The First Fruits of the Metropolitan Utilities District's Digital Transformation

Background The Metropolitan Utilities District (District) provides potable water and gas service to approximately 600,000 people in the Omaha, Nebraska, metropolitan area. Omaha is experiencing robust growth and redevelopment, which is leading to expansion of the City of Omaha's (City's) service areas, as well as significant redevelopment and infill within the City's core. Despite serving a large customer base in a growing community, the District did not have a complete water system hydraulic model and has not had a full system Master Plan for at least 30 years. The District's existing water system contains the following: - 218,000 connected customers - Over 3,000 miles of water mains - 11 pressure zones - 3 water treatment plants - 6 storage reservoirs - 17 pump stations Methodology Step 1 — Transition to GIS The District started their digital transformation in 2008 through the conversion of legacy MicroStation foreman pages into an ESRI geodatabase. The District also developed a process to digitize new facilities into the geographic information system (GIS) database. Then, the District worked to digitize over 15,000 paper leak reports into GIS and Computerized Maintenance Management System (CMMS) to be used for subsequent analyses. This conversion of physical assets into a digital environment laid the groundwork for creation of a hydraulic model and subsequent risk model for linear assets. Step 2 — Build and Calibrate Hydraulic Model and Develop GIS Gateway In 2019, the District wanted to leverage their existing GIS data to develop a water system hydraulic model of their entire distribution system. An initial review of the GIS database yielded a high number of network exceptions and inconsistencies for model import. The most significant were as follows: 1.There was no unique identifier in the GIS database for hydraulic model facilities. 2.There were over 65,000 network disconnects and snapping errors in the water main dataset. 3.The digitization direction around valve and pump features was invalid. EPANET software requires digitization direction around valves and pumps to be 'one in and one out' and to align with the correct direction of flow. 4. Duplicate point features and overlapping line features were identified. Following a comprehensive data reconciliation effort, the final GIS dataset was imported into an InfoWater Pro hydraulic model using the GIS Gateway tool. The final model included 104,000 pipelines and 96,000 junction nodes. A zone isolation analysis was performed to ensure proper pressure zone separation. The model was then calibrated through a series of 30 fire hydrant flow tests to adjust roughness coefficients and boundary-level model conditions until the model was calibrated within AWWA M32 guidelines. Step 3 — Leverage Available Data to Build Risk Model for Water Mains To help maintain the same high level of service amid the expansion and redevelopment, and to help promote water main renewal needs with the City's Public Works project priorities (streets, combined/sanitary and storm sewer), the District recently completed a data-driven, risk-based analysis that will allow the utility to: - manage aging water distribution system assets more cost-effectively; - prioritize asset replacement based on risk; - determine the right investment level to balance cost with level of service; - balance the District's priorities (water main replacements) with the City's priorities (including street and sewer). The District completed an analysis of main break history to assess the likelihood of failure for each pipeline asset. The District assessed the consequence of failure using WaterGEMS to model the hydraulic criticality of each pipe in the water system, measuring the number of customers out of service, the number of critical customers affected, and the demand not delivered as a result of a water main break. The analysis also included a GIS-based analysis to assess other consequence of failure factors, such as cost, potential damage, and community impact. The result is a total risk score for each pipeline asset, combining the results from likelihood and consequence of failure analyses. Figure 1 shows a heat map of the project risk scores across the District's water distribution system. The WaterGEMS model was also leveraged to assess the criticality of all valves in the distribution system. Figure 2 shows the consequence of failure if this valve does not work. If this valve is required for a shutdown and does not work, it would isolate the following: 1. 5,730 feet of pipe (blue lines) 2 .55 meters 3. 4 critical meters serving the Methodist Women's Hospital If a new 12-inch valve was added on the eastern leg of the tee at North HWS Cleveland Boulevard and North 189th Street (the orange circle in Figure 2), existing system looping could be better used to keep all four critical meters in service if any shutdown was required and the yellow valve did not function. When adding a valve would protect at least 50 customers or at least one critical customer, this was characterized as a significant opportunity to cost-effectively improve resiliency. These replacements were weighted first by the number of critical meters protected and then by the number of normal meters protected. Based on this criterion, 134 valve additions were identified by the model and were delivered to client. The analysis was able to determine which valves need new valves adjacent to them to leverage redundancy already built into the system, but it was not able to pinpoint the optimum location for the valve automatically. Therefore, District staff will need to review the pipe on either side of the valve identified to determine the optimum location for a new valve or valves. Step 4 — Size Water Main Renewal Program Utilities in the United States typically underinvest in asset assessment, maintenance, and renewal, replacing just 0.4 percent of their water pipelines each year, far less than the 1.2 percent per year recommended to maintain service levels in AWWA's Buried No Longer report. When renewal needs compete with other improvement priorities, the opportunities to fund existing asset maintenance and replacement can become further limited. The District is now leveraging GIS data and hydraulic model results to 'right size' their renewal program through the following: - Integrating risk factors and weightings into risk modeling software - Implementing Innovyze's InfoAsset Planner software - Developing a water main replacement 5-year plan to better coordinate with City paving projects - Leveraging their risk model to inform and grow the District's condition assessment program - Using risk and hydraulic models to develop a robust water system master plan - Integrating vertical assets and start making more risk-informed decisions across the board Step 5 — Develop Water System Master Plan including Optimization The final step was to leverage the recently completed hydraulic model into a water system master plan that addresses growth, reliability, and resiliency through the 2050 planning horizon. The model was used to: 1. optimize the existing system to identify operational improvements based on current demands; 2. optimize the future system (2050) for operational and capital improvements; 3. develop an optimized Capital Improvement Program to address existing and future system deficiencies. Discussion and Next Steps A comprehensive data reconciliation and model build process was used to transform the District into the digital world of hydraulic modeling, but the model needs to be continuously updated, re-calibrated, and improved so that it remains a valuable evaluation tool for the District in the future. The project team continues to learn the nuances of the District's water distribution system and incorporates changes into the existing model. The model can be used to develop a standard operating procedure, to improve existing operations, and to help automate the operation of the water system. Summary and Conclusions This innovative approach is now driving a number of beneficial outcomes, including the following: - More efficiently prioritizing water main renewal projects within their system based on overall risk to better coordinate plans with street improvement work and other public works projects - Establishing investments in renewal that balances annual spending on pipe replace replacements with level of service goals. - Optimizing capital expenditures to support 2050 water demands - Efficiently evaluating the District's ability to serve other communities in region, and identifying comparative impacts on an optimized capital spending plan - Simulating planned plant and/or pump station outages to assist with operational decisions The result is a data-driven, staff-run program for that helps the District advocate for and justify capital expenditures.