River Engineering

Houston Country Club Holes No. 8 and No. 10 Bank Stabilization Houston, Texas DCCM was contracted by the Houston Country Club to provide engineering services for the channel slope repair on the south bank of Buffalo Bayou (HCFCD Unit No. W100-00-00) along the golf course fairways of holes 8 and 10. The project was previously designed by another firm and partially constructed but never closed out due to channel bank failures associated with a deep geotechnical failure below the slope. DCCM and contractor, BRH-Garver, as well as a geotechnical consultant, Professional Service Industries (PSI), and developed a structural solution with closely spaced drilled shafts to stabilize the failed channel slopes and to prevent future channel bank failures. The project consisted of two separate stretches of bayou being repaired. For one alignment, we performed a slope up from the existing bench and lower the top of bank. For the other channel section, DCCM added a variable height wall to be able to match the existing top of bank. The limits of the channel repair work was 1,225 feet along the fairways of hole 8 and 850 feet along the fairways of hole 10 for a total distance of 2,750 feet. The scope of services included the following: Designing the structural elements required to establish a stable slope system Coordinating the design and details of construction with the design/build contractor and the owner’s representatives Coordinating with PSI geotechnical engineers for a design of a stable slope system Preparing plans, specifications, and estimates (PS&E) Preparing hydrologic and hydraulic (H&H) impact analysis report Obtaining applicable signatures and permits from City of Houston and Harris County Flood Control District (HCFCD) Issuing a Letter of Map Revision at project completion Preparing as-built construction documents to finalize City of Houston and HCFCD permit requirements As a result of teaming with a local geotechnical firm, a deeper global failure was discovered at the location of the failures. A previously unknown slickenside soil layer was encountered at a depth below previous project borings. DCCM resolved this problem by extending drill shafts below this layer of weakened soil immobilizing the failure. At a Glance $10M Construction Cost 2,750 Feet of Channel Repair Work Markets Water Services Water & Wastewater

Little Cedar Bayou Improvements, Phases I and III La Porte, Texas Phase I: DCCM provided preliminary engineering, final design, and construction phase services for improvements to the Little Cedar Bayou inline detention basin. Improvements were required to reduce negative impacts to the downstream watershed after major storm events. Key design and permitting features included: Adding 220 acre-feet in storage volume Land acquisition A reinforced concrete control structure at the crossing of SH 146 Harris County Flood Control District approval USACE permit for mitigation of impacts to regulatory waters Phase II: DCCM provided preliminary design, final design, and construction phase services for 2,500 feet of channel widening improvements in La Porte. The channel widening passes through residential and commercial areas. The project allows this section of Little Cedar Bayou to handle major storm events without negative impacts to the downstream watershed. Services included the following: Land acquisition allowing for widening the channel right-of-way (ROW) from 60 feet to 140 feet Design elements incorporated backslope drains, riprap, grade and slope protections, and new storm sewer outfalls Funding for the project was administered through the Texas GLO. USACE permit Coordination with Harris County Flood Control District and USACE. Changes in USACE’s policy occurred during the project regarding the process for obtaining USACE permits. DCCM proactively met with USACE and modified the proposed channel design to incorporate the use of natural stream design techniques. USACE approved the permit for this project as a result of DCCM’s early coordination. The initial project schedule was maintained throughout the project duration. This project successfully provided flood reduction in adjacent and upstream neighborhoods. At a Glance $1.4M Project Budget 220 Acre-Feet Storage Volume 2,500 Channel Widening Markets Water Services Water & Wastewater

Collins Park Erosion Houston, Texas DCCM was selected to study and provide remedial measures to reduce erosion of the north banks of Cypress Creek (K100-00-00) adjacent to Collins Park. Cypress Creek, within the project limits, is a natural channel migrating to the north and undermining an asphalt trail owned and maintained by Precinct 4, a corridor parallel to K100-00-00. Cypress Creek within this reach does not have backslope swales or interceptors; significant uncontrolled sheet flows in the project area are found to increase erosion and rilling along the banks of K100-00-00. DCCM quantified the impacts of the sheet flows and identified design solutions. The Precinct 4 trail is a public facility. Therefore, the project is sensitive to public interest, and we have approached it with this in mind. Within the project area, there is a 92-inch outfall with a large cast-in-place junction now located in the beds of K100-00-00. The 78-inch outfall has been undermined and disconnected from the manhole, and there is concern about additional erosion around this large manhole, which could cause future issues. DCCM successfully conducted detailed field investigations and provided prompt engineering services, addressing the erosion issues by regrading the slopes and adding stone toe protection and rip rap around the outfalls. This design economically addressed the infrastructure concerns providing a long-term solution. At a Glance $220,000 Project Budget Markets Water Services Water & Wastewater