Refer to the other drop down items on this page for detailed descriptions of the particular services Damwatch provides for particular aspects of investigation, design and analysis as it relates to dam engineering.

Forensic investigation is a methodology that investigates failures in order to learn lessons and improve practices in the design, management, and operation of structures, materials, components, or infrastructure.
This in turn determines the causes of those failures.

Once the causes of failures are identified remedial works can be designed and implemented

Appurtenant structures are deemed to be any associated structure that if it failed, could result in the breaching of a dam or embankment.
Damwatch has the expertise to design, monitor and remediate these structures.

Damwatch has expertise in the design, maintenance and remedial works for gates and mechanical components that may form part of embankment/dam appurtenant structures.
These may consist of:

• Gates: slide, vertical lift, radial, jet flow, and cylindrical.
• Intake and outlet conduit with associated valves and valve controls.
• Trash racks, cranes, winches and lifting components.
• Access stairs and walkways.

Under the NZ Building (Dam Safety) Regulations 2022 all classifiable dams require a building consent from a regional council.
Under the Building (Dam Safety) Regulations 2022, a classifiable dam is defined as follows:

• A dam that has a height of 4 or more metres and holds 20,000 or more cubic metres volume of water or other fluid.

These regulations are under review so applications for regulatory consnt would need to reference the most up todate regulations.

Countries other than New Zealand have their own sets of regulations which Damwatch has extertise in analysing and applying.

A peer review is a professional opinion based on sound engineering analysis and assumptions, good practice, appropriate regulations and unbiased judgement.
Peer reviews can be limited to certain key parts of the engineering work.
A peer review is intended to reveal issues rather than necessarily resolve them. But it can be a key resource for subsequent work towards resolving any issues that are identified.
ref. Engineering NZ

Courts from time to time rely on professional evidence from expert witnesses to facilitate decision making by the court judges.
Damwatch has the expertise (or access to the expertise) to provide expert professional evidence.

• Contractor procurement documentation and contractor selection for clients
• Participation in construction methodology selection with contractors
• On site dam safety supervision during construction
• Development of quality systems and reporting for construction, including real time dam safety monitoring 24/7
• Design support during construction

A dam potential failure mode (PFM) is a mechanism or set of circumstances that could result in the uncontrolled release of all or part of the contents of a dam's stored reservoir.
Failure Modes and Effects Analysis (FMEA) has been used in the international dam safety industry for a number of decades to determine the potential ways that a given dam may fail. The 2015 New Zealand Dam Safety Guidelines recommend that FMEA be completed for all new and existing dams, in particular, for dams with Medium and High Potential Impact Classification (PIC).
FMEA is best completed in a facilitated workshop environment, attended by representatives of the dam Owner, Technical Advisers and others (such as designers, contractors and surveillance staff) with relevant knowledge of the dam's characteristics and its historical performance.
Benefits to the Dam Owner:

• Detailed understanding of all credible potential failure modes for a dam and those most significant to its safety
• Understanding of the likelihood of the development of the potential failure modes
• Key input to determining the consequences of the development of potential failure modes
• Identification of initiating events and key performance indicators for each potential failure mode so that surveillance and emergency plans can be targeted and appropriate response procedures developed
• Identification of potential or confirmed dam safety deficiencies relating to the potential failure modes
• Identification of knowledge gaps that require further investigation to obtain an improved understanding of the dam’s potential failure modes
• Key input to dam safety risk analysis allowing prioritisation of issues and targeted mitigation and remediation
• Key input to development of mitigation and remedial measures to address dam safety deficiencies

Risk:

• A measure of the probability and severity of an adverse effect to life, health, property, or the environment.

Risk analysis:

• The use of available information to estimate the risk to individuals or populations, property or the environment from hazards. Risk analysis generally contain the following steps: scope definition, hazard identification, and risk estimation.

Risk assessment:

• The process of making a decision recommendation on whether existing risks are tolerable and present risk control measures are adequate, and if not, whether alternative risk control measures are justified or will be implemented.
• Risk assessment incorporates the risk analysis and risk evaluation phases.

Risk criteria:

• The terms of reference against which the significance of a risk is assessed.

Risk reduction:

• Actions taken to lower the likelihood of an occurrence or its adverse consequences, or both.

Dam break flood hazard and consequence assessment is an important part of dam safety management and is used for a variety of purposes, including:

• Developing an understanding of the hazards and risk imposed by the dams
• Comparison of risks created by dams within an owner’s portfolio of dams
• Development of flood inundation and hazard maps for use in owner's emergency preparedness plans and by external services for emergency planning
• Development of detailed inundation maps for land use planning
• Development of detailed consequence maps for assessment of damages for insurance purposes
• Communicating the hazard potential of dams to those outside the industry
• Hazard mitigation planning

The information from a dam break flood hazard and consequence assessment is also commonly used to assign a Potential Impact Classification (PIC) to a dam. The current framework to determine a dam’s PIC is outlined in the New Zealand Dam Safety Guidelines, published in May 2015 by the New Zealand Society on Large Dams.

Different levels of dam break flood hazard and consequence assessment can be carried out depending on the purpose and the anticipated level of consequence:

• If the potential downstream impacts on people, property and the environment of a hypothetical dam failure are likely to be fairly limited, then an initial assessment may be sufficient for dam classification purposes.
• Where the potential downstream impacts of a dam failure are likely to be more significant, an intermediate level assessment would be required.
• For dams where failure would have high consequences, and flood inundation maps are required for emergency preparedness plans, a more comprehensive assessment is typically required.

A dam break flood hazard and consequence assessment is typically informed by a Potential Failure Modes Analysis (PFMA) which establishes credible failure scenarios for a dam.

Professional advice can be provided by Damwatch's team of professional dam designers, specialising in fields of:

• Structural engineering.
• Civil engineering.
• Mechanical engineering.
• Geotechnics.
• Geology.
• Hydrology.
• River hydraulics.
• Mechanical engineering.
• Environmental sciences.
• Materials technology.

A peer review is a professional opinion based on sound engineering analysis and assumptions, good practice, appropriate regulations and unbiased judgement.
Peer reviews can be limited to certain key parts of the engineering work.
A peer review is intended to reveal issues rather than necessarily resolve them. But it can be a key resource for subsequent work towards resolving any issues that are identified.
ref. Engineering NZ