On August 24th, Dr. William R. Dupré , Professor Emeritus of Earth & Atmospheric Sciences from the University of Houston, gave a presentation at the Kingwood Community Center sponsored by the Houston Geological Society. The presentation is titled Flooding and Floodplains in the Houston Area: Past, Present, and Future. Professor Dupre’ has given ReduceFlooding.com permission to post his presentation. It consists of two parts. Together, they will help you understand how and why floodplains change over time.
Urbanization is just one of many factors cited by Dr. Dupré that increase flooding.
The Basics of Flooding, Floodplains and Measurement
The difference between drainage basins, networks and watersheds
How stream gages work
How and where to find flood data (USGS, SJRA, Harris County Flood Warning System)
How to compare hydrographs from different locations and assess your risk of flooding
The difference between annual recurrence intervals and annual exceedance probabilities
How to understand flood maps
Assumptions behind flood plain calculations
Different types of flooding (overbook, ponding, sheet flow, etc.)
At the end of Part 1, Dupré shows how some of these concepts apply to different watersheds within Harris County and discusses how flooding dangers differ in various parts of the County.
Changing land use, (i.e., urbanization, prairie restoration, etc.)
Structural changes (dams, levees, channelization and detention/retention basins)
Changing climate
Part 2 concludes with a discussion of changing approaches to flood control and a brief discussion of the recently approved Harris County flood bond.
Do Sand Mines Play a Role?
Part 2 includes a discussion of sand mining under “Causes of Changes in Sediment and Sedimentation. Dupré talks about different types of sand mines and their impacts. While the professor and I disagree about the interpretation of several satellite images, we agree wholeheartedly about the need to locate pits outside of a ‘channel migration’ zone, as regulations in Washington state and Arizona require.
The danger, he says, is that rivers can migrate to and through sand mine dikes. If this happens after abandonment of the mine, no one will me there to repair the dikes and the river will reroute itself through the pit, carrying stored sediment downstream.
Who Will Benefit from This Presentation
If you enjoy earth sciences, as I do, these presentations will feel like going back to college. If you’re simply a homeowner trying to figure out why you flooded, you’ll find lots of food for thought in these two presentations. If you’re debating whether to buy flood insurance, these presentations will make you a believer.
Key Messages
One of the key takeaways from Part 1 is that you should not think of the 100-year (1%) floodplain as a bright line where you’re safe on one of it and not safe on the other. Dupré calls that choice a “false binary.” He urges people to think of flood plains as ever shifting and flood plain boundaries as very fuzzy lines, much like the cone of uncertainty used for hurricane path prediction. The width of the line represents the margin of error behind the calculation of probabilities.
After reviewing Part 2, you should come away with a better appreciation for how gradual, almost unnoticeable changes in your environment can increase your flood risk.
Remember Flood Control Presentation At Community Center on 9/17
Matt Zeve, Director of Operations for Harris County Flood Control, will also discuss flood map revisions in his upcoming talk at the Kingwood Community Center on September 17 at 6:30. Don’t forget to mark your calendar.
Posted by Bob Rehak on September 11, 2018
378 Days since Hurricane Harvey and 17 years since 9/11
00adminadmin2018-09-11 17:09:482018-09-11 17:11:10Flooding and Floodplains in the Houston Area: Past, Present, and Future
Mark your calendar. Houston City Council Member Dave Martin will host a town hall meeting on Tuesday, October 9 at 6:30 p.m., at the Kingwood Community Center, 4102 Rustic Woods, Kingwood, TX 77345. The community is invited to attend and hear from city and community representatives about ongoing projects, issues and community news related to the Kingwood and Lake Houston areas of District E.
Mayor Turner on Rebuild Houston and Fire Dept. Salaries
This fall’s town hall meeting will include a presentation from Mayor Sylvester Turner who will speak on the Rebuild Houston and fire salary referendums that will appear on the November 6 ballot. All registered voters within the boundaries of the City are urged to attend.
Costello, Odum and Zeve on Post-Harvey Mitigation
Residents will also hear from Stephen Costello, City of Houston Chief Resiliency Officer and Marvin Odum, Chief Recovery Officer, on the progress made to rebuild the City post-Harvey. Harris County Flood Control Chief Operations Officer, Matt Zeve, will provide a post-Harris County Flood Control Bond update.
Townhomes on Marina Drive in Forest Cove more than one year after Hurricane Harvey.
Sarman on TIRZ Projects, Huberty on Upcoming Legislation
Stan Sarman, the Chair of the TIRZ 10 board will provide information on a variety of projects including the Northpark Drive Mobility Improvement Project, and the status of area intersection improvements. There will be an update on the Lake Houston Debris Removal Project provided by a member of the City of Houston Solid Waste Department Team. State Representative Dan Huberty is confirmed to provide insight on the upcoming legislative session.
Loop 494 Expansion, San Jacinto Greenway Project and More
For those that arrive to the Kingwood town hall early, there will be information tables available starting at 5:30 p.m. from Harris County Precinct 4 to discuss their upcoming projects in Forest Cove, from the Texas Department of Transportation to educate residents on the expansion of TX Loop 494, and from the Houston Parks Board to provide information on the upcoming San Jacinto Greenway Project. The Houston Department of Neighborhoods and the Houston Police Department’s Kingwood Division will also be on site with information available to residents before and after the town hall meeting.
For more information, please contact Council Member Martin’s office at (832) 393-3008 or via email at districte@houstontx.gov.
Posted on September 9, 2018, by Bob Rehak
376 Days since Hurricane Harvey
00adminadmin2018-09-09 20:18:032018-09-09 20:20:26Houston Council Member Dave Martin To Host Kingwood Town Hall Meeting on October 9
The U.S. Army Corps of Engineers should begin dredging the West Fork of the San Jacinto River next week. The Corps expected to begin dredging this week, but a part failure for one of the dredges caused a slight delay. A replacement part is being remanufactured and shipped to the command site. The replacement part will help hold the dredge in place during operations and should arrive within days.
First dredge has been moved into river and is awaiting one final part.
With the exception of the replacement part, the first dredge is now virtually completed. It is 27 feet wide, 90 feet long and weighs 270 tons.
Second Dredge Also Now In the Water
A second dredge is also nearing completion. It is electrically powered and has also entered the river for final assembly. No pictures of it are available at this time. In the meantime, the rest of the operation is proceeding as scheduled.
4.5 Miles of Pipe
Workers have welded and weighted 4.5 miles – or almost 24,000 feet – of 24-inch dredge pipe made from 40-foot sections. The pipe will pump sand and sediment back to storage pits (placement sites) on both the north and south sides of the San Jacinto river. Each string of pipe is 1000 feet long. Booster pumps will connect the strings to keep sediment moving up-river and uphill.
Dredge pipe being moved into the West Fork of the San Jacinto in preparation for the start of dredging. Each of these strings is 1000 feet long. They weigh hundreds of thousands of pounds. These 24-inch-diameter pipes will eventually move more than 1.8 million cubic yards of sediment to two placement areas.
A tender boat moves dredging pipeline into place along the banks of the San Jacinto river. Approximately 4.5 miles of 1,000 – foot sections of High Density Polyethylene (HDPE) Pipe is being positioned for use next week when dredging should begin.
Even though the start date has been delayed, the date for completion has not.
Dredging Safety Warning
Jet skiers and recreational boaters have been sighted in the vicinity of the dredge command site. Dredging safety officers are asking West Fork San Jacinto recreational boaters to stay clear of submerged pipes and dredge platforms.
Stay away from this section of the river for your own safety. Even though you may be able to see operators, they may not be looking out for you as they struggle to move equipment weighing hundreds of tons. Operators are focused on their job, not you.
As the operational tempo of this project increases, so will the risk of accidents. So please keep your distance.
Posted September 8, 2018 by Bob Rehak
375 Days since Hurricane Harvey
00adminadmin2018-09-07 18:05:432018-09-08 11:03:22Dredging Almost Ready to Begin
Flooding and Floodplains in the Houston Area: Past, Present, and Future
On August 24th, Dr. William R. Dupré , Professor Emeritus of Earth & Atmospheric Sciences from the University of Houston, gave a presentation at the Kingwood Community Center sponsored by the Houston Geological Society. The presentation is titled Flooding and Floodplains in the Houston Area: Past, Present, and Future. Professor Dupre’ has given ReduceFlooding.com permission to post his presentation. It consists of two parts. Together, they will help you understand how and why floodplains change over time.
Urbanization is just one of many factors cited by Dr. Dupré that increase flooding.
The Basics of Flooding, Floodplains and Measurement
In Part 1, Dupré focuses on the basics of flooding, flood plains and measurement. He begins by explaining:
At the end of Part 1, Dupré shows how some of these concepts apply to different watersheds within Harris County and discusses how flooding dangers differ in various parts of the County.
How and Why Floodplains Change Over Time
In Part 2, Dupré goes into greater detail about how floodplains change over time. The four main reasons include:
Part 2 concludes with a discussion of changing approaches to flood control and a brief discussion of the recently approved Harris County flood bond.
Do Sand Mines Play a Role?
Part 2 includes a discussion of sand mining under “Causes of Changes in Sediment and Sedimentation. Dupré talks about different types of sand mines and their impacts. While the professor and I disagree about the interpretation of several satellite images, we agree wholeheartedly about the need to locate pits outside of a ‘channel migration’ zone, as regulations in Washington state and Arizona require.
The danger, he says, is that rivers can migrate to and through sand mine dikes. If this happens after abandonment of the mine, no one will me there to repair the dikes and the river will reroute itself through the pit, carrying stored sediment downstream.
Who Will Benefit from This Presentation
If you enjoy earth sciences, as I do, these presentations will feel like going back to college. If you’re simply a homeowner trying to figure out why you flooded, you’ll find lots of food for thought in these two presentations. If you’re debating whether to buy flood insurance, these presentations will make you a believer.
Key Messages
One of the key takeaways from Part 1 is that you should not think of the 100-year (1%) floodplain as a bright line where you’re safe on one of it and not safe on the other. Dupré calls that choice a “false binary.” He urges people to think of flood plains as ever shifting and flood plain boundaries as very fuzzy lines, much like the cone of uncertainty used for hurricane path prediction. The width of the line represents the margin of error behind the calculation of probabilities.
After reviewing Part 2, you should come away with a better appreciation for how gradual, almost unnoticeable changes in your environment can increase your flood risk.
Related Reading
The points Dr. Dupré makes support the conclusions drawn in a report by the Bayou City Initiative titled “Houston A Year after Harvey: Where We Are and Where We Need to Be,” especially the section on the need to revise outdated flood maps.
Remember Flood Control Presentation At Community Center on 9/17
Matt Zeve, Director of Operations for Harris County Flood Control, will also discuss flood map revisions in his upcoming talk at the Kingwood Community Center on September 17 at 6:30. Don’t forget to mark your calendar.
Posted by Bob Rehak on September 11, 2018
378 Days since Hurricane Harvey and 17 years since 9/11
Houston Council Member Dave Martin To Host Kingwood Town Hall Meeting on October 9
Mark your calendar. Houston City Council Member Dave Martin will host a town hall meeting on Tuesday, October 9 at 6:30 p.m., at the Kingwood Community Center, 4102 Rustic Woods, Kingwood, TX 77345. The community is invited to attend and hear from city and community representatives about ongoing projects, issues and community news related to the Kingwood and Lake Houston areas of District E.
Mayor Turner on Rebuild Houston and Fire Dept. Salaries
This fall’s town hall meeting will include a presentation from Mayor Sylvester Turner who will speak on the Rebuild Houston and fire salary referendums that will appear on the November 6 ballot. All registered voters within the boundaries of the City are urged to attend.
Costello, Odum and Zeve on Post-Harvey Mitigation
Residents will also hear from Stephen Costello, City of Houston Chief Resiliency Officer and Marvin Odum, Chief Recovery Officer, on the progress made to rebuild the City post-Harvey. Harris County Flood Control Chief Operations Officer, Matt Zeve, will provide a post-Harris County Flood Control Bond update.
Townhomes on Marina Drive in Forest Cove more than one year after Hurricane Harvey.
Sarman on TIRZ Projects, Huberty on Upcoming Legislation
Stan Sarman, the Chair of the TIRZ 10 board will provide information on a variety of projects including the Northpark Drive Mobility Improvement Project, and the status of area intersection improvements. There will be an update on the Lake Houston Debris Removal Project provided by a member of the City of Houston Solid Waste Department Team. State Representative Dan Huberty is confirmed to provide insight on the upcoming legislative session.
Loop 494 Expansion, San Jacinto Greenway Project and More
For those that arrive to the Kingwood town hall early, there will be information tables available starting at 5:30 p.m. from Harris County Precinct 4 to discuss their upcoming projects in Forest Cove, from the Texas Department of Transportation to educate residents on the expansion of TX Loop 494, and from the Houston Parks Board to provide information on the upcoming San Jacinto Greenway Project. The Houston Department of Neighborhoods and the Houston Police Department’s Kingwood Division will also be on site with information available to residents before and after the town hall meeting.
For more information, please contact Council Member Martin’s office at (832) 393-3008 or via email at districte@houstontx.gov.
Posted on September 9, 2018, by Bob Rehak
376 Days since Hurricane Harvey
Dredging Almost Ready to Begin
The U.S. Army Corps of Engineers should begin dredging the West Fork of the San Jacinto River next week. The Corps expected to begin dredging this week, but a part failure for one of the dredges caused a slight delay. A replacement part is being remanufactured and shipped to the command site. The replacement part will help hold the dredge in place during operations and should arrive within days.
First dredge has been moved into river and is awaiting one final part.
With the exception of the replacement part, the first dredge is now virtually completed. It is 27 feet wide, 90 feet long and weighs 270 tons.
Second Dredge Also Now In the Water
A second dredge is also nearing completion. It is electrically powered and has also entered the river for final assembly. No pictures of it are available at this time. In the meantime, the rest of the operation is proceeding as scheduled.
4.5 Miles of Pipe
Workers have welded and weighted 4.5 miles – or almost 24,000 feet – of 24-inch dredge pipe made from 40-foot sections. The pipe will pump sand and sediment back to storage pits (placement sites) on both the north and south sides of the San Jacinto river. Each string of pipe is 1000 feet long. Booster pumps will connect the strings to keep sediment moving up-river and uphill.
Dredge pipe being moved into the West Fork of the San Jacinto in preparation for the start of dredging. Each of these strings is 1000 feet long. They weigh hundreds of thousands of pounds. These 24-inch-diameter pipes will eventually move more than 1.8 million cubic yards of sediment to two placement areas.
A tender boat moves dredging pipeline into place along the banks of the San Jacinto river. Approximately 4.5 miles of 1,000 – foot sections of High Density Polyethylene (HDPE) Pipe is being positioned for use next week when dredging should begin.
Even though the start date has been delayed, the date for completion has not.
Dredging Safety Warning
Jet skiers and recreational boaters have been sighted in the vicinity of the dredge command site. Dredging safety officers are asking West Fork San Jacinto recreational boaters to stay clear of submerged pipes and dredge platforms.
Stay away from this section of the river for your own safety. Even though you may be able to see operators, they may not be looking out for you as they struggle to move equipment weighing hundreds of tons. Operators are focused on their job, not you.
As the operational tempo of this project increases, so will the risk of accidents. So please keep your distance.
Posted September 8, 2018 by Bob Rehak
375 Days since Hurricane Harvey