Building A Masterplan Through Thousands Of Field Inspections

BACKGROUND
In conjunction with the City of Fort Collins Utilities (FCU), Ditesco Project and Construction Services compiled a master plan for the water distribution and wastewater collection systems across FCU's service areas. This master plan provided FCU a better understanding of the conditions of the water and wastewater infrastructure across their service area. After extensive field data collection, updates were conducted and specific work tasks were completed, including: ● Updating and evaluating future condition model scenarios for the water distribution system hydraulic model. ● Updating and evaluating future condition model scenarios for the wastewater collection system, and developing tools to assist in project prioritization and analysis. The water and wastewater master plan effort spanned 18 months, including the collection of condition data surrounding both systems and updates that were unique to the City's goals. With an intention to have the system efficiently perform in a reliable and redundant manner to avoid service interruptions, a master plan with these mission elements was developed.
OBJECTIVES
—Develop a plan to provide reliable and resilient service meeting community expectations.—Provide utility service that addresses growth, urban density and land use changes.— Assess the condition of the existing infrastructure.— Recommend and prioritize system-wide upgrades.— Assess service to critical facilities.— Identify future Utility identifying regulation changes, trends and new technologies.
METHODOLOGY
In correspondence with FCU's mission, Ditesco developed a process in which they could prioritize the capital improvement projects within the given timeframe. The team completed field investigations and once the data had been analyzed, the water and wastewater system models were developed. Simultaneously while analyzing the data, a list of recommended projects was developed, including the systems that were in most need of repairs and those needing to be upsized.
CURRENT MASTERPLAN STATUS
After being provided the masterplan, FCU approved the identified list of capital improvement projects for future construction. Following completion of the master plan, multiple projects, from the masterplan project list, have been completed. Water and sewer line replacements, mainly focused in the oldest parts of the City, are continuing to take place. As work is completed, and FCU completes further inspections, the model will be updated to display the changes in status.
FINDINGS
Within the 18-month timeframe, the water model was updated and refined to include the latest AMI demand conditions. The wastewater model was enhanced through use of over 2,000 actual field manhole rim and invert data. Through collection of condition assessment data, modeling and research, over 215 capital improvement projects were developed, best practices were recommended, and a decision analysis tool was created. The results of this effort culminated in the following overarching conclusions: Water ● 13% of the water distribution system was over 60 years old. This age has translated into 5% of the system being categorized as Poor or Very Poor condition. ● Available fire flow, as calculated by the hydraulic model, in downtown Fort Collins is predicted higher than what was actually available. This was due to the model's inability to predict pipe tuberculation and, therefore, a reduction in flow. ● Redundancy projects related to singular service pipelines should be prioritized. ● Water age throughout the distribution system is generally acceptable. Various portions of consecutive systems showed higher age during low demand. FCU's system had small areas of high-water age near the southeast end of the City. Sewer ● 9% of the wastewater collection system was over 60 years old. This age has translated into 5.2% of the system being categorized as Poor or Very Poor condition. ● Inflow and Infiltration continues to plague the collection system and contributes as much as 6 MGD to the wastewater treatment plants during high runoff events. ● Redundancy projects for siphons and sensitive river crossing areas should be further evaluated and prioritized. ● Capacity evaluation along trunk and lateral lines should be further evaluated as the hydraulic model is developed. FCU, overall, does a very good job at operating and maintaining the water distribution system. Programs such as the pipeline replacement, leak detection, backflow prevention, water quality monitoring, modeling and flushing are all very successful. Operations staff began to participate in the AWWA Partnership for Safe Water (PSW) in 2015 (for distribution systems) and has participated in the water treatment PSW program since 1997. Capital improvement projects were identified through the Decision Support Tool and modeling efforts. 131 individual projects were identified that encompass pipelines to be replaced based on condition, fire flow needs, looping and capacity. The overall capital project need is approximately $192,000,000 in value, measured in 2018 dollars. Overall water distribution system condition is shown in Figure 1. FCU does a very good job at operating and maintaining the wastewater collection system. Programs such as CIPP, manhole degreaser, pipeline replacement, cleaning and jetting and modeling are all successful. Recommendations developed as part of this master planning effort are meant to further FCU's goals to achieve excellence in operations and maintenance of its wastewater collection system infrastructure. All recommendations provided will further these goals as well as others noted in this master plan including reduction of inflow and infiltration, control of grease and hydraulic system upgrades. Capital improvement projects were identified through the Decision Support Tool and modeling efforts. 88 individual projects were identified that encompass pipelines to be replaced based on condition and hydraulic constraints. Of the over 2,000 manholes surveyed, 46 manholes were identified for immediate maintenance and repair. The overall capital project need is approximately $98,800,000 in value, measured in 2018 dollars. The overall wastewater collection system condition is shown in Figure 2.
SIGNIFICANCE
FCU and Ditesco were able to work together to complete many hours of field inspections. The data from these inspections were inputted directly into a GIS database on-location, using computer tablets. By utilizing tablets, a vast amount of time was saved, in addition to increasing the accuracy of field conditions. The GIS data is now available for FCU to use and update at any time. The model compiled from this data now represents an accurate portrayal of the exiting layout and conditions compared to previously used field maps. The projects created from this will allow FCU to continually address capital projects based on priority, criticality and condition, calculate future expansion, and stay within annual budgets.