On June 29, 2021, Harris County Commissioners approved two contracts for preliminary engineering on Taylor Gully and the Kingwood Diversion Ditch. The Taylor Gully project includes looking at Woodridge Village in Montgomery County to possibly expand detention-pond capacity there. See more below.
Taylor Gully Project
Harris County Flood Control District (HCFCD) awarded Idcus, Inc. a $180,555 preliminary engineering contract to develop up to five conceptual alternative scenarios for modifying Taylor Gully. HCFCD and Idcus will then select three scenarios for more detailed analysis. Idcus must perform the work within 300 days of the Notice to Proceed.
The alternative modeling scenarios may include:
- Preferred Channel Alternative: This would look at improving the slope, width and lining of channel in conjunction with the existing detention on the Woodridge Village site. This purpose: to determine if the existing detention and proposed channel improvements suffice to mitigate flooding.
- Expanded Detention: This would look at expanding the existing stormwater detention on the Woodridge Village site so that no channel improvements are necessary.
- Alternative Channel/Detention: This would look at a combination of the two scenarios above. It would determine the amount of additional detention and channel improvements necessary to ensure no adverse impact all the way to Lake Houston.
- Optimization Alternative: Building on the alternatives above, this effort would examine additional alternatives to produce a no-adverse-impact solution while maximizing the flood mitigation and minimizing construction costs.
Deliverables for the alternatives include:
- 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 the alternatives.
The scope also includes, when necessary:
- Hydrologic and hydraulic analysis
- Soil sampling
- Environmental site assessment
- Subsurface utility exploration
- Landscape architecture
Finally, Idcus will hold two public engagement meetings near the beginning and end of the project and consult with community groups such as KSA.
Kingwood Diversion Ditch
HCFCD entered into a contract with Neel-Schaffer, Inc. for $437,685 for preliminary engineering on the Kingwood Diversion Ditch. Within 300 days,Neel-Schaffer 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.
HCFCD may also require Neel-Schaffer to provide addition services when necessary, such as:
- Geotechnical investigations, i.e., bridge borings
- Environmental assessment
- “Jurisdictional” determination. Does this channel fall under the jurisdiction of the Army Corps? If so, channel design may need to be altered.
- Determination of detention pond requirements
- Exploration for subsurface utilities
- Obtaining permits from the Corps
- Providing Landscape Architect services
For Complete Text of Contracts…
The first half of each link below contains contract details such as compensation. The second half contains the scope of work.
They were items 146 and 147 respectively on the agenda for the 6/29/21 Commissioner’s Court meeting.
In general, the critical path for each of these projects will follow the project-lifecycle pattern of all HCFCD projects.
- Conduct public meeting
- Develop, review and prioritize alternative designs
- Commissioner’s court reviews and votes on recommendation
- Move to final design of selected alternative with same company
- Engineering company develops construction specs
These were two of many such contracts approved in the last Commissioners Court meeting.
Both came out of the Kingwood Drainage analysis. More on projects affecting other parts of the Lake Houston Area in future posts.
Posted by Bob Rehak on 7/3/2021
1404 Days after Hurricane Harvey