4:30 PM May 16, 2024 – The National Weather Service has issued a trio of alerts that affect the Lake Houston Area. A tornado watch, flood warning, and flood watch are all simultaneously in effect.
Scene Capture from RadarScope Pro at 4:12PM 5/16/24
Tornado Watch
The three include a tornado watch until 10 PM tonight. The watch includes all counties in the Houston Region and then some.
AUSTIN BRAZORIA BRAZOS BURLESON CHAMBERS COLORADO FORT BEND GALVESTON GRIMES HARDIN HARRIS HOUSTON JASPER JEFFERSON LIBERTY MADISON MONTGOMERY NEWTON ORANGE POLK SAN JACINTO TRINITY TYLER WALKER WALLER WASHINGTON WHARTON
Update: At 5:50 PM, issued a tornado warning for NW Harris, Austin and Waller Counties. They spotted rotation on radar. The warning will expire at 6PM, but it speaks to the severity of these storms.
Flood Warning
The Weather Service has also issued a flood warning for the San Jacinto East Fork. Predicted crests are increasing from minor to moderate levels near FM1485. This could affect people in Harris, Montgomery and Liberty Counties. Some are still cleaning up from the flood two weeks ago.
Flood Watch in Wider Area
Finally, a flood watch has been issued due to excessive rainfall across the region. This one could trigger flooding on other creeks, streams and bayous. The watch area includes:
This watch is primarily due to excessive rainfall associated with the approaching storm. It could drop 2-4″ across a wide area, with isolated totals up to 6-8″.
Lake Houston is in the area of highest risk – Level 4 – for excessive rainfall.
National Weather Service (See below.)
Flash Flooding Possible
High intensity rains could produce flash flooding that makes driving dangerous.
The ground is already super saturated from previous rains. “There is just nowhere for the water to go,” said Harris County Meteorologist Jeff Lindner.
According to Lindner, “Widespread rainfall amounts of 2-4″ will be likely north of HWY 105. Isolated totals could reach upwards to 6-8 inches. Amounts will decrease toward the south with totals near the coast less than 1 inch. This will virtually be a carbon copy of the last several rainfall events in terms of location and amounts.”
Lake Report
Lake Conroe was releasing 1590 cubic feet per second until the noon hour today. Then, the SJRA stopped releasing water give the Coastal Water Authority a chance to reduce the level of Lake Houston. Lake Houston continues to release water.
Lake Conroe operators hoped they had enough capacity in the Lake to absorb the expected influx of water. But at 4:30PM, the resumed releasing 1587 CFS.
They also announced that they will “pass through storm water and runoff received in the Upper San Jacinto River Basin until Lake Conroe returns to conservation pool.” (201 feet)
Both lakes just returned close to their normal levels from the floods in early May. However, Lake Houston is still a few inches above normal.
Total inflows into Lake Houston are at 6,627 cfs and outflows are at 8,960 cfs. Lake Houston gates have and will remain open until the gate that is stuck partially open is repaired.
Impact on Sedimentation
Most sediment moves during floods. And the West Fork sure has been piling up sediment lately. KSA just completed a sonar survey in River Grove Park where the Kingwood Diversion Ditch enters the West Fork.
Before the last storm, sand had built up at the mouth so that only about two feet of clearance was available for boats. After the last storm, sand is poking up even closer to the surface…and the river is still about a half foot above normal.
Even with water up about a half foot, you can see sand bars lurking just below surface at the River Grove boat launch.
The City of Houston is getting ready to launch a new $34 million dredging program between Kings Point and FM1960.
DRC/Callan Marine mobilizing for new dredging program south of Forest Cove Pool.
Unfortunately, the new City program won’t include the mouth of the Diversion Ditch. KSA will have to hire its own dredger to keep the boat docks open.
KSA’s dredging interval has gone from 8 to 4 to 2 years. It sure seems as though it would be less expensive if we didn’t have West Fork floods flowing through sand pits.
The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/05/4PM-Front.jpg?fit=1100%2C632&ssl=16321100adminadmin2024-05-16 16:27:222024-05-17 22:48:00Tornado Watch, Flood Warning, Flood Watch In Effect
A report issued by Harris County’s Meteorologist Jeff Lindner puts the May 2024 flood into historical perspective.
Significant flooding occurred along the West and East Forks of the San Jacinto River as well as the lower San Jacinto River below Lake Houston.
While rainfall occurred over a 7-day period, the most intense rainfall in Harris County fell on Thursday, May 2nd. Lindner’s report starts by covering the rainfall totals and intensity during different lengths of time. Then, he discusses the resulting flood heights and impacts.
Locations of 7-day rainfall totals between April 28 and May 5. Upstream areas received twice as much as Lake Houston.
Total Rainfall in 7-Day Period
Total rainfall amounts for the seven-day period averaged 10.0-17.0 inches across the extreme northern and northeastern portions of Harris County. Southern and central Montgomery County were also affected as well as northern Liberty County.
A maximum 7-day rainfall of 16.8 inches was recorded on the East Fork of the San Jacinto River at FM 1485.
The table below indicates maximum rainfall for Harris County gages.
Maximum rainfalls for different periods from 5 minutes to 7 days.
Using Atlas-14 Rainfall Exceedance Probability Tables, Lindner says rainfall during the 7-day time period ranged from:
5- to 10-year events on the San Jacinto West and East Forks as well as below Lake Houston
2- to 5-year events on Cedar Bayou.
2- to 10-year events along Luce Bayou.
Maximum 2-Day and 3-Hour Rainfall Totals
The max rainfall for those same watersheds during the peak 48-hours ranged from 2- to 10-year events.
During the peak 3-hour time period, however, gages on Willow Creek, Spring Creek, Luce Bayou, Cedar Bayou, and the San Jacinto recorded 25- to 50-year rains. The short, high-intensity rains resulted in deep street and flash flooding.
North of Harris County, the rainfall got much more intense.
Locations of Heaviest Rainfall
The majority of the heavy to excessive rainfall occurred across areas north and northeast of Harris County. This was across the headwaters of the West and East Forks of the San Jacinto River, Luce Bayou, and Lake Creek.
Rainfall amounts over the 7-day period averaged 15.0-18.0 inches over southern Walker and northern Montgomery County which drain into Lake Conroe. They averaged 15.0-20.0 inches across eastern Walker County, northern Montgomery County, and San Jacinto County which drain into the East Fork of the San Jacinto River.
“No two storm events are exactly the same with respect to the location, duration, and maximum totals of rainfall.”
Jeff Lindner, Harris County Meteorologist
Comparisons with Other Storms
The May 2024 rainfall had some similarities to the October 1994 flood. Nearly 30 inches fell across Lake Creek and the northwest portions of the Spring Creek watersheds in 1994. In 2024, the highest totals occurred farther to the north – from north of Lake Conroe to northwest of Lake Livingston.
In those locations, the rainfall exceeded 1994. That resulted in near record inflows for both Lake Conroe and Lake Livingston.
Comparison of maximum rainfall totals in different time periods for different storms.Note especially the totals for 1-hour and less.
Flooding in Historical Perspective
Rainfall is only a starting point when investigating flooding. You must also look at rainfall distribution, intensity, longevity, previous heavy rainfall, ground saturation, already swollen watersheds, and convergence of peak flows.
Much of the upper portions of the San Jacinto basin stretch across parts of Montgomery, Walker, and San Jacinto Counties. In April, they experienced rainfall 150% to 500% above normal.
Rainfall on April 28th-29th primed already wet soils for maximum run-off. Then, those same areas received additional excessive rainfall on May 1st-2nd. The second episode generated widespread and significant flash flooding and run-off into the rivers and creeks that drain to Lake Houston.
Second Highest Peak on East Fork
The East Fork exceeded the expected elevation of a 500-year storm. At FM1485, only Harvey exceeded the May peak.
San Jacinto East Fork peaks at FM1485.
Five-hundred year flooding on a 20-year rain resulted when peaks from different rounds of rainfall piled on top of each other from different watersheds.
Fifth Highest Peak on West Fork
West Fork flooding was less extreme. This was the fifth highest flooding on the West Fork since 1994. The May flood qualified as a 10- to 50-year storm based on gage readings at US59.
Five highest peaks on San Jacinto West Fork since 1994.
Fourth Highest Peak at Lake Houston Dam
The height of water going over the spillway at the Lake Houston Dam was the 4th highest peak since 1979.
Downstream at Highway 90, residents saw the 9th highest peak since 1979. Downstream areas saw between a 10-year and 50-year flood.
Third Highest Volume of Stormwater Flowing Into Lake Houston
The table below summarizes volumes of water in cubic feet per second flowing into Lake Houston from the various watersheds during different storms. This May’s event was the 3rd highest total since 1994. Only Harvey and October 1994 surpassed it.
Water flowing into Lake Houston in different storms since 1994. This May was 3rd largest volume.
House Flooding Estimates
Flood depths ranged from 6 inches to several feet in some of the lowest lying homes. The damage numbers below apply only to Harris County. The numbers were supplied by City of Houston and Harris County Engineering.
20 homes flooded with an additional 16 having water in sheds, garages, or other non-living areas on the West Fork.
32 homes flooded with an additional 8 having water water in non-living areas on the East Fork.
Upstream, the flood damage in Montgomery and Liberty Counties was much greater. However, I do not have final totals for those areas yet.
Maps, Tables Galore
Lindner’s report also includes 15 pages of rainfall intensity maps and tables for different watersheds and gages. It’s a treasure trove of information including high water marks. Click here for the full report. For future reference, that’s under the link to the Major Storms tab on the Reports Page. You can compare full reports on other storms there.
After the floods of early May 2024 and as we got yet another flood warning (East Fork at FM1485), people are asking once again, “What can we do to reduce our flood risk?” Ironically, with a few exceptions, the answers are the same as those identified after Harvey. We just need to implement them.
Few of the action items identified years ago have been implemented. Meanwhile, many underlying conditions that contribute to flood risk, i.e., insufficiently mitigated upstream development and sand mining, are accelerating. Sometimes it feels that as fast as we fix things up, others muck them up.
Could have Been Much, Much Worse
The Lake Houston Area narrowly escaped a disaster during the early May floods. A small number of homes flooded. However, a far larger number were almost seriously damaged. Had storms dumped a little more water in the wrong places, that flood could have easily destroyed thousands of homes. Water was lapping at their foundations.
Ironically, the amount of water that caused the flooding this May was about a third of what we received during Harvey.
That should underscore how vulnerable people in the Lake Houston Area remain to flooding. So, let’s look back at what happened to recommendations that came out of Hurricane Harvey studies.
Recommendations from 2020 San Jacinto River Watershed Master Drainage Plan
After Harvey, Harris County Flood Control, Montgomery County, the San Jacinto River Authority and the City of Houston joined forces to identify ways to reduce flood risk in the San Jacinto River Basin.
In December 2020, they published a 3,600 page study called the San Jacinto Regional Watershed Master Drainage Plan.
Pages 36-38 of the executive summary contain recommendations. Page 38 identifies and quantifies the value of 16 recommended flood-mitigation projects.
Short-Term Strategies (Page 36)
Vision Group – to promote collaboration and momentum
Policy – standardizing minimum requirements for future development
Floodplain Preservation – to prevent increases in future flood risk
Flood Monitoring and Warning Enhancements – adding gages along major streams
Flood Response – enhancing communication, identifying and prioritizing flood prone areas, and developing public education strategies
Buyouts – to remove homes and businesses that flood frequently from the floodplain
Floodplain Re-Mapping – to inform people of changes to their risk. Water surface elevations in a 100-year flood have increased between .5 and 4.5 feet with the adoption of Atlas 14.
Watershed Protection Studies – for each sub watershed to identify where we need local drainage improvements.
Long-Term Strategies (Page 37)
Adoption of “No adverse impact” Policy – to ensure upstream mitigation efforts don’t increase downstream flooding
Right of Way Acquisition – purchasing land for future flood mitigation projects
Utilities and Roadways – protecting evacuation routes and critical infrastructure during planning
Project Phasing to Overcome Funding Constraints – due to the high cost of mitigation projects.
16 Specific Channel and Stormwater-Detention Projects (Page 38)
See project rankings in table below along with projected costs.
Top 16 Projects Identified in SJR Master Watershed Plan
Subsequent portions of the report describe each recommendation in each category in more detail. You can find all sections on the HCFCD website. They total hundreds of megabytes.
Not Much Has Happened in Last Four Years
Sadly, while elected officials have been busy chasing funding, not much has been accomplished on the ground in any of these three categories that would actually reduce flood risk. Said another way, we’ve seen little construction. We’ve seen most progress in the first category.
Short-Term Solutions:
Vision Group: The San Jacinto Regional Flood Planning Group was recommended to pull together recommendations for the State’s first flood plan. A draft was released last week.
Policy: Montgomery County is revising its drainage criteria manual. But county commissioners have not yet adopted it. Neither MoCo, nor Liberty County have adopted the minimum drainage standards for areas draining into Harris County.
Floodplain Preservation is spotty. Non-profits, such as the Bayou Land Conservancy have stepped up. And some governmental agencies have discouraged floodplain development. But loopholes exist in regulations and enforcement is lacking in many places even if regulations exist.
Flood Monitoring and Warning Enhancements – SJRA installed several gages upstream from Lake Conroe, but more are still needed. In the last flood, they still couldn’t tell exactly how much water was coming in so that they could match releases to stabilize the lake level.
Flood Response: Harris County Flood Control stepped up its warnings and provided updated river forecasts two to three times a day. The SJRA did too. The Mayor had multiple press conferences in the Kingwood area before and during the flood. He worked with first responders to make sure people were kept out of harms way. That was a far cry from Harvey where a quarter of all the deaths in the county happened in Kingwood. And elderly people found themselves trapped by rising floodwaters in the middle of the night.
Buyouts – HCFCD bought out the townhomes along Marina Drive in Forest Cove that flooded repeatedly. And Montgomery County has also bought up many properties that flooded repetitively. But many more remain.
Floodplain Re-Mapping – FEMA has yet to approve Harris County’s updated flood maps. They’re still approximately three years from completion.
Watershed Protection Studies – Some have been done. Other’s haven’t even started. It’s been spotty. Little has been done with the studies already completed. And no grants will be approved without studiers.
Long-Term Solutions:
“No adverse impact” is violated more than the Ten Commandments.
Right of Way Acquisition – has moved forward on several properties in the Cypress Creek watershed and Harris County bought the 270-acre Woodridge Village Property in Montgomery County from Perry Homes.
Roadways – Lake Houston Redevelopment Authority/TIRZ 10 is expanding Northpark Drive and building an all-weather evacuation route out of Kingwood. It includes a bridge over the UP Railroad Tracks. FM2100 and FM1960 are expanding in Harris County. But the Huffman-Cleveland Road is still cut off in Liberty County. The Grand Parkway has been completed. But FM1485 right next to it has been cut off by floodwaters twice already this year.
Project Phasing – is a standard practice in the industry. But projects associated with the flood bond are moving so slowly that inflation has cost us about 20% of the bond’s purchasing power. Where will the money come from to complete all the projects?
Specific Projects
Not one of these projects listed in the table above has started construction. None is even close. No land has been acquired for any. And yet, unlike studies, these things actually protect property when floodwaters rise.
Engineers looked into Project #2 (Walnut Creek Detention), but by the time they investigated, someone had already purchased the land and announced plans to build a solar farm on it.
Where to Go From Here
Net: We’ve picked some of the low-hanging fruit. But we have a long way to go. Especially with construction projects that actually protect property.
As I interviewed people for this post, it became clear that different entities with different interests has hampered many mitigation efforts. We walk between competing, balkanized fiefdoms.
No one anywhere speaks for all the people of this watershed.
Just as bad, the business processes surrounding flood mitigation sometimes become bewilderingly complex. Many smaller counties, cities and MUDs don’t have the expertise to even apply for grants.
Even worse, some groups undermine improvements. For instance, we’ve dredged the mouth of the Kingwood Diversion Ditch at River Grove Park twice since Hurricane Harvey. And now it needs it again – as the West Fork flows through a sand pit. Even before floodwaters have receded, you can already see sediment poking up through the water. For decades the dredging interval was about once every eight years.
The people of a river basin are inextricably bound together by water. Yet our personal interests (What’s in it for me?) and political boundaries still divide us.
We need to recognize that fact and develop better ways to design solutions. More on that in a future post. I’ll also discuss some things that the San Jacinto River Basin Plan did not address.
Posted by Bob Rehak on 5/14/24
2450 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/05/20240514-LH-FloodMitProjects.jpg?fit=1100%2C793&ssl=17931100adminadmin2024-05-14 21:58:582024-05-15 14:43:03Most Projects To Address Lake Houston Flooding Still Not Started
Tornado Watch, Flood Warning, Flood Watch In Effect
4:30 PM May 16, 2024 – The National Weather Service has issued a trio of alerts that affect the Lake Houston Area. A tornado watch, flood warning, and flood watch are all simultaneously in effect.
Tornado Watch
The three include a tornado watch until 10 PM tonight. The watch includes all counties in the Houston Region and then some.
Update: At 5:50 PM, issued a tornado warning for NW Harris, Austin and Waller Counties. They spotted rotation on radar. The warning will expire at 6PM, but it speaks to the severity of these storms.
Flood Warning
The Weather Service has also issued a flood warning for the San Jacinto East Fork. Predicted crests are increasing from minor to moderate levels near FM1485. This could affect people in Harris, Montgomery and Liberty Counties. Some are still cleaning up from the flood two weeks ago.
Flood Watch in Wider Area
Finally, a flood watch has been issued due to excessive rainfall across the region. This one could trigger flooding on other creeks, streams and bayous. The watch area includes:
This watch is primarily due to excessive rainfall associated with the approaching storm. It could drop 2-4″ across a wide area, with isolated totals up to 6-8″.
Flash Flooding Possible
High intensity rains could produce flash flooding that makes driving dangerous.
The ground is already super saturated from previous rains. “There is just nowhere for the water to go,” said Harris County Meteorologist Jeff Lindner.
According to Lindner, “Widespread rainfall amounts of 2-4″ will be likely north of HWY 105. Isolated totals could reach upwards to 6-8 inches. Amounts will decrease toward the south with totals near the coast less than 1 inch. This will virtually be a carbon copy of the last several rainfall events in terms of location and amounts.”
Lake Report
Lake Conroe was releasing 1590 cubic feet per second until the noon hour today. Then, the SJRA stopped releasing water give the Coastal Water Authority a chance to reduce the level of Lake Houston. Lake Houston continues to release water.
Lake Conroe operators hoped they had enough capacity in the Lake to absorb the expected influx of water. But at 4:30PM, the resumed releasing 1587 CFS.
They also announced that they will “pass through storm water and runoff received in the Upper San Jacinto River Basin until Lake Conroe returns to conservation pool.” (201 feet)
Both lakes just returned close to their normal levels from the floods in early May. However, Lake Houston is still a few inches above normal.
Total inflows into Lake Houston are at 6,627 cfs and outflows are at 8,960 cfs. Lake Houston gates have and will remain open until the gate that is stuck partially open is repaired.
Impact on Sedimentation
Most sediment moves during floods. And the West Fork sure has been piling up sediment lately. KSA just completed a sonar survey in River Grove Park where the Kingwood Diversion Ditch enters the West Fork.
Before the last storm, sand had built up at the mouth so that only about two feet of clearance was available for boats. After the last storm, sand is poking up even closer to the surface…and the river is still about a half foot above normal.
The City of Houston is getting ready to launch a new $34 million dredging program between Kings Point and FM1960.
Unfortunately, the new City program won’t include the mouth of the Diversion Ditch. KSA will have to hire its own dredger to keep the boat docks open.
KSA’s dredging interval has gone from 8 to 4 to 2 years. It sure seems as though it would be less expensive if we didn’t have West Fork floods flowing through sand pits.
For Real-Time Information
To monitor:
Posted by Bob Rehak on 5/16/24 at 4:30 PM
2452 Days since Hurricane Harvey
The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.
HCFCD Report Puts May 2024 Flood in Historical Perspective
A report issued by Harris County’s Meteorologist Jeff Lindner puts the May 2024 flood into historical perspective.
Significant flooding occurred along the West and East Forks of the San Jacinto River as well as the lower San Jacinto River below Lake Houston.
While rainfall occurred over a 7-day period, the most intense rainfall in Harris County fell on Thursday, May 2nd. Lindner’s report starts by covering the rainfall totals and intensity during different lengths of time. Then, he discusses the resulting flood heights and impacts.
Total Rainfall in 7-Day Period
Total rainfall amounts for the seven-day period averaged 10.0-17.0 inches across the extreme northern and northeastern portions of Harris County. Southern and central Montgomery County were also affected as well as northern Liberty County.
A maximum 7-day rainfall of 16.8 inches was recorded on the East Fork of the San Jacinto River at FM 1485.
The table below indicates maximum rainfall for Harris County gages.
Using Atlas-14 Rainfall Exceedance Probability Tables, Lindner says rainfall during the 7-day time period ranged from:
Maximum 2-Day and 3-Hour Rainfall Totals
The max rainfall for those same watersheds during the peak 48-hours ranged from 2- to 10-year events.
During the peak 3-hour time period, however, gages on Willow Creek, Spring Creek, Luce Bayou, Cedar Bayou, and the San Jacinto recorded 25- to 50-year rains. The short, high-intensity rains resulted in deep street and flash flooding.
North of Harris County, the rainfall got much more intense.
Locations of Heaviest Rainfall
The majority of the heavy to excessive rainfall occurred across areas north and northeast of Harris County. This was across the headwaters of the West and East Forks of the San Jacinto River, Luce Bayou, and Lake Creek.
Rainfall amounts over the 7-day period averaged 15.0-18.0 inches over southern Walker and northern Montgomery County which drain into Lake Conroe. They averaged 15.0-20.0 inches across eastern Walker County, northern Montgomery County, and San Jacinto County which drain into the East Fork of the San Jacinto River.
Comparisons with Other Storms
The May 2024 rainfall had some similarities to the October 1994 flood. Nearly 30 inches fell across Lake Creek and the northwest portions of the Spring Creek watersheds in 1994. In 2024, the highest totals occurred farther to the north – from north of Lake Conroe to northwest of Lake Livingston.
In those locations, the rainfall exceeded 1994. That resulted in near record inflows for both Lake Conroe and Lake Livingston.
Flooding in Historical Perspective
Rainfall is only a starting point when investigating flooding. You must also look at rainfall distribution, intensity, longevity, previous heavy rainfall, ground saturation, already swollen watersheds, and convergence of peak flows.
Much of the upper portions of the San Jacinto basin stretch across parts of Montgomery, Walker, and San Jacinto Counties. In April, they experienced rainfall 150% to 500% above normal.
Rainfall on April 28th-29th primed already wet soils for maximum run-off. Then, those same areas received additional excessive rainfall on May 1st-2nd. The second episode generated widespread and significant flash flooding and run-off into the rivers and creeks that drain to Lake Houston.
Second Highest Peak on East Fork
The East Fork exceeded the expected elevation of a 500-year storm. At FM1485, only Harvey exceeded the May peak.
Five-hundred year flooding on a 20-year rain resulted when peaks from different rounds of rainfall piled on top of each other from different watersheds.
Fifth Highest Peak on West Fork
West Fork flooding was less extreme. This was the fifth highest flooding on the West Fork since 1994. The May flood qualified as a 10- to 50-year storm based on gage readings at US59.
Fourth Highest Peak at Lake Houston Dam
The height of water going over the spillway at the Lake Houston Dam was the 4th highest peak since 1979.
Downstream at Highway 90, residents saw the 9th highest peak since 1979. Downstream areas saw between a 10-year and 50-year flood.
Third Highest Volume of Stormwater Flowing Into Lake Houston
The table below summarizes volumes of water in cubic feet per second flowing into Lake Houston from the various watersheds during different storms. This May’s event was the 3rd highest total since 1994. Only Harvey and October 1994 surpassed it.
House Flooding Estimates
Flood depths ranged from 6 inches to several feet in some of the lowest lying homes. The damage numbers below apply only to Harris County. The numbers were supplied by City of Houston and Harris County Engineering.
Upstream, the flood damage in Montgomery and Liberty Counties was much greater. However, I do not have final totals for those areas yet.
Maps, Tables Galore
Lindner’s report also includes 15 pages of rainfall intensity maps and tables for different watersheds and gages. It’s a treasure trove of information including high water marks. Click here for the full report. For future reference, that’s under the link to the Major Storms tab on the Reports Page. You can compare full reports on other storms there.
Many thanks to Jeff Lindner and his team. They keep hundreds of gages around Harris Country watersheds working to provide timely, life-saving information via the Harris County Flood Warning System.
Posted by Bob Rehak on 5/15/24
2451 Days since Hurricane Harvey
Most Projects To Address Lake Houston Flooding Still Not Started
After the floods of early May 2024 and as we got yet another flood warning (East Fork at FM1485), people are asking once again, “What can we do to reduce our flood risk?” Ironically, with a few exceptions, the answers are the same as those identified after Harvey. We just need to implement them.
Few of the action items identified years ago have been implemented. Meanwhile, many underlying conditions that contribute to flood risk, i.e., insufficiently mitigated upstream development and sand mining, are accelerating. Sometimes it feels that as fast as we fix things up, others muck them up.
Could have Been Much, Much Worse
The Lake Houston Area narrowly escaped a disaster during the early May floods. A small number of homes flooded. However, a far larger number were almost seriously damaged. Had storms dumped a little more water in the wrong places, that flood could have easily destroyed thousands of homes. Water was lapping at their foundations.
That should underscore how vulnerable people in the Lake Houston Area remain to flooding. So, let’s look back at what happened to recommendations that came out of Hurricane Harvey studies.
Recommendations from 2020 San Jacinto River Watershed Master Drainage Plan
After Harvey, Harris County Flood Control, Montgomery County, the San Jacinto River Authority and the City of Houston joined forces to identify ways to reduce flood risk in the San Jacinto River Basin.
In December 2020, they published a 3,600 page study called the San Jacinto Regional Watershed Master Drainage Plan.
Pages 36-38 of the executive summary contain recommendations. Page 38 identifies and quantifies the value of 16 recommended flood-mitigation projects.
Short-Term Strategies (Page 36)
Long-Term Strategies (Page 37)
16 Specific Channel and Stormwater-Detention Projects (Page 38)
See project rankings in table below along with projected costs.
Subsequent portions of the report describe each recommendation in each category in more detail. You can find all sections on the HCFCD website. They total hundreds of megabytes.
Not Much Has Happened in Last Four Years
Sadly, while elected officials have been busy chasing funding, not much has been accomplished on the ground in any of these three categories that would actually reduce flood risk. Said another way, we’ve seen little construction. We’ve seen most progress in the first category.
Short-Term Solutions:
Vision Group: The San Jacinto Regional Flood Planning Group was recommended to pull together recommendations for the State’s first flood plan. A draft was released last week.
Policy: Montgomery County is revising its drainage criteria manual. But county commissioners have not yet adopted it. Neither MoCo, nor Liberty County have adopted the minimum drainage standards for areas draining into Harris County.
Floodplain Preservation is spotty. Non-profits, such as the Bayou Land Conservancy have stepped up. And some governmental agencies have discouraged floodplain development. But loopholes exist in regulations and enforcement is lacking in many places even if regulations exist.
Flood Monitoring and Warning Enhancements – SJRA installed several gages upstream from Lake Conroe, but more are still needed. In the last flood, they still couldn’t tell exactly how much water was coming in so that they could match releases to stabilize the lake level.
Flood Response: Harris County Flood Control stepped up its warnings and provided updated river forecasts two to three times a day. The SJRA did too. The Mayor had multiple press conferences in the Kingwood area before and during the flood. He worked with first responders to make sure people were kept out of harms way. That was a far cry from Harvey where a quarter of all the deaths in the county happened in Kingwood. And elderly people found themselves trapped by rising floodwaters in the middle of the night.
Buyouts – HCFCD bought out the townhomes along Marina Drive in Forest Cove that flooded repeatedly. And Montgomery County has also bought up many properties that flooded repetitively. But many more remain.
Floodplain Re-Mapping – FEMA has yet to approve Harris County’s updated flood maps. They’re still approximately three years from completion.
Watershed Protection Studies – Some have been done. Other’s haven’t even started. It’s been spotty. Little has been done with the studies already completed. And no grants will be approved without studiers.
Long-Term Solutions:
“No adverse impact” is violated more than the Ten Commandments.
Right of Way Acquisition – has moved forward on several properties in the Cypress Creek watershed and Harris County bought the 270-acre Woodridge Village Property in Montgomery County from Perry Homes.
Roadways – Lake Houston Redevelopment Authority/TIRZ 10 is expanding Northpark Drive and building an all-weather evacuation route out of Kingwood. It includes a bridge over the UP Railroad Tracks. FM2100 and FM1960 are expanding in Harris County. But the Huffman-Cleveland Road is still cut off in Liberty County. The Grand Parkway has been completed. But FM1485 right next to it has been cut off by floodwaters twice already this year.
Project Phasing – is a standard practice in the industry. But projects associated with the flood bond are moving so slowly that inflation has cost us about 20% of the bond’s purchasing power. Where will the money come from to complete all the projects?
Specific Projects
Not one of these projects listed in the table above has started construction. None is even close. No land has been acquired for any. And yet, unlike studies, these things actually protect property when floodwaters rise.
Engineers looked into Project #2 (Walnut Creek Detention), but by the time they investigated, someone had already purchased the land and announced plans to build a solar farm on it.
Where to Go From Here
Net: We’ve picked some of the low-hanging fruit. But we have a long way to go. Especially with construction projects that actually protect property.
As I interviewed people for this post, it became clear that different entities with different interests has hampered many mitigation efforts. We walk between competing, balkanized fiefdoms.
Just as bad, the business processes surrounding flood mitigation sometimes become bewilderingly complex. Many smaller counties, cities and MUDs don’t have the expertise to even apply for grants.
Even worse, some groups undermine improvements. For instance, we’ve dredged the mouth of the Kingwood Diversion Ditch at River Grove Park twice since Hurricane Harvey. And now it needs it again – as the West Fork flows through a sand pit. Even before floodwaters have receded, you can already see sediment poking up through the water. For decades the dredging interval was about once every eight years.
The people of a river basin are inextricably bound together by water. Yet our personal interests (What’s in it for me?) and political boundaries still divide us.
We need to recognize that fact and develop better ways to design solutions. More on that in a future post. I’ll also discuss some things that the San Jacinto River Basin Plan did not address.
Posted by Bob Rehak on 5/14/24
2450 Days since Hurricane Harvey