Following the federally declared disasters in 2015, 2016, and 2017's Hurricane Harvey, the United States Congress implemented Community Development Block Grant Mitigation funding (CDBG-MIT), through the U.S. Department of Housing and Urban Development (HUD), to disaster-affected communities to execute projects and plans to help communities recover from disasters and reduce their risk from similar hazards in the future. The City of Clute, Texas, located in Brazoria County, which is considered a county within the Houston-Woodlands-Sugar Land metropolitan area, suffered major damage during the floods in 2016. The city developed a capital improvements plan to address several drainage and flood mitigation issues; however they lacked the resources to fulfill the plan. In this case study, we look at how CSRS helped prepare and submit the grant application for this small, flood-prone city that was awarded nearly $10 Million for drainage improvements to address chronic flooding issues in Clute and the adjacent Lake Jackson.
CDBG-MIT funding was distributed to the State of Texas (administered by the Texas General Land Office – GLO), who decided to set up a series of competitions for impacted areas across the State of various disasters since 2015. The City of Clute was heavily impacted by the storm and ensuing flooding events of 2016 and classified by HUD’s analysis as a ‘most impacted and distressed’ county; therefore, CSRS assisted Clute in applying for the 2016 Floods CDBG-MIT competition.
Background
Clute is a city in Brazoria County, Texas, within the Houston metropolitan area. As of the 2010 U.S. Census, the city population was 11,211. According to the United States Census Bureau, the city has a total area of 5.6 square miles, of which, 5.3 square miles is land and 0.3 square miles (5.14%) is water.
Proposed Solutions
Two solutions were proposed to submit the City of Clute’s 2016 Floods State Mitigation Application for funding.
Flag Lake Drive to the Brazoswood Shopping Center Improvements
The first solution proposed regrading and fortifying the roadside ditches along Flag Lake Drive with 1:1 side slopes. The ditch top widths matched the existing top widths due to the limited ROW. Because of the steep slopes and high traffic volume, a guard railing was also proposed for public safety. The culverts along Flag Lake were proposed to be replaced and upsized to be either a 5 ft. x 3 ft, 5ft. x 4 ft. or 5 ft. x 5ft. RCBs, depending on the existing ground elevation. The existing downstream in connection of the west Flag Lake Ditch to Garland Drive is proposed to be plugged and a new 5 ft. x 5 ft. RCB connection under Flag Lake Drive is proposed to redirect flow to the larger SH 288 outfall on the east side of Flag Lake Drive.
The existing cross-culvert connecting west and east Flag Lake Drive located approximately 500 ft. north of Austin Street is proposed to increase flow by upsizing from a 36 in RCP to a 4 ft. x 4 ft RCB. Additionally, the culvert just east of Flag Lake Drive and west of Dixie Drive on the south side of Plantation Drive will need to be plugged to prevent flows traveling alongside south Plantation Drive. This allows flows to be more purposely directed to the Flag Lake system rather than allowing flows to travel east along Plantation Drive. The culverts and ditches just east of the Brazoswood Shopping Center parking lot do not have sufficient capacity to convey flows from the parking lot to Flag Lake Drive; therefore, the ditch is proposed to be fortified, increasing capacity to improve drainage of the parking lot. The ditch top widths match due to limited ROW.
Additionally, the driveway culverts will be upsized to 5 ft. x 3 ft. RCBs. These improvements will provide increased capacity and conveyance for the system to help drain runoff from the parking lot to the Flag Lake Drive system. Nursery Ditch between Garland Drive and Flag Lake Drive will be fortified with 1:1 side slopes to increase the capacity of the ditch between the systems. Due to limited ROW, the proposed ditch will match the footprint of the existing ditch. This ditch provides relief to the Flag Lake system by allowing flow to go to the Garland system by way of the improved ditch.
Areas that directly benefit from these improvements include communities and businesses in the Flag Lake Drive, Plantation at Flag Lake Drive, Brazoswood Shopping Center, and the Garland Drive area. While there are notable reductions in 10-year water surface elevation for the east ditch, the more significant reductions (up to 2 ft.) are experienced in the west ditch. This is due to the increase in ditch capacity as well as the new proposed connection under Flag Lake Drive. By plugging the existing culvert to the Garland Drive SH 288 outfall and proposing a new connection to the larger Flag Lake Drive SH 288 outfall, this area can realize the benefit from proximity and additional downstream capacity.
Plantation to Pin Money Drainage Improvements
The second solution proposes the upsizing and fortifying of culverts and roadside drainage along Plantation Drive from Dixie Drive to Pin Money Ditch. The existing culverts are to be upsized to single 4 ft. x 4 ft. RCB on the north side of Plantation Drive and single 3 ft. x 3 ft. or 4 ft. x 4 ft. RCBs on the south side of Plantation Drive. The box culverts will need to be traffic-rated due to the limited coverage available for driveways on Plantation Drive. Additionally, the ditch sections are deepened, widened, and regraded to consistently slope towards Pin Money Ditch. The proposed ditch improvements include both a fortified section with 1:1 side slopes and a grass-lined section with 3:1 side slopes, depending upon tie-in conditions.
By improving the conveyance of runoff adjacent to Plantation Drive, this project reduces the ponding depths along Plantation Drive between Dixie Drive and Pin Money Ditch. The proposed consistency in slope will also help reduce long-term overflows in the ditches and culverts, as they will be able to drain effectively. While the ditches cannot be fully within the bank during the 10-year storm, there is a considerable reduction in water surface elevation that the surrounding area and areas that drain to this location will benefit from. Additionally, the project proposed includes plugging the culvert under Dixie Drive on the north side of Plantation Drive to better direct flows to the Flag Lake Drive system.
Conclusion
With CSRS' assistance in meeting all of the resilience and mitigation requirements for the GLO competitive statewide 2016 floods program, the proposed City of Clute, CDBG-MIT Grant Application was awarded a budget of $ 9,881,420.00 to fund the two projects to mitigate drainage and flood management in the watershed area. CSRS will also administer the grant to effectively manage the success of the program. For over 40 years, CSRS has leveraged our innovation and leadership expertise to help plan, design, fund, and implement sustainable projects, recover from disaster with more resilience, and navigate political bureaucracy. With a culture of creative thinking - and a background in engineering and architecture - CSRS provides a balance between big ideas and the technical ability to deliver a successful project every time, no matter how large, complex, or challenging.