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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.20051
Ljubljana – November - 2008
Design, Construction and Maintenance of Large Dams
Gerald ZenzGraz University of Technology
Contributors - Dam Surveillance Practice from Kaprun Seminar:P.Obernhuber; P.Schöberl; R.Melbinger;
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.20052
Ljubljana – November - 2008
Design, Construction and Maintenance of Large Dams
Dam Safety in AustriaAuthorization ProcedureMultilevel PrincipleObligation of the Owner
Dam Safety EngineerDam Attendant
Safety During Operation / SurveillanceAnnual InspectionFive Year AssessmentAustrian Commission on DamsAspects of Visual Inspections
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.20053
Ljubljana – November - 2008
Design, Construction and Maintenance
Contributors to Dam Surveillance Practice from Kaprun Seminar:P.Obernhuber; P.Schöberl; R.Melbinger;
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.20054
Ljubljana – November - 2008
MonitoringMeasurementsSurveillanceTesting
EmergencyDraw DownEmergency Plan
Design - ConstructionState of the ArtRegulationsDesign / Concept
AssessmentMaintenance
Dam Safety Seminar – Kaprun - 2005
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.20055
Ljubljana – November - 2008
Dam Safety
StructuralErosionSlidingFracturing
OperationalFlood ReliefDraw DownReservoir Emptying
Dam and FoundationReservoir and Downstream
Appurtenant StructuresEquipment
FailureAgeingSeepage
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.20056
Ljubljana – November - 2008
Authorization Procedure
Project
Construction
Impounding
Permission Construct
Observation
Permission Operation
Stat
e of
the
Art
Design Documents; Reports; Permission
Operation Surveillance
Certification for permitted operation
Construction Permission
Temp. Operation
Unrestricted Operation
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.20057
Ljubljana – November - 2008
DAM SAFETY in AUSTRIA
2 Hazard Categories – H≤15m/I≤500.000m3
– H>15m/I>500.000m3 → special check proceduresPublic Safety and Rights of Third Parties protected by the Water LawHigh Safety Level required → Load scenarios with very low probability of
occurrence considered
Periodical „Safety Assessment“ stipulated by the Law
Awareness and Control of Residual Risk (Risk Management)Sound Engineering Judgement EXPERT – and Multilevel PRINCIPLE
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.20058
Ljubljana – November - 2008
Maintenance, i.e. keep the plant in proper and safe condition, according to the license and to the State of the Art
Stick to the operation rules granted by the authority
Appoint a DAM SAFETY ENGINEER and the necessary deputies
Inform the population periodically regarding provisions made forincidents (H>15m, I>2 Mio m3)
Establish and steadily update a Dam file containing all relevantinformation on the dam
Obligation of the Owner
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.20059
Ljubljana – November - 2008
SAFETY
Des
ign
Con
stru
ctio
n
Emer
genc
y P
repa
redn
ess
Repair/Upgrading
MaintenanceDamage Limitation
Sur
veill
ance
acc.: Fed.Office for Water and Geology/Biel/CH
…in due time!
Sound Engineering Judgement
Competence to decide and
act
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200510
Ljubljana – November - 2008
Dam Safety during Operation
Surveillance
Continuously Safety checksAnnually Institutional AssessmentEvery five years Institutional Assessment
Design Documents; Permissions; Expert Statements; Instructions to Operate, …
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200511
Ljubljana – November - 2008
Continuous Surveillance
Automatic System: Boundary Values
Dam Attendant (DA): Visual, Measurement,Plausibility Check
Dam Safety Engineer(DSI): Plausibility Checks
ProgramVisual Inspection
Measurement Values
Dam File, Reports,Data Base
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200512
Ljubljana – November - 2008
Annual Inspection
Annual ReportStatement for safe dam
operation
Dam Safety Engineer SurveillanceEvaluation of MeasurementsSafety Assessment
Measurement Reports, Report of Dam Safety Engineer, Geologist, …
CompanyManagementEmployee
AuthorityFederalCentral Government
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200513
Ljubljana – November - 2008
Annual Reportwritten by the Dam Safety Engineer
Report:
General: Unusual Events, Data retrievedObservations: Conclusion of Observations
Measurements: Interpretation of behaviourConclusion: Safety Assessment
Attachements:
Inspection Reports, Geology, ..Display of measuremnts
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200514
Ljubljana – November - 2008
Load scenarios static, dynamic, hydraulic
System Characteristics design, condition, material properties
fissures, cracksappurtenant structuressurveillance system
System Behaviour deformations, seepage, uplift
Stake Holder Interests new arising public safety concerns
State of the Art new criteria, new calculation methods
CHANGES
DAM SAFETY = DYNAMIC PROCESS
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200515
Ljubljana – November - 2008
AUTH
ORIT
YD
AM O
WN
ER
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200516
Ljubljana – November - 2008
Five Year Assessment
Commission of Dams – independent Experts:Visual InspectionAssessment of Measurements, Comparision, Long Term BehaviourState of the ArtSafety Assessment
Written AssessmentPermission to operate,
Additional Requirements
Annual Reports, Five Year ReportDam File
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200517
Ljubljana – November - 2008
Austrian COMMISSION on DAMS
Established in the Fed. Min. of Agriculture, Forestry,Environment and Water Management
Experts of all dam related SciencesCheck of the Project in course of the Water Rights Procedure
mandatory if H>15m, I>500.000 m3mandatory if special/unusual methods of design/construction applied, or if difficult foundation conditions
Matters of general importance, fundamental questions (e.g. guidelines)
"Backbone" dam supervision (steady Subcommittee)
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200518
Ljubljana – November - 2008
Dam related GUIDELINES in AUSTRIA
Stability Assessment for Embankment DamsStability Assessment for Dams under Seismic LoadsDesign of Spillways
Resolutions of the Commission on Dams:– Requirements for the Dam Safety Engineer– Education of Personnel, Dam Safety Courses– Supervision on Minor Dams
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200519
Ljubljana – November - 2008
The DAM SAFETY ENGINEER
„Central Switchboard“ for all issues of dam safetynormal operationextraordinary events/incidents
Requirements (DSE+Deputies) Techn. Top Management Dam Expertfamiliar with the plantreliableappropriate Directive Power to take measuresappropriate availability
Comprehensive Liabilities regardg. Dam SupervisionComprehensive Liabilities as to Reporting
Annual Safety Report (Safety assessment)Approval by the Water Authority!!!
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200520
Ljubljana – November - 2008
Dam Surveillance – Structural Safety Assessment
Attendant
Dam Safety Engineer
Water Authority
Visual Inspection
Annual Inspection
Five Year Assessment
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200521
Ljubljana – November - 2008
upstream face (if visible),downstream face,crest cracks
flakingdamages in concretejointswet areassintering
concrete dams
Visual inspection - what ?
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200522
Ljubljana – November - 2008
inspection galleries cracksflakingdamages in concreteblock jointsconcreting jointsrock (if visible)pipes (grouting, drainage)wet areasleakagepercolation water
concrete dams
visual inspection - what ?
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200523
Ljubljana – November - 2008
block joint 7/9 block 19, annual joint
date: 13th October 1999, reservoir level: 1776,38m
Photo documentation - Schlegeis dam
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200524
Ljubljana – November - 2008
Schlegeis dam, block 2, radial inspection gallerydate: 29th May 2001, reservoir level 1722,29 m
crack leakage
Schlegeis dam, block 9, inspection gallery 3date: 28th May 2002, reservoir level 1723,65 m
Items of Visual Inspection
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200525
Ljubljana – November - 2008
surfaceleakages: wet areas
seepagespringssiltationvegetation
deformations: bulgingcrackingslidingsettlements
inspection galleriessee concrete dams
embankment dams
visual inspection - what ?
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200526
Ljubljana – November - 2008
reservoir, slopes sliding, settlementsvegetationriver branchesglaciersdriftwood
downstream dam area springssettlementsslidings
tunnels and caverns flaking of rock or shootcretecracks in rock or shootcreteleakages
hydromechanical equipment damages leakages
visual inspection - what ?
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200527
Ljubljana – November - 2008
Durlaßboden dam springs
date: 28th August 1985, reservoir level 1404.25 m
down stream dam area
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200528
Ljubljana – November - 2008
Waag reservoir, date: 12th August 2004
leakage showed by vegetation
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200529
Ljubljana – November - 2008
Schlegeis dam, spring in downstream areadate: 14th August 2002, reservoir level 1772,02 m
Eberlaste dam, relief welldate: 9th September 2003, res. level 1115,92 m
Leakages
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200530
Ljubljana – November - 2008
Bennett Dam, British Columbia
"Sinkhole"
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200531
Ljubljana – November - 2008
Birecik dam, date: 26th May 2003repaired bulging
Bürg reservoir, date: 31st May 2001local subsidence of reservoir bank
rip rap shore surrounding
Damages, Deteriorations
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200532
Ljubljana – November - 2008
Bürg reservoirleft quay
local sliding ofreservoir slope
date: 18th February 1998
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200533
Ljubljana – November - 2008
Bürg dam Valle di Lei dam / Switzerland
no danger danger of plugging
Driftwood and spillways
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200534
Ljubljana – November - 2008
supporting structure
concrete steps
Damages, Deteriorations
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200535
Ljubljana – November - 2008
earliest recognition of
deteriorationsdefectsdamagesfailuresabnormal incidents
and
start of necessary measures
visual inspection - why ?
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200536
Ljubljana – November - 2008
of
hydromechanical equipment
bottom outlets
spillway (if gated)
emergency power supply
voice transmission lines
signal transmission lines
warning and safety devices
measuring equipment
remote monitoring system
testing
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200537
Ljubljana – November - 2008
testing - when ?
signaltesting 1 yearpractice 5 years
warning signals1-3 monthmalfunction signal
standby generatorstart 1 month
emergency power supply1 monthlimiting values
1 monthcommunication devices
partial opening1 year
full opening dry1 year
hydro mechanical equipment
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200538
Ljubljana – November - 2008
emer
genc
yga
te
mai
nga
te
1. emergency gate(no discharge)
Testing scheme for the bottom outlet
2. main gatepartial opening
3. main gatefull opening (dry)
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200539
Ljubljana – November - 2008
attention in the river bed !!
even testing of manual drive !!
• date, reservoir level• circumstances• opening value, discharge• time for opening, closing• hydraulic pressure• current consumption
Documentation of Bottom Outlet Testing
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200540
Ljubljana – November - 2008
Significant reduction of water load (danger)Complete draw down of reservoir Control of reimpoundingOther purposes:
• Sediment flushing• Minimum flow in the river• Flood mitigation (lowering res. level before flood)• River diversion during construction
BOTTOM OUTLETS
SAFETY OPERATIONALPURPOSES
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200541
Ljubljana – November - 2008
Equipment
≥ 2 Gates or Valves– Main Control/Service Gate– Standby/Emergency Gate (suitable to cut
off discharge)– Types:
sluice/radial gates, plunger/ hollow jet/butterfly valves
DESIGN (continued)
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200542
Ljubljana – November - 2008
Flushing(dredging)
SEDIMENT MONITORINGSEDIMENT CONTROL
Depending on catchment area conditions
COMPREHENSIVE REFURBISHMENT/OVER-
HAUL/UPGRADING
Depending on before mentioned assessment
Reservoir empty →scope and schedule of maintenance
works
ASSESSMENT OF STATE INCLUDING UNDER WATER COMPONENTS
10 years
High reservoir levelpartial opening
DISCHARGE TEST1 year
Accessible componentsVISUAL ASSESSMENT OF STRUCTURE
Periodical dam inspection (dam attendant)
Extreme conditions(load / discharge)
(Hydraulic Model Test)
COMPREHENSIVE TESTACCEPTANCE TEST
End of construction /major design alterations
INSPECTION and TESTING
Include check of remote monitoring / control systems!!
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200543
Ljubljana – November - 2008
Discharge extreme floods Safety HIGHProbability LOW
Keep reservoir level within allowable limits
SPILLWAYS
MAINLY SAFETY PURPOSES
Types (preferred): ▪ ungated – fixed sill, free flow conditions
▪ gated – gates opened by water pressure
Flood control, flood mitigation
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200544
Ljubljana – November - 2008
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200545
Ljubljana – November - 2008
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200546
Ljubljana – November - 2008
Availability / Operational Reliability
– Energy Supply redundant! see Bottom Outlets– Reliability/availability of control/monitoring systems
high!Redundant/self monitoring systems
– Access to Control Chamber all over the year– Availability under extreme weather conditions
Ice (heating)Snow
– Provisions to prevent cloggingTrash racks, log boomsControl of sedimentation level at intake
DESIGN
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200547
Ljubljana – November - 2008
Fixed rack
Log boom
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200548
Ljubljana – November - 2008
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Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200549
Ljubljana – November - 2008
Plunge Pool after flood
Institute for Hydraulic Engineering and Water Resources Management
Professor Horst Cerjak, 19.12.200550
Ljubljana – November - 2008
MAINTENANCE
Weathering, CorrosionAbrasionFissures, cracksLeakage, seepageScourWear of moveable components (gearboxes, seals)Material deficiencies (e.g. in cast metal, welding)Damage to access paths
Discrepancy with STATE of the ART
UPGRADING
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