Quattrone Develops a Cost-efficient Stormwater Network Solution

Developing an Affordable Rental Complex

Coastland Residential is developing Mallory Townhomes as an affordable rental housing complex in the city of Fort Myers, Florida. These homes are designed to provide modern, superior communal living for local families. Offering a key West coastal vibe, the development is a gated, villa-style community with 21 two-story buildings, featuring 126 two-bedroom and 38 three-bedroom units, as well as amenities, including gym facilities, a pool, children’s play area, and a dog park. 

About a year into construction, the underground contractor identified a conflict with the final stormwater outfall structure while connecting a reinforced concrete pipe (RCP) from one of the originally designed stormwater structures with the existing master stormwater network. Providing civil engineering, water management, and site planning services, Quattrone & Associates were brought on site to evaluate and discuss potential remedies to keep construction on schedule. 

Addressing Network Issues Mid-construction

The original design plan called for connecting a 42-inch stormwater RCP into one of the existing stormwater structures. However, the riser was not wide enough to connect with the RCP. The existing structure was also much lower than anticipated—located approximately 10 feet below the water table. The city of Fort Myers requested that the proposed RCP be lowered to connect to the base of the existing structure instead, where it was wide enough to make the connection. This proposal would have been cost prohibitive and would have delayed construction. These issues were not brought to Quattrone’s attention, and the RCPs were already purchased. Therefore, Quattrone wanted to reuse all the RCPs that the contractor originally purchased so that the material was not wasted. 

OpenFlows StormCAD Facilitates Optimal Design Solution

Upon learning about Bentley Systems’ OpenFlows StormCAD, Quattrone thought that it might be a useful application to quickly input the current stormwater scenario and modify the design to reroute the network. 

A first-time user, Quattrone, found Bentley’s hydraulic modeling and analysis application easy to use. The ease of dropping catch basins, maintenance holes, and outflow structures proved quick and accurate. The software’s flexibility allowed the team to consider and incorporate local storm events to run the model specifically for this project site while generating detailed reports. Working in Bentley’s digital environment provided a visual and analytical model to help redesign the stormwater layout, determining an optimal design solution to reroute all the existing piping while also re-networking the entire system amid construction. 

Advanced Hydraulic Modeling Drives Savings 

By performing advanced hydraulic modeling and analysis with OpenFlows StormCAD, Quattrone could evaluate and visualize their design solution, reusing all the existing RCP materials to keep construction moving forward. This process lowered lead times of new construction material and costs greatly. 

The original proposed remedy of modifying the existing master stormwater structure would have cost over $10,000 and resulted in a six-month or more construction postponement. Using OpenFlows StormCAD, Quattrone could cost effectively redesign the stormwater network within one day to keep the project on schedule.