Tucked into the southwest coast of Florida, the beauty of Charlotte Harbor has drawn countless people to its shores. A regional effort is underway to improve and protect this crucial natural resource which impacts ecosystems, fisheries, marine and wildlife habitats, beaches, coastal wetlands, our tourism industry, home values, and overall quality of life. As a part of this effort, Charlotte County developed the Blue Water Strategy to ensure and sustain the quality of natural water resources to protect and provide a safe water supply, a recreational haven and an environmental resource. The Blue Water Strategy consists of four key components: wastewater, reclaimed water, stormwater, and drinking water.
As a part of the Blue Water Strategy, the County enlisted Jones Edmunds to prepare the county-wide sewer master plan. Studies found that aging septic tanks drain into nearby waterways, contributing to water quality issues that can impact this resource. To improve the harbor’s water quality, Charlotte County plans to replace about 25,000 septic tanks with an affordable, reliable, and efficient wastewater collection and treatment system. We prioritized neighborhoods to convert the oldest septic systems near waterways first and developed a plan to help connect 14 neighborhoods to centralized wastewater system during the first 5-year phase to lower nitrogen loads. We were also tasked with identifying wastewater transmission and treatment facility improvements or expansions that would be needed to provide reliable service to the County’s growing population. The Geographic Information System-based models we developed provided data and cost-estimating tools for prioritizing the work.
Gainesville Regional Utilities (GRU) has historically invested significant resources to evaluate and reduce I&I sources but recognized the need for a more programmatic approach for prioritizing rehabilitation and replacement efforts. GRU provides wastewater service to approximately 200,000 people. The GRU wastewater collection system includes over 1,100 miles of piping, 15,500 manholes, 170 lift stations, and 65,000 customer connections.
Recognizing that GRU has excellent technical staff with great institutional knowledge of their system and many lessons learned about what works best for their system and staff, we developed the I&I Reduction Program in a highly collaborative process with them. A decision we made collectively at the beginning of the project was to use an early-out area to go through the tasks that GRU would perform on an annual basis after our team had developed the Program as a way to make refinements and fill data gaps prior to going into a full-scale production. By completing the field investigations, including flow monitoring, smoke testing, manhole inspections, and night-time flow isolation in the early-out area, the Program team was able to determine processes that can best be used moving forward in other parts of the system, with lessons learned being applied.
One of the next major elements of the project was converting lift stations runtimes to flow hydrographs for the most recent two years of data for approximately 170 lift stations. We then compared the hydrographs to NEXRAD rainfall and quantified dry- and wet-season groundwater infiltration, base wastewater flow, and rainfall-dependent I&I. This analysis allowed us to prioritize the lift station basins for field investigation based on where the biggest return would be for the rehabilitation effort at a cost that was significantly less that flow monitoring. Results were corroborated with 10 permanent meter locations, metered winter water use, and known problems at lift stations. We then used short-term flow monitoring in some of the larger basins to further identify specific locations that are most in need of rehabilitation for I&I flow reduction, using other data to also evaluate structural integrity and risk of failure. The Program is set up to have rolling priorities set 2-3 years in advance for field investigation – followed by targeted rehabilitation – so that each step can be properly planned and budgeted.
The Program team also developed level-of-service (LOS) criteria that consider the unique challenges that GRU faces, including being more influenced by groundwater infiltration than by rainfall-derived I&I. The LOS criteria are tied to key performance indicators (KPI), with assumptions, methods of measurement, frequency of measurement, regulatory and internal drivers, influencing factors, and potential solutions identified for each KPI. We also performed an economic analysis to determine at what point conveyance and treatment is more cost-effective than rehabilitation, understanding that the collection system degradation is an ongoing process. The economic analysis was also used to refine the LOS criteria to ensure that the criteria are affordable.
Jones Edmunds understands the technical details, but also the bigger picture of regulatory drivers and funding required to meet wastewater collection, treatment, and disposal needs. Our technical team understands wastewater as an integral part of our integrated water resource. Our wastewater services fit into a whole spectrum of planning, designing, and implementing infrastructure for current and future environmental requirements and water needs. Our clients have a better understanding of how to develop long-term wastewater strategies to protect environmental water quality. We offer the following services: