White Oak Bayou Federal Flood Control
This Corps of Engineers sponsored improvement project is approximately 12.5 miles in length, situated from West Tidwell Road to FM 1960 in Harris County, Texas. The project involves widening the Bayou bottom width and deepening by approximately 2 feet.
The improvements will be done in accordance to the GRR and will incorporate significant adjacent detention facilities. This project has been “in the books” for many years pending funding until 2017 when Congress signed a Bi-Partisan Bill in response to Disaster Recovery Relief for Hurricane Harvey. CobbFendley performed full topo from waters edge to waters edge within the bayou along with detailing all outfalls to the ROW. Our surveyors created a digital terrain model (DTM) file and then merged this data into the HCFCD 2018 LIDAR dataset, creating a 3D DTM of the bayou from ROW to ROW. For the bridge crossings, we used terrestrial laser scanning (TLS) methodology to capture full structural detail of all bridge crossings, both for streets and for pedestrian bridges. The resulting point cloud detail was then modeled into 3D solids for each bridge location. Modeling was then merged into the overall 3D DTM, yielding a complete design file.
CobbFendley concurrently performed a boundary survey of the entire ROW including abstracting and boundary reconnaissance in order to establish the existing right-of-way limits. Once the ROW was established, CobbFendley prepared the proposed ROW parcels. This involved creating parcel exhibits for ROW acquisition, review/approval from HCFCD, and assigning parcel number identification for all associated parcel documentation. Once the tract numbers were issued, CobbFendley completed the legal descriptions, parcel exhibits and sent to HCFCD for processing with the Corps. During the parcel development process there was “push back” from citizens whose property was to be acquired.
CobbFendley designed a retaining wall in 3 specific reaches of the channel in order to reduce ROW takings. CobbFendley worked closely with HCFCD staff to design the wall and determine preliminary construction estimates and schedule in order to compare to the ROW taking duration and cost. The information will be shared with the Corps for a determination.
For our design tasks, CobbFendley began by coordinating design submittals and schedule with HCFCD. Due to the high-profile of this project, a quick timeline was established (16 months to completion).
The project was broken into two design packages E005 (FM 1960 to Hollister) and E006 (Hollister to West Tidwell). Due to public pressure from Jersey Village, package E005 will be submitted first. To accomplish this, CobbFendley engaged their geotechnical subconsultant to perform a geotechnical investigation including bore holes. As CobbFendley completed segments of the 3D topo file, it was sent to HCFCD to design the proposed improvements between the existing bridges in a Civil 3D model. This file was then returned to CobbFendley, where we incorporated the design underneath the existing bridges into the Civil 3D model. This file transfer occurred in 2 to 3 mile segments until the proposed design was completed. CobbFendley also utilized a design subconsultant to adjust approximately 320 pipe outfalls and manholes/inlets for both packages.
Prior to the 60% submittal for package E006, HCFCD increased CobbFendley scope to include the design of a bike path along the majority of the mainstem of the channel, the bypass channel and multiple adjacent detention facilities. CobbFendley performed the utility investigation along the entire channel reach identifying approximately utility crossings and coordinated with other consultants on the proposed placement of such utilities as large diameter waterlines.
As part of the final design package CobbFendley is responsible for preparing the cover sheet, project layout sheets, survey control sheets, channel plan and profile sheets detailing the bikeway and alignment, bridge layout and slope paving detail sheets, point table sheets, SW3P sheets, general notes, and estimate sheets. At the beginning of the project, CobbFendley developed a schedule and updated it throughout the project duration and produced progress reports every two weeks along with meeting minutes. CobbFendley is also responsible for providing bidding services, construction phase services and a as-built post construction survey.