In the past decade Brays Bayou has flooded several times due to massive peak flows and urban stormwater runoff. The increase in volume of runoff can be attributed to both increased urbanization and changing weather patterns. However, as flooding issues continue to worsen along the Bayou and are especially dangerous in vulnerable areas such as the Texas Medical Center, this project seeks to redesign the portion of the Bayou between Fannin Street and Main Street in order to mitigate the flood threat. In the early 2000s, the U.S. Army Corps of Engineers (USACE) and the Harris County Flood Control District (HCFCD) launched Project Brays, which outlined specifications for the redevelopment of the entire Bayou. One goal of this project is to design improvements that meet the specifications outlined by USACE and HCFCD. The development of the Bayou will consider increased stormwater flow due to the construction of a new hotel on Main St., and will require close coordination with the developers of the new 7200 Main Street Hotel. The area between the hotel and Bayou will be designed with guest amenities such as trails, terraces, access points, trees, and landscaping. In addition, this project will redesign the Greenbriar Bridge between Braeswood Boulevard and Main Street in order to reduce its backwater effect on the Bayou and ensure that it abides by the elevation specifications mandated by Harris County.

1. BRAYS BAYOU + BRIDGE
Fall 2015 Concept Presentation
Presented by:
Julianne Crawford, Avi Gori, Kasia Nikiel

2. Project Description + Goals
➔ Design Brays Bayou channel modifications
➔ Reconstruct of Greenbriar Bridge between Braeswood & Main
➔ Consider of additional stormwater flow from 7200 Main
➔ Coordinate with 7200 Main development for other features
➔ Protect Meyerland area from future flooding

3. Brays Bayou between Fannin St. and Greenbriar St.

4. Greenbriar Bridge

5. Background Research + Modeling

6. Project Brays
➔ Funded by US Army Corps and HCFCD
➔ Comprehensive re-design of Brays Bayou
◆ Channel Modifications
◆ Bridge Replacement/Renovation
◆ New Detention Area
➔ Aimed at mitigating riverine flooding throughout Brays Bayou Watershed
➔ Status:
◆ Upper Reach: Completed
◆ Middle Reach: In Progress
◆ Lower Reach: In Progress
➔ Scheduled to be completed in 2021

7. Project Brays Proposed Improvements

8. 100-year Floodplain (TSARP Model - 2004)

9. 100-year Floodplain (Current Conditions - 2010)

10. 100-year Floodplain (Post Project Brays - 2021)

11. 100-year Floodplain (TSARP) at Site Location

12. 100-year Floodplain (Post Project Brays) at Site Location

13. Bridge - Current Conditions

14. Concept Design

15. OPTION 1: Widen the Channel

16. HEC-RAS Geometry for Greenbriar Section
Main Street
Greenbriar Street
Fannin Street

17. Cross Section Comparison - Downstream (RS 56478)
Current 100-yr Level (44.07 ft)
PPB 100-yr Level (43.47 ft)
PPB Geometry
Current Geometry

18. OPTION 1: Widen the Channel -- BRIDGE

19. OPTION 2: Retaining Wall

20. HEC-RAS Geometry for Greenbriar Section
Main Street
Greenbriar Street
Fannin Street

21. Cross Section Comparison - Upstream (RS 59882)
Current 100-yr Level (45.70 ft)
PPB 100-yr Level (44.96 ft)
PPB Geometry
Current Geometry

22. OPTION 2: Retaining Walls -- BRIDGE

23. Existing Plan View of Bridge Deck

24. 87.0’
Bridge Tie-Ins With Existing Roads
87.0’
5% Grade 4.35’

25. Proposal

26. Modified Scenario
➔ Retaining walls and some
widening on both banks
from Main to Greenbriar
➔ Retaining walls and
substantial widening on the
right bank from Greenbriar
to Fannin

27. Modified HEC-RAS Geometry Examples (Upstream - RS 58740 )
Modified Geometry
PPB Geometry

28. Modified HEC-RAS Geometry Examples (Downstream - RS 57958)
Modified Geometry
PPB Geometry

29. Modified Scenario Results - RS 59882
Modified Geometry
PPB Geometry
Modified 100-yr Level
PPB 100-yr Level
44.71 ft 44.96 ft

30. Modified Scenario Results - RS 56478
Modified Geometry
PPB Geometry
Modified 100-yr Level
PPB 100-yr Level
43.47 ft 43.37 ft

31. Proposed Bridge Cross-Section

32. Proposed Plan View of Widened Bridge Deck

33. Impact of Proposed Modifications
➔ Modifications along the Main to Fannin portion of the channel should not have
drastic adverse effects on downstream sections.
➔ According to the 100-year floodplains, both current and post project brays, the
areas downstream of our site already face a much lower inundation hazard
than the middle and upper reaches.

34. Moving Forward

35. Brays Bayou
➔ Finalize channel modifications for Main to Fannin segment
➔ Add additional cross sections to existing HEC-RAS geometry
➔ Perform unsteady state HEC-RAS analysis
➔ Incorporate additional flow from hotel if necessary

36. Proposed HEC-RAS Geometry Modification

37. Bridge
➔ Finalize aesthetic design with 7200 Main St. group
➔ Determine appropriate foundations
➔ Superstructure/Substructure design of the bridge

38. Meyerland

39. May 2015 Storm - Comparison of Flooding to Current 100-year Floodplain

40. May 2015 Storm - Damage Reports in Meyerland

41. 100-year Floodplain (Post Project Brays) at Meyerland

43. Appendix

44. Channel Profile
Fannin Greenbriar Main
Direction of Flow

45. Construction

46. Green Space
➔ Finalize design for green space with hotel
➔ Ensure that all trails are integrated smoothly

47. Meyerland 100-yr Floodplain - Current Conditions v. Post Project Brays