A high density area undergoing rapid redevelopment in the City of Aurora (City) experienced historical flooding due to undersized stormwater infrastructure constructed in the 1970s. As a result, the City prioritized implementation of the Fitzsimmons-Peoria Stormwater Outfall Project to comply with current stormwater standards and provide much needed flood mitigation. The project was a large-scale effort that replaced approximately 15,000 feet of aging, 24- to 96-inch storm drain through a highly urbanized area that is undergoing rapid redevelopment. The project improved flood protection for approximately 230 residences and 40 businesses. Following preliminary design, Carollo assisted the City in contracting a Construction Manager at Risk (CMAR) contractor, BT Construction. Final design efforts were completed as a collaborative team consisting of the City, the CMAR contractor, and Carollo. Together, the team evaluated alternatives to mitigate site constraints throughout the project while minimizing public disruption and project cost. Carollo constructed a computer model using InfoWorks ICM with 1-D and 2-D components. Pipeline alignments were evaluated for hydraulic capacity and selected with consideration to construction sequencing, construction duration, protection of existing utilities, minimizing disruptions to traffic, and project cost. Carollo also performed HEC-RAS modeling of Sand Creek utilizing the existing published FEMA FIRM maps and base flood elevations with new flow rate inputs for the project basin. While the discharge flow rate increased significantly, the discharge time was well ahead of the peak attenuation of base flood elevations at the discharge location. Therefore, our team was able to prove a no-rise condition and avoid the need to submit a LOMR. Most of the pipeline was constructed using open trench construction with passive shoring (trench boxes). Four major arterial roadways required large diameter trenchless crossings. The variability of ground conditions required a combination of open face tunnel boring machines (TBM) for two of the tunnels and closed face microtunnel boring machine (MTBM) for the other two crossings. The project team evaluated each construction technique with consideration to cost, feasibility, safety, and minimizing public impact. The project also required large manholes and junction structures which were designed as a combination of both cast-in-place and pre-cast structures, with a preference for pre-cast to minimize construction duration where feasible. Now fully complete, the new storm drain system has the capacity to collect and convey the 100-year storm event to the discharge at Sand Creek. Using the CMAR delivery method, the City was able to develop alternatives during the design phase that improved basin stormwater management, mitigated risk, minimized public impacts, and totaled an overall cost within the Contractor's $31M Guaranteed Maximum Price.

The City of Ft. Myers contracted GHD to develop a Digital Master Plan for their drinking water, wastewater, and reuse systems. The goal of the Team was to identify projects prioritized by risk, condition, and capacity in the Capital Improvement Program (CIP). The development of the CIP differed from a typical Master Plan because it used the EPA Asset Management framework to determine the best blend of investment into maintenance, operations, and capital projects to sustain performance while minimizing lifecycle costs at an acceptable level of risk. The plan was leveraged through a cloud-based decision-making platform by integrating the available tools, processes, and information to make informed decisions, and is designed to inform data driven decision support quickly without ambiguity. Master Planning is an important component of any municipality's program to meet future needs. This 'roadmap' is designed for short-, medium- and long-term planning horizons for future growth, water supply, wastewater management and water reuse. Tasks to help the City improve investment decisions and have more information available on their assets included developing an asset hierarchy, risk framework, risk analysis, and project prioritization for linear assets. The approach to the Capital Improvement Planning task was using age and capacity as failure mode triggers in risk calculations to develop projects and determining project prioritization. Typically, master plans provide a static presentation of future conditions. However, for the City, a dynamic plan was developed by prioritizing projects using management strategies that included a combination of capacity, risk and condition. Priority Level 1 and 2 are given the highest priority (replacement as the intervention strategy) since capacity deficiencies is considered the imminent failure mode. Priority levels 3 to 5 (Rehabilitation/Monitoring as the intervention strategy) are purely based on condition of the asset and has been divided according to the core-risk scores. The intervention strategies for assets are updated dynamically through the cloud-based decision-making system considering the uncertainty and change that occurs over time to reduce inefficiencies and shortcomings of planning for a static predicted future. Project prioritization based on the core risk scores and the improvements proposed through hydraulic modeling for each planning horizon can be visualized in a digital format for ease of presentation and use. As new data are available; these models are changed so the City can have better insight of their system and the investments needed to maintain their service to their customers. This digitized plan using risk-based approach provides a positive return on investment, reduces operating costs, and lowers asset failure risk. The platform greatly enhanced knowledge of the City's linear assets with respect to knowing the remaining useful life and relative Consequence of Failure (CoF). The outcome is a future state structured for continued successes in meeting future needs and challenges. The presentation will illustrate with a demonstration of the application of the framework, explain why it is important to plan for uncertainty, and provide the benefits of digital plan. Using this approach and technology will enable municipalities create robust and flexible long-term strategies that will also employ the best use of municipal dollars.

The rural communities and small towns of Virginia's Eastern Shore have traditionally utilized septic systems for their wastewater treatment needs. With the regions notoriously high water tables and corrosive soil conditions, these systems can often leak and fail over time. To limit groundwater contamination and improve the regions wastewater treatment systems, the Hampton Roads Sanitation District (HRSD) has recently completed a regional small community collection system on the Eastern Shore. This extensive design-build construction project included the installation of over 30 miles of 4-inch through 12-inch sewer force mains, over 50 horizontal directional drills (HDD), complex hydraulic modeling, construction of 5 new pump stations, modifications to 3 other stations and complex environmental / historical permitting and research. This project conveys sewer flows from numerous small towns to the regional HRSD Wastewater Treatment Plant, where the water will be properly treated with modern technology before being discharged to coastal waters. Through this project and other local efforts, the picturesque towns of Wachapreague, Onancock and Exmore have been updating their sewer systems from old septic tank technology to modern collection systems including hundreds of grinder pumps and low-pressure force mains. As most of the region still utilizes well water for their drinking water supply, this project not only will improve each resident's sewer treatment, it will improve drinking water quality by eliminating the risks and impacts of leaking septic systems. By improving coastal groundwaters and improving sewer treatment effluent, the project will have regional and even national impact through its positive effects to the regional coastal aquaculture and most importantly the world-famous Chesapeake Bay crab, oyster and clam populations. The coastal nature of this broad project made for some challenging engineering and construction. The water table was essentially at the ground surface which complicated excavation and pump station wet well designs. The regions narrow roadways are maintained by the Virgina Department of Transportation (VDOT) which required the collection system piping to be primarily installed via HDD. The area is also subject to regular hurricane and nor-easter flooding, which required significant flood protections and storm hardening for the new infrastructure. These new Eastern Shore facilities will greatly benefit the regions residents, tourists, farmers, fisherman and anyone in the County who enjoys its world-famous Chesapeake Bay crab cakes, steamed clams or oysters on the half shell. This presentation will be of great interest to all small communities, Coastal communities, rural Counties, utility owners of any size and any contractor or engineer interested in the design-build process and the complex coordination between stakeholders that such projects require.

The objectives of the MacArthur Lake Stormwater Capture Project (Project) are to contribute to regulatory compliance for the Ballona Creek Watershed by treating both dry and wet weather flows from 200 acres of urban watershed in a disadvantaged community in downtown Los Angeles. In addition to water quality benefits, the Project will offset potable water use with treated stormwater, provide water supply benefits through water recycling, and increase the recreational value of the park with a terraced water feature and educational signage. The Project will also aesthetically enhance the Park with a new pedestrian bridge designed in alignment with the park's existing Art Deco style features. The Project was first identified as one of the top 10 One Water integration opportunities in the One Water LA 2040 Plan because it requires multi-agency collaboration and closes the urban water cycle with a variety of water quality, water supply and community benefits. Extensive community engagement efforts conducted during the One Water LA 2040 Plan contributed to broad support for Measure W, a parcel tax to fund the design, construction, and operation/maintenance of stormwater projects in LA County. Since its passing in 2018, Measure W now generates $300 M/year to fund LA County's Safe Clean Water Program (SCWP) projects. This Project received funding in the first round of applications through a competitive process, and is planned for construction in 2026: it is anticipated to become the second of more than 150 SCWP projects to be implemented. Combined with the historic nature of MacArthur Park, the Project has high visibility and is primed to function as a role-model stormwater project. The Project Final Design is currently undergoing final reviews by the City of Los Angeles and is expected to go out to Bid in mid-2025, with Construction anticipated to start in early 2026. This presentation will include an overview of One Water LA and the SCWP, a summary of the Project's design components, and valuable lessons learned during the planning, preliminary design, final design, and CEQA process, such as: - Right-sizing of the stormwater infrastructure to maximize water quality benefits for both dry and wet weather conditions. - Early involvement and close collaboration between LA Sanitation (LASAN), Recreation and Parks (RAP), Bureau of Engineering (BOE), and Los Angeles Department of Water & Power (LADWP) from the start of the feasibility study through final design. - Early and meaningful community engagement with a local non-profit to build community support, employing creative outreach strategies, such as a telenovela with professional actors to educate the community on the project benefits in English and Spanish. - Special design considerations to minimize community impacts to the unhoused community in the Park, local businesses (street vendors), the Park's recreational functionality, and (public) transportation impacts. The presentation will also highlight how the original project concept idea evolved from the One Water LA 2040 Plan to the Project's 2019 Feasibility Study, and the subsequent preliminary design and final design phases. Modifications made to deliver a design that meets the SCWP's regulatory water quality objectives while also enhancing the Park and maximizing community benefits will provide practical ideas for the audience to implement in their own multi-benefit stormwater and One Water projects.

After a deficiency was experienced in one of their lift stations, the North Texas Municipal Water District requested for their wastewater system meters to be evaluated for accuracy and functionality for 141 of their billing meters, of which 90 were for billing purposes. The goal of the evaluation was to evaluate the accuracy and functionality of the existing meters. Using data recorded at five-minute increments from January 2022 to March 2024, meter downtime analysis, flow balances, and comparisons with billing data were conducted. Wastewater systems use meters to record flow rates of wastewater flowing throughout to determine how much to bill customers. If meters are calibrated accurately and placed in strategic locations, a clear picture on how the system cascades can be painted. If not, unmetered flows from undeterminable sources occur leading to potentially inaccurate billing of customers. A combination of statistical methods was employed to assess the accuracy of each meter. First, flow data was compiled using Python scripts to organize data for easier processing in the future and graph raw data and calculate daily averages. Daily averages were calculated using a rolling 24-hour sum to eliminate noisy data. Next, the meter data and monthly billing data were graphically compared and triaged into layers of severity based on discrepancies noticed. The severities ranged from a few months of no readings or spikes to obvious magnitude differences, with highest severity noticed in meters that were not metering over the two years of data. By triaging the meters, the municipality would know which meters to target first for maintenance and which to ignore in an efficient manner. Then, a meter downtime analysis was conducted to determine which meter would need to be properly calibrated or replaced. The percentage of how often the meter was down, which was determined by a threshold decided upon after manually inspecting the data, was calculated and used to highlight meters that needed maintenance or replacement. Finally, a flow balance of the system was conducted. Three general cases were identified. The ideal case was when the basin is under metered by around a 10% to 20% margin due to inflow and infiltration in the gravity mains. The other two cases were over metering and under metering. Over metering was noticeably caused by possible double counting by meters near a treatment plant or inaccurate metering and warranted a recalibration if the problems occurred more recently or replacement if it had been a constant issue. Under metering was noticeably caused by unmetered residential flows in between meters, significant down time, which was verified by the meter downtime analysis, or inaccurate metering which warranted a recalibration, replacement, or relocation of a meter. The presentation is intended to inform the methods on processing and assessing data from existing flow meters to assist a municipality in managing their assets.

This paper presents a sedimentation risk evaluation via modeling for a sanitary sewer siphon system design project in Carrollton, Texas and Farmers Branch, Texas, suburbs of Dallas, Texas. The audience will learn about selecting dry and wet weather hydraulic conditions to use for evaluating sediment, how to use modeling to proactively identify the predicted locations and severity of sedimentation risks to assist designers and utilities to select design alternatives, predict sedimentation accumulation, and incorporate sedimentation control and maintenance strategies during the design phases. The Trinity River Authority (TRA) of Texas is the largest water and wastewater service wholesale provider in Texas. TRA is in the process of developing rehabilitation and replacement plans for portions of its Central Regional Wastewater System (CRWS) Elm Fork Interceptor. The project involves the design of three channel crossings. For the crossing at Cooks Branch (Figures 1 and 2 ) in the City of Carrollton, the proposed crossing is an inverted siphon (hereafter, 'siphon') with parallel 42-inch and 66-inch pipes (Figures 3 and 4). There is a proposed weir upstream of the 66-inch barrel, so it only conveys the wet weather flow (WWF), and the dry weather flow (DWF) will only pass through the 42-inch pipe. The siphon is sized to convey projected 2070 future peak WWF during a 5-year design storm. Since the DWF is much lower than the WWF, the designers and TRA had concerns about sedimentation issues in the siphon at low-flow velocities. TRA has a hydrologic and hydraulic model in Autodesk InfoWorks ICM. The model can perform DWF and WWF projections and hydraulic grade line simulations of the collection systems for existing and design conditions. It was proposed to use ICM's water quality module to analyze sediment fate and transport for the siphon system. The Ackers-White method is chosen for the Erosion / Deposition Model. ICM can simulate two sediment fractions independently, but only one fraction (SF1) was used for this analysis, assuming the suspended solids particle size compositions and settling characteristics have no significant variations that warrant refined differentiations. The solids size is based on the average sediment particle size parameter of d50. Based on literature references, average and high sediment parameter values for particle sizes d50, concentrations, specific gravity and settling velocity were used for the evaluation (Table 1). The high sediment parameters represent high risks of sedimentation accumulation for the worst conditions. Long-term historical rainfalls were used for WWF projection as it occurred in the area and are expected to repeat in the future. Historical annual rainfall data (1899-2023) from the Dallas/Fort Worth (DFW) International Airport weather station was collected from NOAA's National Weather Service website and statistically analyzed (Figure 5). The lowest annual rainfall is 17.91 inches in 1921. The median rainfall is 33.59 inches in 2021. Unfortunately, finer time step (15-minute) rainfall data necessary for modeling is not available for the DFW station. However, the 15-minute time step rainfall data for recent years is available at a nearby Fort Worth WSFO Station. The data from 2000-2013 (Table 2) shows the 2008 rainfall of 12.4 inches is less than the 1921 rainfall, and the 2009 rainfall of 34.5 inches is close to the median rainfall of 2021. The two calendar years of rainfall contain a very dry year-duration with higher risks of sedimentation accumulation followed by an average year with average wash-out condition. Therefore, it is considered a reasonable rainfall period to evaluate the sedimentation risks for the siphon. A 5-year design storm was added at the end of 2009 to evaluate additional cleaning effects at the design condition. The simulated flow to the siphon is shown in Figure 6. The peak flow is 78.6 mgd for the 5-year design storm. The following summarize the results (Table 3) and conclusions of the evaluation: Average sediment parameter inputs: - No sediment issue is predicted for the 42-inch barrel. - For the 66-inch barrel: --Upstream Junction: The sediment accumulation at the weir location is due to stagnant water. --The influent pipe to the Downstream Junction: It has incremental sediment build up during dry weather periods due to low recirculation flow from the 42-inch pipe. The downstream end can be washed out by most of the storms. The upstream end has accumulations. High sediment parameter inputs: - The 42-inch barrel: --It can have 3.5 hours of sediment accumulation during early morning low-flow period, but the sediment will be washed out during higher flow hours (Figure 7). - The 66-inch barrel: --Upstream Junction: Sediment accumulation occurs for the first two sections downstream of the weir due to stagnant water (Figures 8 and 9). --The influent pipe to the Downstream Junction (Figure 10):It has incremental sediment build up during dry weather periods due to low recirculation flow from the 42-inch pipe. The downstream end can be washed out by most of the storms. The upstream end has accumulations. --The rest of the pipes can self-clean (Figure 11) - The sediment doesn't increase the head loss significantly for the 5-year storm after a 2008-2009 rainfall condition. However, it could be further verified by detailed modeling such as computational fluid dynamics (CFD) modeling. Based on the evaluation, the following were recommended: - The current Cooks Branch Siphon sizing is confirmed and recommended. - A Texas Commission on Environmental Quality (TCEQ) variance may be required as the weekday peak DWF velocity is less than 3.0 ft/s. - Consider the following sediment management options for the 66-inch pipe: --A back flow prevention device. --An inspection program and maintenance plan to remove the accumulation periodically. --Supplemental water for sediment cleansing. --Sluice gate at 42-inch pipe inlet. Conclusion/Recommendation: The sediment accumulation in collection systems can be modeled in conjunction with Hydrologic and Hydraulic models with available modeling software. The model uses typical sediment and erosion/deposition theories and equations. Reasonable sediment parameter ranges and DWF/WWF projections are required for the modeling. Using average and more conservative conditions for both sediment parameters and rainfalls can provide sensitivity analysis of sediment risks in the systems. The model can identify potential sediment accumulation locations/causes and help refine the designs to minimize the impact by incorporating operation and maintenance strategies into the design. Status of Completion: At the time of submittal, the study confirms the design and sizing of the Cooks Branch Siphon. Based on the sediment location/cause results, the design team is considering several options to manage the potential sediments. Similar analysis will be applied to two additional channel crossing sites.

Summary: The City of Austin hired K Friese & Associates (KFA) to optimize the Northwest Area regional collection system by redistributing flows among four lift stations. This effort involved expanding two lift stations, rerouting and reversing force mains, and decommissioning one lift station. Abstract: Austin Water operates 143 lift stations and 2,927 miles of wastewater pipelines. In 2018, the City of Austin selected KFA to modernize the Northwest Area's lift station network through the 'Rock Harbour Area Improvements' project. This included flow conveyance upgrades between the Boulder Lane (BL), Rock Harbour (RH), Four Points #1 (FP #1), and Four Points #2 (FP #2) lift stations. The project addressed increasing flows at BL and RH stations, planned service area growth, and outdated infrastructure. It also reduced inefficiencies by decommissioning FP #2 and reconfiguring the force mains. Initially, FP #1 and FP #2 were oversized due to early planning assumptions of high-density development. However, environmental constraints like the establishment of the Balcones Canyonlands Preserve led to limited growth. Meanwhile, flows to RH and BL increased, necessitating system improvements. Previously, BL flows were pumped to RH, which received additional gravity flows from its service area before discharging to FP #2 via FP #1. This overly complex flow pattern contributed to inefficiencies. The improvements streamlined this system by expanding BL and RH lift stations, bypassing FP #2, and rerouting and reversing flows. These upgrades were implemented in phases, each designed with future projects in mind. The RH station was first expanded with pumps capable of handling interim flows and later adapted for increased capacity using a larger-diameter force main. Subsequent projects included rerouting the RH force main (RH FM), reversing an existing force main to accommodate FP #1 flows, and decommissioning FP #2. BL station upgrades were completed independently, ensuring compatibility with increased flows downstream. Key Improvements: 1. Expansion of RH lift station. 2. Construction of a new 18' RH FM to bypass FP #2. 3. Connection of FP #1 to the reversed 12' RH FM. 4. Decommissioning FP #2. 5. Expansion of BL lift station. Project Execution: The design and construction of the projects required detailed sequencing to minimize operational disruptions and construction complexities. The RH FM reroute involved three interdependent designs: the new 18' FM to bypass FP #2, reversal of the existing 12' RH FM, and rerouted connections to FP #1. The RH lift station was expanded to accommodate these changes, with its design incorporating flexibility for future system curves. To decommission FP #2, FP #1 flows were redirected via the reversed 12' RH FM to the expanded RH lift station. Pre-design efforts ensured seamless integration of phased improvements while maintaining system functionality. Coordination between these interconnected projects was essential to avoid service disruptions and optimize efficiency. Challenges and Solutions: Several challenges emerged during the planning and execution phases, offering critical lessons: 1. Strategic Foresight: Early planning ensured the initial projects could accommodate subsequent improvements. This minimized costs and disruptions while simplifying future construction. 2. Phased Execution: Careful sequencing of the RH FM reroute project (comprising three of the five improvements) ensured prerequisite components were in place before proceeding with later phases. 3. Staffing Continuity: Staffing transitions posed risks to institutional knowledge. KFA retained the same project manager and lead engineer throughout the program, ensuring consistency. A diverse client team from Austin Water (AW), Development Services Department (DSD), and others supported continuity despite turnover. 4. Site Constraints: Limited workspace at the RH and BL stations required innovative approaches, such as phased construction, unique storage solutions, and close coordination with facility operators. 5. Infrastructure Retrofitting: Existing infrastructure was repurposed to reduce costs and timelines but introduced uncertainties due to unknown underground conditions. Record drawings and coordination with city operators helped mitigate risks. 6. Material Delays: Extended lead times for equipment like generators disrupted schedules. Lessons from the RH station informed bid evaluations for BL, including pre-purchasing and timeline adjustments. Early engagement with suppliers proved essential. Lessons Learned: The iterative nature of the project allowed the team to address issues proactively in later phases. Design refinements incorporated feedback from earlier projects, addressing material changes, site access, and installation challenges. The project also highlighted the importance of anticipating supply chain disruptions and planning buffer periods to accommodate delays. Conclusion: The integrated improvements program streamlined flow conveyance in Austin's Northwest Area, addressing current inefficiencies and planning for future growth. The project involved lift station expansions, force main rerouting, flow reversal, and decommissioning outdated infrastructure. Key achievements included strategic planning, phased execution, and adaptive design. These efforts reduced costs, improved system reliability, and provided valuable insights for managing complex wastewater improvement programs. The approach exemplifies innovative, sustainable infrastructure solutions that balance operational needs, environmental constraints, and long-term development.

The Central Everglades Planning Project (CEPP) New Water Everglades Agricultural Area Stormwater Treatment Area (EAA-STA-A-2), herein after referred to as A-2 STA, consists of approximately 7,000 acres of land and is a principal component of the EAA Storage Reservoir and Treatment Wetland Project. The purpose of the project is to further reduce the number, return frequency, and severity of undesirable, damaging high-volume discharges from Lake Okechobee, thereby improving salinity and water quality conditions in the St. Lucie and Caloosahatchee Estuaries. Hydraulics near the proposed structures of the A-2 STA Project could be challenging when considering combinations of low/high flow-stage conditions. Velocities could be excessively high, and depths could create undesirable conditions to the operation of such structures that could not be properly identified with the use of one-dimensional (1D) or two-dimensional (2D) modeling. This paper discusses modeling results associated with the design of two critical project features: (1) the S-619 Discharge Structure, a triple barrel, 10-ft x 10-ft box culvert, to be constructed under the STA 3/4 Inflow Canal to allow treated water from the A-2 STA to flow south in the Miami Canal; and (2) the S-640 Pump Station, a temporary pump station that will deliver water to the A-2 STA during an interim period while the A-2 Reservoir is being constructed. Simulation results showed that the original design could lead to undesirable hydraulic conditions, such as eddies. This prompted modifications to the original design by the Design Team to improve the hydraulics near these structures. The results of the CFD analysis provided detailed predictions of hydraulic parameters in and around the structures, offering additional insight to the Design Team and the South Florida Water Management District regarding their capacity and performance under different hydraulic and hydrologic conditions. As such, the modeling results were key input in the decision-making process involving stakeholders regarding how the various conveyance channels and structures would be operated and maintained during the project's lifespan.