Midtown Drainage Improvements - CDBG-DR

Project Name: Midtown Drainage Improvements

Project Number: CDBG-DR

Project Manager: Jacquelyn Thomas

Current Design Phase: 90%

Construction Estimate: $1,700,000

Construction Start Year: 2021

Project Information: The Midtown/Aquarena Springs project area is located in San Marcos, TX east of the intersection at IH-35 and Loop 82/Aquarena Springs Drive and is generally bounded by development along Aquarena Springs on the north, IH-35 on the west, Davis Lane on the south, and the Blanco River on the east. The area is primarily multi-family residential and commercial property with businesses located along IH-35. The area is not located within the 100-yr flood plain, thus local flooding and inadequate conveyance likely cause the drainage issues reported at this location. City staff has indicated that the Loop 82/Aquarena Springs underpass at IH-35 is one of the first major intersections in the City to flood during significant rainfall events. The area falls within one (1) census tract which is 84.13% low-to-moderate income.

The project will receive funding from the U.S. Department of Housing and Urban Development (HUD) Community Development Block Grant – Disaster Relief (CDBG‐DR) program.

Historically, the Loop 82/Aquarena Springs intersection is known to flood in major rainfall events. A preliminary engineering study of the land contours indicates that the low point in the intersection is located just east of the northbound IH 35 feeder road. Stormwater that drains to this low point is not able to reach the TxDOT drainage ditch and drain south as it was designed.

Based on this data, the recommended improvements to remedy this include curb cuts and inlet improvements adjacent to the low point location combined with an inlet to send water from the north side of the road away from the intersection.

Clean-out, minor excavation, and reshaping of the TxDOT ditch vegetation that is currently overgrown is recommended to restore the ditch to the original design capacity and convey the necessary stormwater in major and minor rainfall events for the area.

Additionally, the channel’s culvert crossing at Davis Road should be modified by adding 2 additional 8’x 4’ culverts to increase the capacity of this crossing.

Proposed plans also include bank stabilization repairs and new culverts at the railroad overpass at River Road.

Midtown Historical Figure 2