Midtown/Montrose Drainage and Paving Project

Background

The Build Houston Forward Initiative (formerly ReBuild Houston) is the City of Houston’s voter approved pay-as-you-go plan to rebuild drainage and street infrastructure.

Its goal is to improve the quality of life and mobility for residents through the reconstruction and proper maintenance of drainage and street improvements. From daily repairs like fixing potholes, to major reconstruction, the program makes sure the infrastructure is serving the community now and in the future.

The program is designed to improve Houston infrastructure without incurring new debt by using funding sources like property taxes, third party funds, and drainage fees.

“The City of Houston is committed to build for the future, and not simply replace projects in kind,” said Juan Chavira, PE, PMP, CEM, Assistant Director, Capital Projects at Houston Public Works. “We are committed to be stewards of the taxpayers’ money by providing solutions that consider future developments, population growth, traffic conditions, and changing climate conditions.”

The Montrose and Midtown Area Drainage and Paving Project is an active example of collaborative project success.

The Montrose/Midtown drainage improvements project included floodplain management, design, and construction. The project site is in a historic area west of downtown Houston encompassing a 1,070-acre area of mixed residential and commercial development. A portion of the project area borders the historic Freedman’s Town District within Houston’s 4th Ward, an area included within the National Registry of Historic Places. During the project, the design team encountered historic bricks along Gillette Street at Andrews Street. These bricks were laid by freed slaves when they built the vibrant community.

“It is extremely important for Houston Public Works to upgrade its aging infrastructure, build it for future conditions, while maintaining the rich historical integrity and significance across the City of Houston,” said Chavira. “This is not done in a vacuum – it takes an immense effort in coordinating amongst key stakeholders from various agencies and local communities, working towards a common and mutual goal; and ultimately one that everyone can feel proud of at the end.”

Characterized by over 100 years of progressive development and redevelopment, located on the south side of Buffalo Bayou, the project area has experienced repetitive structural flooding and street ponding. The goal was to identify and to alleviate repetitive flooding while preserving the historic value in the area, provide additional outfall capacity into Buffalo Bayou, a major drainage channel that runs through downtown Houston, without affecting surface water elevations, and accommodate infrastructure development within high profile Eleanor Tinsley Park located on the Bayou.

Evaluating resolution options

The project, as originally identified, included a 152-acre sub-set of the 1,070-acre area ultimately considered. Originally, existing and proposed 2-yr and 100-yr, 2-dimensional hydrologic and hydraulic (H&H) models and inundation maps and infrastructure recommendations as per the original scope were prepared. However, project goals could not be met without removing outfall constraints and recommended that overall outfall capacity be improved, providing beneficial impact to the entire 1,070-acre area. An alternative analysis and recommendations as well as complete inundation maps and hydraulic profiles demonstrating hydraulic grade line improvements was prepared. The alternatives included (1) increase the existing outfall capacity, (2) add an additional outfall, and (3) improve system conveyance for a portion of the system referred to as the Crosby trunk line.

Innovative Solution

The recommended solution included the installation of a new 10-ft.x10-ft. Reinforced Concrete Box (RCB) relief outfall along Gillette Street so that the overburden on the existing Crosby outfall could be reduced. The route selected for the new storm sewer was evaluated to have the smallest impact on area businesses, traffic, and utility relocation requirements.

The improvements were installed through a three-phase, $37 million effort so that the project time could be compressed, and local funding could be utilized. It included the construction of over 12,000 feet of new storm sewer trunk lines ranging in size from 72” RCP to 10’x 10’ RCB through the area connected to existing systems along the route. The new outfall bi-sects the original drainage area so that roughly 50% of the area drains to the Crosby street outfall and 50% drains to the new Gillette Street outfall. Additionally, multiple storm sewer interconnections were left in place throughout the project so that flow would be equalized between the two outfalls.

Installation of large storm sewer pipes within existing fully developed right of way provided numerous design and construction issues. A key hurdle was maintaining the existing traffic patterns and keeping utility in service at all times.

Every street that the new storm sewer utilized had existing water lines, sanitary sewer lines, storm sewers and private utilities. Typically, the sanitary sewer lines and storm sewers were located under street pavement, water lines were located near one side of the right of way and private utilities were located along the opposite side of the right of way, under the street pavement and crossing the street. Existing utilities under the pavement needed to be moved away from the middle of the streets to the outer fringes of the right of way. Typically, this involved relocating private utilities and water lines to one side of the right of way, and moving the sanitary sewer lines to the opposite side right of way to create an open area that would allow for the installation of the new storm sewer.

Land use throughout the project was mixed, consisting of local businesses, apartments, condominiums, single family homes, and schools, so that all streets had to remain open during all phases of the construction. Installing and relocating the underground utilities required detailed block by block traffic control plans that included temporary pavement that allowed for property access throughout construction.

The storm sewer route crossed several major arterial roads with heavy traffic patterns to/from downtown, such as Allen Parkway, W. Dallas Street, and W. Gray streets. Because lane closures were not allowed on these roads, tunneling of 10-ft x 10-ft boxes was required at certain locations. Additional tunneling was required under a large AT&T utility that could not be relocated and at the Spur 529 overpass. This project included the implementation of settlement monitoring during construction of the large storm sewers to protect potentially impacted businesses and identify unwanted trends and timely data to develop and evaluate corrective measures.

Coordination with multiple agencies was required during design and construction. METRO, TxDOT, Houston Parks, The Buffalo Bayou Partnership, Federal Reserve Bank, local civic groups, Midtown TIRZ, Texas Historical Society, Downtown CDBG group, existing and new businesses groups and others were all involved at various times to complete the work.

“It was a pleasure to work with all of the multiple stakeholders to accomplish this major infrastructure project in such a vital area of Houston,” said Stephen Sparks, PE, Vice President Water Resources at HR Green. “Every entity involved from the Houston Mayors office, Houston Parks, Houston Public Works, Metro, Midtown TIRZ, the Federal Reserve and HISD worked together in a positive manner to make the challenging project a success. The contractors on the project included Texas Sterling, BRH Garver Construction and Harper Brothers Construction. All three contractors went above and beyond to make the project a success.”

Looking ahead

This three-phase, $37M drainage and pavement project provided storm sewer improvements and a new outfall structure into Buffalo Bayou achieving the following:

• Relieved an undersized storm sewer system that provides conveyance for a 1,070-acre drainage area located near downtown Houston
• Improved local flooding problems by installing approximately one mile of 10 ft. x 10 ft. concrete boxes
• Relieved an undersized outfall from excessive flows that have caused flooding by subdividing the existing drainage area
• Redirected additional flows when the system becomes overloaded by intercepting numerous storm sewer pipes and connecting to the existing outfall system

The system was put to the test during Hurricane Harvey and subsequent events in this once flood-prone area and minimal structural flooding was recorded. Additionally, because of the timing of the peak flow hydrographs, through HEC-RAS modeling along Buffalo Bayou, the system did not increase water surface elevations in the receiving stream. Therefore, the use of additional detention was not required, minimizing the impact, and preserving community value as well as providing no adverse impact to downtown Houston.

Results

The community value was preserved by eliminating the need for above ground detention within an area with high land values. Additionally, eliminating recurring flood impacts to structures improves the safety and economics of the area. Coordination with local community groups to preserve the historic bricks was very important to the community. Specific issues were resolved through construction with respect to placement of these bricks. Special plans were made to categorize, number, remove, store, and replace the bricks in accordance with federal historical site guidelines.

Work at the storm sewer outfall in Eleanor Tinsley Park required close coordination with the Buffalo Bayou Partnership and City Parks group. Cooperatively, the outfall design was developed to enhance the look and theme of the park as well as provide an aesthetically pleasing appearance. The circular/stepped headwall design was non-traditional, with an overflow weir designed to ensure it was integrated visually into the surrounding area.

“Houston Public Works is very proud to be part of the team that includes everyone from our engineering consultants, to our construction contracting partners, to local business and community organizations, to local government officials and to our sister agencies,” said Chavira. “This project was entirely a team effort, and the result is a testament to what can be achieved when everyone comes together to deliver a project that will benefit future generations of Houstonians.”