Painted Tree Flood Study

The Painted Tree development is a multi-phased single-family residential development of approximately 1,100 acres planned for McKinney, Texas along Franklin Branch. Cardinal Strategies performed a flood study for each phase of the project as well as a final flood study for the overall Painted Tree development. The Franklin Branch stream was mapped as a Federal Emergency Management Agency (FEMA) Zone A floodplain; meaning the floodplain was mapped by FEMA for the 100-year storm event without establishing base flood elevations.

Cardinal Strategies first performed a Letter of Map Revision (LOMR) for Franklin Branch prior to any proposed development to better define the 100-year floodplain extents as well as establishing base flood elevations, updating the mapping to a FEMA Zone AE. This was done by setting up hydrologic and hydraulic models for the Franklin Branch watershed.

In addition to the pre-project LOMR, the fully developed City of McKinney flood study, and the LOMR that will be required at the end of construction, Cardinal Strategies has also been tasked by the design team to perform LOMR-Fs. LOMR-Fs are Letter of Map Revisions Based on Fill. These allow for the removal of individual or multiple lots from the floodplain based on actual survey of the lot(s) to show that their finished floor elevations are above the base flood elevations. Construction of some lots along the floodplain will be completed before others for the Painted Tree development. The LOMR-Fs that Cardinal Strategies will perform will allow for individual homeowners to avoid mandatory flood insurance for a handful of homes that show to have FEMA floodplain on the lot until the final LOMR is complete.

Analyses were performed for Franklin Branch to observe the impacts of the proposed development. Due to the unknown timeline for development of the separate phases, each phase required its own flood study to ensure that individual phases would not cause adverse impacts. Following the acceptance of flood studies for each phase, a fully developed flood study was performed for a full build-out of all the Painted Tree development phases.

Cardinal Strategies collaborated with the design team to help determine where and how much floodplain reclamation could take place in each phase without causing adverse impacts to the proposed development and all off-site areas along Franklin Branch and its tributaries as well as to size multiple proposed culverts for many of the phases. Cardinal Strategies also helped coordinate with the Natural Resources Conservation Service (NRCS) to satisfy no loss of storage for the SCS Pond #4 downstream structure.