On June 29, 2021, Harris County Commissioners approved two contracts for preliminary engineering on the Kingwood Diversion Ditch and Taylor Gully Projects. This week, I’ve been getting reports of boots on the ground. So I grabbed my camera and went looking for activity this morning. I found a soil survey truck at Kingwood Drive next to the Diversion Ditch. I also found regular surveyors on Taylor Gully about a block south of Woodridge Village.
Both activities are among the first steps in preliminary engineering. And both are among the first steps in finding flood-mitigation solutions for a huge percentage of Kingwood’s population.
Taylor Gully Objectives and Scope
HCFCD has asked Idcus, Inc. to develop up to five conceptual alternative scenarios for modifying Taylor Gully. Alternative scenarios may include:
- Expanding Detention On Woodridge Village Site so that no channel improvements are necessary.
- Determining amount of detention and channel improvements necessary to ensure no adverse impact all the way to Lake Houston.
- Finding the optimum balance between maximum flood protection and minimum construction costs.
- Channel and basin layouts
- Estimates of benefits for various levels of storms (100-year, etc.)
- Right-of-way requirements
- Cost estimates for right-of-way acquisition, engineering and construction management.
- Performance metrics, i.e., estimated acreage of land inundation, number of structures in floodplain, number of structures flooded and miles of inundated roadway.
- A scoring matrix to rank alternatives.
Kingwood Diversion Ditch Objectives and Scope
HCFCD hired Neel-Schaffer, Inc. for preliminary Kingwood Diversion Ditch engineering. They must:
- Evaluate existing site conditions, previous studies, other projects that could affect this one, topography, rights-of-way, utilities, and soil surveys.
- Evaluate existing bridges
- Conduct and H&H analysis to assess existing and proposed conditions (from 2-year to 500-year storms).
- Analyze Channel Improvements including the:
- Impact of TIRZ #10’s latest design to replace the Northpark Bridge
- Diversion structure at the confluence of Bens Branch and the Diversion Channel
- Drop structures in lieu of a concrete lined channel to minimize high velocities due to the steep grade between
Walnut Lane and Deer Ridge Estates Blvd.
- Develop phased construction plans based on available funding, potential impacts and benefits.
- Conduct two public engagement meetings and coordinate with community groups.
- Geotechnical investigations, i.e., bridge borings
- Environmental assessment
- “Jurisdictional” determination. Does this channel fall under the jurisdiction of the Army Corps as it nears the West Fork? If so, channel design may need to be altered.
- Determination of detention pond requirements
- Exploration for subsurface utilities
- Obtaining permits from the Corps
- Landscape architect services
Why These Two Projects First?
Both of these projects evolved from the Kingwood Drainage Analysis finalized late last year. That study identified nine channels that needed improvement. These two were recommended for immediate help because:
- They help the largest number of people.
- HCFCD already owns land to expand and deepen the Diversion Ditch.
- Diversion Ditch enhancement will immediately take pressure off Ben’s Branch, and help flooding there.
Note that Ben’s Branch has already gone through a four-phase major maintenance project designed to restore its original conveyance.
Here is Harris County Flood Control District’s Summary of Results from the 600-page Kingwood Area Drainage Analysis.
A Good Sign
Both of these projects go far beyond maintenance, which portions of both of these ditches have already received. While we’re still far from construction, the work that kicked off this week will improve flood safety for a large part of Kingwood.
Posted by Bob Rehak on 8/4/2021
1436 Days since Hurricane Harvey