Review and discuss an update of the Brazos River Bank Erosion Study.

In 2011 the City identified the need to develop a more robust emergency action plan related to riverine flood events and coordination with Fort Bend County and the levee improvement districts. This was completed in 2012 and included as a part of the City's Emergency Operations Plan shortly after. This plan was put to good use over the past three years with record rainfalls occurring within the lower river basin as well as Hurricane Harvey's impacts.

 

An issue that was identified through the development of the Emergency Action Plan was the lack of an accurate flood forecasting model for the lower Brazos River basin. In 2014 discussions, lead by the Brazos River Authority (BRA), began regarding a more realistic model for the lower basin. BRA sought partnerships with every county and some cities within the lower basin as well as some special districts that would partner with them and the Texas Water Development Board (TWDB) for funding a complete lower basin study. The City was included and officially joined last summer with the City Council's approval of the interlocal agreement with BRA for the Lower Brazos River Flood Forecasting Study. This study will be complete later this year and has been updated and calibrated with the past rain/flood events and Hurricane Harvey. 

 

Following the flooding events in 2015, 2016, and 2017, severe erosion along the Brazos River at several locations had already occurred. The erosion rates are significantly higher than what has been experienced on the river in the past 30 years. The City has determined that it is important to monitor and assess the projected loss of river bank and how this loss will threaten infrastructure within the City such as bridges, levees, parks, roads and utilities. It is also important that this effort be closely coordinated with Fort Bend County and other stakeholders that might be impacted by the rivers movement.

In December 2017, the City Council authorized a professional service contract with Huitt-Zollars Inc., to conduct a study of the Brazos River Bank Erosion along the 9 miles of river within Sugar Land city limits. The Engineering Department will present to City Council an update of the project activities completed in the study including:

 

1. Topographic survey of the Brazos River banks at critical erosion areas

2. Development of a methodology with Huitt-Zollars and Texas A&M University to determine risks and consequences associated with erosion at areas of interest within the City of Sugar Land.

3. Detailed geomorphology analysis of the Brazos River erosion using the available hydrologic and hydraulic models with the latest information and refine the river movement projections.

4. Analysis of probability of failure and consequences of bank failure.

Staff will also discuss the next steps of the project. The following activities are anticipated to be completed by May 2018:

 

1. Identify possible sources of funding for potential improvements and make recommendations on  regulatory actions and assist Fort Bend County in developing more detailed budget projections needed to address river erosion within the city limits and possibly the county.

2. Conduct workshops and informational meetings with LIDs, Fort Bend County and TxDOT representatives to share the findings and share information concerning their plans to address bank erosion along the Brazos River.

 

Once the project is completed, staff plans to present the study results to the City Council in a future workshop.