Hydro Review

Dam Safety: Ontario Ministry Develops Dam Management Plan

Balancing the responsibilities of dam ownership with the requirements of dam management can be a challenging task. The Ontario Ministry of Natural Resources' multi-functional dam asset management plan allows efficient and effective management of a large fleet of dams for the best environmental, economic and recreational outcomes.

By David G. Judge, Hugh John Cook and Allan Chow

Dam infrastructure in the Canadian province of Ontario serves a variety of purposes related to: protection of public resources to enhance ecological sustainability, management of water to enhance economic opportunities, and protection of life and property against floods and dam failures. The Ontario Ministry of Natural Resources (MNR) owns more than 400 dams and is responsible for maintaining these dams for the well-being of provincial residents, to provide economic benefits, and to protect the environment. Most of the dams were constructed between 1956 and 1970 and are 40 to 55 years old. Nine of the dams impound water for hydropower operations.

The core business objectives supported by MNR dams are protection of: life and property from floods and erosion; ecosystem health, including fishery management and preservation of fish and wildlife habitat; and wetlands, especially those deemed "provincially significant." The provincially significant wetland designation is established by MNR biologists and specially trained and approved private sector biologists using a complex scoring system that evaluates the size of the wetland, the biota within that wetland and the rarity/importance of the biota. MNR's dams also provide barriers to lamprey and other invasive fish species; reservoirs for hydro power production; and recreation, boating, and navigation opportunities. Among these core business objectives, protection of life and property and the provision of measures for public safety are regarded as the most important.

The government of Ontario has created a Ministry of Infrastructure and requires that all provincial infrastructures be professionally managed using asset management plans. As a result, MNR commissioned the development of a formal dam asset management plan (DAMP) to enable them to manage their dams on a lifecycle basis to minimize total costs while still achieving the required service levels at a reasonable level of risk to the environment and public. Previously the dam assets were managed using an informal system that dealt with specific problems as they were identified. DAMP, developed by consultant Hatch Ltd. with MNR staff, provides access to comprehensive information about the assets, including a risk assessment, so that the dams can be efficiently and effectively managed.

DAMP was developed to allocate funds necessary for the sustainable lifecycle management of dams, as well as to ensure that dam safety, economic and environmental aspects are well-handled. The DAMP model was configured into a proprietary database called the Total Capital Planning Solution or TCPS®. TCPS goes beyond conventional engineering-based condition assessments by overlaying an organization's business objectives/strategies against many identified technical options, thus providing a scalable and sustainable approach to strategic asset management.

The DAMP model includes application of a Risk Based Profiling System (RBPS) based on work originally done by the U.S. Bureau of Reclamation. RBPS was originally developed to address dam safety issues, and it is used within the DAMP model to ensure high-risk structures are identified and deficiencies are resolved through prioritized allocation of limited funds. As funds are allocated in the planning model, the risk profile is adjusted to show the direct benefit.

Background on MNR's dam safety program

Dams have been built and maintained by the province to meet the business goals previously mentioned: protection of the life and health of Ontario citizens, ensuring healthy aquatic ecosystems that safeguard human health and quality of life and support the natural environment. Initially, many of the dams were developed by private interests for economic activity related to forestry, mining and hydropower. Most of the dams that were originally developed for hydro purposes have remained within this business sector and are not presently owned by MNR. Dams that were originally developed for forestry have, in many cases, been handed over to MNR for ongoing ownership and management. A smaller number of dams were developed for flood management and environmental purposes. MNR dams are typically small (less than 10 meters tall) and consist of a variety of structure types, including concrete, earthfill and rockfill, steel sheet pile, and timber crib dams.

DAMP provides updated information about the assets themselves, as well as a better understanding of the risks associated with the existence and operation of the dams and of their importance in supporting MNR's ecologic and economic objectives. In this way, DAMP helps MNR staff make a strong case for predictable and stable funding needed to support responsible ownership, operation and maintenance of its dams.

MNR is in a unique position as both an owner and regulator of dams. MNR owns and manages dam assets but also oversees itself to ensure that these dams comply with all applicable dam safety standards. In fact, MNR is in a position where it needs to lead by example and demonstrate to other dam owners in the province that it is in full, responsible compliance with the law.

MNR has completed Dam Safety Assessments (DSAs) for 200 of its dams over the past 15 years. The DSAs look at the design and construction of each dam, its present condition, and the risks and consequences associated with possible failure of each dam. This information is central to RBPS. MNR determined that these dams were of significant enough importance and value to warrant formal, detailed study. The rest of its dams are small and do not contribute significantly to MNR's core business goals. As well, they are not deemed to present any significant risk to humans or the environment should they fail.

Funding sources

In the early 2000s, the government of Ontario committed to invest C$8 million (US$8.15 million) annually in dam infrastructure management, but recently the funding level has been reduced by half because of other provincial requirements for funding. As a result, there is a significant backlog of deferred capital expenditures needed to upgrade the MNR aging dam infrastructure. With the available funding, each of MNR's regional Engineering Offices has undertaken work on dams that fall into three main categories, as discussed below.

Major capital projects

Major capital projects are large construction projects on individual dams, usually costing more than C$100,000, intended to address serious structural and/or hydraulic deficiencies. This category of work includes reconstruction or replacement of dams but also includes works that extend the structure's life or reduce operational costs, as well as decommissioning of dams that don't serve a useful function.

In any one year, major capital projects are performed on a discretionary basis because dams deteriorate relatively slowly. For this reason, decisions to defer such projects have been typical in the past five years. Over time, however, deferring critical capital projects represents an ongoing public safety risk, as the likelihood of these dams failing continues to increase and the consequences of failure can be large.

If the level of risk is high, options are available to manage the risk without undertaking major capital projects. Options include conducting a risk assessment to confirm and quantify the risks and ensure they are below the unacceptable level, modifying dam operations, lowering the normal water level to reduce pressure on the structure, and developing and documenting emergency preparedness plans.

Dam safety support

Annual maintenance is vital to the safety of the dams. Routine inspections of dams by operators and engineers, as well as full-scale dam safety reviews, are conducted annually, every five years, and every 10 years. MNR also conducts regular safety training for all those involved with the operation of the dams and periodically replaces employee safety equipment.

In addition, minor maintenance is annually required to address worker and public safety around dams. Stoplogs, booms, railings, stairs, warning signs and safety lines are inspected, upgraded and repaired as needed. Maintenance of automated control systems, water level and flow data loggers, and records management - including the dam database and provincial dam information portal - ensure proper operation and process documentation at each dam.

Dam operation costs

The costs in this category are primarily associated with the resources and activities needed to regulate water levels. MNR typically allocates C$800,000 (US$815,744) annually to cover dam operating costs. The funding in this category is non-discretionary as it is required to meet the water level demands for recreational use communicated by the public and dam safety requirements during extreme floods.

For capital plan development, C$1.8 million (US$1.83 million) - C$1 million (US$1.02 million) for dam safety support, plus C$800,000 (US$815,744) for dam operations - is required every year as non-discretionary funding. In addition, major capital funding is required on an annual basis to ensure the long-term safety and utility of MNR's dams. The extent of the major capital funding required was evaluated using the DAMP tool.

MNR dam management

For DSAs, the primary criterion for selecting the structures to be assessed was a risk profile of the dams in terms of the consequences of accidental dam failure due to unforeseen floods or earthquakes or due to inadequate original design or ongoing maintenance. As part of the DSA preparation process, all of these factors were evaluated to determine the features and conditions of the present infrastructure (at the time of the individual DSAs) that were acceptable and unacceptable to MNR in terms of regulatory compliance with applicable dam safety standards.

Whenever unacceptable dam characteristics have been identified, MNR has dealt with them to the extent that available funding permitted such work to be completed. Nevertheless, unacceptable features have remained in some cases, either because sufficient funding was not available or because a subjective evaluation determined that the immediate risks to the public, the environment and the economy were acceptable.

In 2007, MNR determined this subjective evaluation of risk was not adequate and embarked on a program to develop a more consistent and objective approach to dam safety risk assessment. In 2008 and 2009, as a first step in this program, MNR developed an RBPS to help determine the risk profiles of the dams. RBPS evaluates risk to people (both dam operators and the general public), the environment and other infrastructure of economic and cultural importance, including downstream roads, bridges, residential housing, hospitals, schools and historic buildings.

In the initial development and related study performed in 2008 to 2009 by Hatch Ltd. in conjunction with MNR, RBPS was applied to 43 dams identified by MNR as warranting an early evaluation. In the present study, the RBPS methodology has been applied to the remaining 133 dams for which there are sufficient data to do an evaluation. The results of the RBPS analyses form the basis for a significant portion of the funding needed for MNR to remain in compliance with its own regulatory requirements.

Establishing DAMP

In response to a request from the Ontario Ministry of Infrastructure in 2010, MNR embarked on a process of developing a formal DAMP for its dams. DAMP is a tool MNR can use for comprehensive, all-inclusive, consistent and logical management of its dam assets. Initially, the goal was to develop a DAMP for the next 30 years; however, the DAMP that has been developed as part of the present contract is a living document/plan that will be continually updated using TCPS, a sophisticated data management tool developed by Altus Capital Planning (now VFA Canada Corporation) for the purpose of managing any type of asset.

DAMP was developed by combining TCPS with a second tool designed by Hatch to factor MNR's core objectives into the decision-making process. This tool, known as the KPI module, calculates key performance indicators (KPIs) that reflect the relative value of each dam in supporting MNR's three main objectives discussed previously.

Data collection/compilation

Development of the asset management plan required solid supporting data to assess priorities for funding allocation.

The primary goal of the project was to develop the process for evaluating and prioritizing spending requirements, not to focus on data collection. Therefore, reasonable efforts were made to obtain as much data as possible from existing sources, with the expectation that refinements and data additions would be made over time.

Data were collected from MNR's Microsoft Access database, RBPS, dam safety assessments, and questionnaires directed to MNR staff in the regional and district office throughout the province. These MNR staff members were identified as having directly relevant experience with the dam structures. All of the data was then combined and analyzed as a whole.

Key performance indicators

For each of MNR's provincial objectives, a key indicator was selected to reflect the relative importance of each dam in meeting the objective. These indicators are described below.

Public safety

Public safety was addressed using the RBPS that was developed based on extensive previous work by the Reclamation. The Reclamation methodology was adapted and modified to suit MNR dams, which cover a much smaller range of types and sizes. RBPS uses extensive, dam-specific data as input, such as age and condition, materials and type of construction, spill capacity, foundation and stability data, hydrologic characteristics and more.

This information is useful in determining safety rankings and the worst case loading condition that would trigger dam failure and the most severe consequences that would result, as well as an index to determine the risk and severity of failure.

MNR has used results from application of RBPS to assess each dam in terms of classical probability versus consequence plots so that MNR could determine which of its dams were of greatest concern and which warranted funding to protect provincial interests. The total failure index (TFI) was chosen as the key parameter of interest for evaluation purposes. TFI is built up using physical characteristics and assessments of the dam. These data include age, composition, type of construction, foundation material, overall condition and stability (see Figure 1 on page 32).

The design of the TFI calculation is such that the total range is 0 to 1,000. Many dams with TFI values of 25 or less are very small structures that have not been deemed important enough to warrant having dam safety assessments completed. A project is under way to evaluate these structures in more detail.

However, TFI does not tell the whole story by itself, because it gives a sense only of the likelihood that a dam will fail, with no indication of the magnitude of the potential consequences. To fill this gap, the hazard potential classification (HPC) of the dam was also included, as shown in Figure 2 (see page 36).

Economic benefits

To reflect the value of each dam in supporting provincial economic interests, an economic ranking index was developed. It is calculated by assigning a ranking score to various parameters based on the responses to a series of questions about the number and value of houses, hotels, and other living spaces on the reservoir; the importance of the reservoir in terms of hydro, navigation, commercial operations, and recreational activities; and accessibility by road or boat.

Environmental/ecological value

To reflect the value of each dam in supporting provincial environmental interests, an ecologic ranking index was developed. This index is calculated by assigning a ranking score to various parameters based on responses to a series of questions about the effect of dams on fish species and populations, wildlife, and wetlands.

The ecologic parameters are then given appropriate weightings and added up to produce a single ecologic index. The design of the ecologic ranking index calculation is such that the theoretical maximum value for any dam is 10. Unlike the other two KPIs, however, the minimum value is less than 0 because the present existence of a dam might well have an overall negative environmental/ecologic impact.

Unlike economic interests - to which a dam might, at worst, make no beneficial contribution (and is assigned a score of 0) - it is possible that a dam might actually have a detrimental effect on some ecologic parameters. In such cases, a value in the range from -10 to 10 may be assigned.

To easily assess the overall value of a dam in terms of supporting provincial objectives, the economic and ecologic ranking indices have been added together to create a single index, designated briefly as E+E. Figure 1 (see page 32) shows the TFI versus E+E. This plot clearly shows there are important dams with a TFI that is too high for dam safety purposes. These dams require attention. The combined index can be used both to identify the dams having the greatest value, as well as those having the least value. The first group consists of dams to which MNR should allocate funding is shown in Table 1 (see page 40).

TCPS software platform

The TCPS software platform was used to compile and store the large amount of physical data concerning the more than 400 MNR dams. This data includes details concerning dam height, type, generating capacity, age, condition, spillway capacity, design and construction, and more.

TCPS efficiently and effectively manages the large amount of data so that it can be used for further asset management/funding assessments. TCPS elegantly addresses four different "worlds" of capital expenditure: asset renewal, asset functionality, regulatory compliance of assets and strategic use of assets.

TCPS essentially addresses questions that are directly important for asset sustainability, such as the conditions of the assets, corrective actions needed, and costs of the improvements.

However, because of the specialized nature of the MNR dam assets, it was also necessary to address MNR's KPIs as previously discussed.

Development of DAMP

The MNR DAMP is undergoing study and assessment within the overall context of budget plans for the Ontario government. The plan has not yet been approved, and it seems likely changes will be required because of ongoing fiscal austerity measures being implemented in the province. The provincial government has been prorogued until February 2013, so approval and further implementation of DAMP are on hold. For this reason, specific details of the plan, including project names and funding scenarios, are not disclosed. Nevertheless, the process that was used can be described.

Six key funding areas were addressed: ongoing normal annual maintenance; ongoing annual dam safety support; information management; major capital spending for new dams and replacement of severely deteriorated dams; major capital spending for major maintenance/rehabilitation of existing dams; and dam removal/decommissioning/divestment for dams that do not contribute significantly to MNR's three core business goals.

At the present time, there is a large backlog of work that needs to be done with respect to dam replacements and major rehabilitation. This major rehab work generally includes structural measures such as concrete repair and anchoring and spillway capacity increases. As well, there are many dams that do not meet MNR's core business goals and that should be removed, decommissioned or divested. This is being assessed in more detail using the information contained within the DAMP.

Turning data into dollars

Following assessment of all of the funding requirements, it was possible to develop a proposed schedule of recapitalization funding that would adequately address MNR's three core business goals. Figure 1 (see page 32) shows an ongoing capital backlog where available funding is not adequate to properly look after the asset base. Unfortunately, this is not an unusual situation.

An asset management plan has been developed that outlines the funding requirements for adequately managing the province's dam assets. This plan is being evaluated by the Ontario Ministry of Infrastructure in conjunction with similar plans for other provincial assets such as hospitals, roads and bridges. It remains to be seen if the allocated funds will adequately address the outstanding asset management requirements.

DAMP has resulted in the efficient, effective and safe management of MNR's dam assets, and it will continue to evolve and change based on ongoing condition assessments and inevitably shifting government budget allocations. As the program is fine-tuned, MNR believes it will provide continual support to the decision-making processes faced by the government and dam owners and operators, as well as offering a model for other governments and organizations to replicate.

David Judge is senior project manager and Hugh Cook is water resources engineer at Hatch Ltd. Allan Chow is engineering services supervisor, Northwest and Northeast Regions, with the Ontario Ministry of Natural Resources.

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