City of Clute Community Development Block Grant Disaster Recovery-Mitigation (CDBG-MIT) Program

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. 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 from various disasters since 2015.

The City of Clute, located in Brazoria County, Texas, a county within the Houston-Woodlands-Sugar Land metropolitan area, was heavily impacted by the storm and ensuing flooding events of 2016 and was classified as a 'most impacted and distressed' county by HUD. The City developed a capital improvements plan to address several drainage and flood mitigation issues; however, resources to fulfill the plan were lacking. The City of Clute then contracted CSRS to assist in applying for the 2016 Floods CDBG-MIT competition.

With the assistance of our team of experts, the City of Clute met all of the resilience and mitigation requirements for the GLO competitive statewide 2016 floods program. The CSRS team helped prepare and submit the grant application that resulted in an award of nearly $10 million for drainage improvements to address chronic flooding issues in Clute and the adjacent Lake Jackson. The award will fund the two proposed projects submitted within their grant application to mitigate drainage and flood management in the watershed area. CSRS will also administer the grant to manage the success of the program effectively.

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 was 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 right-of-way. Because of the steep slopes and high traffic volume, a guard railing was also proposed for public safety. Additionally, CSRS recommended replacing culverts along Flag Lake and upsizing to 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 connecting the west Flag Lake Ditch to Garland Drive was proposed to be plugged and the installation of a new 5 ft. x 5 ft. RCB connection under Flag Lake Drive 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 was 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 needs to be plugged to prevent flows from traveling alongside Plantation Drive. This allows for a more purposeful direction of flows to the Flag Lake system rather than allowing flows to travel east along Plantation Drive. The culverts and ditches east of the Brazoswood Shopping Center parking lot did not have sufficient capacity to convey flows from the parking lot to Flag Lake Drive. CSRS recommended fortification of this ditch to increase capacity and improve drainage of the parking lot. The ditch top widths match due to limited right-of-way.

Additionally, the driveway culverts will be upsized to 5 ft. x 3 ft. RCBs. These proposed improvements will increase 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 ditch capacity between the systems. Due to limited right-of-way, 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 along Flag Lake Drive, the Plantation at Flag Lake Drive area, Brazoswood Shopping Center, and the Garland Drive area. While there are notable reductions in 10-year water surface elevation for the east ditch, the west ditch experiences more significant reductions (up to 2 ft.). This is due to the increase in ditch capacity and 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 benefit from proximity and additional downstream capacity.

Plantation to Pin Money Drainage Improvements

The second solution proposed upsizing and fortifying 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 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 a fortified section with 1:1 side slopes and a grass-lined section with 3:1 side slopes, depending on 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 entirely 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 included plugging the culvert under Dixie Drive on the north side of Plantation Drive to better direct flows to the Flag Lake Drive system.