City of Scottsdale,
Asset and Capacity Management Program and Integrated Master Plan
- Asset management plan
- Water resources evaluation
- Capacity management program
- Distribution and collection system planning
- Integrated water and wastewater master plan
The City of Scottsdale is currently planning for buildout around the year 2020. As a result, new growth and development in the City’s planning area has generally been identified resulting in minimal water and wastewater related expansion projects remaining in future Capital Improvement Project (CIP) plans. The City’s desire to prioritize these capital improvement projects resulted in the need for this project, which is based on the following primary objectives:
- Assist the City in its desire to enhance its business operations by expanding the scope of its current asset management system, including the development of an overall “roadmap” for expanding into a comprehensive asset management program (AMP). The overall AMP will include asset inventory and condition assessments, followed by CIP prioritization and financial analyses.
- Update the existing water and wastewater system hydraulic models using a GIS framework for developing demand and load projections on a land use basis, in order to evaluate infrastructure needs and deficiencies for redevelopment, revitalization, and infill to buildout conditions.
- Develop an evaluation tool to provide for the reliability of the water systems during times of drought or other emergencies in coordination with ongoing Vulnerability Assessment (VA) efforts by others.
As the City of Scottsdale nears buildout, the Water Resources Department is shifting from an expansion-oriented organization to one that focuses on the maintenance and preservation of existing assets. Carollo developed an AMP intended to provide the City with a “roadmap” for the maintenance and replacement of system assets, while balancing level of service objectives with financial optimization and risk management.
A successful AMP provides the framework for the City to maximize capital investments and the use of resources, whether monetary or personnel related. Tracking asset condition and the risk associated with an asset’s failure, or degradation, allows the Department to optimize the investment in its water and wastewater system and meet its level of service objectives. The program also provides the Department with a mechanism to demonstrate to stakeholders and managers that utility assets are being adequately maintained at acceptable levels of risk. Further, this program aids the Department in gaining buy-in for capital investments by more clearly communicating needs. In total, the AMP is an assessment, optimization, planning, and communications tool. The AMP is intended to be a long-term, dynamic program that will span the full activities of the Water Services Department.
Phase 1 of the overall AMP was completed using the following tasks:
- Strategic Vision. The first step was to define the vision, which provides a general understanding of the Department’s need, gain commitment from all levels of the organization, and establish clear goals and objectives. This was accomplished through a series of interviews and workshops.
- Asset Guidelines. Once the objectives and best practices for cost-oriented asset management are in place, it is important to continually evaluate the progress of the program. A key component of an AMP is to define “performance metrics” that track and measure progress in attaining specific objectives.
- Data Needs Assessment. Many sources of data were evaluated, including static asset data, conditional assessment data, maintenance data, operations data, computer modeling, and staff knowledge.
Phase 2 of the overall AMP focuses on the inventory of assets and their associated condition assessments through desktop analyses, computer modeling, and field assessments. The primary objective of the AMP is to optimize costs while providing a chosen level of service at an acceptable level of risk. Risk is defined as a product of the asset condition, or its “vulnerability,” and the criticality of that asset in providing water or wastewater service.
- Asset Inventory. The inventory of a number of above-ground (vertical) and below-grade (linear) assets was performed through a review of existing information, supplemental staff interviews, development of asset classification system, customization of the asset management software, and preparation of the software for the subsequent condition assessments. This effort utilized Carollo’s Water/Wastewater Asset Manager™ (WAM) software. The overall intent of the inventory process is to determine asset criticality. The criticality evaluations focus on four criteria – public health and safety, effect on customers, environmental impacts, and the cost of repair.
- Condition Assessments. Condition assessments for vertical assets included field evaluation by a multidiscipline engineering team to determine the overall vulnerability of the asset and its remaining useful service and economic life. For the linear assets, the assessment strategy included initial desktop assessments to determine groupings, criticality and vulnerability; preliminary risk calculations resulting from asset failure and subsequent cost assessment; and supplemental field inspections (manhole inspections, pipeline CCTV, pipeline coupon testing, etc.). These efforts are being completed in close coordination with City staff.
- Asset Replacement Costs. Utilizing and evaluating the existing financial information, including historical costs, year of installation, and original ENR indices, the current and replacement costs for each asset will be developed and populated into the asset management software and database.
Phase 3 of the overall AMP will focus on project prioritization and financial analysis. Based on the outcome of Phases 1 and 2, this phase will provide the City with an approach for prioritizing projects, considering the needs for funding between water and wastewater, as well as between treatment and operations.
- Project Prioritization. This effort focuses on establishment of metrics and drivers needed to implement a renewal or replacement project, including regulatory drivers, costs and level of service goals for the given asset; establishment of ranking criteria for project prioritization on a system-wide basis, including timing for implementation and risk of failure; and development of decision flow diagrams to evaluate which projects should be included in the CIP, providing a clear process for determining what information is needed to optimize the annual CIP process.
- Financial Analysis. This effort focuses on conducting a financial analysis to evaluate the effects of recommended CIP on water and sewer rates and fees, coverage ratios, and reserve funds. The analysis will allow the City to run “what if” scenarios regarding capital costs, project timing, asset replacement options, and other significant variables.
- Development of CIP Guidelines. This effort identifies the decisions to be made to evaluate and optimize the annual CIP process, including development of a schedule and the roles and responsibilities of the different groups involved. It also identifies the analytical tools needed to evaluate and implement the CIP to perform cost/benefit and risk/return analyses of the potential projects.
With the City approaching buildout within the next 10 to 15 years, the need to perform updates to both the water and wastewater (sewer) master plans was identified. The primary purpose of these master plan updates is to identify both water and sewer capital improvements needed to serve the City through buildout. In addition to infill of the City service areas, redevelopment is planned for some of the downtown areas and other high traffic corridors. This redevelopment is anticipated to result in high-rise buildings that have greater water and wastewater requirements than the existing buildings.
- Planning Framework. Carollo initially focused on the planning framework, consisting of identifying the demand and load projections and the criteria used to evaluate the adequacy of the water and wastewater infrastructure. Development of the projections was performed using a GIS framework on a land use basis. The land use plan utilizes land use types, growth rates, population densities, and ultimate service areas that apply to both water and wastewater systems. Water unit demands were developed from customer billing records and water production information. Wastewater unit projections were developed from flow meter data from the last calibration. Peak wet weather flow projections were based on estimated infiltration and inflow (I/I) projections. Performance criteria was also developed as the standard against which the systems are evaluated, including deficiencies in the existing system and future infrastructure sizing.
- Water Master Plan Update. The H2ONET modeling software used for the City’s water distribution system extended period simulation (EPS) model was updated and recalibrated for 2006 demand conditions. Using the land use plan and demand projections, the future demands were applied to the model to determine water infrastructure needs and deficiencies. The water infrastructure was tested under maximum day, peak hour, average day, and fire flow demand conditions.
- Wastewater Master Plan Update. The H2ONET Map sewer modeling software was purchased and used to convert the existing sewer collection system model, including the use of sewer flow monitoring from March of 2006 for calibration and model validation. Using the land use plan and flow projections, the model was used to determine sewer infrastructure needs and deficiencies. The model was tested under annual average day, peak dry weather, and peak wet weather flow conditions.
- Near-Term Emergency/Contingency Modeling. As a supplemental task to the water distribution system modeling efforts, Carollo developed a “near-term emergency/contingency model” for the City to utilize as a system vulnerability planning tool. The supply scheme for the City’s water system consists of SRP and CAP surface water (two separate water treatment plants) and a number of well clusters throughout the City. The planning tool model allows the City to simulate a number of supply scenarios such as limited WTP production or water quality limitations in various wells, and to quickly assess capacity and pressure requirements throughout the overall system as a result of the varying conditions.