CTRMA SH 45SW

Improving System Connectivity, Mobility and Travel Times with an Efficient Alternative Route

Project Purpose

The purpose of the project was to improve system connectivity, local mobility, and travel times, while providing an efficient alternative route to congested local roadways in northern Hays and southern Travis Counties. The project is located within the City of Austin ETJ, the Barton Springs Edwards Aquifer Conservation District, and the TCEQ Edwards Aquifer Recharge Zone. KFA prepared the drainage impact, risk assessment and mitigation report.  KFA supported inter-local technical work groups to shape the project design and  provided hydraulic design services for the Bear Creek Bridge; cross culverts;  water quality treatment best management practices, including batch detention ponds; and prepared the WPAP for permitting with the TCEQ.

Project Approach

The project is located within an environmentally sensitive area of the region and is located within the Barton Springs Edwards Aquifer Conservation District, the Travis County Balcones Canyonlands Conservation Plan area, and the TCEQ Edwards Aquifer Recharge Zone. The intensive inter-local and inter-agency coordination was an opportunity for KFA staff to interface with regional experts and to refine the project design based on their input.  As part of KFA’s project design role, the firm managed the preparation of the offsite drainage design, the impact and risk assessment, and coordination with the local floodplain administrators (FPA). Providing Water Quality Design support for the project, KFA also managed the permanent water quality design in accordance with the Edwards Aquifer Protection Program regulations and the 1991 Consent Decree between TxDOT and the Barton Springs Edwards Aquifer Conservation District (BSEACD). KFA prepared and permitted the TCEQ Water Pollution Abatement Plan Permit, which includes best practices of vegetative filter strips, permeable friction course, eight batch detention ponds, and use of the existing vertical sand filtration ponds as extended detention ponds. The firm supported the project with participation in public outreach events, public meetings, and stakeholder technical work groups (TWGs) as well as coordination with the BSEACD, Travis County, CTRMA staff, TxDOT, and the city of Austin. KFA led the TWGs discussion sections regarding water quality design and, through the TWG process, KFA refined design features such as the pond lining systems.

Project Results

The Central Texas Regional Mobility Authority opened 45SW to traffic in the Summer of 2019. The new road was constructed with environmental sensitivity at the forefront, and is expected to save drivers time while protecting the environment.

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