January 29, 2013

Lake Diefenbaker Reservoir OperationProposed Operating Manual Development

Outline• Background• About Lake Diefenbaker• Typical Operations • 2010/11 Operations• University of Saskatchewan Review of 2010/11 Operations• 2012 Stakeholder Engagement• Reservoir Operations Manual Template • Proposed Process for Lake Diefenbaker ROM

Background• WSA responsible for operation and maintenance of 45 dams,

control structures and/or weirs. • Provincial 25 Year Saskatchewan Water Security Plan calls

for review and update of reservoir operating plans (now operating manuals) on a priority basis

• Government has committed to completing ROM for Lake Diefenbaker be early 2014.

Lake Diefenbaker Specifications

Reservoir Design Full Reservoir Design Full Supply Level (FSL)Supply Level (FSL)

556.87 metres556.87 metres

Effective drainage Effective drainage areaarea

126,000 km126,000 km22

Maximum depthMaximum depth 58 metres at FSL58 metres at FSL

LengthLength 225 km at FSL225 km at FSL

AreaArea 43,000 hectares at 43,000 hectares at FSLFSL

Storage at FSLStorage at FSL 9,400,000 dam9,400,000 dam3 3

(total)(total)

4,300,000 dam4,300,000 dam3 3 (live)(live)

Operation Targets for Lake Diefenbaker

Minimum

545

546

547

548

549

550

551

552

553

554

555

556

557

558

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Full Supply Level = 556.87 m

Minimum

Maximum

Target Elevations

(1) West Side Pumping Plant 549.86 m(2) Grainland W.U.A. 550.47 m(3) Miry Creek W.U.A. 551.41 m(4) Elbow Harbour 552.00 m(5) July 1 Piping Plover Target 555.00 to 555.30 m

(5)

(1)

(2)

(3)

(4)

Daily Mean

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

0

500

1000

1500

2000

2500

Inflow

Outflow

Upper Quartile Inflow

Elevation

Median Elev

Diefenbaker Lake 2010 to 2011(Inflow, Outflow, Elevation)

1 2 31,2,3 Three reductions for S'toon Pipeline

2 Units Full

Reduced Outflow to Avoid Spilling on SaskRiver Hydro

Well Above Upper Quartile Prairie Inflow

1st 2011 Alta Rain Event

2nd,3rd Alta RainWell Above

Upper Quartile Summer Inflow

Started Spill May 2, 2011

Diefenbaker Lake Levels

Diefenbaker Flows and Levels

1:10 year Peak Inflow

U of S Review of 2010/11 Lake Diefenbaker Operations

• Reviewed flow and operational records, data records, interviewed staff and external experts

• Final report delivered February 2012• 8 major recommendations

• First identifies the need for a document clearly outlining the priorities and rules for operating the reservoir over the range of expected flow conditions

• Second identifies the need to clarify the operating objectives.• Remaining deal with data, modeling, and understanding of river

ice.

2012 Stakeholder Engagement• WSA recognized need for stakeholder input in fall 2011 • Independent consultant retained to conduct an engagement

process starting in late May 2012. • Separate meetings for each sector (d/s municipal,

environment, First Nations, government, industry, u/s municipal, recreation, metis)

• Explored values and priorities• Report provided to WSA in December 2012.• Posted on website

https://www.wsask.ca/Lakes-and-Rivers/Dams-and-Reservoirs/Developing-and-Operating-Plan-for-Lake-Diefenbaker/

ROM Template• Intended primarily for use by Forecasting & Operations• Provides clarity, consistency, defensibility, multiple forecasters• Intended to fit into OM&S manuals required by CDA guidelines• Applies to current realities• Seven sections plus Appendices

1. Introduction and background2. Objectives (purposes and priorities)3. Constraints (dam safety, physical, legal)4. Operating Zones and Rule Curves5. Operating Plans6. Protocol to determine operating recommendation7. Procedure to execute decision

ROM Template

5. Operating Plans (flow conditions terminology from CDA)Routine

Below normal flow (not all users satisfied)Normal flow (all or most users satisfied)Moderate floods (not all users satisfied)

Unusual Large floods (multiple users not satisfied)

EmergencySituation in which the dam is potentially threatenedRefers to Emergency Response Plan if available

ROM Template

6. Protocol to determine Operating Recommendation

• For use by Forecasters• What meteorologic stations, hydrometric stations• What hydrologic and routing models, where they are• May include flow charts and check lists• What documentation is required and where it is to be

filed• May refer to Products and Procedures Manual (under

development)

ROM Template

7. Procedure to execute decision

• Procedure to move from recommendations to implementation…decision chain

• Communication of decision externally – Who, how and when notification of decision is provided to reservoir users and downstream stakeholders

• May include flow charts and check lists• What documentation is required and where it is to be

filed

Process for Lake Diefenbaker ROM• Revise existing into new ROM format• Develop suite of alternative Operating Plans

• 2010/11 Review• Stakeholder Engagement report• Internal consultation and buy-in

• Develop reservoir performance measures• Assessment of alternative Operating Plans

• WRM modeling for water supply and seasonal and inter-annual variability

• Flood routing assessment, reservoir peak levels and duration, downstream flows and levels

• Simple economic assessment

Process for Lake Diefenbaker ROM• Selection of preferred alternative

• Compile assessment results• Internal review and selection• Finalize documentation of assessments and process

• Preferred draft ROM and supporting documentation available for government approval

Questions?