/31/2017
75981 SOW Colville Confederated Tribes 2008-111-00 EXP TWIN LAKES ENHANCEMENT History $146,140 4/25/2017 - 3/31/2018
73548 REL 27 SOW Colville Confederated Tribes 2008-111-00 EXP TWIN LAKES ENHANCEMENT History $11,922 4/1/2018 - 3/31/2020

Annual Progress Reports
Expected (since FY2004):14
On time:4
Status Reports
On time:24
Avg Days Late:5

                Count of Contract Deliverables
Earliest Contract Subsequent Contracts Title Contractor Earliest Start Latest End Latest Status Accepted Reports Complete Green Yellow Red Total % Green and Complete Canceled
47609 52300, 61663, 65574, 68324, 72000, 75981, 73548 REL 27 2008-111-00 EXP TWIN LAKES ENHANCEMENT Colville Confederated Tribes 04/01/2010 03/31/2020 History 36 48 0 0 16 64 75.00% 8
Project Totals 36 48 0 0 16 64 75.00% 8

The table content is updated frequently and thus contains more recent information than what was in the original proposal reviewed by ISRP and Council.

Review: 2018 Research Project Status Review

Council Recommendation

Assessment Number: 2008-111-00-NPCC-20210302
Project: 2008-111-00 - Twin Lakes Enhancement
Review: 2018 Research Project Status Review
Approved Date: 12/20/2018
Recommendation: Implement
Comments: Recommendation: Project closing out. Council encourages sponsor to publish results and disseminate to a broad audience. See programmatic issue on Information Sharing and Reporting.
Review: Resident Fish, Regional Coordination, and Data Management Category Review

Council Recommendation

Assessment Number: 2008-111-00-NPCC-20120313
Project: 2008-111-00 - Twin Lakes Enhancement
Review: Resident Fish, Regional Coordination, and Data Management Category Review
Proposal: RESCAT-2008-111-00
Proposal State: Pending BPA Response
Approved Date: 3/5/2014
Recommendation: Implement with Conditions
Comments: Implement North Twin Oxygenation activities through FY 2017. Sponsor to address current ISRP qualifications (ISRP 2012-2) to demonstrate progress in community efforts to reduce external nutrient loading in their next annual report. Expansion into South Twin Lake based on favorable ISRP review of statistical results from lake comparison study indicating both cost benefit and benefit to fish.

Independent Scientific Review Panel Assessment

Assessment Number: 2008-111-00-ISRP-20120215
Project: 2008-111-00 - Twin Lakes Enhancement
Review: Resident Fish, Regional Coordination, and Data Management Category Review
Proposal Number: RESCAT-2008-111-00
Completed Date: 4/17/2012
Final Round ISRP Date: 4/3/2012
Final Round ISRP Rating: Meets Scientific Review Criteria - In Part (Qualified)
Final Round ISRP Comment:
Qualification #1 - Qualification #1
In Part: While initial results of the oxygenation of North Twin Lake are promising, the ISRP believes that additional time is needed to fully characterize the costs and benefits of this fishery enhancement effort. One to two years of data may not be enough to adequately characterize the whole-lake response to a restoration at this scale, especially in view of several confounding factors identified below, which occurred during the initial phase of the study. For this reason we feel that proceeding with an oxygen generation plant for both lakes is not scientifically justified at this time. Provided that sufficient oxygen can be obtained from local suppliers for North Twin, additional data should be collected comparing oxygenated North Twin versus non-oxygenated South Twin. Project staff should obtain statistical assistance to determine the point at which results clearly demonstrate that oxygenation is cost-effective before committing to oxygenating both lakes on a regular basis.
Qualification #2 - Qualification #2
Qualified: In the last review, the ISRP requested specific results indicating that external nutrient loading was being reduced, but these results were not included in the proposal or in the last annual report. An update should be added to the proposal quantitatively summarizing the reduction of discharge into the lakes. Has the concept of large tanks that are periodically pumped and hauled away been considered, instead of using septic fields that eventually drain into the lakes?
First Round ISRP Date: 2/8/2012
First Round ISRP Rating: Meets Scientific Review Criteria - In Part (Qualified)
First Round ISRP Comment:

1. Purpose: Significance to Regional Programs, Technical Background, and Objectives

The project sponsors cite that the project goals follow those in several subbasin plans including the Upper Columbia and Columbia River plans, the CCT Fish and Wildlife Management Plan, and the MERR document guidelines when monitoring and evaluating fish planting strategies. The project is adequately described in the context of regional trout enhancement efforts. In the Annual Report for 2010 (April 2011), one of the goals of this project is stated to be enhancement of the population of interior rainbow ("redband") trout in both North and South Twin lakes so that they can support a sustainable fishery without the need for hatchery augmentation. However, at present both lakes are stocked with hatchery rainbow trout, and the decision to switch from redband trout to rainbow trout needs to be included here.

The objectives (below) are straightforward and measurable - when linked with deliverables.

OBJ-1:Improve the trout fishery in North and South Twin Lakes

OBJ-2:Oxygenate North and South Twin Lakes


2. History: Accomplishments, Results, and Adaptive Management (ISRP Review of Results)

The proposal itself presents several graphs pertaining to limnological investigations and net captures, but figure captions and an adequate discussion of the data they portray are needed. More details are in the 2010 annual report. Results indicate that the two lakes are similar in some respects but somewhat different in others. For this reason, the response of fishes and aquatic invertebrates to the proposed oxygenation of South Twin Lake, which was not oxygenated in the past, cannot be predicted with certainty. Results do show, however, that oxygenating North Twin Lake has created conditions more suitable for benthic invertebrates and that trout now use the cool hypolimnion during warm summer months.

It would be easy to assume that increased angler catch rates with oxygenation would make North Twin Lake a better place to fish; however, Table 6 and Table 7 suggest that catch per unit effort in South Twin exceeded that of North Twin in some months, even with the higher carryover rate of trout in North Twin. This raises the question of how stocking has been carried out in the lakes and how hatchery supplementation has influenced harvest during the initial period of oxygenation. It also raises the more general question: will the relatively high cost of oxygenation, especially if the oxygen generating plant is constructed, result in enough fish and/or enough larger fish to justify the expense?

The work in 2009, 2010, and 2011 clearly showed that once North Twin Lake was oxygenated, fish utilized the hypolimnion and survived at a higher rate than at South Twin Lake. Differences were statistically significant. As a result of the success at North Twin Lake, stocking strategies changed which confounds the growth rate and condition factor data collected during the study. Angling pressure, catch-per-unit-effort, survivability of marked release groups of trout, growth and condition of fish have been measured to establish if goals of project have been met. As a result stocking numbers have been reduced by 60%, but the size of fish caught has increased from 230g to 435g, while reducing CPUE by only 10%. The percentage of carryover fish increased by five times and angler satisfaction has increased.

A short paragraph on adaptive management only indicates that the management changes which have occurred have been adjustment of stocking numbers in response to oxygenation effects. However, during the project site visit we were told that a switch in type of fish planted from redband stock to triploid rainbow occurred because the redbands were emigrating from the lakes. This discussion plus the rationale for the switch could/should also be added as an example of adaptive management.

3. Project Relationships, Emerging Limiting Factors, and Tailored Questions for Type of Work (hatchery, RME, tagging)

In general, the project sponsors have made progress in addressing the questions posed by the ISRP. Additional research to understand the limnological processes in the two lakes will be very helpful. One emerging factor that deserves more discussion is the presence of non-native largemouth bass and golden shiners in the lakes. What is being done to monitor the effects of oxygenation on these species?

Several long-term issues are of concern: (1) what are the long-term effects on macroinvertebrates and will changes effect fish growth, and (2) hypolimnetic anoxia is a result of sediment oxygen demand (SOD) and now that external nutrient loading has been reduced, will SOD be reduced as the hypolimnion continues to be oxygenated and will future oxygen supplementation continue to be required? Some evidence indicates that SOD will be reduced, but this needs to be monitored and documented for a longer period of time. Mercury analyses from the two lakes have been confusing to date. More information is needed over time. Another issue of concern is how will the oxygenation affect uptake of methylmercury in fish. Present levels are below EPA cautionary guidelines.

4. Deliverables, Work Elements, Metrics, and Methods

The project should consider expanding the number of sites for continuous oxygen measurements in the lakes. According to the descriptions of the sampling program in, only a single site from each lake will be continuously monitored. More sampling locations are needed, especially if trout prefer different places in the lakes over the course of a year.

4a. Specific comments on protocols and methods described in

The methods published in have sufficient detail for the most part but should also include the stocking regimes for the two lakes, including species and size at release. Additional details on the benthic and plankton surveys would also be helpful.

Modified by Dal Marsters on 4/17/2012 2:55:56 PM.
Documentation Links:
Review: Fish Accord ISRP Review

Independent Scientific Review Panel Assessment

Assessment Number: 2008-111-00-ISRP-20100323
Project: 2008-111-00 - Twin Lakes Enhancement
Review: Fish Accord ISRP Review
Completed Date: None
First Round ISRP Date: 7/24/2009
First Round ISRP Rating: Response Requested
First Round ISRP Comment:

This proposal lacks sufficient technical justification, background information, and detail in other areas (including study design, objectives, and methods) to enable the ISRP to evaluate the scientific merit of the proposal. The ISRP requests a response for the proponents to provide the following information in order to complete this review: Summary results and reports (with web based links to reports if available) from the three years of redband trout studies in Twin Lakes by the Colville Confederated Tribes should be included in the Technical Justification section. What is the source(s) of anthropogenic phosphorous loading to Twin Lakes? The proposal does not present basic limnological data about the project lakes. Included should be such data as catchment basin area, water surface area, maximum and mean water depth, shoreline development, water sources and flux, and the characteristics of lakebed sediments and aquatic macrophytes. Lacking such basic information, the ISRP cannot evaluate reasonability of the project. Include a discussion of how redband trout can be re-established in an already diverse fish community dominated by non-native species. Section E indicates that this is a new project, but clearly this project is ongoing (~three years?). Please explain. Unless there are mortality or growth data on redband trout available from Twin Lakes studies, the objectives in Section F will need to be revised. Work Elements (WE) 2 and 3 (the main ones) are too general, and much more detail is needed on hydroacoustic and creel survey designs and methods. Can golden shiner be used to monitor changes in methyl mercury during the study?

Documentation Links:

Project Relationships: This project Merged To 1985-038-00 effective on 3/14/2019
Relationship Description: Starting with FY19 contracts, all work/$ moved to 1985-038-00 Colville Hatchery O&M.

Name Role Organization
Peter Lofy Supervisor Bonneville Power Administration
Billy Gunn Administrative Contact Colville Confederated Tribes
Kary Nichols (Inactive) Interested Party Colville Confederated Tribes
Randy Friedlander (Inactive) Supervisor Colville Confederated Tribes
Amy Mai Project Manager Bonneville Power Administration
Zachary Gustafson (Inactive) Env. Compliance Lead Bonneville Power Administration
Bret Nine Project Lead Colville Confederated Tribes
Jody Lando Project SME Bonneville Power Administration