A study by consulting firm Freese and Nichols looked at the value of adding flood gates to the Lake Houston Dam. It found that during Harvey, new gates would have lowered the level of flooding around Lake Houston by up to 1.9 feet depending on the number of gates added. Obviously, the gates by themselves won’t protect us from another Harvey, but they are an important part of a comprehensive solution that includes ongoing river dredging, ditch maintenance, debris removal, additional upstream retention, and better warning systems and more.
Modeling the Effect of More Gates on a Harvey-type Flood
Freese and Nichols conducted the gate study, which modeled flood levels only for the Hurricane-Harvey case. It did not address the impact of adding gates on smaller floods, such as those that occurred in 1994, 1998, 2001, 2015 and 2016.
Extent of modeling in Freese and Nichols study on the effects of adding floodgates to Lake Houston
Would Pre-release Help with a Storm as Big as Harvey?
Additional gates were originally proposed as a concept that could enable pre-release of water from Lake Houston as a flood mitigation strategy. The idea behind a pre-release strategy is to lower the level of a lake BEFORE a storm. The lake then has more capacity to absorb heavy rains before overflowing its banks and flooding residents, much as the City of Houston did before a small flood at the end of March.
Pre-release is currently difficult for Lake Houston because the dam consists mainly of a spillway with a fixed height – 42.5 feet above mean sea level. The Lake Houston dam does have two small gates, but they have less than one tenth the capacity of the flood gates on Lake Conroe. This makes it difficult to coordinate discharges between the two lakes.
The SJRA repeatedly cited fear of overloading the Lake Houston watershed as a reason for delaying its release from the Lake Conroe dam during Harvey. Additional gates might have reduced those concerns, encouraging the SJRA to release water earlier.
Theoretically, that could have reduced the volume of water coming down the west fork at the peak of the storm. At the peak, Lake Conroe’s release constituted one third of all the water coming down the West Fork where most of the damage occurred. It’s therefore easy to see how reducing the peak flow down the west fork could have spared hundreds of homes and businesses.
However, Freese and Nichols found that the volume of water coming into the lake during Harvey from multiple sources was too great to realize much benefit from pre-release. The amount pre-released would have quickly filled back up again – within a few hours.
Primary Benefit Comes from Additional Discharge Capacity
This does not mean that Freese and Nichols recommended against adding gates. They found that gates would have benefitted the community, but in a different way than originally anticipated. Surprisingly, they found that the largest reduction in flood levels came simply from the additional discharge capacity that the gates provided during the peak of the flood.
Freese and Nichols states in its conclusion, “Adding additional gates to the spillway at Lake Houston would be a feasible alternative to allow for additional discharge capacity to reduce the impact of very large flood events. … Though additional gates would provide the ability to lower the lake quickly in advance of an anticipated major flood event, the additional capacity of the gates would have far more impact on the flood level than any preliminary lowering of the lake.”
Cost/Benefit Ratio
Like many engineering studies, Freese and Nichols says that any decision to build the gates depends on whether elected officials find benefits worth the costs. However, the scope of the study did not include cost savings to home and business owners. So let’s look at that.
FEMA, the agency that would likely pay for most of the gates evaluates projects primarily on the number of people helped. They want to provide the most “benefit-per-buck” possible.
Looking at the world from FEMA’s Point of View
The City of Houston is currently in the process of developing the FEMA grant application. Mayor Sylvester Turner stated at a community meeting in Kingwood in March that he supported 10 additional gates, which he estimated would cost $47 million.
FEMA estimated in November of 2017 that 16,000 homes and 3,300 businesses in the Lake Houston area were damaged. Therefore, to reduce the impact of flooding, this project would require an expenditure of less than $2,500 per structure. Repairs to flooded structures in virtually all cases cost 10 to 100 times more than that. I know of at least one case where repairs cost $600,000. It doesn’t take many of those to equal the cost of the additional gates that the mayor proposed – $47 million.
The gates would completely eliminate flooding at the edge of the flood, and would reduce the depth of flooding inside of that.
It’s not clear at this point how many homes sit within that band where flooding could have been eliminated. Nor is there a precise estimate of damage to those homes.
Calculating the Value of Flood Reduction
Looking at homes that would seen reduced flooding, it’s important to note that the cost of repairs correlates highly with the level of flooding. According to Bill Fowler, a real estate tax expert and Co-Chair of the Lake Houston Area Grass Roots Flood Prevention Initiative, the Harris County Appraisal District is lowering valuations on homes by the amount of flooding they experienced.
Lowering flood levels usually lowers repair costs. Lower flood levels can also lower flood insurance costs, losses to insurance companies, damage to contents, and damage to vehicles. Value can be measured many ways.
It’s also important to note when calculating value in floods smaller than Harvey, pre-release might actually become a viable strategy and greatly reduce or eliminate flooding altogether. Freese and Nichols did not evaluate additional gates from that perspective; they considered only Harvey-level flooding.
Adding floodgates to Lake Houston will be a valuable flood mitigation tool. It must be viewed as an essential PART of the solution, not THE solution. Consider its value within the context of other mitigation efforts, such as dredging, ditch maintenance, and additional upstream storage capacity.
Posted June 10 by Bob Rehak
285 Days since Hurricane Harvey
00adminadmin2018-06-08 13:12:172018-06-10 01:08:00Freese and Nichols study finds more gates on Lake Houston dam could have lowered flood during Harvey
On Monday, June 11, two representatives from the U.S. Army Corps of Engineers (USACE) will meet Kingwood residents to discuss dredging of the West Fork of the San Jacinto River. The meeting, sponsored by the Lake Houston Area Grassroots Flood Prevention Initiative, will start at 6:30 PM at the Kingwood Community Center. The emergency dredging will be one of the first flood mitigation projects related to Hurricane Harvey to be implemented in the entire Houston area.
Some Details Known, Many Yet to be Revealed
The Corps finished survey work for the West Fork Dredging Project in April. Since then, Corps members have been busy evaluating their findings, determining project specifications, soliciting bids, and planning logistics. Initial estimates indicated they would move enough sand to fill the Astrodome two and a half times.
The Corps currently expects to open bids within a week of the Kingwood meeting and quickly make a selection. Bidders have been notified that they must start the project within five days. They must also staff the project so that they can finish within six months.
Bid documents indicate dredging will extend from River Grove Park to slightly past the West Lake Houston Parkway Bridge. Residents have raised questions about additional dredging in other areas, including near Lake Houston and on the East Fork.
The Corps has identified two disposal sites for the sand. Both are existing sand pits. The first is south of the river and east of US59; the second is north of the river and west of US59. Details pertaining to mobilization, removal methods, and the extent of dredging have not yet been revealed. At the time of bidding, two removal alternatives were under consideration: mechanical and hydraulic dredging.
Meet Two Corps Representatives
Featured speakers include two representatives from the Corps who will present details of the project and field questions from residents. They are Eduardo Irigoyen, the Project Manager, and Michael Garske, a hydraulic engineer and certified floodplain manager. Both are with the Corps of Engineers’ Galveston District office.
Eduardo Irigoyen, Project Manager
Eduardo Irigoyen, U.S. Army Corps of Engineers Project Manager
Eduardo (Eddie) Irigoyen currently serves as the Emergency Dredging Project Program Manager for the West Fork of the San Jacinto River, which is funded by the Federal Emergency Management Agency (FEMA).
Irigoyen has served as a Project Manager within the Corps since May 2015. He has extensive experience within USACE ranging from programs to construction management, operations and maintenance.
His current duties include managing the planning, scope, development, design, construction, and direction of several projects along the Texas Gulf coast.
Irigoyen is a native of Brownsville, Texas. He received a Bachelor of Science in Mechanical Engineering from The University of Texas at Brownsville in 2004.
Michael Garske, Hydraulic Engineer
Michael Garske, U.S. Army Corps of Engineers Hydrologist
Michael Garske has served as a Hydraulic Engineer and Certified Floodplain Manager for USACE since September 2014.
As one of the District’s lead hydraulic modeling engineers, he’s produced inundation mapping for White Oak, Brays, and Buffalo Bayou projects, helping local officials make accurate flood mitigation decisions.
He provided critical emergency modeling data during the Tax Day, Memorial Day and Harvey floods. He has also helped design dredging templates, ecosystem mitigation banks, and water storage systems; and demonstrated their effects on flood levels.
Garske grew up in Clear Lake. In 2014, he earned a Bachelor of Science degree in Maritime Systems Engineering and an Associate of Arts degree in Maritime Administration from Texas A&M University-Galveston.
Boating Safety Measures During Project
Boaters need to be aware of dredging activities. Ultimately, the project will restore navigation on the river to pre-Harvey conditions and allow the boat launch at River Grove Park to reopen. However, until completion of the project, boaters need to avoid work sites and dredging lines for their own safety.
Agenda Including Other Speakers
The meeting will start at 6:30 p.m. at the Kingwood Community Center 4102 Rustic Woods and last until 8. It will include:
Mark Micheletti, one of the two new SJRA board members from Kingwood, giving updates about SJRA flood mitigation projects.
Bill Fowler, co-chair of the Lake Houston Area Grassroots Flood Prevention Initiative and a real-estate tax expert, will talk about revised valuations from the Harris County Appraisal District.
Bob Rehak, host of ReduceFlooding.com, (or a representative from Harris County Flood Control) will give a brief overview of the upcoming Harris County flood bond.
Irigoyen and Garske will make brief presentations and take questions from the audience. Please attend and show the Corps your appreciation for their hard work and long hours on this project.
A representative from FEMA will also be there to answer questions about how communities can extend projects like dredging over the long term.
The meeting is free and open to the public, so please plan to attend.
Do Not Confuse This with Flood Bond Meeting
Please note: there has been some confusion between this meeting and the Harris County Flood Bond meeting because of their dates. The County Flood bond meeting, originally scheduled for June 14, is being rescheduled for July so that County Judge Ed Emmett can attend. A new day for that meeting has not yet been determined. The meeting with the Army Corps will happen as planned on Monday evening, June 11.
Posted June 8, 2018 by Bob Rehak
Thanks to Dianne Lansden and Jacque Havelka for Planning this Meeting
283 Days since Hurricane Harvey
00adminadmin2018-06-08 07:06:302018-06-08 20:20:23Mark Your Calendar: Meet U.S. Army Corps of Engineers Monday Night
In several places on this website, I’ve talked about sand mines on the West and East Forks of the San Jacinto River. Now, the sand miners are talking about this website – in Austin – to state legislators via their trade group, TACA also known as the Texas Aggregate and Concrete Association.
Fresh sand deposits after Harvey coming out of the sand mines on the west fork of the San Jacinto adjacent to Kingwood. Note that the height of the dune is engulfing several medium sized trees.
In the document, TACA makes direct references to photos and a presentation that appear on this website. “One might look at an aerial image or fly over these operations,” they say, “and errantly [emphasis added] speculate that these operations are a potential source of sediment in a stream or river.” Later they say, “…not all sand operator stock piles were flooded in the recent storm.” They also claim, “…sand operations help to mitigate flooding.”
Sand mine in Porter next to Caney Creek covers approximately 600 acres. This stockpile covers approximately 34 acres. Note erosion patterns from Harvey in this shot taken on 9/14/17. Thirty acres of Kingwood’s East End Park, just downstream from here, was covered with sand dunes up to ten feet high during Harvey.
Sand mines on the west fork of the San Jacinto adjacent to Kingwood. Note what appears to be a breach of the dike between the mine on the left and the river about two-thirds of the way up the left side of the photo. Also notice how close the dikes are to each side of the river bank. They leave little room to accommodate flood waters.
Sand mines on the west fork of the San Jacinto adjacent to Kingwood.
Harvey’s floodwaters breached dikes surrounding the sand mines on the west fork of the San Jacinto. This let sand escape. It was carried downstream and deposited in Humble, Forest Cove, Kingwood and Atascocita.
Please Read White Paper Carefully and Closely
I urge you to read The Societal and Environmental Benefits of Sand and Gravel Mining in its entirety and draw your own conclusions. I ask only that you read it very carefully and closely, as you would a contract, because in a sense, what we are talking about IS a social contract.
Sand mines are given a license to operate next to the source of drinking water for millions of people. Are these particular sand mines operating responsibly?
In upcoming posts, I will discuss research I’ve done into best management practices for sand mining.
Posted June 7, 2018 by Bob Rehak
282 Days since Hurricane Harvey
00adminadmin2018-06-07 02:53:382018-06-07 04:28:59TACA Spells Out Industry Position on Societal and Environmental Benefits of Sand Mining
Freese and Nichols study finds more gates on Lake Houston dam could have lowered flood during Harvey
A study by consulting firm Freese and Nichols looked at the value of adding flood gates to the Lake Houston Dam. It found that during Harvey, new gates would have lowered the level of flooding around Lake Houston by up to 1.9 feet depending on the number of gates added. Obviously, the gates by themselves won’t protect us from another Harvey, but they are an important part of a comprehensive solution that includes ongoing river dredging, ditch maintenance, debris removal, additional upstream retention, and better warning systems and more.
Modeling the Effect of More Gates on a Harvey-type Flood
Freese and Nichols conducted the gate study, which modeled flood levels only for the Hurricane-Harvey case. It did not address the impact of adding gates on smaller floods, such as those that occurred in 1994, 1998, 2001, 2015 and 2016.
Extent of modeling in Freese and Nichols study on the effects of adding floodgates to Lake Houston
Would Pre-release Help with a Storm as Big as Harvey?
Additional gates were originally proposed as a concept that could enable pre-release of water from Lake Houston as a flood mitigation strategy. The idea behind a pre-release strategy is to lower the level of a lake BEFORE a storm. The lake then has more capacity to absorb heavy rains before overflowing its banks and flooding residents, much as the City of Houston did before a small flood at the end of March.
Pre-release is currently difficult for Lake Houston because the dam consists mainly of a spillway with a fixed height – 42.5 feet above mean sea level. The Lake Houston dam does have two small gates, but they have less than one tenth the capacity of the flood gates on Lake Conroe. This makes it difficult to coordinate discharges between the two lakes.
The SJRA repeatedly cited fear of overloading the Lake Houston watershed as a reason for delaying its release from the Lake Conroe dam during Harvey. Additional gates might have reduced those concerns, encouraging the SJRA to release water earlier.
Theoretically, that could have reduced the volume of water coming down the west fork at the peak of the storm. At the peak, Lake Conroe’s release constituted one third of all the water coming down the West Fork where most of the damage occurred. It’s therefore easy to see how reducing the peak flow down the west fork could have spared hundreds of homes and businesses.
However, Freese and Nichols found that the volume of water coming into the lake during Harvey from multiple sources was too great to realize much benefit from pre-release. The amount pre-released would have quickly filled back up again – within a few hours.
Primary Benefit Comes from Additional Discharge Capacity
This does not mean that Freese and Nichols recommended against adding gates. They found that gates would have benefitted the community, but in a different way than originally anticipated. Surprisingly, they found that the largest reduction in flood levels came simply from the additional discharge capacity that the gates provided during the peak of the flood.
Freese and Nichols states in its conclusion, “Adding additional gates to the spillway at Lake Houston would be a feasible alternative to allow for additional discharge capacity to reduce the impact of very large flood events. … Though additional gates would provide the ability to lower the lake quickly in advance of an anticipated major flood event, the additional capacity of the gates would have far more impact on the flood level than any preliminary lowering of the lake.”
Cost/Benefit Ratio
Like many engineering studies, Freese and Nichols says that any decision to build the gates depends on whether elected officials find benefits worth the costs. However, the scope of the study did not include cost savings to home and business owners. So let’s look at that.
FEMA, the agency that would likely pay for most of the gates evaluates projects primarily on the number of people helped. They want to provide the most “benefit-per-buck” possible.
Looking at the world from FEMA’s Point of View
The City of Houston is currently in the process of developing the FEMA grant application. Mayor Sylvester Turner stated at a community meeting in Kingwood in March that he supported 10 additional gates, which he estimated would cost $47 million.
FEMA estimated in November of 2017 that 16,000 homes and 3,300 businesses in the Lake Houston area were damaged. Therefore, to reduce the impact of flooding, this project would require an expenditure of less than $2,500 per structure. Repairs to flooded structures in virtually all cases cost 10 to 100 times more than that. I know of at least one case where repairs cost $600,000. It doesn’t take many of those to equal the cost of the additional gates that the mayor proposed – $47 million.
It’s not clear at this point how many homes sit within that band where flooding could have been eliminated. Nor is there a precise estimate of damage to those homes.
Calculating the Value of Flood Reduction
Looking at homes that would seen reduced flooding, it’s important to note that the cost of repairs correlates highly with the level of flooding. According to Bill Fowler, a real estate tax expert and Co-Chair of the Lake Houston Area Grass Roots Flood Prevention Initiative, the Harris County Appraisal District is lowering valuations on homes by the amount of flooding they experienced.
Lowering flood levels usually lowers repair costs. Lower flood levels can also lower flood insurance costs, losses to insurance companies, damage to contents, and damage to vehicles. Value can be measured many ways.
It’s also important to note when calculating value in floods smaller than Harvey, pre-release might actually become a viable strategy and greatly reduce or eliminate flooding altogether. Freese and Nichols did not evaluate additional gates from that perspective; they considered only Harvey-level flooding.
Adding floodgates to Lake Houston will be a valuable flood mitigation tool. It must be viewed as an essential PART of the solution, not THE solution. Consider its value within the context of other mitigation efforts, such as dredging, ditch maintenance, and additional upstream storage capacity.
Posted June 10 by Bob Rehak
285 Days since Hurricane Harvey
Mark Your Calendar: Meet U.S. Army Corps of Engineers Monday Night
On Monday, June 11, two representatives from the U.S. Army Corps of Engineers (USACE) will meet Kingwood residents to discuss dredging of the West Fork of the San Jacinto River. The meeting, sponsored by the Lake Houston Area Grassroots Flood Prevention Initiative, will start at 6:30 PM at the Kingwood Community Center. The emergency dredging will be one of the first flood mitigation projects related to Hurricane Harvey to be implemented in the entire Houston area.
Some Details Known, Many Yet to be Revealed
The Corps finished survey work for the West Fork Dredging Project in April. Since then, Corps members have been busy evaluating their findings, determining project specifications, soliciting bids, and planning logistics. Initial estimates indicated they would move enough sand to fill the Astrodome two and a half times.
The Corps currently expects to open bids within a week of the Kingwood meeting and quickly make a selection. Bidders have been notified that they must start the project within five days. They must also staff the project so that they can finish within six months.
Bid documents indicate dredging will extend from River Grove Park to slightly past the West Lake Houston Parkway Bridge. Residents have raised questions about additional dredging in other areas, including near Lake Houston and on the East Fork.
The Corps has identified two disposal sites for the sand. Both are existing sand pits. The first is south of the river and east of US59; the second is north of the river and west of US59. Details pertaining to mobilization, removal methods, and the extent of dredging have not yet been revealed. At the time of bidding, two removal alternatives were under consideration: mechanical and hydraulic dredging.
Meet Two Corps Representatives
Featured speakers include two representatives from the Corps who will present details of the project and field questions from residents. They are Eduardo Irigoyen, the Project Manager, and Michael Garske, a hydraulic engineer and certified floodplain manager. Both are with the Corps of Engineers’ Galveston District office.
Eduardo Irigoyen, Project Manager
Eduardo Irigoyen, U.S. Army Corps of Engineers Project Manager
Eduardo (Eddie) Irigoyen currently serves as the Emergency Dredging Project Program Manager for the West Fork of the San Jacinto River, which is funded by the Federal Emergency Management Agency (FEMA).
Irigoyen has served as a Project Manager within the Corps since May 2015. He has extensive experience within USACE ranging from programs to construction management, operations and maintenance.
His current duties include managing the planning, scope, development, design, construction, and direction of several projects along the Texas Gulf coast.
Irigoyen is a native of Brownsville, Texas. He received a Bachelor of Science in Mechanical Engineering from The University of Texas at Brownsville in 2004.
Michael Garske, Hydraulic Engineer
Michael Garske, U.S. Army Corps of Engineers Hydrologist
Michael Garske has served as a Hydraulic Engineer and Certified Floodplain Manager for USACE since September 2014.
As one of the District’s lead hydraulic modeling engineers, he’s produced inundation mapping for White Oak, Brays, and Buffalo Bayou projects, helping local officials make accurate flood mitigation decisions.
He provided critical emergency modeling data during the Tax Day, Memorial Day and Harvey floods. He has also helped design dredging templates, ecosystem mitigation banks, and water storage systems; and demonstrated their effects on flood levels.
Garske grew up in Clear Lake. In 2014, he earned a Bachelor of Science degree in Maritime Systems Engineering and an Associate of Arts degree in Maritime Administration from Texas A&M University-Galveston.
Boating Safety Measures During Project
Boaters need to be aware of dredging activities. Ultimately, the project will restore navigation on the river to pre-Harvey conditions and allow the boat launch at River Grove Park to reopen. However, until completion of the project, boaters need to avoid work sites and dredging lines for their own safety.
Agenda Including Other Speakers
The meeting will start at 6:30 p.m. at the Kingwood Community Center 4102 Rustic Woods and last until 8. It will include:
The meeting is free and open to the public, so please plan to attend.
Do Not Confuse This with Flood Bond Meeting
Please note: there has been some confusion between this meeting and the Harris County Flood Bond meeting because of their dates. The County Flood bond meeting, originally scheduled for June 14, is being rescheduled for July so that County Judge Ed Emmett can attend. A new day for that meeting has not yet been determined. The meeting with the Army Corps will happen as planned on Monday evening, June 11.
Posted June 8, 2018 by Bob Rehak
Thanks to Dianne Lansden and Jacque Havelka for Planning this Meeting
283 Days since Hurricane Harvey
TACA Spells Out Industry Position on Societal and Environmental Benefits of Sand Mining
In several places on this website, I’ve talked about sand mines on the West and East Forks of the San Jacinto River. Now, the sand miners are talking about this website – in Austin – to state legislators via their trade group, TACA also known as the Texas Aggregate and Concrete Association.
Things You Never Knew About Sand Mines
Read the TACA White Paper On The Societal and Environmental Benefits of Sand And Gravel Mining. I’m publishing it here verbatim because it is not posted publicly on the group’s own website.
Fresh sand deposits after Harvey coming out of the sand mines on the west fork of the San Jacinto adjacent to Kingwood. Note that the height of the dune is engulfing several medium sized trees.
In the document, TACA makes direct references to photos and a presentation that appear on this website. “One might look at an aerial image or fly over these operations,” they say, “and errantly [emphasis added] speculate that these operations are a potential source of sediment in a stream or river.” Later they say, “…not all sand operator stock piles were flooded in the recent storm.” They also claim, “…sand operations help to mitigate flooding.”
Sand mine in Porter next to Caney Creek covers approximately 600 acres. This stockpile covers approximately 34 acres. Note erosion patterns from Harvey in this shot taken on 9/14/17. Thirty acres of Kingwood’s East End Park, just downstream from here, was covered with sand dunes up to ten feet high during Harvey.
TACA states that one of its objectives is to promote sustainability and environmental stewardship.
One of my objectives is to promote understanding.
Sand mines on the west fork of the San Jacinto adjacent to Kingwood. Note what appears to be a breach of the dike between the mine on the left and the river about two-thirds of the way up the left side of the photo. Also notice how close the dikes are to each side of the river bank. They leave little room to accommodate flood waters.
Sand mines on the west fork of the San Jacinto adjacent to Kingwood.
Harvey’s floodwaters breached dikes surrounding the sand mines on the west fork of the San Jacinto. This let sand escape. It was carried downstream and deposited in Humble, Forest Cove, Kingwood and Atascocita.
Please Read White Paper Carefully and Closely
I urge you to read The Societal and Environmental Benefits of Sand and Gravel Mining in its entirety and draw your own conclusions. I ask only that you read it very carefully and closely, as you would a contract, because in a sense, what we are talking about IS a social contract.
Sand mines are given a license to operate next to the source of drinking water for millions of people. Are these particular sand mines operating responsibly?
In upcoming posts, I will discuss research I’ve done into best management practices for sand mining.
Posted June 7, 2018 by Bob Rehak
282 Days since Hurricane Harvey