Towne Lake

In 2006, Caldwell Companies sought to create Towne Lake as a community where residents and services could be connected by water. Their vision included boat docks and marinas augmenting traditional walking trails to navigate a vibrant residential community. EHRA was the perfect partner to take Caldwell Companies’ vision and create this livable suburban oasis.

Cane Island Parkway

The new roadway design comprises of one-half major thoroughfare, conventional drainage, a 600-ft long bridge over Willow Fork Bayou, Retaining walls and intersection improvements at FM 1463 (including traffic signals and illumination).

League Line

EHRA performed preliminary drainage area delineations for nine creek crossings and calculated approximate 100-year flows for each culvert crossing. Culvert structures were sized for each of the six crossings, ranging from 48” round pipe culverts up to dual 5’x5’ box culverts.

Meridiana

The purpose of this project was to convert the existing at-grade crossing of Brazoria County Road 56 (CR 56) and State Highway 288 (SH 288) into a diamond interchange that includes a new overpass bridge and providing access to the newly developed Meridiana Development. Coordination with TXDOT, area landowners, utility companies, and Brazoria County was integral in obtaining approval and acceptance of the project. The main design challenge for this project was to accommodate double intersections on the west side of SH 288 to tie into existing access roads with two-way traffic and a new southbound on-ramp within a close proximity. EHRA coordinated with TxDOT throughout the project from preliminary concepts for the intersection and bridge through final design and construction. Each component of this project was designed in accordance with TxDOT standards and criteria.

MUD 188

EHRA planners, hydrologists and landscape architects worked together to propose an alternative use for the space, re-developing the basin into an amenity pond. EHRA carefully selected native plant materials for both their ability to survive in the harsh conditions of the basin as well as providing filtration for improved storm water quality.

29 June 2022

Project InFocus: Foxwood Subdivision Improvements

Andy Palermo P.E. CFM Senior Vice President

Foxwood Subdivision Improvements

Harris County enlisted EHRA to perform a planning-level engineering investigation for the Foxwood Subdivision, located in northern Harris County. The objectives of the investigation were to determine the causes of flood losses reported within the residential community, to reduce the risk of structural flooding and improve resiliency in the subdivision.

Project Manager Jennifer Hundl, PE, CFM, LEED AP applied the Rational Method when analyzing the existing storm sewer system for the two-year rainfall design. In addition, our engineers analyzed extreme event flow paths using the Hydrologic Engineering Center’s River Analysis System two-dimensional (HEC-RAS 2D) software. This system’s rain-on-grid exercise utilized available light detection and ranging (LiDAR) information and rainfall for the existing one percent 24-hour event. Our investigation also involved taking an inventory of existing utilities and ingress/egress routes to the neighborhood.

After critical data was compiled, EHRA recommended changes intended to increase inlet capacity in the areas of repetitive flood loss. The results of the HEC-RAS 2D analysis revealed that Foxwood did not have adequate extreme event overflow infrastructure. To resolve this deficit, we recommended the acquisition of a particular property that would allow construction of the necessary extreme event overflow structure and reduce the risk of structural flooding.

EHRA participated in a community engagement meeting to discuss investigation results and subsequent recommendations. Our team fielded comments and addressed community member questions. EHRA further initiated and engaged in discussions amongst local MUD and Harris County Precinct 4 staff members to encourage a construction partnership between the entities.

EHRA performed another subsequent drainage analysis in the area. This analysis was a non-detailed, two-dimensional study evaluating how rainfall interacts with the local topography. The purpose of this additional study was to identify overflow limits versus surveyed finished floor elevations. Previous recommendations were then appraised using updated Atlas 14 rainfall totals. The project was completed in 2021.

HYDROLOGY & HYDRAULICS Project In Focus