Harris County Flood Control District (HCFCD) contractors have completed removal of virtually another 10,000 cubic yards of sediment that had accumulated in Bens Branch between Rocky Woods Drive and Kingwood Drive. While a little cleanup work and equipment removal remains, we can call this job “well done.”
Scope of Work Completed
HCFCD widened and deepened half mile stretch of the creek/ditch. Flood Control also re-sloped the banks, straightened the flow lines, replaced backslope interceptor drains, restored the original conveyance of the ditch, and replanted grass.
Tens of Millions in Nearby Damages during Harvey
During Harvey, dozens of homes flooded along both sides of this channelized stream. So did Kingwood High School and the old H-E-B shopping center north of Kingwood Drive. The shopping center is still mostly vacant because of flood damage. And the Humble ISD spent $70 million to restore Kingwood High School which flooded to the second floor.
Approximately 1000 Truckloads of Sediment Removed
Given that your average dump truck holds about 10 cubic yards, contractors removed about a 1000 truckloads of sediment during this phase of the Bens Branch project.
The first photo below was taken in January before the start of the project. I shot the rest on April 16.
Bens Branch at Rocky Woods in January 2021 before start of clean-out project.Bens Branch at Rocky Woods after completion of project on April 16, 2021. The greenish tinge on the slopes is hydro mulch. Hydro mulch is grass seed embedded in a gelatin which can be sprayed on the slopes. Nutrients in the gelatin help ensure that grass will begin to grow in the least amount of time possible, hopefully before heavy rains can erode the slopes.In fact, new grass shoots are already poking out of this ground. This new drain at Laurel Garden replaces one that had collapsed and become almost totally blocked. The average service life of galvanized corrugated metal pipe is up to 40 years.New entrance to drain behind maintenance road on side of ditch.Note the warning. Waste dumped in these drains blocks them and contributes to neighborhood flooding. Even if waste does not block the drain, it can wind up in Lake Houston or Galveston Bay.Looking back upstream toward the new drain at Laurel Garden.This shot dramatizes the proximity of Kingwood High School to the ditch. Looking downstream. Notice Lake Houston in the background in the upper left.Looking upstream from Town CenterLooking downstream from the middle of the Bens Branch project toward Town Center.Only removal of the temporary crossing and three pieces of equipment (lower left) remain.Every building in the background flooded during Harvey.
No More Bens Branch Projects Scheduled At This Time
This was the fourth and final phase of Bens Branch restoration. Previous projects addressed Bens Branch from:
HCFCD says it has no plans at this time to address the portion from the Y to the West Fork near Kings Harbor.
No one can guarantee that this work will prevent a future flood, but it will certainly make one less likely.
Thanks to the women and men of HCFCD and their contractors who kept the Bens Branch project moving through the pandemic. And to the US Department of Agriculture’s National Resources Conservation Service which provided partial funding.
Thanks also to the Bear Branch Trail Association, Kingwood Service Association and Kings Forest CA. All helped provide access to the project area across their property.
Onward to other projects such as Woodridge Village Detention, Taylor Gully restoration, and Diversion Ditch expansion. More on those in future posts.
Posted by Bob Rehak on April 17, 2021
1328 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/04/20210416-DJI_0406.jpg?fit=1200%2C900&ssl=19001200adminadmin2021-04-17 11:26:412021-04-19 12:56:36HCFCD Completes Removal of Another 10,000 Cubic Yards From Bens Branch
According to Jose Pedraza who works for Stuart Consulting, the contractor began work at the upstream/Rocky Woods Drive end of the site and is moving downstream. So far, they have completed about 1500 linear feet of work on both sides of the stream.
At the start of the project, surveyors found that accumulated sediment had severely constricted the conveyance of the channel.
Ben’s Branch at start of project in January. The area between the red lines filled with sediment since Friendswood first constructed the ditch in the 1970s.Looking south from between Rocky Woods and Valley Way Drive.This is how the section above looks today from a drone.Photo taken 3/13/2021.Note Kingwood High School in upper right.Farther downstream, looking east toward Kingwood Town Center in background. Contractors have just started working on this reach of the stream.Looking back upstream toward the west and Kingwood High School, you can see same reach from the opposite direction.
Work to Date Has Included…
So far, the contractor has:
Conducted excavation and off-site disposal
Installed import fill, 3×5 granular fill, and grade 1 riprap
Graded channel side slopes on both sides of the channel for 1500 linear feet.
Expected Completion by July 4 or Earlier
Due to weather and other small delays, projected duration of the job increased from 150 to 168 days. Expected completion was extended to July 4, 2021. However, based on recent on-site inspection reports, work is now moving faster. So, with luck, the finish date may be pushed forward into June once more.
Preserving Property, Tax Dollars
Homes on both sides of this stream flooded during Harvey. So did Kingwood High School. The building flooded to the second floor. It suffered $67 million dollars in damages and lost another $10 million in contents.
Hopefully, this project will reduce flood risk. Conveyance of the channel had been reduced from a 100-year level of service to a 2-year level in some places. A 2-year level of service means that the creek will flood in a 2-year rain. The goal of this project is to restore the channel to its original conveyance capacity. That includes straightening, widening and deepening clogged parts of the channel.
Posted by Bob Rehak on 3/15/2021
1294 Days after Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/03/20210313-DJI_0295.jpg?fit=1200%2C900&ssl=19001200adminadmin2021-03-15 12:34:582021-03-15 12:43:32Bens Branch Clean-out North of Kingwood Drive Already 40% Complete
The Harris County Flood Control District has released a Report Summary of results from the 600-page Kingwood Area Drainage Analysis. HCFCD will hold an online community meeting Tuesday night to discuss the results. It may help to review this summary or HCFCD’s before the meeting.
Objective: Protect Homes/Businesses from Bigger Rains
The objective of the Kingwood Area Drainage Analysis: to provide the knowledge needed to protect homes and businesses from flooding in a 100-year (1% chance) rain as defined by the new, higher Atlas-14 Rainfall Probability Statistics. Said another way, the engineers want to make sure that if you bought a home outside the 100-year flood plain, that you STILL won’t be flooded in a 100-year rain. Engineers call that “the 100-year Level of Service (LOS).”
Steams, ditches and channels evaluated as part of the Kingwood Area Drainage Analysis. Please note ditch numbers for any comments you make as the flood control district identifies them by that number.It will help communication.
What Study Included
To accomplish their objectives, engineers:
Evaluated historical floods and mapped flood damage
Created hydrologic and hydraulic models to quantify flooding risks along streams, channels and open ditches
Identified drainage issues associated with storm sewers and streets
Performed an overland flow analysis
Used LiDAR, record drawings, previous surveys and data collected in the field
Incorporated the impact of potential storm sewer improvements on channel capacity
Quantified detention capacity needed to prevent increasing flows into Lake Houston
Determined how many structures would benefit from each improvement (or planned future improvement)
Researched rights-of-way and flowage easements
Recommended channel-capacity improvements
Recommended bridge and culvert improvements
Developed preliminary cost estimates
Recommended construction sequencing
In places where ditches provide less than a 100-year level of service, storm sewers cannot empty into them during a 100-year rain. When that happens, water backs up into streets and can flood homes. So engineers are looking at the performance of the drainage system from end to end in conjunction with the City of Houston.
Limitations: What Study Does NOT Include
The study does NOT:
Include new topographic surveys
Evaluate improvements for greater than 100-year events
Examine Montgomery County issues except for North Park Drive
Identify sites for detention basins
Duplicate the San Jacinto River Basin Master Drainage Plan or associated sedimentation and sand trap studies
No construction is included as part of this project. This project will only lay the groundwork for subsequent construction projects.
Study Identified Nine Channels That Need Improvement
Not surprisingly, the Kingwood Area Drainage Analysis found that many channels do not need improvements. Said another way, they already provide the required level of service. However, engineers identified nine channels that DO need improvement to protect homes and businesses.
Six of those nine have rights-of-way controlled by HCFCD. They include:
For summary sheets of each recommended Kingwood Area Drainage Analysis project, click on the associated links. The Taylor Gully project will need to be re-analyzed if the Woodridge Village purchase goes through; that area could turn into a regional detention facility.
This table contains a summary of streams, channel types, ownership, current level of service, improvements, rights of way needed, cost estimates and detention estimates for all the projects considered in the Kingwood area.
Two Projects Recommended Immediately
Based on the results of the Kingwood Area Drainage Analysis, HCFCD recommends two projects: G103-38-00 (Kingwood Diversion Ditch) and G103-80-03.1B (Taylor Gully) move to the next phase: engineering design. Additionally, HCFCD recommends the Taylor Gully project be reanalyzed to determine how the use of Woodridge Village for detention could modify the recommended plan.
These two projects were chosen because:
They help the largest number of people.
HCFCD owns land to expand and deepen the Diversion Ditch.
Diversion Ditch enhancement will immediately take pressure off Ben’s Branch, and help flooding there.
Thus, these two projects address the three biggest needs. The remainder will have to wait for Capital Improvement funds.
First Step of Many
The Kingwood Area Drainage Analysis is a feasibility study that helped identify the problem areas. As you can see from the lifecycle diagram below, it represents the first step of several. The Flood Control District included $10 million in the bond fund (See F14) for Kingwood projects. That can be local-match seed money for attracting state and federal grants.
HCFCD will hold an online meeting Tuesday night. Engineers will describe the project and recommendations in more detail. You will also have a chance to interact with team members, make suggestions, and ask questions.
Or by phone at 855-925-2801 with Meeting Code: 9541
Please login a few minutes early. The Flood Control District has a brief survey on the login page that will help them track your concerns.
What the Flood Control District Needs from You
The Flood Control District needs to know about local issues that they may NOT have identified near you.
For example, culverts under Kingwood Drive for a ditch near me are almost totally blocked by sediment. That could have affected their analysis. And the stream may have correctable issues that could easily prevent future flooding.
Another example. The recommendations include taking out the low water crossing near Bear Branch Elementary School. Many kids use that to walk or bicycle to school. Removal without replacement would create a major inconvenience. It might also negatively affect downstream bridges damaged in previous storms.
A final example: the study did not recommend any changes to the bridge over Taylor Gully at Rustling Elms. However, many Elm Grove residents identified that as a major issue in two floods last year.
The Rustling Elms Bridge is a road over twin culverts, not a true open bridge like the one farther downstream in the background.
Please join the meeting Tuesday night and be prepared to discuss such issues. Volunteer your local knowledge. Speak up now or live with the results.
Credits
The Kingwood Area Drainage analysis cost $700,000. Funds from the 2018 Harris County Flood Bond and TIRZ 10 paid for this study.
Posted by Bob Rehak on 10/19/2020
1147 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/10/hvr7ksjet8llq3oonj3l.jpeg?fit=1599%2C1188&ssl=111881599adminadmin2020-10-19 16:50:002020-10-20 20:26:12Sneak Peak at Results of Kingwood Area Drainage Analysis; Review Before Meeting Tuesday Night
