1.3.5 Administration Matters 11

Contents 1.3.6 Meetings 11

2. SURVEILLANCE 12

2.1 Prescribed Dams 12 CONTENTS 5 2.2 Proposed Dams and Modifications – OVERVIEW BY CHAIRMAN 1999/2000 6 Requirements and Procedures 12 2.3 Existing Dams –Surveillance Reports Our Objectives 6 and Inspections 13 Targets 6 2.4 Current Situation on Dam Safety 13 Highlights 6 2.4.1 Status of Dam Safety Assessment 13 Our People 7 2.4.2 Flood Capability 17 Our Stakeholders 7 Appendix B – 2000 Current Prescribed Dams 18 The Future 7 2.4.3 Seismic Structural Capability 22 1. ABOUT THE COMMITTEE 8 2.4.4 Structural Safety under Normal Operating Conditions 23 1.1 Role and Function 8 2.4.5 Operation, Maintenance and Surveillance 23 1.2 Policies, Procedures and Practices Update 9 2.5 Dam Safety Emergency Planning 24 1.3 Organisation 9 2.6 Flood Retarding Basins 24 1.3.1 General Operations 9 2.7 Liaison With Other NSW Regulators 25 1.3.2. Committee Members 10 2.8 Liaison with Snowy Mountains Hydro-Electric 1.3.3. Committee Staff 11 Authority (SMHEA) 26 1.3.4 Sub-Committees 11 2.9 Liaison with Dam Owners/Authorities Outside NSW 26 3. MINING 27

3.1 Administration 27

3.2 Monitoring Programmes 27

3.3 Future Mining 28

4. EDUCATION AND TRAINING 29

4.1 Continuing Education and Training of Committee Members and Staff 29

4.2 Dam Owner Education and Training 29

5. PERFORMANCE AND FUTURE OBJECTIVES 30

5.1 Performance Indicators 30

5.2 Future Objectives 30

5.2.1 Dams Surveillance and Safety 30

5.2.2 Mining 31

6. FINANCE 32

6.1 Dams Safety Committee Certificate 32

6.2 Auditor General’s Certificate 33

6.3 Finance Summary 34

Appendix A – Dam Owner Summary – 30 June 2000 36 6.4 Dams Safety Committee 1998/99 Budgetary Information 36

7. COMMITTEE INFORMATION 36 DAMS SAFETY COMMITTEE

ANNUAL REPORT

1999 / 2000

2 A STATUTORY CORPORATION OF THE NSW GOVERNMENT Floor 3, 10 Valentine Avenue PO Box 3720 NSW 2150 Phone: (02) 9895 7363 The Hon. Richard Amery, MP Fax: (02) 9895 7354 Minister for Agriculture and In reply please quote: Minister for Land and Water Conservation Our ref: 10.102.007 Parliament House NSW 2000 Your ref:

Dear Mr Amery,

I have pleasure in submitting to you, for presentation to Parliament, the Committee’s Annual Report for the year ended 30th June 2000.

Yours sincerely,

Len McDonald Chairman

1 CONTENTS & INDEX

NEW SOUTH WALES DAMS SAFETY COMMITTEE ANNUAL REPORT 1999/2000

CONTENTS OVERVIEW BY CHAIRMAN 3 2.7 Liaison with Other Regulators 22 2.8 Liaison with Snowy Mountains 1. ABOUT THE COMMITTEE 5 Hydro-Electric Authority (SMHEA) 23 1.1 Role and Function 5 2.9 Liaison with Dam Owners/Authorities 1.2 Policies, Procedures and Practices Outside NSW 23 Update 6 1.3 Organisation 6 3. MINING 24 1.3.1 General Operations 6 3.1 Administration 24 1.3.2 Committee Members 7 3.2 Monitoring Programmes 24 1.3.3 Committee Staff 8 3.3 Future Mining 25 1.3.4 Sub-Committees 8 4. EDUCATION AND TRAINING 26 1.3.5 Administration Matters 8 4.1 Continuing Education and Training 1.3.6 Meetings 8 of Committee Staff 26 2. DAMS SURVEILLANCE 9 4.2 Dam Owner Education and Training 26 2.1 Prescribed Dams 9 5. PERFORMANCE AND FUTURE OBJECTIVES 27 2.4 Current Situation on Dam Safety 10 5.1 Performance Indicators 27 2.4.1 Status of Dams Safety Assessment 10 5.2 Future Objectives 27 2.4.2 Flood Capability 14 5.2.1 Dams Surveillance and Safety 27 2000 Prescribed Dams Details – 5.2.2 Mining 28 Appendix B (Pullout Section) 15 6. FINANCE 29 6.1 Dams Safety Committee Certificate 29 2.4.3 Seismic Structural Capability 19 6.2 Auditor General’s Certificate 30 2.4.4 Structural Safety under Normal 6.3 Finance Summary 31 Operating Conditions 20 6.4 Dams Safety Committee 1998/99 2.4.5 Operation, Maintenance and Budgetary Information 33 Surveillance 20 2.5 Dam Safety Emergency Planning 21 7. COMMITTEE INFORMATION 33 2.6 Flood Retarding Basins 21 APPENDIX A — Dam Owner Summary 33

INDEX Activities; nature and range 5, 6 Address Inside front cover Assets 6, 31, 32, 33 Auditor General’s Opinion 30 Budget 33 Business and Service Hours Inside front cover Code of Conduct 8 Contacting the Committee Inside front cover Committee, purpose, origin 5 Dams, prescribed, statistics 15-18, 33 Equal Employment Opportunity 8 Emergencies Inside front cover, 21 Financial Statement 31, 32, 33 Freedom of Information 8 Information Sheets 33 Legislation 5 Management Improvement Plans and Achievements 3, 4, 27, 28 Meetings, attendance at 8 Members, appointment of 7 Members, name / position / qualifications 7 Mining 24, 25 Objectives 27, 28 Performance Measures 27 Staff, name/position/qualifications 8 SubCommittees 8 Telephone of Office Inside front cover

NOTE: The Committee has prepared 300 copies of this report for distribution to Parliament, relevant organisations and the public at a cost of 7,550.00 (ie. $25.17 per copy).

2 low risks that remain. Planning is in OVERVIEW BYBY CHAIRMANCHAIRMAN 1999/20001999/2000 hand to again bring the storage of Lake Hume to full supply level, expected in late 2000, following completion of OUR OBJECTIVES In managing threats to the security the main upgrading works. The owners of stored waters, or to dam structures, of these dams are to be commended The NSW Dams Safety from mining under or near the for their responsible attitude in Committee’s mission is to develop and , there is not the same degree committing substantial funds to the implement policies and procedures: of guidance from international safety improvement of their dams. · for effective dams safety management practice. Upon establishment of the Further substantial progress was made Committee in the late 1970s, a in planning for the safety upgrading of · for regulation of mining that affects cautious approach was taken in , and low cost, but dams or stored waters. regulating mining activity, based on important, safety improvements were The dams of interest to the the then existing scientific knowledge made on this dam. Significant progress Committee are the 261 dams whose of such effects as subsidence and was made with planning of the risk failure would threaten lives or would vibration caused by mining. Careful reduction measures for other dams, as have significant impacts in terms of monitoring of the effects of mining was detailed in the report. economic loss or environmental established and, as knowledge and experience has been gained, the There were no significant dam safety damage. Such dams are known as incidents during the year. There were “prescribed” dams. The Committee Committee has gradually modified its requirements in order to allow the no floods of note and no damaging takes into account the Australian earthquakes. A minor problem with a National Committee on Large Dams winning of more coal and mineral resources than would otherwise be flood retarding basin was dealt with (ANCOLD) guidelines and relevant promptly. international practices in deciding on available. As a result, there has been tolerable risks from dams. The chance significant economic benefit to the Last year I reported that the of dam failure that is tolerable for a State, whilst ensuring the security of Committee issued a notice under particular dam depends on the stored waters and the safety of the Section 18 of the Dams Safety Act 1978, potential failure consequences, dams in question. requiring the owner of Humphreys Creek tailings dam, in northern which may range from slight to TARGETS catastrophic, and on the degree to , to provide reports which community interests would be The Committee has adopted the on the safety of the dam. During this affected. Thus the tolerable chance of targets given in Section 5 of this report. reporting year the owner has had a failure can range from as high as 1 in Attention is drawn to the key targets dams engineer assess the safety of the 100 per annum at the low consequence requiring that there be programs, dam, and is now implementing the end to around 1 in a million per annum approved by the Committee, for engineer’s recommendations and at the highest consequence end. The reducing risks to tolerable levels on taking other measures to make the dam Committee expects that public dams identified as having significant safe. consultation will be part of the deficiencies, that the Committee The Committee is maintaining its approval process for any safety monitor progress against the interest in the role that risk assessment decision where dam failure could program, and that it follow up in a concepts can play as an aid to dam result in loss of life. Against this timely manner. The identification of safety management. Understanding background, a dam is classified as deficiencies and implementation of is evolving rapidly in this field, but “safe” if it meets the Committee’s risk reduction measures usually there is as yet no settled approach that requirements relative to the potential requires a period of several years. The could be described as authoritative failure consequences. Committee must monitor progress good practice. A further Tolerable throughout the whole period, assist the Risk Forum was arranged by the The fact that no prescribed dam process as needed and be prompt in Committee and held in November has failed does not demonstrate an stating its requirements. 1999 to exchange views with adequate dam safety management representatives of the nuclear safety HIGHLIGHTS program. International experience and land planning regulators on risk has shown the need for systematic The safety upgrading and management practices. programs, involving consequence augmentation of Dam In early 2000 the Committee rating, responsible operations, near Bathurst commenced in the latter published revised requirements for maintenance and emergency part of 1999. Substantial progress assessment of the earthquake safety preparedness practices, regular was made on construction of an of dams, to take account of the surveillance reporting, periodic auxiliary for Warragamba ANCOLD Guidelines for the Design of safety reviews and implementation Dam, the largest project that has been Dams for Earthquake that were of necessary risk reduction measures. implemented under the State’s dam published in late 1998. The Committee has structured safety improvement program. The the dam safety program for New Murray-Darling Basin Commission The approval of mining applications South Wales in line with the continued with works to further is making increased demands on staff ANCOLD Guidelines on Dam Safety improve the safety of , and time and is presenting the Committee Management, which reflect current is undertaking studies to decide on with some challenging issues, as international good practice. necessary measures to deal with those mining has now reached the nominal

3 that the Committee will need to revise OVERVIEW BY CHAIRMAN 1999/2000 a number of information sheets setting out its normal requirements. In addition there is to be an information one kilometre restriction zone around technical staff attended the 1999 sheet on tailings dams, as mentioned . ANCOLD Conference on Dams. above. These tasks will be undertaken Other training for members and staff in the coming year. Also inquiries to The environmental damage included attendance at two computer major overseas agencies in late 1999 resulting from the failure of a mine software courses, and refresher to determine their approach in tailings dam in Romania in February courses on first aid and safety in ensuring safety against piping (internal 2000 is a reminder of the potential confined spaces. The Committee erosion of embankment dams or dangers inherent in the storage of toxic appreciates the dedication of staff in foundations) of old existing dams, has wastes. There are a number of such their efforts, through the Staff Forum, revealed no clear guidance in dams in NSW and the Committee to improve the efficiency of the international practice. The Committee has resolved to prepare safety Committee’s operations. has resolved to prepare an information requirements that are specific to this sheet on good design practice in order type of dam. OUR STAKEHOLDERS to address this and other problems. The During the year the Committee Dam owners, mining companies, Committee is continuing with its initiated a review of all of its policy and their engineering consultants, have support of research on piping failures resolutions made since its the most immediate contact with the by the University of New South Wales. establishment in 1979. Some have Committee. The Committee seeks to Committee members will continue been rescinded, some have been work co-operatively with these people to be active in the development of confirmed and others are being in order to achieve mutually Australian and international guidelines updated to suit current circumstances. satisfactory outcomes to dam safety on risk assessment for dams. A joint and mining issues. The great majority All targets were met, except that ANCOLD and Committee Workshop of dam owners and mining companies inspections of high risk dams by on Tolerable Risk is under understand their responsibilities and Committee personnel were below consideration for early 2001. Also liability, and have an interest in safe target due to the demands on staff Committee members will be involved practices. A flexible approach is taken time. There is now virtually no backlog with the ICOLD Congress in Beijing, by the Committee and consideration in submission and review of dam China, in September 2000, with one is given to proposals on their merits, Surveillance Reports, following efforts of the four key topics to be discussed provided they will achieve tolerably low of the Surveillance Sub-Committee in being risk assessment for dams. risks. The Committee monitors the addressing an emerging problem satisfaction of dam owners and mining Careful attention is now being given during the previous reporting year. companies with its administration. to the completion of required safety documentation, such as Dam Safety Most owners wish to properly manage OUR PEOPLE their dams but often their staff lack Emergency Plans and Operations and awareness and training in dam safety. Maintenance Manuals, for high and The Committee continues to be significant consequence dams, as the Consequently, the Committee places active in the affairs of ANCOLD and considerable importance on educating, target date of December 2000 for its ICOLD (International Commission and providing technical information to, completion approaches. on Large Dams). There are Committee owners and their consultants. To this New South Wales has an advanced personnel on two ANCOLD working end, Technical Information Sheets and dam safety program by world groups; those producing revised relevant technical papers are available standards. Each year there is significant Guidelines on Risk Assessment and on CD-ROM and at the Committee’s progress in reducing the risk posed by Guidelines on Environmental Internet site. Dam operator training dams. The Committee plans to Assessment and Management for courses were conducted jointly with continue this process until all dams Dams. During the year, two other the Department of Land and Water have tolerably low risks. The long term working groups on which the Conservation in November 1999, management of risks at tolerable levels, Committee had been represented February 2000 and March 2000. once these are achieved for all dams, is completed their assignments with the being assured through the publication of ANCOLD Guidelines on THE FUTURE implementation of routine monitoring, Selection of Acceptable Flood Capacity surveillance, safety review, staff training for Dams and Guidelines on Assessment In March 2000, ANCOLD and dam safety documentation of the Consequences of Dam Failure. The published Guidelines for the Selection of procedures. The task of bringing all Committee is also represented on two Acceptable Flood Capacity for Dams and dams up to standard will not be ICOLD committees; those on Dam in May 2000 Guidelines on Assessment completed for some years, but steady Safety (producing a bulletin of of the Consequences of Dam Failure. The progress is being made and risks are international practice on risk previous guidelines on flood capacity much lower than those of a decade ago. assessment, one of our members were published in 1986, and the being chairman), and Dams and guidelines on assessment of Floods. The Committee is also consequences are the first to be represented on the Board of the Mine published on this topic. Significant new Subsidence Technological Society. thinking and improvements in Len McDonald Most Committee members and methodology have been introduced, so Chairman

4 welfare, especially as major dams are welfare. The Committee minimises the 1.1. ABOUTABOUT THETHE COMMITTEECOMMITTEE expected to stand for several centuries. risks posed by dams by requiring their Consequently, dam safety needs to owners to arrange: be regularly reviewed to take into • regular monitoring and 1.1 ROLE AND FUNCTION account changing standards and surveillance of their dams; knowledge since the time of Currently, 261 dams in NSW are construction, as well as the ageing of • appropriate operation and prescribed under the NSW Dams a dam’s materials and changing maintenance procedures and Safety Act as warranting regulatory circumstances downstream. This practices for their dams; control to safeguard community was highlighted in 1999 at Lake • ongoing assessments of their interests to standards appropriate for Endeavour Dam, where investigations dams’ behaviour on the basis of the potential consequences of failure. confirmed concerns regarding the monitoring and surveillance Dams are essential to provide vital dam’s flood capability and stability. information; storage for water supply, irrigation, The owner was requested to hydro-power and industrial uses to implement short term emergency • regular review of the compliance counter the high variability of the planning while undertaking the of their dams with current Australian climate, with its prolonged necessary investigations to determine requirements; droughts and intense storms. They options for the long-term safety • reviews of all such information by also provide some measure of flood upgrading of the dam. experienced personnel, followed mitigation and environment by action to ensure that their protection, while being strategic The consequences of a dam failure generally increase with time as dams are maintained in a safe infrastructure assets that cannot be condition. readily replaced. On the other hand, population and resource demands the failure of large dams can cause increase. The activities around, on, • preparation of Dam Safety extensive loss of life, damage to and under dams, and their storages, Emergency Plans for their dams property and the environment, and loss and changes in development in association with flood plans of vital water supply, often for several downstream, need to be regularly downstream prepared by the years. In fact dam failures have caused reviewed to determine the current State Emergency Service. potential impacts of a dam failure, more deaths this century than any The Committee audits the and any requirements for controls. other peacetime artefact. effectiveness of these dam safety In the 1970s, international concern measures by requiring dam owners Unfortunately dams continue to fail at failures of relatively new major dams to submit five yearly summary throughout the world, and there are led to the Australian National Surveillance Reports, and by many more near failures. In particular, Committee on Large Dams undertaking inspections at regular there was the failure of Shih-Kung (ANCOLD) raising the need for intervals between reports to check Dam during the large earthquake dam safety regulation. The NSW performance. that shook Taiwan in September Government, with these factors in 1999. At this dam a fault running mind, constituted the NSW Dams The Committee is closely under the multi-gated spillway section Safety Committee in 1979. The monitoring compliance with its policy was displaced 10m vertically by the Committee has a regulatory ongoing that the owners of all NSW dams, earthquake destroying the dam “watchdog” role to ensure the owners that have the potential upon failure to spillway section. In addition, there of the State’s prescribed dams conform cause loss of life or significant was a cyanide release incident from to appropriate safety requirements and downstream impacts, have in place a tailings dam in Romania in February therefore prevent uncontrolled loss of appropriate dam safety emergency 2000, and there have been several their storages with consequent plans by December 2000. These plans failures of small dams world wide community and environmental effects. are to guide dam operating personnel (eg Europe, USA) caused by flood In this context, a “safe” or “low risk” and their supervisors in the event an overtopping during several extreme dam is taken to be one that complies emergency occurs. Dam owners are floods in 1999/2000. An incident with the Committee’s current also to provide relevant emergency in NSW, with the potential to cause requirements. These are updated planning material to the State dam failure had it not been detected regularly to conform to developing Emergency Service and local by inspection, involved an uncontrolled national and international practices emergency management agencies to leakage around the outlet pipe from and provide for a range of requirements assist them in their statutory Cecil Park Retarding Basin 3A in rather than a system of absolute responsibility for flood planning February 2000. The pipe inlet was standards. Their aim is to provide a downstream of dams. This does not subsequently blocked off and long- basis for actions by owners to reduce imply that such dams have defects, or term remedial measures were the probability of failure of any are likely to fail, but represents a instigated by the owner. particular dam to a tolerably low level prudent safety measure widely adopted throughout the world. It is an These incidents highlight the need related to the potential consequences for effective regulation and proper of dam failure. extension of normal flood and disaster planning and recognises that no asset management, incorporating The Committee has statutory engineering structure can ever be systematic dam safety programmes functions under the Dams Safety Act absolutely safe. involving operation, maintenance, 1978 and the Mining Act 1992 and emergency preparedness, surveillance “prescribes” only those dams, the The Committee also requires and safety review procedures, for the failure of which could threaten owners proposing to upgrade an long-term proper functioning of dams downstream life, cause extensive existing dam, or to construct a new under all conditions. This is an property or environmental damage, or dam, to provide design and important matter of public safety and have a severe impact on the public construction details at an early stage

5 expectations as well as technological Even though the Committee and 1. ABOUT THE COMMITTEE changes and developments. staff are small in number, the Committee continued to develop Total Committee members and staff Quality Management principles during also keep actively involved on the to establish that they conform to the year. Surveillance monitoring Executive and various working appropriate engineering criteria for procedures were improved and parties of ANCOLD, and ICOLD present and foreseeable future updated, the Committee’s data base (International Committee on Large conditions. Furthermore, the was upgraded and, through the staff Dams), updating and initiating Committee reviews the curricula forum, changes were made to the office guidelines on various aspects of vitae of dam designers to determine layout, internal procedures and dam safety. In particular, Adrian that they have appropriate expertise. practices in order to achieve improved Williams is currently chairman of A design report is also required efficiency and effectiveness. ANCOLD and chairman of the upon completion of the design. Upon ICOLD Committee on Dam Safety, completion of a new dam, or upgrading while Keith Murley is on the ICOLD of an existing dam, the Committee 1.3 ORGANISATION Committee on Dams and Floods. requires certification that construction Len McDonald is a member of the 1.3.1 General Operations has been undertaken to the designer’s ICOLD Committee on Dam Safety. requirements. The Dams Safety Committee is a He is also the Convenor of a working small statutory body with virtually no A number of major storages are party that was appointed to update assets; it owns no real estate, employs located above or adjacent to large coal the ANCOLD “Guidelines on Risk no staff itself but uses staff seconded reserves or mineral deposits. Mining Assessment”, and is also the from member organisations, and hires activity in these areas has the potential co-ordinating author assisting the subcontractors when required. As the to endanger the safety of these dams ICOLD Committee on Dam Safety Committee raises minimal revenue or their storages. The Committee in its preparation of a bulletin on risk and is primarily funded from overviews these mining activities assessment for dams. Len is also a Consolidated Fund Recurrent through provisions in the Dams member of the working party that is Expenditure, it has no overall pricing Safety Act and Mining Act, thus preparing the ANCOLD “Guidelines policy. enabling the Committee to make on Environmental Assessment and recommendations to the Minister Management for Dams”. The Committee operates through administering the Mining Act on two main Standing Sub-Committees, In addition, Keith Murley was conditions which should be applied responsible for Dam Surveillance and Convenor, and Norm Himsley was to mining leases granted in the vicinity for Mining matters, together with ad Secretary, of the ANCOLD working of dam storages. These conditions hoc Advisory Sub-Committees on party that prepared the ANCOLD allow the Committee to control and Hydrology and on Emergency “Guidelines on Selection of Acceptable monitor the resultant mining Management matters. Flood Capacity for Dams”, which were operations, in order to ensure that the issued in March 2000. Norm Himsley Most business is dealt with, in the risks to the dams and their stored water was also a member of the working first instance, by the appropriate Sub- are tolerable. party that prepared the ANCOLD Committee, which reports to main Guidelines on the “Assessment of the Committee meetings. In routine 1.2 POLICIES, PROCEDURES Consequences of Dam Failure” which matters, the Executive Engineer and AND PRACTICES UPDATE are ready for publication. standing Sub-Committees act for the The Committee continues to update Committee. Between meetings, an National guidelines are essential to its various information sheets, to Executive comprising the Chairman, ensure consistent dam safety policies provide the latest information on Deputy Chairman and Executive throughout . The involvement evolving Committee policies, Engineer, deals with urgent important of Committee personnel assists in requirements, procedures and business or emergencies on behalf of shaping Committee policies and practices. This information has also the Committee. Policy initiatives requirements, and ensures they are at been converted for presentation in originate both in full Committee and the leading edge of dam safety a CD ROM format and is available in Sub-Committees, but all policies are practices. The Committee is at present in the Committee’s web site at approved by the Committee. specifically working to develop and http://www.damsafety.nsw.gov.au. integrate risk assessment techniques Committee requirements for into dam safety practice to supplement structural and operating safety, seismic the prescriptive, engineering safety design, flood capability, surveillance standard basis for dam design that reporting and emergency planning has been the traditional approach. This require regular review to ensure owners will complement risk management are maintaining appropriate standards, methodologies and practices in related and to take account of the results of engineering and industrial fields, with local and world wide data collection the potential for a comprehensive and research in these areas. These understanding of critical risks, and policies and procedures evolve development of more cost effective gradually with interaction from all solutions. relevant parties, taking into account evolving social perceptions and

6 1.3.2. Committee Members Ian Anderson, B.E. (Mining),M.E., Ian Forster, B.Sc., M.A.I.G., M. Aus IMM. RPGeo. The Committee has eight part-time (appointed to (appointed to members appointed for four yearly June 2002). June 2001). dsc/c terms and generally reappointed to Nominee of the Nominee of maintain a continuity of experience in 24x32 Minister for dsc/f Pacific Power. the Committee. Seven of these Mines. Initially 24x32 Initially members are nominated for their appointed 1994. appointed 1989. experience in dam engineering and one for experience in coal mining. Ian is Senior Ian is the Senior Inspector of Coal Geologist / Dam The composition of the Committee Mines with the Department of Mineral Safety and Geo-technical Services with during 1999/2000, with brief Resources. He has over twenty years Pacific Power International, the biographies of each member, is set experience in underground, and open cut, engineering consulting arm of Pacific out as follows: coal mining and is a member of the Power. He has over thirty years experience Committee’s Mining Sub-Committee. in geotechnical engineering and Leonard McDonald, B.E., M. Eng. hydrogeology related to dams, power Sc., M.I.E. Aust, Ross Barrie, B.E., M.Eng.Sc., MBA, stations, tunnels and coal mining. He is C.P. Eng., MIE Aust, Chairman of the Committee’s Mining L.G.E. C.P.Eng. Sub-Committee and a board member of (appointed to dsc/a (appointed to the Mine Subsidence Technological June 2001) March 2003). Society. 24x32 Chairman, dsc/d Nominee of the Nominee of 24x32 Department of Jeffrey Gleeson, B.E., F.I.E. Aust, Institution of Land and Water C.P. Eng. Engineers, Conservation (appointed to Australia. (State Water). December Initially appointed 1987. Initially 2001). Nominee dsc/g Len has practised as a private consultant appointed 1999. of Hunter Water 24x32 Corporation. in dams engineering since his retirement Ross is the Assets Services Manager of Initially from his position as Assistant Principal State Water, the commercial arm of the appointed 1990. Engineer of the Dams and Civil section Department of Land and Water of the NSW Department of Public Works Conservation. He has over thirty years Jeff is Manager, & Services. He took over the experience in the water industry and is Chairmanship of the Committee in mid HWE Consulting Engineers, the the Chairman of the Committee’s consultancy division of the Hunter Water 1997. He is the Assistant Secretary to Emergency Management Sub-Committee ANCOLD and is currently a member of Corporation. He has over twenty-five the ICOLD Committee on Dam Safety. years experience in the water and waste- He has a wide background in all aspects Brian Cooper, B.E., M. Eng. Sc., water field with involvement in various of dam engineering having been involved Grad. Dip. Eng. aspects of dam engineering and structural in the investigation, design and Mgt., M.I.E. design. He is the Chairman of the construction of numerous dams. Len has Aust, C.P.Eng. Committee’s Surveillance Sub- (appointed to Committee. over twenty-five years experience in the dsc/e water industry and for over twenty years June 2001). has been a full time specialist in dam 24x32 Nominee of the Keith Murley, B.C.E., E.W.S., F.I.E. design. Minister for Aust, C.P. Eng. Public Works. (appointed to Adrian Williams, B.E., F.I.E. Aust, Initially June 2001). C.P. Eng. appointed 1997. Nominee of dsc/h (appointed to Institution of Brian is Principal Engineer, Dams June 2003) 24x32 Engineers. Safety, with the Department of Public Nominee of Initially Works and Services. He has over thirty Sydney appointed 1989. years experience in the water industry Catchment including extensive dam design experience Authority. Keith practices as a through his work with the Department of Initially private consultant and is Chairman of the Public Works and Services and formerly appointed 1986. Committee’s Hydrology Sub-Committee. with the Water Conservation and He has over forty-five years experience in Adrian is General Manager, Dam Safety Irrigation Commission. He is a member all aspects of dam engineering and the in the Sydney Catchment Authority. He of the Committee’s Surveillance Sub- water resource field through his has over thirty four years investigation, Committee. consultancy work and previously with the design and construction experience with then Victorian Rural Water Commission. dams through work with AWT/Sydney He was also the convenor of the Water and formerly with the Water ANCOLD working party set up to Conservation and Irrigation Commission. prepare the ANCOLD “Guidelines on He is currently the Chairman of Selection of Acceptable Flood Capacity for ANCOLD and the Chairman of the Dams” and is on the ICOLD Committee ICOLD Committee on Dam Safety. on Dams and Floods.

7 In addition, during the year the areas and the Committee wishes to 1. ABOUT THE COMMITTEE Committee utilised the services, and acknowledge the assistance of these assisted in the training, of migrant organisations. engineers under a State Government As part of the Committee’s 1.3.3. Committee Staff Migrant Training Assistance Scheme. administrative arrangement with the At separate times, Mr Marlo Vergara, DLWC, it has been agreed that the The Committee is assisted by a full was seconded from the Central Sydney Committee’s Freedom of Information time staff of four, seconded from Area Health Services, and Mr Ghatora, (FOI) statistics will be published in authorities nominating Committee from the State Rail Authority, to assist the corresponding issue of that members, with subcontract assistance in this regard with various Committee Department’s Annual Report. A where required. Given the extensive duties. supplement, pursuant to the Annual workload of the Committee’s activities, Reporting Requirements issued by this small staff provides an effective and 1.3.4 Sub-Committees the Premier’s Department on 27 June efficient service to the Committee’s The standing Sub-Committee on 1991, will accompany the functions. During the year the Dam Surveillance comprised Messrs Committee’s statistics. There were Committee staff comprised: Gleeson (Chairman), Cooper and no requests for information under Executive Engineer: Norman Himsley along with Mr Clynt Sheehy FOI legislation during the year, Himsley, B.E., (Manager, Safety and Audit from the probably due to the ready assistance M. Eng. Sc., DLWC) and Mr Ian Landon-Jones given by staff to the numerous Grad Dip Bus, (Senior Consultant, Dam Safety from inquiries that were received. This F.I.E. Aust, C.P. Sydney Catchment Authority), with assistance is part of the Committee’s dsc/i Eng. (Seconded support from Mr Karp. policy of maintaining close liaison with 24x32 from DLWC. The Mining Sub-Committee dam owners and the public. Joined the comprised Messrs Forster Because of the close links between Committee (Chairman), Anderson and Himsley the Committee and the DLWC, the in 1986). along with Mr Raper (Specialist, Rock Committee has adopted that Over twenty-five Mechanics from AWT/), Department’s Code of Conduct and years investigation, design and with support from Mr Reid. Mr Raper Ethics, with necessary minor construction experience in dams and resigned from Sydney Water late in adaptations, to ensure the engineering services. 1999 and the Committee would like maintenance of appropriate to express its thanks for his invaluable standards of work practice in the Surveillance Engineer: Michael contribution to the Mining Sub- Committee. In addition, as part of its Karp, B.E. Committee to that date. contracted administration assistance (Seconded from There are two ad hoc Sub- to the Committee, the DLWC DLWC in April implement EEO and Ethnic Affairs dsc/j Committees that meet as required. The 1999). Over Emergency Management Sub- policies for, and with, the Committee. 24x32 fifteen years Committee is chaired by Mr Barrie, As well, the Committee pursues experience in with representatives of various individual initiatives in these areas and, water and dams Government departments and in relation to Ethnic Affairs matters, engineering with supported by Mr Himsley. The the Committee’s internet site provides Departments of Hydrology Sub-Committee is chaired initial information about the Public Works by Mr Murley, with hydrological Committee in several languages. The and Land and Water Conservation. representatives from NSW and Committee also participated in the Victorian authorities, and again migrant engineer training scheme Engineering Geologist: Peter supported by Mr Himsley. during the year, with Messrs Ghatora and Vergara being placed with the Reid, B.Sc. B.A. Mr Himsley has been appointed to Committee for various terms to gain (Seconded from each of the Sub-Committees for Australian engineering experience. Department his technical input, and to provide The Committee would like to dsc/k of Mineral effective liaison between the Sub- acknowledge their valuable assistance 24x32 Resources in Committees and the Committee. He during these periods. 1987). Over ten also provides an effective and years experience important role of liaison with dam 1.3.6 Meetings in geological owners. mining fields. The Committee held eight meetings 1.3.5 Administration Matters during the year, of which six were in Ilse Glockemann, Administrative Sydney and one each at Bathurst and The Committee continues to rent Port Macquarie in association with Officer office space with the Department of dam inspections. Attendance at (Seconded Land and Water Conservation Committee meetings was as follows: from DLWC (DLWC) in Parramatta and in 1995). dsc/l reimburses the DLWC for use of Mr L.A. McDonald attended 8 out of 8 that Department’s administration Mr A.C. Williams attended 7 out of 8 24x32 assistance, accounting and legal Mr K.A. Murley attended 6 out of 8 services, as is appropriate for a low Mr I. Forster attended 7 out of 8 budget organisation. Other Mr I. Anderson attended 4 out of 8 authorities which nominate a member Mr J. Gleeson attended 8 out of 8 to the Committee, continue to provide Mr R. Barrie attended 8 out of 8 technical assistance in specialised Mr B. Cooper attended 7 out of 8

8 After review by the Committee and consultants to implement the 2. DAMS SURVEILLANCE during the year, thirteen dams were detailed design. The Committee prescribed and four dams also requires the preparation of deprescribed. A list of the 261 dams, design reports and submission of 2.1 PRESCRIBED DAMS prescribed as at 30th June 2000, is copies for the Committee’s records. included as a central pull out section The Committee’s functions relating of this Report, with their locations During construction of prescribed to dams refer primarily to prescribed shown on the map on the back cover. dams, the Committee requires dams or dam sites. Appendix A, and Of these dams, 101 are classified designers to be integrally involved in the centre pull-out section, provide as having at least a HIGH hazard the process and to approve any basic statistics and information on (ie. major consequences upon failure) design changes. A compliance dams prescribed by the Committee as requiring more comprehensive certificate, to the effect that designers at 30 June 2000. The Committee’s reporting and higher safety standards have been so involved, is required at policy is to avoid unnecessary than lower hazard dams. the end of construction. Committee impositions on dam owners, and to staff also undertake inspections minimise its administrative workload 2.2 PROPOSED DAMS AND during construction to check and need for staff. The potential construction practices, compliance community consequences of dam DAM MODIFICATIONS – with design drawings and failure are the Committee’s primary REQUIREMENTS AND specifications, and to maintain close concern. Therefore the Committee PROCEDURES contact with, and assistance to, the prescribes all dams higher than 15 m owner’s personnel. and those smaller dams (including For proposed dams and dam flood retarding basins and tailings modifications, the Committee requires After construction, the Committee dams) which could pose a threat to dam owners to provide pertinent dam requires dam owners to submit work- public safety, property or the design information for review by the as-executed drawings and a environment or which, through the loss Committee before proceeding to construction certificate for the of their function, could adversely affect construction. In all, eleven such Committee’s records. Owners must the community. submissions were processed by the also advise the Committee of any Committee during 1999/2000. The concerns during the ongoing operation The Committee continually reviews Committee does not have, or require, of the dam. The Committee’s first its list of prescribed dams in the light the resources to examine designs in formal requirement after dam of new proposals, changed conditions, detail, but checks to ensure major construction is the submission of a surveillance reports, staff inspections, safety criteria (eg. flood capability, Surveillance Report summarising the and information supplied by dam adequate filter provisions) are behaviour of the dam since owners, to ensure that only the addressed, and that the designers construction. This is to be submitted necessary minimum are prescribed. In are competent to undertake the to the Committee for its consideration, addition, damsites outside mining proposed dam design. In essence, usually after first filling of the dam, areas are only prescribed after a final the Committee audits the design which is a critical phase in dam safety, decision to construct a dam has been process, relying on the professional but no later than one year after made. competence of the owner’s personnel completion of dam construction.

pic 2 166 x 98

MARDI DAM. Flood capability upgrading was recently completed on this 26 m high town water supply dam.

9 in 1983. These reports are stored in In addition to the Surveillance 2. DAMS SURVEILLANCE the Committee’s files, and relevant Report Review Procedures, the information from the reports is being Committee continued its essential progressively incorporated into a practice of regular staff inspection 2.3 EXISTING DAMS – computer database. of dams, and discussion with owners, throughout the State. There are also SURVEILLANCE REPORTS Surveillance Reports are initially inspections by the Committee in AND INSPECTIONS reviewed by Committee staff to identify conjunction with its country meetings. any obvious omissions and However, from a practical point of Surveillance Reports on prescribed discrepancies, and to highlight features dams are required to be provided by view, Committee staff undertake the deserving attention. The Surveillance majority of dam inspections. Overall the dam owners to the Committee at Sub-Committee then reviews the five yearly intervals in accordance with 115 prescribed dams were inspected Reports. As a result, further during the year in liaison with dam the Committee’s Surveillance information, or an inspection of the Procedures. These reports provide the owners (see Appendices A and B for dam by Committee staff, may be details). Committee with basic information requested. Finally, the Sub- on the safety status of existing dams. Committee reports on all Surveillance Such inspections are an essential They also enable the Committee to Reports to the full Committee, whose adjunct to Surveillance Reports. They monitor whether dam owners, who members have the opportunity to enable Committee members and are ultimately responsible for the safety personally review all material staff to assess, at first hand, the general of dams, are continuing with a presented. The Committee then condition and safety standard of each responsible approach to their dams at endorses the Report and/or instructs dam’s structure and its foundations, all stages during the lives of the the dam owner to undertake any and to audit the actual performance structures. The extent of reporting additional necessary works, or of each dam owner in complying with varies depending on the Hazard implement any procedures required to any Committee requirements. In (Consequence) Category and size ensure dam safety in line with accepted addition, the dam’s hazard rating is of dams, with comprehensive reporting practices. reviewed in light of any downstream required for large high hazard dams, development. At the same time, any down to brief reports for low hazard The Committee considers that the deficiencies detected are brought to the dams. content and presentation of attention of the owner’s representative, Surveillance Reports is now of a and any concerns discussed on site. During 1999/2000, 40 dam generally high standard, having The inspections also provide a useful Surveillance Reports were reviewed by background of first hand knowledge, the Committee (see Appendices A markedly improved as a result of Committee guidance and as owners including photographs and videos, and B for details). This was slightly and their technical representatives have against which Surveillance Reports, less than the number that need to submitted by owners, can be evaluated be processed annually to avoid a gained more experience. The Committee is currently updating backlog developing. To redress the and assessed by the Committee. its Technical Information Sheet situation, letters have been sent to dam owners who have Reports outlining requirements in this area, in 2.4 CURRENT SITUATION ON outstanding, stressing their liabilities line with feedback from dam owners and world-wide practice. Overall, DAM SAFETY and the importance of submitting these Reports on time. the Committee considers that owners 2.4.1 Status of Dam Safety are responding in a positive and Except for recently prescribed dams, responsible manner to the Assessment at least one Surveillance Report (and Committee’s requirements, and The effective safety management up to four reports) for each prescribed are aware of their responsibility and engineering of dams requires dam has now been received and to the community, and their continual updating by drawing on the reviewed since introduction of the potential legal liability in the event results of operational experience with Committee’s Surveillance Procedures of dam failure. existing dams and the introduction of more sophisticated techniques for design, construction and asset management. The Committee is well aware that dam safety management and dam engineering are not exact sciences, and require considerable experience and judgement in assessing a wide variety of inputs (eg. technical, legal, social, environmental), to assess that dams continue to have a safety status commensurate with community expectations. In particular, the Committee recognises that each dam is site specific and uncertainties exist in the following areas related to dam safety assessment:

BETHUNGRA DAM. Emergency warning systems have recently been installed at this 13 m high dam while long term options for the dam are being investigated.

10 Dam Foundations to keep itself informed in all areas in decision making, and the procedures Each dam’s foundation has unique and of dam safety management. for assessing these difficult aspects are inherent variations in rock and soil continually evolving. properties which must be adequately It achieves this knowledge through investigated and assessed so that the the continuing education of staff The Committee’s monitoring of the foundation materials can be and members, and their attendance at evolving use of risk assessment has conditioned to form a safe and stable relevant technical symposia, along revealed that the risk assessment base for the dam and its imposed with contact and meetings with approach provides a framework for loadings. representatives of interstate and comprehensive assessment of dam overseas dams’ organisations. In safety over the whole range of potential Dam Materials addition, to provide background data failure situations and provides a better Materials must be assessed and placed needed for detailed risk assessment understanding of relative risks and to ensure provision of the most studies, the Committee has continued consequences. The risk assessment economic structure(s) for the dam, to actively encourage dam owners approach should not be considered as while meeting service and safety and Government agencies to install a methodology that leads to less costly requirements. and maintain rainfall/runoff and remedial works being implemented seismic monitoring installations. The than would be required using a Dam Loadings Committee considers it vital to develop standards-based approach alone. In The variable, complex and often and maintain an effective state- some situations it could assist in uncertain forces applied by nature wide network of monitoring justifying a less costly solution, but it (eg. floods, earthquakes) need to installations as a basis for providing may just as easily lead to the realisation be appropriately translated to an increased database of information that more stringent safety levels, than representative design loadings for to assist in improving the estimation those of a “standards” based design each dam. of appropriate design loadings for approach, are required. The purpose Dam Design rare, but credible, extreme floods of risk assessment is to enhance the The design methodology, level of and earthquakes. traditional evaluations in order to safety and degree of design provide for more informed decision sophistication needs to be During the year the Committee has making. Risk assessment requires determined. actively fostered discussion and skilled and detailed analyses to investigation of various areas in the formulate an informed overall Dam Management developing field of risk based decision judgement of a dam’s safety status, and The resources and scheduling making in relation to dams. It has there is the need to effectively provided to ensure adequate dam also fostered research into the communicate this information to the asset management, while maintaining assessment of risk associated with public at risk. safety standards, needs to be piping in embankments and optimised for each owner’s dam(s). foundations, the derivation of One critical factor in determining extreme design storms, and the risk that risks are a slow as reasonably Community Requirements assessment of slopes. practical is the effectiveness of Dam engineering and management emergency response actions in must take into account current A process of risk assessment, used reducing loss of life should a dam tolerable risk criteria (which are to enhance the understanding gained failure occur. This response difficult to assess and quantify), from the traditional methods of effectiveness is difficult to determine environmental concerns and liability assessment, is now considered before the emergency occurs. However issues relating to dam safety. All of desirable to assist in evaluating the the Committee, through its these can change with time and relative safety of each dam, and Emergency Management Sub- perception. to assess risk reduction options, and Committee, has developed a protocol Dam owners (and their agents) are their priority, to meet appropriate with the State Emergency Service legally obliged and responsible to assess safety requirements. Accordingly, (SES), which has the statutory all these uncertainties and make the Committee has continued to assess responsibility for flood planning and informed judgements, to ensure the developments in risk assessment control, to prioritise and develop degree of risk associated with their as applied to dams, but considers that appropriate interim emergency dams is tolerable relative to the risk to life criteria are usually the procedures for deficient dams in NSW. consequences of dam failure. dominant community issue in risk It is also examining the feasibility of However, this must be balanced by assessment and these criteria must be developing acceptable “long term” the consideration that it is not based on sound acceptable principles. flood emergency plans to minimise the reasonably practical to provide river The Committee’s approach is based risk to life from dam failure events as valley communities with absolute on developments in ANCOLD part of evolving dam safety risk protection from the risk of dambreak Guidelines and world practice, and on management practice. floods. current legal opinions relating to duty of care. The Committee considers they From the ongoing information The Committee is therefore are not unduly conservative for long received on dams throughout NSW, prepared to consider proposals life structures such as dams, given the the Committee identifies dams with from dam owners, which achieve devastation that dam failure can cause. possible deficiencies and confirms with appropriate dam safety in a cost Indeed, they appear to be broadly the dam owner the arrangements, and effective manner, provided they consistent with requirements adopted the timetable, for investigations are soundly researched, within the for other high hazard facilities, such as to determine the seriousness of bounds of accepted international chemical and nuclear power plants, as these deficiencies. Once it has practice, and prove acceptable to the revealed by the Committee’s ongoing been established that a dam has a community through Environmental communication with specialists in significant deficiency based on the Impact Statement processes and these industries. In addition, social, Committee’s requirements, the priority approvals. To adequately assess political, environmental and economic for upgrading is determined. In this these proposals, the Committee needs aspects must also be taken into account regard, the Committee regularly

11 public, and compliance with all will enable the owner to operate the 2. DAMS SURVEILLANCE statutory requirements determined. to a higher level.

The Committee then considers the The dams currently identified as owner’s proposal, including reviewing updates its provisional safety-ranking posing significant safety risks are the priority it should be given having ranked in Table 2.2 together with the table of dams in NSW to assist in regard to the seriousness of the dam assessing the priority for upgrading year in which the deficiency was failure consequences, the degree of determined, and status of the works at deficient dams. In addition, dam safety deficiency, community and the SES is kept informed so that upgrading programme for each dam. environmental considerations, and As can be seen from this table, dam interim flood emergency planning can funding availability. Overall, it has to be put in place at deficient dams. owners have commenced remedial be recognised that such a programme studies or upgrading works for all of can necessarily extend over several More detailed investigations are these deficient dams, and the years from initial identification of a then undertaken by the owner to Committee continually monitors their deficiency, before firm proposals for determine the most effective and progress. Where this monitoring shows remedial works are prepared, and economical risk reduction measures. that dam owners have failed to set or subsequently works are completed. This normally requires the comparison achieve satisfactory programmes for of a number of alternative options As a result of this process, upgrading remedial works, the Committee works (both structural and non-structural). of thirty-five deficient dams has been with the owners to ensure an improved It may also involve obtaining better completed in NSW, over the last outcome. In this regard, the local data on geology, dam materials sixteen years, as shown in Table 2.1. Committee has taken up the matter of and foundation properties, hydrology In 1999/2000 structural upgrading remedial action programmes with a or seismicity, in conjunction with a works commenced on Ben Chifley couple of owners during the year. review of the need to provide any other Dam and continued on Warragamba In addition, the Committee is improvements to the dam, such as Dam, and Hume Dam. Upgrading of monitoring progress by owners in increased storage. Possible also continued, developing action programmes for environmental impacts must be with commencement on the dams with minor deficiencies, and reviewed in consultation with the construction of a new spillway, which investigations by owners into several

TABLE 2.1 – DAMS UPGRADED SINCE 1984

YEAR UPGRADING DAM DEFICIENCY COMPLETED NATURE OF UPGRADING Burrinjuck Flood 1996 Dam raised 15 m and post-tensioned Blackbutt Flood 1995 Spillway upgraded Bonalbo Flood 1989 Spillway upgraded Captains Flat Flood/Stability 1993 Dam post-tensioned Cataract Flood/Stability 1987 Dam post-tensioned Chichester Flood/Stability 1995 Dam post-tensioned, abutment stablised Coalcliff Flood/Stability 1999 Spillway enlarged, embankment upgraded Cordeaux Flood 1988 Internal drainage improved Dungowan Flood 1992 Spillway augmentation, dam raising Dunn Swamp O&M 1995 New outlet, wall repair Foothills Road Flood 1997 Embankment stabilised, new spillway Glenbawn Flood 1986 Dam raised, storage augmented, new spillway Googong Flood 1992 Dam raised, spillway stabilised Grahamstown Flood 1997 Dam core raised, rock armouring of face Honeysuckle Creek Flood 1991 Post-tensioned and raised Hume Stability/Seismic 1996 ongoing Embankments substantially stabilised, gates and outlets being progressively upgraded Killara Stability 1994 Embankment walls stabilised Lyell Flood 1996 Dam raised, spillway and storage augmented Manly Flood 1984 Dam post-tensioned Mardi Seismic/Flood 1991/99 Embankment stabilised, crest raised Moolarben Flood 1993 Spillway augmented Nepean Flood/Stability 1992 Spillway augmented, dam post-tensioned Northmead Reserve Flood 1994 Embankment raised, strengthened Oberon Flood 1996 Dam raised, additional spillway Orange Agricultural Flood 1997 Spillway augmented Palm Tree Grove Flood 1990 Embankment raised, strengthened Pindari Flood 1993 Dam raised, storage augmented, new spillway Prospect Seismic 1997 Upstream dam embankment stabilised Rydal Stability/Flood 1996 Dam wall stabilised, spillway augmented Tilba Flood/Stability 1997 Dam wall raised, toe drained Tumbarumba Stability 1999 Embankment drainage installed Warragamba Flood 1992 Interim Dam post-tensioned, raised 5 m (see Table 2.2) Wentworth Falls Flood 1993 Dam raised, spillway augmented Wollondilly Washery Flood 1998 Dam raised, emergency spillway installed Woronora Flood 1988 Internal drainage improved

12 TABLE 2.2 – STATUS OF DAMS WITH SIGNIFICANT SAFETY RISKS

DEFICIENCY DAM Type Identified 1999/2000 UPGRADING PROGRESS

Warragamba F 1985 Auxiliary spillway construction well advanced. Completion due late 2001(FWS) Company F 1992 Upgrading planned for 2000 Keepit F 1995 Upgrading investigations commenced, low cost safety improvements made Hume F, E, S 1994 Substantial upgrading works completed during year, final requirements under review (FWS) Sooley F 1992 Upgrading design being finalised (FWS) Lake Endeavour F, E, S 1995 Upgrading options being investigated, risk assessment completed (FWS being installed) Wellington F, E, S 1996 Storage drained, flood warning system installed, long term options being evaluated (FWS) Coeypolly Creek 2 F 1993 Flood deficiency being assessed (FWS) Spring Creek F, S 1994 Site investigations undertaken, preferred concepts progressed (FWS) Burrendong F 1993 Preliminary screening risk assessment completed Redbank Creek F, E, S 1996 Further refinement of preferred option Emigrant Creek F 1992 Upgrading design finalised (FWS) Imperial Lake F 2000 Hazard reassessed, upgrading options to be investigated Bethungra F, E 2000 Upgrading options being investigated (FWS) Chifley F 1992 Upgrading commenced in late 1999 (FWS) Malpas F 1994 Risk based upgrading options being finalised (FWS) Tenterfield Creek F 1998 Upgrading options being investigated Wyangala F 1999 Preliminary screening risk assessment completed Rylstone F 1993 Finalising upgrading design (FWS) Blowering F 1999 Preliminary screening risk assessment completed

F – Inadequate Flood Capability E – Inadequate Earthquake Structural Resistance S – Structural Inadequacy under Normal Operating Conditions FWS – Flood Warning Systems Installed other dams to confirm their safety Authority’s current $150 million safety where investigations instigated by the status and any need for remedial action upgrading of the dam, which Committee and the Murray-Darling (see Appendix B for details). commenced in 1999 and is scheduled Basin Commission (MDBC) in 1993, As mentioned in previous for completion in the year 2001. The identified several dam safety Committee Annual Reports, Committee also endorses the current deficiencies in the earth embankments, had been revision of the complementary in the junction sections between the identified as a high priority for downstream flood preparedness concrete spillway and earth upgrading to Probable Maximum programme by the State Emergency embankments, in gate operation and Flood (PMF) capability, because of the Service, in conjunction with works by in flood capability. As a result, the potentially catastrophic failure state and local authorities, to maximise MDBC adopted a responsible consequences for the Hawkesbury- the effectiveness of emergency flood prioritised program of remedial works Nepean valley below, and the impact preparedness and evacuation that commenced in 1996. Works to of the loss of Warragamba Dam’s procedures in the Hawkesbury- upgrade the dam gates, and bring the major contribution to Sydney’s water Nepean Valley. main embankments and southern supply. The Committee strongly Another major dam receiving junction section to acceptable safety endorses Sydney Catchment extensive attention is Hume Dam, levels, have been substantially completed at a cost of some $70 million. In addition, a Dam Safety Emergency Plan (DSEP) by the owner, and a downstream flood plan by the relevant emergency agencies, have been instituted to minimise the risks to downstream residents. Priorities are being determined for the implementation of further remedial works at the dam to bring it up to appropriate long term safety levels given its strategic value to the Murray Valley, and its catastrophic impact on the community in the unlikely event of a failure. The Committee issued an order on HUMPHREYS CREEK TAILINGS DAM. The storage has been treated and is being drawn the owner of Humphreys Creek down while the owner investigates long term remedial options for the dam.

13 foreseen even fifteen years ago and, dam, and the Committee has stressed 2. DAMS SURVEILLANCE hydrologists have developed improved to dam owners the need for a rational methodologies. As a result, current consistent approach in this area, given estimates of potential extreme floods the many uncertainties in methodology Tailings Dam in March 1999 to indicate that some dams now have a and parameters. Accordingly, the upgrade its safety. The owner has made higher risk of flood failure than was Committee, in setting out its a positive response to this order by understood when they were designed. requirements, has been guided by its having a consultant do a safety review, Hydrology Sub-Committee, which To keep pace with this increasing maintains a close and constant liaison and implementing an innovative knowledge, the Committee requires treatment of the toxic storage materials with ANCOLD, the Institution of NSW dam owners to do regular Engineers, Australia, and hydrologists to allow draw down of the storage reviews of the flood capabilities of their and improvement of its safety status. from various dam-owning authorities dams and determine the need for any throughout Australia. In addition, The Committee has been working remedial action(s). These reviews are Committee member, Keith Murley, is closely with the Department of Land often fairly lengthy and can involve a Chairman and Executive Engineer, and Water Conservation in its risk number of complex steps as set out Norm Himsley, is Secretary of the assessment program for its portfolio of below. national working group that recently dams and, in particular, the need for Current methodology requires finished preparing the ANCOLD the priority investigations of Keepit revised generalised Probable “Guidelines on Selection of Acceptable Dam, Bethungra Dam and Wellington Maximum Precipitation (PMP) Flood Capacity for Dams”. This was a Dam. At Keepit Dam, site estimates to define the extreme storm major revision of the ANCOLD 1986 investigations have been undertaken for each dam catchment. Generalised Design Flood Guidelines, which and some interim remedial actions procedures are now available in NSW formed the main basis for the implemented to improve the flood for PMP storms of any duration and Committee’s flood design handling capability of the dam. Interim area, although the Bureau of requirements. Mr Murley is also the flood warning systems have been Meteorology is currently revising Australian representative on the implemented at Bethungra and its initial long duration tropical ICOLD Committee on Dams and Wellington Dams to minimise the risks storm estimates, which may have Floods. The exchange of expertise to downstream residents while implications for larger dams in gained from regular meetings of these community consultations have been northern NSW. Work on this review, various groups has enabled Messrs initiated to resolve long term options by the Bureau of Meteorology, Murley and Himsley to provide for these two dams. commenced in 1999 with industry significant input and advice to the support from Western Australia, Committee to assist in its Queensland and New South Wales. understanding of national and 2.4.2 Flood Capability The Committee is involved in the international hydrologic practice. The In line with world-wide experience, project’s Steering Committee and in Committee is currently updating its inadequate flood capability continues co-ordinating financial support from normal flood requirements to reflect to be the most serious problem faced the NSW dam’s industry. its position in relation to these new ANCOLD Guidelines. by NSW dam owners. This is reflected It should be noted that PMP events, in the deficient dams listing (Table 2.2) while rare, are plausible and several In keeping abreast of emerging where the majority of dams listed have near PMP events have occurred. For methodologies, the Committee is significant deficiencies in flood example, a storm in 1984 at Dapto was currently monitoring research into capability. These deficiencies have recorded as being a near PMP event various methods of estimating more become apparent over the last 15 years (ie 520 mm of rainfall in 6 hours), reliable probabilities for extreme storm as meteorologists have gained better exceeding previous record extreme events for input into dam risk data and a clearer understanding of the storms world wide for its duration and assessments (eg development of the extreme nature of climatic conditions. area of influence. FORGE method for storms to 1 in Meteorologists, with improved 5,000 chance per year). In addition, methodology, are now predicting Rainfall estimates then need to be the Committee sponsored and co- greater intensity rainfalls than were converted to flood predictions at each ordinated industry support for an extreme flood envelope research project by the University of New England that was completed in 1998. The Committee has used the results and data from this project for preliminary “sanity” checks of Probable Maximum Flood (PMF) estimates relative to catchment area to enable an initial identification of potential flood capability deficiencies. Committee members and staff have also been closely involved with the Institution of Engineer’s Committee in the preparation of a revised chapter of “Australian Rainfall and Runoff- 1987”, relating to extreme flood

WARRAGAMBA DAM. Construction of the auxiliary spillway for the dam is proceeding on schedule for completion in 2001.

14 APPENDIX B – 2000 CURRENT PRESCRIBED DAMS

PULL OUT SECTION

DAM BUILT TYPE HEIGHT STORAGE OWNER (m) (ML) Aldridges Creek * 1994 ER 24 1200 Hunter Pastoral Antiene Mine Lease Tailings * 2000 TE/ER 15 3000 Rio Tinto Coal P/L Avon 1927/71 PG/ER 72 214400Sydney Catchment Authority Bagnalls Beach Rd Ret. Basin (P) *1998 TE 2 5 Port Stephens Council Bamarang (S) 1983 TE 26 3800 Shoalhaven Council Banks Road Ret. Basin 1997 TE 4 40 Liverpool Council Baryulgil Mine 1996 TE 8 70 Dept. of Mineral Resources Bayswater Ash * 1985 TE 39 22000 Macquarie Generation Bayswater Brine Decant 1986 TE 21.5 650 Macquarie Generation Bayswater Cooling Makeup 1984 TE 16 460 Macquarie Generation Bayswater 3 - MMPW1 TE 9 50 Bayswater Colliery P/L Beardy Waters 1932/60 PG 8.5 500 Glen Innes Municipal Council Beargamil (M) 1914 TE 16 480 Parkes Council Ben Boyd (I) * 1978 TE 29 800 Bega Valley Council Bendeela Pondage * 1973 TE/ER 18 1200 Sydney Catchment Authority Bengalla Mine Raw Water 2000 TE 11 270 Bengalla Mining Co Pty Ltd Bethungra (R) * 1895 PG 13 580 DLWC Blackbutt Reserve 1957/95 TE 6 25 Shellharbour City Council Blowering (R) * 1968 TE/ER 112 1628000 DLWC Bogolong (M) 1932 TE 11 360 Central Tablelands Cnty Cncl Bonalbo (R) 1969/89 TE 13 55 Kyogle Council Boorowa (S) N/A PG/TE 8 180 Boorowa Council Bootawa 1967 TE 25 2270 North Power Borenore Creek 1928 VA 17 230 Cabonne Council Brennans Creek 1976 DR 17 320 Coal Cliff Collieries Pty Ltd Brogo (I) 1976 DR 43 9800 DLWC Brokers Rd Retarding Basin * 2000 TE 5 70 Council Brooklyn Retarding Basin 1995 ER 5 5 State Rail Authority Broughton Pass Weir (S) * 1888 PG 6 50 Sydney Catchment Authority Browns Creek Tailings * 1991 TE/ER 32 1400 Hargraves Resources NL Buckland’s Retarding Basin * 1991 TE 5 2 P. Buckland Bulli Colliery Mine (1) (P) * 1981 TE 6 33BHP Coal Ltd – Illawarra Colliers Bundanoon 1960 VA 35 2040 Wingecarribee Council Burrendong (R) * 1967 TE/ER 76 1188000 DLWC Burrinjuck * 1928/56/96 PG 93 1026000 DLWC Cadiangullong (S) * 1997 PG 45 4200 Cadia Holdings Pty Ltd Cadia Tailings Stage 2 (S) *1997/2000 TE/ER 56 40000 Cadia Holdings Pty Ltd Cadia Southern Tailings (P) - TE/RE 79 91000 Cadia Holdings Pty Ltd Cadia Water Holding (P) - TE 31 3000 Cadia Holdings Pty Ltd Campbelltown North Ret. Basin (P) - TE 3 30 Campbelltown Council Captains Flat 1939/93 PG 16 820 Yarrowlumla Shire Council Carcoar (S) * 1970 VA 46 35800 DLWC Cascade 1 1915 VA 15 160 Sydney Catchment Authority Cascade 2 1926 TE 26 320 Sydney Catchment Authority Cascade 3 1938 TE 30 1700 Sydney Catchment Authority Cataract * 1907/87 PG 56 94300Sydney Catchment Authority Cecil Hills Ret. Basin 100 TE 4 30 Liverpool Council Cecil Park Basin 3A (M) (S) * 1992 TE 6 52 Blacktown Council Centennial Pk Res No. 1 1899 PG 7 82 Sydney Water Centennial Pk Res No. 2 1925 PG/TE 11 89 Sydney Water Chaffey (R) (S) * 1976 TE/ER 54 61800 DLWC Chichester (M) * 1923/84/95 PG 41 21000 Hunter Water Corporation Chifley (R) * 1957 TE/ER 27 16000 Bathurst Council Clarrie Hall (M) 1982 DR 43 16000 Tweed Council Coalcliff * 1971 TE 7 130 Illawarra Coke Co Pty Ltd Cochrane * 1958 TE 29 3085 Pacific Power Coeypolly Ck 1 1932 VA 19 860 Parry Council Coeypolly Ck 2 (R) 1955 TE 21 5435 Parry Council Colongra Ck Ash 1965 TE 6 5550 Delta Electricity Comberton Grange Retarding Basin1990 TE 15 65 Shoalhaven Council Company (R) * 1867 TE 6 113 Weddin Council Copeton (R) * 1976 TE/ER 113 1364000 DLWC Cordeaux 1926/77/88 PG 49 93600Sydney Catchment Authority Cowarra * 1999 TE 40 10000 Hastings Council Cowarra Creek Tailings (M) 1986 ER 23 52 Horizon Pacific Ltd Crookwell 1937 PG/VA 15 450 Crookwell Council

15 APPENDIX B – 2000 CURRENT PRESCRIBED DAMS

DAM BUILT TYPE HEIGHT STORAGE OWNER (m) (ML) CSA Tailings (S) * 1960 TE 8 1932 Cobar Management / DMRes CSIRO Retarding Basin (S) * 1990 TE 6 58 Holroyd Council Danjera 1971 CB/ER 30 7700 Shoalhaven Council Dapto Heights Retarding Basin * 1991 TE 7 16 Wollongong Council Dartbrook Mine Water (P) * 2000 TE 11 450 Dartbrook Mine Deep Creek 1983 TE 31 4500 Eurobodalla Council Delegate Retarding Basin (R) 1984 TE 7 7 Bombala Council DEP Retarding Basin * 1990 TE 9 110 Blacktown Council Dora Creek Effluent Pond 1993 TE 8 150 Hunter Water Corporation Dover Heights Reservoir (S) * 1929 PG/TE 8 85 Sydney Water Drayton 1690 * 1993 TE 16 440 Drayton Coal Pty Ltd Drayton W.S. (S) * 1980 TE/ER 18 390 Drayton Coal Pty Ltd Dumaresq (R) * 1896 PG 12 440 Armidale Council Dungowan 1957/92 TE 27 5900 Tamworth Council Dunn Swamp * 1930/95 VA 16 400 (est) Australian Cement Ltd El Klaros * 1995 TE 25 200 CCS Holdings P/L Emigrant Creek (R) 1968 TE/PG 12 820 Rouse County Council Eraring Ash 1982 TE 25 20500 Pacific Power Fattorini Creek * 2000 TE 25 2500 Kempsey Council Fitzroy Falls * 1974 TE/ER 14 22200 Sydney Catchment Authority Flatrock Creek (S) * 1933 VA 15 400 Shoalhaven Council Floraville Road Basin * 1992 TE 4 20 Lake Macquarie Council Foothills Estate Ret. Basin 1 * 1994 TE 5 20 Wollongong Council Foothills Estate Ret. Basin 3 * 1995 TE 5 20 Wollongong Council Foothills Rd Basin * 1982/97 TE 5 24 Wollongong Council Fountaindale (I) 1915 VA 15 61 Kiama Council Fox Hills Retarding Basin 1990 TE 4 127 Blacktown Council Galambine * 1982 TE 18 227 Gooree Pastoral Co Gannet Place Ret. Basin 1992 TE 10 5 Wollongong Council Garden Suburbs Ret. Basin 2 (P) * 2000 TE 8 17 Lake Macquarie City Council Geo. Bass Drive Ret. Basin (P) * 2000 TE 3 11 Eurobodalla Council Glenbawn (M) * 1958/86 TE/ER 100 750000 DLWC Glenlee Tailings * Progressive ER 29 1500 Sada Pty Ltd Glenmore Park Ret. Basin (S) 1997 TE 4 232 Penrith Council Glennies Creek (M) 1983 DR 67 283000 DLWC Glenquarry Cut * 1974 PG 18 34510 Sydney Catchment Authority Gooden Reserve Ret. Basin * 1997 PG 5 380 Baulkham Hills Council Googong * 1977/1992 ER 67 124000 ACT Electricity & Water Gosling Creek (M) 1890 PG 8 650 Orange Council Grahamstown * 1964/96 TE 11 132000 Hunter Water Corporation Greaves Creek 1942 VA 17 320 Sydney Catchment Authority Green Meadows Ret. Basins * 1981/93 TE 4 165 Shellharbour Council Gunyah Park Basin 1992 TE 4 5 Wollongong Council Greaves Creek (S) * 1942 VA 17 320 Sydney Water Hamilton Valley Ret. Basin 5A 1993 TE 4 135 Albury Council Hamilton Valley Ret. Basin 5B * 1993 TE 3 62 Albury Council Hillgrove Tailings 1 (M) (S) * 1982 TE 40 700 Hillgrove Gold NL Hillgrove Tailings 2 (P) * - TE/ER 40 1280 Hillgrove Gold NL Honeysuckle Creek * 1962/91 PG 9 12 Killara Golf Club Ltd Hovell Weir (M) 1986 TE 8 2000 Tumbarumba Council Hume (R) * 1936/1967 PG/TE 51 3038000 Murray Darling Basin Commission Humphreys Creek * 1988 TE 15 750 Norminco Ltd Humphreys Creek Tailings (R) * 1989 TE/ER 15 1100 Norminco Ltd Hungerford Hill (M) * 1970 TE 8 545 B. Seppelt & Sons Ltd Huntley Colliery 2 Progressive TE 28 59 Powercoal Imperial Lake * 1967 TE 8 700 Broken Hill Water Board Junction Reefs (S) 1898 MB 19 300 DLWC Kanahooka Ret. Basin 1993 TE 5 26 Forest Grove Estate Kangaroo Pipeline 1974 ER/PG 20 23500 Sydney Catchment Authority Karangi 1980/96 TE 38 5600 Coffs Harbour Shire Council Keepit (R) (S) * 1960 PG/TE 55 423000 DLWC Kentucky Creek 1944/84 PG 12 500 Uralla Shire Council Killara Reservoir * 1931/94 PG/TE 11 166 Sydney Water (1) 1918 VA 12 700 Orange City Council Lake Endeavour (R) 1940 TE 21 2400 Parkes Shire Council Lake Inverell 1938 PG 13 1500 Inverell Shire Council Lake Medlow 1907 VA 20 290 Sydney Catchment Authority 1857/98 VA 14 490 Parramatta Council Lake Rowlands (I) x 1953 CB 20 4690 Central Tablelands Cnty Cncl

16 APPENDIX B – 2000 CURRENT PRESCRIBED DAMS

DAM BUILT TYPE HEIGHT STORAGE OWNER (m) (ML) Lake Tullimba 1982 TE 18 1200 New England Uni Lemington Mine Tailings (S) * 1991 TE/ER 12 2000 Lemington Mine Lemington Mine Tailings 5 * 2000 TE/ER 22 2000 Lemington Mine Liddell Ash 1971/82 TE 37 28500 Macquarie Generation Liddell Cooling Water 1968 TE 43 148000 Macquarie Generation Liddell Water Supply 1970 TE 31 4500 Macquarie Generation Lithgow 1 (M) 1896 VA 11 69 Lithgow Council Lithgow 2 (M) (S) 1907 VA 27 440 Lithgow Council London Victoria Tailings * 1988 TE 16 3000 Hargraves Resources NL Lostock 1971 TE/ER 38 20000 DLWC Loyalty Rd. Ret Basin * 1995 PG 27 1520 Upper Parramatta Trust Lucky Draw Tailings (S) 1989 TE 25 1500 Renison Gold Lyell * 1983/96 DR 50.5 33500 Delta Electricity Maddens Plain Holding Dam - TE/ER 11 16 Metropolitan Collieries Malpas (R) * 1968 TE/ER 31 13000 Armidale Council Mangrove Creek (S) * 1983 DR 80 170000 Gosford Council Manly 1892/1922/84 PG 18 2000 Sydney Water Mannering Ck Ash * 1963 TE 12.5 20000 Delta Electricity Mardi (M) * 1963/91 TE 26 7280 Wyong Council Maroubra Reservoir 1966 PG/TE 12 128 Sydney Water Maryvale Winter Storage * 1993 TE 13 2100 ANM Mill McCoy Park Ret. Basin (I) 1989 TE 6 500 Parramatta Council McKinnons Gold Project 1996 TE 17 3030 Burdekin Resources Medway 1964 VA 23 1270 Wingecarribee Council Menindee Storages (M) 1960 TE 12 2287280 DLWC Minmi Rd Retarding Basin (S) * 1995 TE 5 55 Newcastle City Council Molong Creek (M) 1987 PG 16 1000 Cabonne Council Moolarben Creek * 1957/93 ER 12 375 Ulan Coal Mines Ltd Moore Creek (S) 1898 VA 19 220 DLWC Muirfield Golf Club 1969 TE 8 6 Muirfield Golf Club Muirfields Golf Course Ret. Basin 1993 TE 4 12 Baulkham Hills Council Murrurundi 1984 TE 11 170 Murrurundi Council Narranbulla 1966 TE 7 1445 Narranbulla Pastoral Company Nepean (S) * 1935/92 PG 81 81400 Sydney Catchment Authority Nixon 1971 TE 16 222 J. Nixon Northmead Ret. Basin (M) 1990/94 TE 6 30 Baulkham Hills Council North Parkes Tailings (S) * 1993 TE 20 25000 North Parkes Mines Nyrang Park Ret. Basin 1993 TE 4 21 Wollongong Council Oak Flats Reservoir * 1978 TE 15 56 Sydney Water Oaky River 1956 PG/ER 18 2700 New England County Council Oberon (S) * 1949/96 CB 34 45400 DLWC Orange Research Station (S) * 1993/97 TE 7 175 NSW Agriculture Dept Palm Tree Grove Ret. Basin 1975/90 TE/ER 3 3 Gosford Council Pasminco Broken Hill Site D 1998 TE 26 6600 Pasminco Broken Hill Mine Peak Gold Mine Tailings (S) * 1990? TE 13 4200 Peak Gold Mines Pty Ltd Pejar (S) 1979 TE/ER 23 9000 Goulburn Council Pindari (M) 1969/93 DR 85 312000 DLWC Pipers Flat 1920 TE 10 645 Centennial Coal Pty Ltd Plashett * 1987 TE 46 70000 Macquarie Generation Port Macquarie * 1980 TE/ER 19 2500 Hastings Council Porters Creek (M) 1968 TE/PG 17 2541 Shoalhaven Council Port Macquarie * 1980 TE 19 2500 Hastings Council Port Waratah Fines Disp (M) (P) (S) *1990 TE 5 1750 Port Waratah Coal Potts Hill Res. 1 * 1890 TE 8 437 Sydney Water Potts Hill Res. 2 1923 PG/TE 8 799 Sydney Water Prospect * 1888/1979/97 TE 26 50200 Sydney Catchment Authority Puddledock Creek 1928 VA 21 1730 Armidale Council Ravensworth Inpit 1994 TE 12 1000 Peabody Resources Redbank Creek (R) * 1899 VA 16 180 Mudgee Council Rocky Creek (R) * 1953 TE 28 14000 Rouse County Council Rouse Hill Ret. Basin 5 1993 TE 4 72 Sydney Water Rouse Hill Ret. Basin 9 1993 TE 5 46 Sydney Water Rouse Hill Ret. Basin 13 1994 TE 5 99 Sydney Water Rouse Hill Ret. Basin 16 * - TE 4 13 Sydney Water Rydal (S) 1957/96 TE 15 370 DLWC Rylstone (R) * 1953 VA 15 3210 Rylstone Council Sawyers Swamp Creek Ash 1979 TE 40 8500 Delta Electricity School House Creek Ret. Basin * 1989 TE 4.5 138 Penrith Council Seladon Ave Ret. Basin 1993 TE 2 3 Newcastle Council

17 APPENDIX B – 2000 CURRENT PRESCRIBED DAMS

PULL OUT SECTION

DAM BUILT TYPE HEIGHT STORAGE OWNER (m) (ML) Sheahan-Grants Tailing 1990 TE 26 1280 Climax Management Pty Ltd Sierra Place Ret. Basin (I) * 1991 TE/ER 9 213 Baulkham Hills Council Smiths Ck Ret. Basin 1 - TE 9 55 Campbelltown Council Smiths Ck Ret. Basin 2 1996 TE 8 50 Campbelltown Council Smiths Ck Ret. Basin 3 1996 TE 7 32 Campbelltown Council Sooley (R) * 1930/1961 PG 13 4500 Goulburn Council South Bulli Stormwater Dam * 1992 TE 9 89 Bellambi Coal Company P/L Spains Tank (P) * 1910? TE 6 200 Peak Gold Mines Ltd Split Rock (M) * 1987 DR 66 397370 DLWC Spring Creek (R) * 1931/47/69 TE 16 4700 Orange Council Stephens Creek (R) 1892/1909 TE 15 20400 Broken Hill Water Board St Josephs Schl Ret. Basin (R) * 1990 TE 5 17 Shellharbour Council Stockton Borehole Tailings 1982/1985 TE/ER 21 360 Broken Hill Proprietary Co Ltd Stoney Pinch Reservoir 1940 PG 8 86 Hunter Water Corporation Stratford Coal WS 1995 TE 20 1800 Stratford Coal Project P/L Suma Park (R) * 1962 VA 34 18000 Orange Council Sunlight Gully Dams * 1900? TE 4/5 28/65 Hillgrove Gold NL / D Hanlan Tallong Railway 1883/1975 MB 7 318 State Rail Authority Tallowa * 1976 PG 46 110200 Sydney Catchment Authority Tenterfield Creek (R) 1930/74 PG 11 1170 Tenterfield Shire Council The Cove (M) 1972 TE 7 140 Old Sydney Town Thompsons Creek 1992 TE/ER 53.5 27500 Delta Electricity Thornleigh Reservoir 1971 TE 9 409 Sydney Water Tilba (M) * 1970/97 TE 17 135 Bega Valley Council Timor 1961 VA 19.5 1140 Coonabarabran Council Toonumbar 1971 TE/ER 44 11000 DLWC Triako Tailings 1989 TE 12.5 950 Triex Ltd Tumbarumba 1972 TE 6 68 Tumbarumba Council Tumut Paper Mill Freshwater 1999 TE 11 190 Visy Pulp & Paper Mill Tumut Paper Mill Wastewater 1999 TE 11 700 Visy Pulp & Paper Mill Umberumberka 1914 PG 26 8180 Broken Hill Water Board Upper Cordeaux 2 1915 VA 19 1200 Sydney Catchment Authority Upper Mooney 1961 VA 27 4630 Gosford Council Vales Point Ash 1984 TE 6 42000 Delta Electricity Wallerawang (S) * 1978 TE 14 4300 Delta Electricity Warkworth Tailings (S) * 1992/94 TE 24 3500 Warkworth Mining Warkworth Tailings 2 (S) * 1997 TE 21 1900 Warkworth Mining Warragamba (R) * 1960/92 PG 113 2091800 Sydney Catchment Authority Warringah Reservoir 1936/95 PG/TE 8 77 Sydney Water Waverley Reservoir WS133 1917 PG/TE 8 19 Sydney Water Wellington (R) (S) * 1899 VA/PG 15 90 DLWC Wentworth Falls Lake (M) * 1906/93 TE 10 300 Blue Mountains Council Whitford Rd Ret. Basin (S) * 1997 TE 4 44 Liverpool Council Winburndale (M) 1936 PG 25 1850 Bathurst Council Windamere (M) * 1984 TE/ER 67 368000 DLWC Winding Creek 5 Ret. Basin 1993 TE 5 72 Hunter Water Corp Wingecarribee (M) * 1974 TE/ER 20 34510 Sydney Catchment Authority Wollondilly Washery Tailings * Progressive ER 40 490 Sada Pty Ltd Woodford Creek 1928/48 VA 18 850 Sydney Catchment Authority Woodlawn Mine Evaporation 1989 TE 6 750 Woodlawn Mines Woodlawn Mine No. 2 Evap 1989 TE 10 290 Woodlawn Mines Woodlawn Nth Tailings 1977 TE/ER 18 2100 Woodlawn Mines Woodlawn Sth Tailings 1982 TE/ER 25 2400 Woodlawn Mines Woodlawn West Tailings 1989 ER 35 2400 Woodlawn Mines Woolgoolga 1967 TE 14 270 Coffs Harbour Council Woronora 1941/88 PG 63 71800 Sydney Catchment Authority Wyangala (R) (S) * 1971 TE/ER 85 1220000 DLWC Yarrawonga Weir (M) (S) * 1939 PG/TE 7 120000 Murray Darling Basin Comm Yass 1927 VA/PG 12 1125 Yass Council

LEGEND: * Inspected by Committee &/or Staff - 1998/99 DR Decked rockfill embankment (S) Surveillance Reports reviewed 1998/99 NA Not Available PG Concrete gravity (P) Prescribed 1998/99 U/C Under Construction CB Concrete buttress (I) Safety Status under Investigation TE Earthfill embankment VA Concrete arch (R) Significant Risk ER Rockfill embankment MB Masonry buttress (M) Minor Risk

18 estimation. The Committee is inherently stable during seismic events, are significantly different to those developing its requirements in this area although they may suffer significant usually experienced in western USA, since the release of the revised “Book deformation and damage. Fortunately where much earthquake engineering VI” document in late 1999. dams of these types form the bulk of has been developed. The Committee prescribed dams in NSW. Accordingly, notes that the comprehensive seismic As rainfall and flow data are very the Committee has directed its initial monitoring network, installed by limited in Australia, and not available seismic stability concerns to the owners Sydney Water (now Sydney for many dam catchments, the of the few vulnerable dams, which are Catchment Authority) for its dams Committee has continued to old poorly compacted earthfill dams in the nearly 1990s, has already encourage dam owners to install and dams built on potentially recorded evidence of minor seismicity hydrologic instrumentation around liquefiable or faulted foundations. on the Lapstone fault to the west of their dams. This can provide valuable It should be noted, in this regard, that Sydney and provided valuable data site rainfall and flow data to assist in the failure of Shih-Kung Dam in from the Appin earthquake in March calibration of hydrologic models for Taiwan in August 1999, was caused by 1999. Records of seismic events in this dam catchments, and will contribute a large earthquake triggering a 10m area will provide useful data for the to the improvement of knowledge of vertical movement across a fault zone future evaluation of dams and other rainfall/runoff processes within the in the foundation area beneath the structures in the Sydney area. industry. The data will also assist in dam’s gated spillway section. estimating available yield for water The Sydney Catchment Authority supply, as well as providing valuable Following investigations by their network complements the Newcastle input to planning and warning for owners, seismic stability remedial area network installed after the 1989 emergency flood conditions. works have been completed at Mardi earthquake, along with the seismic and Prospect Dams while network at selected DLWC and Snowy 2.4.3 Seismic Structural embankment remedial works, to dams, and various country and urban protect against earthquake shaking, are installations installed as part of a Capability nearing completion at Hume Dam. national grid by the Australian Several earthquakes of around Geological Survey Organisation Seismic stability reviews are now (AGSO). The Committee will Magnitude 7 have occurred in being included in the regular safety Australia since European settlement, continue to urge dam owners and the reviews of prescribed dams in NSW. Government to maintain and expand and the 1989 Newcastle earthquake To provide guidance for designers and (Magnitude 5.6) provided a recent this seismic network throughout NSW reviewers, the Committee produced to provide valuable insight into seismic reminder that large damaging and issued to dam owners in 1993 an activity in NSW. earthquakes can occur in NSW. Information Sheet entitled “Interim In particular, there have been two Requirements for Seismic Assessment similar magnitude events in the of Dams”. The Information Sheet was Newcastle area within the past 130 well received, as no similar information years, along with events at least as was available elsewhere in Australia. large elsewhere in NSW and in However, the Committee was other states. In 1999/2000 the largest conscious of the need to progressively seismic event in NSW was a update its requirements in line with the Magnitude 3.0 earthquake near development of Australian seismic Frogmore in July 1999, and the methodologies. In this regard, the largest national event a Magnitude Committee was an instigator for the 7.2 earthquake at the Cocos Islands formulation of the ANCOLD off the West Australian coast in June “Guidelines on Design of Dams for 2000. The largest event in mainland Earthquakes” which were released in Australia, was a magnitude 4.3 event late 1998, with Len McDonald and at Jamestown, in Brian Cooper being members of the August 1999. working group who prepared the Today seismologists indicate that, Guidelines. In 1999, the Committee even in what had been assumed as reviewed these Guidelines and the “stable” continental area of adopted them with some modifications Australia, major earthquakes (ie up to as its normal requirements for dams Magnitude 7.5) could occur, although, in NSW. The Committee subsequently as with extreme floods, it is impossible issued its requirements in a new to predict the magnitude, location Technical Information Sheet (DSC or timing of such events. It should also 16) which replaced its interim be noted that a Magnitude 7.5 requirements. earthquake has about 1000 times the Of concern to the Committee is the destructive power of the Magnitude lack of long-term seismic data in NSW 5.6 Newcastle earthquake. to use as a basis for determining the On the positive side, however, many current seismic design loadings overseas dams have survived intense for dams. Preliminary data and earthquakes up to Magnitude 8. This evidence indicates that earthquake experience, along with the results of characteristics and effects in Australia modern analytical seismic assessments of dams, indicates that well constructed REDBANK CREEK DAM. Upgrading options concrete, and compacted earth/rockfill, are being finalised for this old 16 m high arch dams on good foundations are dam at Mudgee.

19 2.2. DAMS DAMS SURVEILLANCE SURVEILLANCE

2.4.4 Structural Safety under Normal Operating Conditions Dams are long life structures, with the oldest dam in Europe some three thousand years old, and the oldest prescribed dam in NSW, Lake Parramatta Dam, being over 140 years old. Given that the average age of major NSW dams is over 40 years, the structural safety of most dams under normal operating conditions is considered to be satisfactory when checked using current methodology to assess dam behaviour. However, where concerns have been raised, or surveillance has revealed deficiencies, the Committee has supported owners in the undertaking of safety reviews and any consequent remedial action to . Testing of the spillway gates and erosion capability of the spillway for this provide long term safe operation of 113 m high irrigation dam. these dams. Particular areas of ongoing concern requested several dam owners to major Australian dam owning to the Committee include: investigate and monitor their organisations, was completed in conduits on a priority basis 1998 with valuable new • The stability of older earth dams, (eg Mardi Dam inspected in 1999). understanding developed. As a which have wet downstream face result, the Committee has decided and toe areas due to the lack of • The inability to monitor the long- to foster and sponsor further intercepting filters to control piping term performance of post- research in this area (ie. slope and seepage. These conditions tensioning tendons installed prior failure risks, piping failure risks). could result in loss of support for to 1980 in concrete dams. The the dam, which may require deterioration of these tendons could buttressing and/or supplementary lead to dams having insufficient 2.4.5 Operation, stability to resist water loads (eg. drainage. Hume, Mardi, Tilba, Maintenance and Rydal and Tumbarumba dams have Sooley Dam, Tenterfield Creek been upgraded in recent years to Dam, Porters Creek Dam). Dams Surveillance post-tensioned since 1980 are provide additional safety margins in All dam materials, components and generally not of concern due to the this area. machinery deteriorate with time. use of more sophisticated stressing Effective continuing operation, During the year the Committee systems which are fully load- maintenance and surveillance of a dam wrote to various overseas agencies monitorable. regarding their safety requirements should never be neglected, otherwise against piping in dams. However the • The long term stability of some reduced life expectancy or failure of a response to these letters indicates older concrete dams is now in dam could result (eg. failure of outlet that there is no established question, as a result of increased pipe through Muratore Dam in international practice in this area flood loadings and a better Victoria in 1999 and piping failure of and the Committee is now understanding of concrete a dam at Hazelwood Power Station, producing an Information Sheet on behaviour (eg. alkali aggregate Victoria in 2000). As such, the good good design practice which will seek reaction), and foundation operation and maintenance of a dam to deal with this problem. hydrostatic forces, that could be not only provides protection for the large enough to destabilise owner, but to the general public as well. • The deterioration, with time, of dams (eg. Emigrant Creek Dam, Furthermore, the cost of proper unencased pressure conduits , Winburndale Dam, operation and maintenance is small through embankments. Such Bethungra Dam, Wellington Dam). compared with the cost of the possible deterioration could ultimately result consequences of neglect, which could in uncontrolled high-pressure • The problems of assigning realistic range from major repair, to loss of life leakage through the embankment, probabilities to various failure or property with resulting litigation leading to washout or sliding of the mechanisms, in and around dams, if a dam fails. The deterioration dam. Recently, there was an outlet when using a risk-based decision that can occur is illustrated by the pipe leakage incident at Cecil Hills making process for assessing the extensive rehabilitation works Retarding Basin 3A, detected by safety of dams (eg. Hume Dam). or decommissioning now being routine inspections. This basin was To assist in overcoming this formulated for several older dams in drawn down pending remedial problem a two year research NSW (eg. Wellington Dam, Bethungra action and is being closely programme in this area by the Dam, Redbank Creek Dam). monitored by the Committee. In University of NSW, sponsored by addition, the Committee has the Committee and several of the

20 The Committee continually objective, the Committee requires that concerned. This is done so that promotes the need to develop and dam owners prepare Dam Safety effective flood emergency planning maintain basic operation and Emergency Plans (DSEP) for dams is implemented in a timely manner, maintenance programmes in posing a risk to downstream residents. both at, and downstream of, a dam conjunction with regular safety This planning covers monitoring once it is assessed as potentially unsafe. monitoring and surveillance, based on procedures, the actions to be taken by organised procedures and systematic the owner’s personnel when a threat In addition, as a result of the Sub- inspections. The Committee audits the materialises, and the owner’s Committee’s activities, an amendment performance of dam owners in this transmission of advice to emergency has been made to the State Disaster area through the owner’s five yearly management agencies of threats to the Plan recognising the responsibilities of Surveillance Reports to the integrity of the dam and on the nature the Committee and DLWC in the area Committee, and by regular inspections of dambreak flooding. of dam emergencies. The Sub- of dams by Committee members and Committee also provides a channel for staff. The Committee also requires dam information exchange between the owners to assist emergency Committee and the SES, giving the While the Committee’s primary management agencies to develop SES regular updates on the safety concern is dam safety, these operation, appropriate Flood Plans to protect status of dams in NSW. maintenance and surveillance downstream residents against the The SES has continued to prepare programmes also provide a valuable impacts of major floods that pass and update flood emergency plans for input to the owner’s Asset through dams, including a potential communities downstream of deficient Management Procedures. In this dam failure. These plans are usually an NSW dams during the year regard, the Committee envisages that extension of State Emergency Service (eg. Warragamba Dam, Port the proposed ANCOLD guidelines on flood plans. Macquarie Dam, Malpas Dam) and asset management, currently being The benefits of these plans were planning work is advanced at many compiled, will provide valuable demonstrated to good effect during the others (eg. Lake Endeavour Dam). assistance to dam owners. Committee August 1998 floods in the Bathurst The Committee is pleased with the members have provided input to the area, with the timely evacuation of public response to implementation of formation and development of these residents downstream of Chifley Dam. this planning, and continues to press Guidelines, and presented papers on for early and comprehensive public various aspects related to Asset In addition, it should be noted that awareness campaigns to inform Management at seminars arranged to owners of dams without identified residents downstream of the details of provide input to the Guidelines. deficiencies also have a responsibility these flood emergency plans. to develop appropriate emergency In addition, the Committee procedures for events at their dams maintains an active education (including a potential dambreak), programme to ensure the preparation, which could impact on downsteam 2.6 FLOOD RETARDING updating and usage of appropriate population and property and on the BASINS operation, maintenance and environment. This was demonstrated Flood retarding and pollution surveillance manuals by dam owners. in 1999 with activation of the Lyell control basins are holding ponds The Committee considers these Dam DSEP, and complementary SES normally constructed in urban areas. manuals are essential for quality asset flood plan, facilitating the timely They temporarily store some, or all, of management, particularly in view of evacuation of campers downstream of the stormwater runoff from a the turnover and loss of experienced Lyell Dam after the unexpected failure catchment, and hence reduce personnel over time, and the of the inflatable spillway section at the downstream flood levels and consequent loss of experience and dam. knowledge related to particular dams. environmental effects. There has been In this regard, the Committee requires Accordingly, the Committee has a marked increase in the need for, and the owners of all high and significant a requirement that dam owners usage of, these basins over the last ten hazard dams to have these manuals in develop, by December 2000, years to alleviate the increases in place by December 2000. appropriate emergency plans for flooding resulting from urban their high and significant hazard development. There are over one The ANCOLD “Guidelines on dams, and thatthese plans are thousand basins of various sizes Dam Safety Management-1994” set regularly updated and trialled. existing within NSW urban areas. out up to date requirements in this Owners also need to provide These structures are usually designed area, based on industry best practice. relevant information to emergency to mitigate small, but frequent, floods The Committee’s Executive Engineer management agencies for their usually up to the 1% Annual was a member of the working group, information, to assist in preparation Exceedence Probability (AEP) flood which produced these revised of flood plans downstream. level (ie. 1 in 100 chance of occurrence guidelines. They provide a basis for a per year). As well as flood and more uniform national approach to Responsibility for developing environmental protection, the basins proper dam safety management, and and maintaining flood plans in may also have considerable community the Committee has adopted them as NSW rests with the State Emergency benefits (eg. recreational areas, scenic its requirements for use in NSW. Service (SES). This responsibility ponds, etc). is recognised in the State Disaster Plan developed in accordance with the These basins vary in size from 2.5 DAM SAFETY State Emergency and Rescue commercial/industrial on-site storages EMERGENCY PLANNING Management Act 1989. To mesh the up to large basins several hectares in responsibilities of dam owners and the area, such as the Loyalty Road The Committee’s primary objective SES, the Committee’s Emergency Retarding Basin, upstream of is to protect the public from the Management Sub-Committee meets Parramatta, which was completed in uncontrolled release of water from dam as necessary to review and monitor the 1996 and is formed by a concrete dam storages. Consistent with this procedures used by the agencies over 20 m high. However, when these

21 maintenance some basins receive in the member of the Committee’s 2. DAMS SURVEILLANCE long term. Several basins inspected Surveillance Sub-Committee. recently have been significantly Another area, where the Committee overgrown with trees, which can lead is involved with other regulatory to bank failures, or were found to have basins store water they act as dams, agencies, is that relating to tailings partially to severely blocked outlets and the Committee prescribes those dams. Tailings dams are generally reducing the basins’ flood capability. that pose a significant potential threat required in mining operations to These maintenance concerns to downstream communities or the contain, within the mine site, significantly increase the risk of failure environment, if they fail. Although deleterious waste which could cause in flood events. To this end, the these basins are generally small, their pollution. These dams are usually Committee requires that prescribed potential threat to a community can designed for a short active life span retarding basins are subject to be as significant as that from a major during the mining operation, with long relevant procedures regarding dam due to their location within term rehabilitation generally surveillance, inspection, operation residential areas. The Committee has comprising drying out, capping and and maintenance. In particular, these a responsibility to ensure these revegetating to transform the dam basins are normally to be inspected communities are protected to into an artificial hill formation. The monthly as part of their maintenance appropriate low risk levels. Committee prescribes those tailings schedule, as well as after significant dams which are designed to contain Primarily, the Committee requires flood events. that, where lives could be threatened, substances, which, if released during the basins are designed and To disseminate these concerns to dam failure, would have life threatening constructed in accordance with good basin owners and their designers, the or significant environmental/property dam engineering practice and the Committee maintains close liaison damage effects. Committee’s published requirements with basin owners during the design Since seepage from these tailings for flood capacity of dams. Thus, for stage, particularly to oversight urban dams is normally the concern of basins which threaten lives drainage designers whose experience mining and environment protection downstream, the structure must be of dams engineering is often limited authorities, the Committee has capable of withstanding floods larger to small structures. Committee staff instituted formal links with the than the usual mitigation limit of the also carry out regular basin inspections. Environment Protection Authority 1% AEP flood for community In addition, the Committee has (EPA). As part of this liaison it has protection. Although the Committee’s prepared an information sheet on put in place trial procedural requirements for flood capability may retarding basins, which was updated arrangements to ensure the result in some additional costs, it must in 2000 and issued to local councils responsibilities of both agencies are be realised that design standards, such and consultants to disseminate the adequately discharged, and as the 1% AEP flood used for urban Committee’s views and concerns to appropriate requirements for flood drainage design, only provide an basin owners. handling/containment capabilities assessed economic limit for mitigation Further information has also been of these storages are implemented. of urban flooding, and do not preclude given to practitioners in this field by In addition, to facilitate appropriate the occurrence of bigger floods. The the presentation of relevant papers, by control of all mining dams, Committee community at risk generally does not the Committee’s Executive Engineer, staff continued their meetings with appreciate the potential for larger Mr Himsley, to appropriate local mine’s inspectors from the floods to occur. One recent example Government and Stormwater Department of Mineral Resources was the storm event in Wollongong in Conferences. during the year to ensure effective August 1998 which caused severe Committee involvement at all stages damage to urban areas, except in those of mine dam developments. controlled by prescribed flood 2.7 LIAISON WITH OTHER In addition to tailings dams, the retarding basins meeting the NSW REGULATORS Committee’s requirements, even Committee has also formalised its links though the storm was in the order of a The Committee has developed with the EPA to devise appropriate 1 in 200 event. Indeed, with several working protocols with various NSW requirements for sewerage ponds hundred basins in the Sydney area, regulatory agencies which may have licensed by the EPA. It has been there is a strong possibility that one or influences or requirements on the agreed that the Committee will only more basins could be tested annually owners of prescribed dams. In this prescribe those ponds whose failure by a large storm. regard the Department of Urban would affect life or property, or cause Affairs and Planning, as a matter of significant environmental damage. As The Committee’s concerns for procedure, forward Environmental a result, only a small number of these community safety can often be Impact Statements involving dam ponds are affected throughout NSW. addressed in the overall layout of such proposals to the Committee for its The Committee has drafted conditions projects, to ensure that the basin will consideration. In addition, the for the EPA to insert in the licences of withstand very large floods appropriate Department of Land and Water the remaining ponds, which will ensure to risk to life criteria, or that basin Conservation has regulatory powers an adequate annual check is made of failure does not involve a significant under the Local Government Act to their safety management. In addition, risk of loss of life. The design should ensure the safety of local Council the Committee is pursuing, with the also allow for future catchment and dams. The Committee has developed EPA, a means of jointly establishing a downstream development, and the procedures, and has regular meetings protocol for consideration of the “domino effect” of basin failure, if there with the DLWC, to co-ordinate design, environmental consequences of flood are multiple basins in a cascade construction and surveillance releases and failure of all water supply arrangement within the catchment. requirements for Council dams to and power dams, even though they do Of particular concern to the ensure consistency in the exercise of not contain noxious substances. Committee, as highlighted by its regulatory roles. Mr Heinrichs, the For all these prescribed inspections, is the poor degree of responsible DLWC officer, is a environmental protection dams, the

22 Committee’s primary concern is to ensure appropriate standards are employed at all stages, from design to decommissioning, to minimise the risk of uncontrolled release of their storage. In line with Committee requirements for all dams, these safety standards are achieved by reviewing the design and construction phases of these dams/ ponds, by requiring and reviewing Surveillance Reports and by regular staff site inspections during the operational phase of the dams. To benchmark the Committee’s requirements against other hazard monitoring regulatory authorities, the Committee has convened several workshops (the latest in November 1999) with representatives of agencies controlling nuclear and toxic ROUSE HILL RETARDING BASIN 16. the SMHEA engineer responsible for Construction of this flood retarding basin industries. The workshops involve an its dam safety management program, was completed in 2000 to protect exchange of views in risk assessment attended some of the Committee’s downstream residents from flooding. techniques and identification of areas Surveillance Sub-Committee meetings to explore in more detail in future during the year to update the forums to consolidate a consistent Dam in Queensland and Dartmouth Committee on the SMHEA dam approach across all authorities in Dam in Victoria, whose failure would safety programme, and provide relation to hazard reduction and have serious impacts on NSW SMHEA with a closer insight into acceptable safety levels. residents downstream. Committee activities. In particular In addition, in May 2000, Brian SMHEA carried out detailed Committee staff have also been cooper held discussions with Dr Jean investigations at Eucumbene and invited to Western Australia over the Le Guen of the United Kingdom’s Khancoban dams during the year as past year to provide assistance in Health and Safety Executive (HSE). part of its risk assessment and dam running dam safety management The HSE is the major safety regulator upgrading programme. training courses, and to provide input for industrial installations in the UK to organisational implementation of The SMHEA’s policy on dam safety and has wide experience in safety appropriate procedures and practices management is aligned with policy and risk assessment. Mr Cooper in relation to dams. This work has been ANCOLD practice and guidelines, also attended a workshop on risk funded by the inviting external which also form the basis of the assessment convened by the British organisations. Such involvement Committee’s procedures. The Dams Society. The outcomes of the provides the Committee with a broader Committee has reached an agreement discussions have been conveyed to the perspective on dam safety that the SMHEA makes available Committee to assist in its evolving management problems. its regular Dam Surveillance Reports development of risk management to the Committee for comment. The Committee also regularly policies. This has resulted in reports corresponds with, and meets being provided on a number of representatives of, organisations involved with dam safety throughout 2.8 LIAISON WITH SNOWY SMHEA dams during 1999/2000 and SMHEA staff have attended Australia and overseas to exchange MOUNTAINS HYDRO- dam operator training courses run by information and assist the Committee ELECTRIC AUTHORITY the DLWC in association with the in keeping pace with world practice. (SMHEA) Committee. To this end, the Committee’s Chairman, Mr McDonald, was invited Although it currently has no formal The Committee considers that the to attend a “ Workshop on Risk jurisdiction over SMHEA dams, the SMHEA standard of dam safety Analysis” held in Utah in March 2000. Committee has maintained a regular management is generally comparable During this visit he also spent time liaison with the SMHEA for many to that prevailing in NSW, and will discussing dam safety matters with years. This was considered necessary continue its liaison with the SMHEA representatives of organisations from to ensure a common standard of dam to ensure that this position is USA and Canada. Information gained safety management within NSW. It is maintained. from the visit will be passed on to NSW proposed that arrangements will be dam owners, and provided an formalised with the prescription of 2.9 LIAISON WITH DAM important input to the Committee’s SMHEA dams when the authority is OWNERS/AUTHORITIES recent updating of its trial risk ranking corporatised. This is expected to occur of NSW dams. In addition several of in late 2000. OUTSIDE NSW the Committee members have been involved as consultants on interstate This liaison has included a number The Committee maintains a close and international projects on dam of meetings with SMHEA relationship with Commonwealth and safety management and related issues management, joint inspections of its interstate authorities, which own or with this involvement providing dams, and Committee reviews of control dams in order to encourage a valuable background experience as SMHEA data and reports, which the common standard of dam safety input to Committee decision making. SMHEA has made available from time management. This is particularly to time. In this regard, Mr Grimstad, important for dams such as Glenlyon

23 which, mining would be unlikely to of the structure, which has resulted in 3.3. MINING prejudice the integrity of the dam and acceptable minor cracking of the dam its storage. The delineation of these and increased leakage through the boundaries for additional dams foundation. These movements and 3.1 ADMINISTRATION continued during 1999/2000 with the effects were foreseen and assessed to computer digitising of boundary co- be tolerable for this dam subject to In the mid 1970s, the ongoing ordinates, and their incorporation in a appropriate corrective action after disputes between coal miners and dam Geographical Information System mining. In addition, intensive owners, with respect to the extent of (GIS) formulated by the Department monitoring of the structure has been extraction of coal near NSW storages, of Mineral Resources. Mining is often undertaken during mining, by the staff provided an additional incentive for the approved within Notification Areas, of the dam owner and the colliery, to formation of the NSW Dams Safety but the conditions attached to mining ensure the overall safety was not Committee to act as an independent leases allow the Committee to ensure compromised. arbiter between the various parties. A such mining is carefully controlled. By resolution of the conflict was initially When a mining company wishes to making recommendations on the type achieved by the Committee making mine near a prescribed dam, or make of mining to be permitted, and the recommendations to the Minister significant changes to its existing degree of monitoring required, the responsible for the Coal Mining Act, mining approval, the required Committee is able to ensure that the in respect of the granting of coal leases procedure is for the Company to safety and integrity of prescribed dams, in close proximity to prescribed dams. contact the Committee for discussions and their storages, are maintained Procedural arrangements have been on the proposal. A formal review and while mineral extraction is maximised. progressively upgraded in the light of approval process follows, and is monitoring information obtained from Initially, the Committee’s mining completed when the Minister mining in the vicinity of dams. In requirements, to safely maximise administering the Mining Act grants addition, the Coal Mining Act was coal extraction, were based on the then approval on the recommendations of superseded by the Mining Act 1992, recognised empirical approaches. the Committee. However, if there is and by amendments in December However, with the increasing depth only a small change required to an 1996, so that the Committee now has and range of data becoming existing approval, the Committee may a role in regulating all mining available from monitoring of approve the change as a “Minor operations near prescribed dams. Committee controlled mining Variation”. Such minor variations are operations, and the development of processed quickly, usually under The Committee sets formal various advanced technological delegated authority. Table 3.1 Notification Areas around selected monitoring and analysis procedures summarises details of mining lease prescribed dams (see map on Report’s (eg. micro-seismics), the Committee matters considered during 1999/2000. back cover) as a means of ensuring has progressively developed its mining that it is informed of any proposed requirements to reflect a more mining in close proximity to these scientifically based approach. The 3.2 MONITORING dams. Notification of these areas is Committee’s requirements are PROGRAMMES published in the NSW Government outlined in printed Information Sheets, Gazette. The areas are defined on the Mining undertaken in areas subject on CD ROM, or through the basis of previous mining experience to to the Committee’s approval requires Committee’s Internet site. provide a minimum buffer area around routine monitoring and reporting of its each dam and reservoir, outside of During 1999/2000 under the effects as it progresses. For Committee’s guidelines, 2.7 million underground mining, this normally tonnes of coal were extracted from involves surface settlement and strain mine workings within the Notification monitoring over the extraction area, Areas of prescribed dams in NSW, along with underground monitoring of without affecting the integrity of these mining conditions and water inflows, dams or their storages. Prior to the and measurement of groundwater formation of the Committee, the conditions. Where the mining has the majority of these coal deposits would potential to impact on a dam structure not have been mined, due to the safety the Committee will normally require concerns of dam owners. This aspect increased monitoring of that structure has been highlighted this year, with the during mining. For open cut mining significant extent of long wall mining adjacent to dams monitoring of surface undertaken adjacent to Broughtons blasting effects is normally a priority. Pass Weir and the continuation of The purpose of such monitoring is longwall mining beneath the storage to continually assess original of Cataract Dam. The mining near performance predictions in the light of Broughtons Pass Weir has caused actual performance. Monitoring will significant mining induced movement also highlight any unexpected developments, and expand the BROUGHTONS PASS WEIR. The Committee has been regulating and monitoring mining information database for future activities near this weir to ensure mining prediction analyses. Details of effects on the weir are within tolerable limits. monitoring programmes undertaken

24 monitoring programs over the past five TABLE 3.1 – MINING APPROVAL SUMMARY years, the results have led to a better understanding of mining effects in this Item 1997/98 1998/99 1999/2000 area. As a result, the Committee has Coal Removed from Notification Areas (million tonnes) 1.8 2.2 2.7 permitted the Colliery to increase the Current Approvals: Actively Mining 5 8 7 widths of its longwall panels from Actively Monitoring 7 9 8 100m to 150m. This has effectively Applications Processed 4 3 2 increased the percentage of coal Variations to Existing Approvals 10 4 5 extracted and represents considerable Coal Titles Processed 2 0 2 cost savings to the Colliery. New Proposals Discussed 4 2 2 Site Inspections (man days) 5 7 2 3.3 FUTURE MINING in 1999/2000 under Committee associated investigations for the Following initial extraction of seven requirements are given in Table 3.2. extraction of several long wall panels, longwall coal panels under the south Typically, the Committee receives commenced by South Bulli Colliery arm of Cataract Reservoir monthly reports on each of these (now Bellambi West Colliery) in 1994 (ie. Bellambi-6 application), the programmes, which are reviewed by under the southern arm of Cataract Bellambi West (formerly South Bulli) Committee staff before presentation to Reservoir. In addition to normal Colliery successfully mined a further the Committee’s Mining Sub- monitoring requirements, the six panels closer to the dam wall Committee for review and any Committee requested newly developed under approval recommended necessary action. The Sub- sensitive strain monitoring by the Committee (ie. Bellambi-7 Committee’s actions are normally instrumentation be installed in application). Since no adverse impacts reported to the Committee at its next boreholes around the site. The results were evident from this mining, the meeting. However, important matters to date from this investigative Committee approved the extraction may be referred to the Committee for technique have been valuable in of a further two longwalls (ie. Bellambi- its consideration and approval. delineating the spatial effects of 8 application) with appropriate mining, and should enable more monitoring including the use of micro- The Committee continually scientific assessment of similar future seismics. This mining commenced in monitors developments in methods mining applications. For the current early 1999. used to measure changes in surface and phase of extraction the Committee has subsurface conditions (eg. stress, Under other approvals, Appin requested the colliery to monitor the strain, water pressure, movements) Colliery is currently undertaking long extent of cracking around the mined caused by mining, so that appropriate wall mining near Broughton’s Pass area using a new technique involving monitoring programmes are designed Weir, and Elouera Colliery has micro-seismic sensing, with the results to better delineate mining effects, and commenced first workings in a coal to date appearing promising. Detailed produce data for future assessment. seam under Avon Reservoir in groundwater studies have also been The latest developments in this area accordance with previous Committee carried out with the aim of determining are monitored through Ian Anderson’s approvals. Coal mining is also the height of fracturing above the position as Senior Inspector of Coal continuing at Wyee Colliery under mining. This work was carried out Mines and Ian Forster’s involvement Mannering Creek Ash Dam, Liddell using a sidewall-piezometer tool that as a Board member of the Mine Coal near Liddell Cooling Water Dam, proved to be more effective and less Subsidence Technological Society. Westcliff Colliery near Brennans Creek expensive than traditional methods. Dam and at Cooronbong Colliery near Of particular note during 1999/2000 Dora Creek Effluent Dam. were the ongoing results received from Although the Colliery has invested the monitoring programme and a considerable amount on its

TABLE 3.2 – ACTIVE MINING APPROVAL STATUS Possible Effect on Mining Active Dam Dam Currently Approval Colliery Dam Type Mining Storage Structure Monitoring Bellambi 6,7,8 Bell. West Cataract Longwall Yes Yes No Yes Bellambi 9,10,11 Bell. West Cataract Longwall Yes Yes Yes Yes +Liddell 1 Liddell Coal Liddell Open Yes Yes Yes Yes Cooling water cut/auger Wyee 11 Wyee Mannering Longwall Yes No Yes Yes Creek Ash Westcliff 2 Westcliff Brennans Creek First workings Yes Yes Yes Yes Appin 2 Appin Broughtons Longwall No Yes Yes Yes Pass Weir

+ separate approvals for open cut and auger mining.

25 and/or its staff to meet owners’ 4. EDUCATION AND TRAINING representatives to discuss relevant issues. Such meetings are invaluable in reaching a common understanding 4.1 CONTINUING in Sydney in November 1999 with of the problems facing these owners EDUCATION AND representatives of authorities regulating in regard to asset management and TRAINING OF hazardous industries. responsibilities to the community, and COMMITTEE MEMBERS obtaining feedback for enhancing the AND STAFF 4.2 DAM OWNER Committee’s education role. To The Committee’s members and staff EDUCATION AND provide a basic background in this area, have extensive and varied experience TRAINING the Committee ran its first training in dams’ engineering and mining. course in 1991 for Local Government The Committee recognises that to However, it is essential in any and private dam owners. As a result achieve its role of dam safety it is organisation to keep abreast of modern of the positive feedback, and ongoing essential to continually educate dam developments in all the technical and discussions, the then NSW Public owners to keep them up to date with societal fields related to its functions. Works Dams Surveillance Group (now their responsibilities and with This is particularly important in the part of DLWC) instituted regular international standards, practice and case of the Committee, because of the training courses for Local Government technology. It actively communicates diverse technical knowledge required and other dam operators, run with the its objectives and concerns to dam from its small staff. Accordingly, the assistance of Committee staff. Three owners and their representatives Committee’s members and staff day courses for dam operators were through various avenues, including its attended relevant conferences, courses held in November 1999, February Internet site. To assist in this role, the and symposia during the year. 2000 and March 2000 at Port Committee has assembled a Macquarie as part of this programme. In November 1999, the Committee’s considerable library of publications, In addition, Committee members and Executive Engineer attended a national manuals and videotapes on various staff addressed Council meetings on a Emergency Risk Conference in aspects of dams and their number of occasions during the year. Canberra to bring practitioners up to management. This material is actively date in current emergency risk promoted and freely loaned to dam The increasing emphasis by the management practices owners to assist in the training of their Committee on owner education in staff. NSW has been reflected in numerous In November 1999, the Chairman, requests from dam owners outside Executive Engineer and Surveillance Close contact is also maintained by NSW for educational assistance. In Engineer attended the 1999 the Committee with the major NSW this regard, Committee staff were ANCOLD Conference on Dams held dam owning authorities, through their invited to make presentations on in Jindabyne, NSW. The majority of nominees on the Committee, and management, operational, surveillance the other Committee members also through meetings held during the year and safety matters in respect of dams attended, most as representatives of to discuss specific dam requirements to Western Australian authorities their own organisations. Various papers and general procedures. In addition, during the year. Such involvement is were presented on community, legal Committee staff ran or assisted in of value to the Committee in and environmental concerns with presenting, various training courses for broadening its experience of dam dams, along with recent developments the staff of major dam owning safety management concerns. in dam engineering. In addition, some authorities during the year. This work Committee members and staff were is seen as a key part of the Committee’s actively involved in the organisation of educational role for dam owners in the meeting and were able to provide NSW and accordingly Committee cost input to the various open meetings recovery is limited to out of pocket held by ANCOLD Working Groups expenses (ie. travel, accommodation) which were preparing new and revised associated with attending these training national Guidelines. sessions. During the year, Committee staff The dam safety education of local attended various one day local government authorities, mining technical seminars. Relevant companies and private dam owners is Committee members and staff also of particular interest to the Committee, updated their confined spaces because the staff of these bodies proficiency at a course in February generally do not have specialist 2000 and their first aid training at a engineering knowledge of dams. course in April 2000. In addition, the Education of these owners is assisted Committee convened a risk workshop by regular site visits by the Committee

26 released ANCOLD Guidelines in 5. PERFORMANCE PERFORMANCE ANDAND FUTUREFUTURE OBJECTIVES these areas. 5 Pursue a programme to ensure all 5.1 PERFORMANCE Committee’s database on dam owners of high and significant hazard dams have in place INDICATORS information extended and consolidated to assure the timely appropriate Operation and During the year the Committee provision of information on dam safety Maintenance Manuals and Dam monitored performance indicators, as matters. In conjunction with these Safety Emergency Plans by shown in the following table, which activities the Committee will continue December 2000, and will maintain reflect the objectives of its mission to review its policies in various areas its close liaison with the State statement. Because of the nature of in line with emerging international Emergency Service in this regard. the Committee’s work, and the trends and developments in dam 6 Actively work with dam owners to relatively small size of its organisation, technology. The Committee’s aim is avoid an unacceptable back log of quantitative indicators are often not to keep dam owners informed of these Surveillance Reports. entirely appropriate and some of its matters by the regular release of significant indicators are therefore updated Information Sheets in paper The Committee plans to prescribe qualitative. format, as well as on CD ROM and and oversight the dams owned by the on the Committee’s Internet site. Snowy Mountains Hydro-Electric 5.2 FUTURE OBJECTIVES In particular, the Committee will : Authority when that Authority is corporatised (current estimate is late 5.2.1 Dams Surveillance and 1 Continue to develop its risk ranking 2000). In addition, the Committee will Safety of dams, for prioritisation of be maintaining, and fostering close detailed investigations and work, in The Committee’s basic objective is liaisons with other NSW dam owners order to achieve the greatest rate of to ensure that all prescribed dams are by increasing the emphasis on risk reduction with the available designed, constructed, maintained education, and by the running, or resources. and, if necessary, decommissioned to assisting in the running, of training appropriate safety standards, in line 2 Further develop the integration courses for dam owner personnel. This with relevant international best of traditional methods of dam education will be fostered by practice, to present a tolerably low risk safety evaluation into the risk Committee staff assisting with appropriate to downstream residents, assessment framework and will presentations at appropriate meetings property, the environment and continue to sponsor appropriate and conferences on relevant dam associated community needs. risk research programmes. matters, and by the input of Committee members and staff to the To further this objective, the 3 Further its research and inquiries development of ANCOLD Guidelines Committee will maintain a in regard to safety of dams against on such subjects as Acceptable Flood commitment in 2000/2001 to ongoing piping (internal erosion) and slope Capacity, Risk Assessment, Asset implementation of Total Quality stability failure modes. Management and Hazard Rating. Management principles. Accordingly, 4 Revise its flood and hazard rating procedures and practices will be In 2000/2001, the Committee requirements for dams in formalised progressively, and the will continue to support programmes conjunction with the recently and initiatives for the improved

PERFORMANCE ITEM PERFORMANCE INDICATOR RATING

1 Request remedial programs for known deficient dams Percentage of deficient dams with 100% programs requested 2 Follow up action taken within three months of due date Subjective Good Per centage performance 90% 3 Reports and programs reviewed and response sent within Subjective Very Good three months of receipt Percentage performance 100% 4 High risk dams (30) inspected yearly Number inspected this year 22 (Fair) 5 Medium risk dams (50) inspected every two years Number inspected this year 26 (Good) 6 Low risk dams (170) inspected every five years Number inspected this year 67 (Good) 7 Request programs for preparation of dam safety Percentage of dams with 100% documentation for each dam documentation requested 8 Update dam safety education material every two years Time since last update issued Being updated 9 Annual involvement in providing at least one dam safety Number of courses this year 3 education course in NSW 10 Compliance with approved Committee budget Subjective Good Percentage deviation < 3% 11 Active mining areas, subject to Committee requirements, Percentage inspected 60% (Fair) to be inspected yearly

27 The Committee will continue to 5. PERFORMANCE AND FUTURE OBJECTIVES explore the use of new equipment and techniques for prediction and monitoring, to provide a clearer picture monitoring and recording of basic data, The Committee will continue to of ground behaviour patterns induced such as flood and seismic data, essential closely monitor programs for remedial by mining. Of particular note is the for the economic design and safety action on dams, especially those potential for data obtained from review of dams. identified as having significant tectonic strain monitoring, micro- deficiencies. While the Committee The Committee will continue to seismics and borehole monitoring at appreciates that there can be problems advise dam owners of the value of Cataract Reservoir to be used to with funding limitations and installing appropriate rainfall and validate mathematical modelling of environmental / community processes, outflow monitoring equipment to future coal mine extraction it will continue to press owners to carry maximise the effectiveness of applications. Applications of risk out their responsibilities to implement catchment/storage management and management to mining developments suitable measures within a reasonable flood warning, and to provide data to will also be investigated. This will time period, having regard to the assist in flood analysis and design. In include monitoring overseas and practicable implementation of such addition, the Committee will continue Australian practice, experience and programmes. These actions are to foster and oversight research into developments, and exchanging essential to the effectiveness of the extreme flood estimation, particularly information with relevant personnel NSW dam safety programme. relating to probability assessment. and organisations as a basis for the progressive updating of The Committee sees the need to 5.2.2 Mining Committee guidelines and procedural maintain, if not expand, the seismic requirements. The Committee will monitoring network in NSW, and will The Committee, with its view to also continue to work closely with the make representations, as needed, in maximising coal extraction while NSW Department of Mineral this regard. The Committee will preserving dam safety, continues to Resources, colliery owners and staff, collaborate with other agencies in the develop a more scientific approach to and facilitate discussions with affected development of improved seismic prediction of the effects of mining, dam owners, to achieve mutual analysis of dams, relevant to the with increasing confidence in the understanding of each others’ concerns characteristics of Australian utilisation of a growing data base of and objectives. The aim of this earthquakes. information, allied with modern cooperation is to ensure minimum technology and more sophisticated The Committee will further its restriction on the development of computer simulation techniques. In programme to determine the condition mineral resources, consistent with coal mining, this is reflected in the of unprotected pipelines through maintaining the integrity of dams and increasing sophistication of mining dams, which can lead to leakage and their stored waters. applications reviewed by the possible dam failure if not assessed and Committee. It has resulted, over time, appropriately treated. in the Committee being able to The Committee will also maintain approve the extraction of increasing its liaison with the Environment percentages of coal from under NSW Protection Authority and Department storages. This increasing usage of of Urban Affairs and Planning to predictive technology has in turn been ensure that appropriate dam safety supported by the application of more requirements safeguard the selective and advanced monitoring environment from toxic or polluting techniques for existing mining materials, and devastating floods operations, to improve knowledge of resulting from dam failure generally. the interaction of the coal extraction Similarly, close liaison will continue process with overlying strata. with the Department of Mineral Resources in respect of oversighting dam matters relating to mining applications.

28 6. FINANCE

6.1 DAMS SAFETY COMMITTEE CERTIFICATE

DAMS SAFETY COMMITTEE FINANCIAL STATEMENT FOR THE YEAR ENDED 30 JUNE 2000 CERTIFICATE PURSUANT TO THE PUBLIC FINANCE AND AUDIT ACT, 1983

In our opinion the financial statements read in conjunction with the Notes attached thereto for the financial year ended 30 June 2000, exhibit a true and fair view of the financial position and transactions of the Dams Safety Committee. The financial statements have been prepared in accordance with the provisions of the Public Finance and Audit Act, 1983 as amended and the Public Finance and Audit (General) Regulation, 1995 and with the Treasurer’s Directions as they relate to the preparation of those Accounts.

We are not aware at this time of any circumstances which would render any particulars in the financial statements to be misleading or inaccurate.

This certificate is given in accordance with a Resolution of the Committee made on 28 June 2000 and is signed for and on behalf of the Committee.

L A McDonald A C Williams Chairman Deputy Chairman

31 July 1999 31 July 1999

29

DAMS SAFETY COMMITTEE 6.6. FINANCE FINANCE STATEMENT OF CASH FLOWS For The Year Ended 30 June 2000 1998/99 Note 1999/2000 6.3 FINANCE SUMMARY $$ CASH FLOWS FROM “This is the beginning of the Audited Annual OPERATING ACTIVITIES Statements.” Receipts DAMS SAFETY COMMITTEE INCOME & EXPENDITURE 50,400 Industry Contribution 54,325 STATEMENT For The Year Ended 30 June 2000 7,564 Interest Income 10,806 586 Other Minor/Miscellaneous Income 17,701 1998/99 Notes1999/2000 $$58,550 82,832 INCOME CASH FLOWS FROM 439,000 State GovernmentRecurrent GOVERNMENT ACTIVITIES Allocation 7 439,000 Consolidated Fund 0 Net Gain on Disposal of 439,000 Recurrent Allocation 439,000 Non Current Assets 4 7,088 9,182 Interest Income 11,620 497,550 521,832 50,400 Other Contributions from Industry 54,325 Payments 4,436 Other Minor Income 16,720 (273,327) Employee Related (311,603) 503,018 528,753 (27,260) Members’ Expenses (35,813) (238,407) Suppliers (152,411) EXPENDITURE 32,642 Members’ Expenses 11 35,813 (538,994) (499,827) 160,081 Dam Surveillance 6 184,758 Net Cash used in 49,907 Mining Investigations 6 67,013 41,444 Operating Activities (22,005) 7,875 Depreciation 11,639 6,958 Conferences 6 6,915 31,140 Owner’s Education 6 43,911 CASH FLOWS FROM 60,715 Research 6 63,320 INVESTING ACTIVITIES 167,432 Administration 6 132,667 0 Payment for property, plant 3,800 Audit Fee 8 3,900 & equipment (27,257) 0 Proceeds from Disposal 520,550 549,846 of Non-Current Assets 21,800 (17,532) Operating Deficiency (21,093) 0 (5,457) ACCUMULATED FUNDS AT THE 109,489 BEGINNING OF FINANCIAL YEAR 91,957 (41,444) NET (DECREASE)/INCREASE OF Accumulated Funds at CASH HELD 16,548 91,957 end of Financial Year 70,864 The accompanying notes form part of these financial statements. 123,897 Cash at Beginning of Year 82,453 82,453 CASH AT END OF YEAR 15 99,001

DAMS SAFETY COMMITTEE BALANCE SHEET As At 30 June 2000 DAMS SAFETY COMMITTEE NOTES TO AND FORMING PART OF THE ACCOUNTS FOR THE YEAR ENDING 30 JUNE 2000 As At As At 30 June 30 June 1. Statement of Purpose 1999 Notes 2000 The Dams Safety Committee was constituted in 1979 to CURRENT ASSETS adopt a regulatory ongoing “watchdog” role to ensure the 82,453 Cash 15 99,001 owners of the State’s major dams conform to appropriate 8,329 Accounts Receivable 9 8,126 safety requirements in order to prevent uncontrolled loss of their storages with consequent effects on the community, 90,782 Total Current Assets 107,127 environment and water supply. NON-CURRENT ASSETS 2. Statement of Accounting Policies 22,019 Plant, Equipment & Motor Vehicle 5 22,925 Basis of Financial Statements: The Committee’s financial statements are a general purpose financial report. The 22,019 Total Non-Current Assets 22,925 statements have been prepared in accordance with 112,801 TOTAL ASSETS 130,052 applicable Australian Accounting Standards and other authoritative pronouncements of the Australian Accounting CURRENT LIABILITIES Standards Board (AASB), the provisions of the Public Finance 20,844 Creditors & Accruals 10 59,188 and Audit Act 1983, UIG Consensus Views, the Public Finance and Audit (General) Regulation, 1995 and the Treasurer’s 20,844 TOTAL CURRENT LIABILITIES 59,188 Directions. In the absence of applicable Accounting 20,844 TOTAL LIABILITIES 59,188 Standards, other authoritative pronouncements of the AASB or Urgent Issues Group Consensus Views, the hierarchy of 91,957 NET ASSETS 70,864 other pronouncements as outlined in AAS 6 “Accounting Policies” is considered. EQUITY 91,957 Accumulated Funds 70,864 The statements have also been prepared under the historical cost convention using accrual accounting, and do not take 91,957 70,864 into account changing money values or, except where stated, the current value. The accompanying notes form part of these financial statements. General: For comparative purposes, where applicable, the 1999 figures have been reclassified to conform to the 2000 financial statement’s presentation.

31 6. Expenses 6. FINANCE Some of the major items include: 30.6.00 30.6.99 $$ Financial Instrument: A financial instrument is any contract Employees’ Salaries & related oncosts 314,639 271,531 that gives rise to both a financial asset of one entity and a Rent for Office Space 35,654 37,334 financial liability or equity instrument of another entity. For Board Committee Members’ Expenses 18,552 18,947 the Dams Safety Committee, financial instruments range from Administration Fees paid to DLWC 15,250 15,250 cash at bank and accounts receivable to creditors. In With expenditure, Employee Related and Rental costs have accordance with AAS 33 “Presentation and Disclosure of been redistributed directly to various expense categories Financial Instruments” information is disclosed in Note 16 in such as Dam Surveillance, Mining Investigations, Conferences, respect of the interest rate risk and credit risk of financial Owners’ Education, Research and Administration reflecting instruments. All such amounts are carried in the accounts at actual cost delivery. Stores expenditure of 1998/99 has been net fair value unless otherwise stated. reclassified to Administration this financial year. Revenue Recognition: Parliamentary appropriations and contributions from other bodies (including grants and 7. Significant Government Subsidies donations) are recognised as revenues when the agency The Dams Safety Committee obtains the major portion of its obtains control over the assets comprising the appropriations funding from the State Government through a budget / contributions. Control over appropriations and contributions allocation ($439,000 in 1999/00 and $439,000 in 1998/99). are normally obtained upon the receipt of cash. Other expenditure incurred by government departments Revenue is recognised to the extent that it is probable that and other statutory authorities in direct support of the the economic benefits will flow to the agency and the Committee, for the year ended 30 June 2000 was estimated revenue can be reliably measured. The following specific to be $94,000 ($95,000 for 1998/99). This expenditure is not criteria must also be met before revenue is recognised. disclosed in these financial statements. Interest: Control of a right to receive consideration for the provision of, or investment in, assets have been attained. 8. Audit Fee Contributions of assets including grants and subsidies: The fee for auditing the financial statements for the year Revenue is recognised when control of the contributions (at ended 30 June 2000, is $3,900 ($3,800 for 1998/99). The Audit their fair value) has passed to the agency. Office of NSW received no other benefit. Disposal of non-current assets: Revenue from sale of non- 9. Accounts Receivable current assets is recognised when the sale proceeds have been received. Represents Interest Income accrued, prepayment of registration fees and accrued income. 3. Employees and Employee’s Entitlements Employees: Employees undertaking work for the Dams 10. Accounts Payable Safety Committee are on secondment from other 30.6.00 30.6.99 government departments. Salary costs are reimbursed $$ together with an oncost to cover salary related costs. Comprises: Creditors & Accruals 59,188 20,844 Annual Leave Entitlements: No provision is made for annual Trade accounts payable is normally settled within 30 days. leave in respect of salaried staff as this cost is included as part of the oncost paid to the seconding organisation. 11. Emoluments or Other Benefits Paid or Due and Payable 4. Net Gain Disposal of Non-Current Asset to Committee Members The Net Profit on Disposal of Non Current Assets is $7,088 for Fees of $35,813 ($32,642 for 1998/99) were paid or due and 1999/2000 (Nil for 1998/99). payable to Committee members. 30.6.00 30.6.99 $$12. Contingent Laibilities Proceeds on Sale 21,800 0 The Committee is not aware of any contingent liabilities in Written Down Cost (14,712) 0 existence at balance date, or which has emerged subsequent to balance date, which would impact on the Gain on Sale 7,088 0 financial position of the Committee as shown in the accounts supported by these notes. 5. Non-Current Assets Accounting control of assets is maintained by way of an 13. Commitments for Expenditure asset register. The Committee believes that the written down The commitment for expenditure as at 30 June 2000 was value of its fixed assets represents a fair approximation of $Nil ($24,630 in 1998/99). market value. Depreciation is raised on a straight line basis over the life of the asset to the Committee. The Committee 14. Consultancies has determined the useful life of the asset classes to be: Office Equipment – 4 years; Scientific Instruments – 5-8 years; Consultancy engagements during 1999/2000 were $Nil Motor Vehicles – 5 years. Non-Current Assets held as at (nil in 1998/99). 30 June 2000 were: Office Scientific Motor Total Total 15. Statement of Cash Flow At Cost Equip. Instr. Vehicles 30.6.00 30.6.99 For the purpose of the Statement of Cash Flows, cash includes $$$ $$ cash on hand, in bank and at Treasury, net of bank overdrafts. Balance at 1 July 30,168 2,135 22,633 54,936 54,936 Cash at the end of the financial year as shown in the Additions 1,267 0 25,990 27,257 0 Statement of Cash Flows is reconciled to the related item in Disposals (8,412) 0 (22,633) (31,045) 0 the Balance Sheet as follows: Balance at 30 June 23,023 2,135 25,990 51,148 54,936 30.6.00 30.6.99 Accum. Depreciation $$ Balance at 1 July (23,963) (1,787) (7,167) (32,917) (25,042) Cash 99,001 82,453 Depreciation for year (6,205) (348) (5,086) (11,639) (7,875) Disposals 8,412 0 7,921 16,333 0 Balance at 30 June (21,756) (2,135) (4,332) (28,223) (32,917) Written Down Value as at 30 June 1,267 0 21,658 22,925 22,019

32 Reconciliation of net cash provided by operating Activities 6.4 DAMS SAFETY COMMITTEE 1998/99 to Operating Surplus 1998/00 1997/99 BUDGETARY INFORMATION $$ Operating (Deficiency)/Surplus (21,093) (17,532) 1999/00 1999/00 2000/2001 Add: Non-Cash Operating Budget Actual Budget Expenditure: Depreciation 11,639 7,875 $$ $ Deduct: Non Cash Operating INCOME Income: Net Gain on Disposal of Non-Current Assets (7,088) 0 Consolidated Fund 439,000 439,000 450,000 Changes in Asset & Liabilities: Nett Gain (Loss) on Decrease /(Increase) in Disposal of Assets 7,000 7,088 8,000 Accounts Receivable 203 (5,834) Increase/ (Decrease) in Industry Contribution 50,000 54.325 50,000 Accounts Payable 38,344 (25,953) Interest Income 10,000 11,620 10,000 Net Cash (Used in)/Provided by Miscellaneous 3,000 16,720 5,000 Operating Activities (22,005) (41,444) Total 509,000 528,753 523,000 16. Additional Financial Instruments Disclosures (i) Interest Rate Risk EXPENDITURE Interest rate risk, is the risk that the value of the instruments Employee Related 36,000 35,813 30,000 will fluctuate due to changes in market interest rates. The entity’s exposure to interest rate risk and the effective interest Administration 109,000 132,667 87,000 rates of financial assets and liabilities at the balance date Dam Surveillance 191,000 184,758 177,000 are as follows: Mining Investigations 64,000 67,013 66,000 Fixed Interest Rate Information Technology n/a n/a 74,000 Maturities Total Research 69,000 63,230 69,000 Weighted Carrying average amount Conference & Training 5,000 6,915 8,000 effective Floating 1 year More Non as per the Audit Fee 4,000 3,900 4,000 interest interest or 1 to 5 than 5 interest Balance rate rate less years years bearing Sheet Information Delivery 47,000 43,911 27,000 %$’000 $’000 $’000 $’000 $’000 $’000 Depreciation 7,000 11,639 8,000 30 June 2000 Financial Assets Total 532,000 549,846 550,000 Cash 4.25 99 99 Receivables 8 8 Total Financial Operating Deficiency 23,000 21,093 27,000 Assets 99 8 107 Financial Liabilities Creditors 59 59 Total Financial Liabilities 59 59 7. COMMITTEE INFORMATION 30 June 1999 Total Financial Assets 3.86 82 9 91 General information on the Committee’s activities and Total Financial Liabilities 21 21 various dam safety educational material (ie. Information Sheets, books, papers, reports, videos) is available on request (ii) Credit Risk to the Committee with a summary of this material available Credit risk is the risk of financial loss arising from another party on the Committee’s web site. to a contract/or financial position failing to discharge a financial obligation thereunder. The entity’s maximum exposure to credit risk is represented by the carrying amounts of the financial assets included in the balance sheet.

“This is the End of the Audited Financial Statements”

APPENDIX A – DAM OWNER SUMMARY – 30 June 2000 Prescribed Dam Reports Dams Inspected by Dam Owner Prescribed Dams Received During 1999/00 Committee & Staff 1999/00 Councils 107 10 40 Sydney Water / Catchment Authority 37 3 14 + Pacific Power, Delta, Macquarie Generation 17 1 5 Dept of Land & Water Conservation (DLWC) 23 9 14 Other State Authorities 8 2 4 Non State Authorities 3 1 3 Mining Companies 50 12 28 Other Ownership 16 0 7 Total 261 38 115

* 2 reports was also reviewed in relation to SMHEA dams. + Pacific Power was split in 1996 into three separate companies currently named Delta Electricity, Pacific Power and Macquarie Generation with dam ownership divided between these groups.

33 N.S.W. DAMS SAFETY COMMITTEE

FLOOR 3, MACQUARIE TOWER

10 VALENTINE AVENUE,

PARRAMATTA, NSW 2150

(PO BOX 3720, PARRAMATTA, NSW 2124)

FAX: (02) 9895 7354

OFFICE PHONE: (02) 9895 7363

CAR PHONE: (014) 604 989

EXECUTIVE ENGINEER (02) 9895 7349

Website: http://www.damsafety.nsw.gov.au Email: [email protected] DX: 28360

BUSINESS AND SERVICE HOURS ARE NORMALLY 9.30 am TO 4.00 pm, MONDAY TO FRIDAY

(Please note that the Committee only has a small technical staff who are often away from the office on dam inspections etc. Accordingly, technical questions may not be able to be answered immediately, although every effort will be made to pass on messages to ensure a prompt response.)

Cover Picture: KEEPIT DAM. First stage flood capability improvements have been implemented on this 55 m high irrigation dam. Long term remedial options are being investigated.

Design & Production: G-Line Productions, 4 Chapman Street, Gladesville NSW 2111. ISSN 0816-2727

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