At its February 2020 board meeting, the San Jacinto River Authority (SJRA) Board of Directors will consider NOT lowering Lake Conroe during the spring and fall rainy seasons. Lake Conroe residents have mobilized to protest the lowering which they see as a costly inconvenience. They have started spreading disinformation about the policy. The SJRA Board has reportedly already received more than a hundred letters protesting the policy.
Reason for Lowering and Current Status
The strategy of lowering Lake Conroe on a seasonal basis reduces the risk of flooding downstream residents by increasing the capacity of Lake Conroe to store water. The SJRA Board of Directors and City of Houston review the strategy annually. Both entities own water rights in Lake Conroe.
The gates at Lake Conroe can release water at up too 150,000 CFS but are currently releasing 0 CFS. Lake lowering ended October 1st.
After Hurricane Harvey, the State of Texas called on the SJRA Board of Directors and the City of Houston to participate in regional strategies to reduce flooding. The temporary lowering of Lake Conroe has reduced releases from Lake Conroe during storms. SJRA and downstream communities realize and understand the inconvenience that the strategy can create around Lake Conroe. We ask for understanding for the duration of this temporary mitigation strategy.
Seasonal Lake-Lowering FAQs
Who Decides?
The City of Houston and the SJRA collaborate on the decision to temporarily lower Lake Conroe for flood mitigation because it effects the water supply of both entities.
How Long Will It Continue?
Seasonal lake lowering is a temporary flood mitigation initiative to increase the capacity of Lake Conroe to catch rainfall and runoff while long-term and short-term flood mitigation strategies are implemented downstream.
The motion made by the SJRA Board states that the intent of the proposal is to provide “a near-term, temporary flood mitigation benefit while more permanent mitigation strategies, such as dredging of the lower West Fork, are completed.”
When Does It Happen?
Seasonal lake lowering occurs twice annually – first in April/May and second in August/September.
How Much is It Lowered and for How Long?
In the spring, releases begin on April 1st. SJRA gradually reduces the level of Lake Conroe to 200’ mean feet above sea level (msl)—one foot below the normal Lake Conroe pool level of 201’ msl. Starting on June 1st, SJRA recaptures flows to restore normal lake elevation to 201’ msl.
In the fall, releases begin on August 1st. SJRA gradually reduces the level of Lake Conroe with a goal of reaching 200’ msl by August 15th. After August 15th, gradual lowering continues with a goal of reaching (and maintaining) 199’ msl—two feet below normal pool—by August 31st. Starting October 1st, SJRA begins to capture flows to restore normal lake elevation to 201’ msl.
What If The Lake Is Already Down?
If the lake level has already dropped to the target elevation due to evaporation, no releases are made.
What if It Rains While the Lake is Already Lowered?
If a storm enters the forecast while seasonal releases are being made to lower the lake level, releases are stopped and the river is allowed to drain out until rainfall is out of the forecast.
Is There Science Behind This Policy?
Two engineering reports by Frees & Nichols from early 2018 show the benefits in terms of flood mitigation and the potential negative impacts to water supply. These reports as well as additional information about seasonal lowering can be found at: https://www.sjra.net/floodmanagement/.
Has it worked? Is there real value in terms of flood mitigation?
Yes. Looking at recent rainfall events, seasonal lowering resulted in both lower peak lake levels during storms and lower release rates from the dam.
Seasonal lowering also reduces the peak Lake Conroe level during storms, which reduces negative impacts around the lake such as damage to docks and other personal property. During Harvey, several hundred homes around Lake Conroe flooded.
Data for the May event, and for all releases from the dam, including those during seasonal lowering periods, can be monitored by visiting SJRA’s home page at www.sjra.net. Click on the “Lake Operations and Rainfall Dashboard.”
What is the cost of the release?
Lake Conroe was built as a water supply reservoir in the 1970s through a partnership between SJRA and the City of Houston. Two thirds of the water in Lake Conroe belongs to the City of Houston and one third to SJRA. The City of Houston can call for the release of its water at any time, and water supply reservoirs are built to fluctuate as demands or operational needs dictate.
Releases such as those made for dam repairs and seasonal lowering are not charged to any particular customer, therefore it is not possible to assign a value to the water released. In addition, temporary, non-customer releases do not reduce long-term water supplies, therefore they are not considered lost revenue.
To be considered as lost revenue, releases would have to happen at a time when the SJRA could not meet demand with water from Lake Conroe. But that has not happened.
And most important, if the water supply in Lake Conroe were ever threatened, say from drought, the SJRA would not be releasing water anyway. The lake level would already be far below the target level, making a release unnecessary.
Is This a Permanent Program?
No. Seasonal lowering is a temporary flood mitigation strategy that must be reconsidered each year by the City of Houston and the SJRA Board of Directors while more permanent mitigation strategies, such as dredging of the lower West Fork, are completed.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/04/LC-Dam-e1719277556742.jpg?fit=1200%2C549&ssl=15491200adminadmin2019-11-23 11:00:262020-01-17 08:57:17FAQs About Lowering Lake Conroe to Reduce Downstream Flood Risk
Efforts have started already to lobby against the seasonal lowering of Lake Conroe again next year. They seem to be organized and inspired by the Lake Conroe Association again. I understand that the lowering inconveniences some Lake Conroe residents, especially boaters who live in areas like Grand Harbor where the water depth is shallow to start with. However, the inconvenience pales in comparison to the damages suffered in the Lake Houston Area. The lowering helps provide a buffer against downstream flooding during the wettest months of the year. The SJRA will vote on whether to extend the lowering policy at its February board meeting.
A Campaign of Misinformation
The Lake Conroe Association and its proxies are deliberately spreading falsehoods to rile up people against the lowering. The same misinformation contained in the Lake Conroe Association presentation on their news page, is repeated in the website Stop Draining Lake Conroe (https://www.stopdraininglakeconroe.com) and the Grand Harbor YouTube video below.
Lake Conroe homes are being damaged by the lake lowering. Really? How does that work? Is it the same as 250,000 CFS coming through your living room? That’s what happened to 81 townhomes in Forest Cove. See below.
One of 81 empty townhomes on the West Fork in Forest Cove after the Lake Conroe release. Note the bulk-heading. Harris County Flood Control demolished this building earlier this month. Many others remain, affecting property values around them.
Lake lowering is damaging bulk-heading around Lake Conroe. How does that work? Does evaporation destroy the bulk-heading? See the bulk-heading along the West Fork above.
Downstream residents are trying to turn this into a permanent plan. Please tell me who. I’m not aware of any organized effort. The plan has always been to reconsider the lowering every year until flood mitigation measures such as dredging were complete.
SJRA is throwing away $5.33 million of water revenue. It would only be throwing away the revenue if it could sell the water. But there’s no unfilled demand due to water shortages in the lake. And the water replenishes itself as rain falls from the sky.
Water level of Lake Conroe is at 198. That’s an exaggeration to rile up the people in Grand Harbor, who normally only have four feet of water. The lake level is normally at 201′ and currently at 198.82′. That’s 198 and ten inches. So those Grand Harbor people have half their normal water, not one quarter. Current release rate is 0.
Lake Conroe only provided 15% of the water that flooded Kingwood. Lake Conroe only affects the West Fork, but the statistic includes the East Fork. During Harvey, West Fork flooding caused the vast majority of the damage. The Lake Conroe release comprised ONE-THIRD of the water coming down the West Fork through the highly populated Humble/Kingwood corridor where virtually 100% of the businesses are located. Lake Conroe released 80,000 CFS of the 240,00 CFS coming down the West Fork. So the 15% statistic is extremely misleading.
Video Makes Many of Same False Claims And Some More
The video includes many of the same false claims and a few new ones. Let me focus on the new ones.
The video states or implies that:
Describing the lowering as Seasonal rather than Temporary implies we are trying to make it Permanent. I’m not sure how you get from either of those words to “permanent.” This is a logical fallacy. It’s a falsehood designed to inspire fear.
Recent events show that Lake Conroe is being unfairly blamed for downstream flooding. Kingwood still flooded during Imelda “even though we didn’t release anything” during Imelda. Please! The vast majority of all Kingwood flooding during Imelda was street flooding or related to Woodridge Village. Some homes did flood on the East Fork, but I can’t believe any of those residents would blame it on a fictional release from Lake Conroe that wasn’t coming down the West Fork.
There was an “organized effort” in Kingwood to send an unspecified number of “letters” to the SJRA board thanking them for not releasing during Imelda. So what is it? Are we allegedly blaming you for flooding us during Imelda or thanking you for not flooding us? Show me the letters. I’m not aware of any such organized effort. See the comment above.
Kingwood is trying to increase the lowering to 3 feet and Kingwood is winning that fight by a large margin.I’m aware of no effort to increase the lowering and no fight that we’re winning by a large margin.
Wading birds that require shallow areas are being destroyed. Duh! They’re saying birds need shallow water, but they want to make the lake deeper. So if water depth had something to do with destroying birds, who would be destroying them?
Boating Vs. Flooding
Let’s face it. The big reason Lake Conroe residents don’t want to see their lake lowered is that it makes boating more difficult. No argument there.
But the big reason Lake Houston area residents want more dredging is not boating. It’s to reduce flood risk. The mouth bar forms a sediment dam behind the dam that reduces the conveyance of the river through the heavily populated Humble/Kingwood corridor. And until it’s dredged, we need the help of Lake Conroe residents. The lake lowering strategy gives us the only effective way to mitigate flooding for now.
After the Army Corps removed 500,000 cubic yards of sediment from the West Fork mouth bar, Imelda promptly redeposited much of it. Here’s what it looked like after Imelda.
700 yards south of the mouth bar, RD Kissling, a kayaker, photographed himself in 1 foot of water AFTER the Corps finished dredgingand after Imelda.
Compare These West Fork Damages
Tens of thousands living north of the West Fork who used I-69 for commuting experienced massive traffic jams every day for 11 months while TxDoT reconstructed the southbound lanes after Harvey.Photo taken 6/19/2018.
We are certainly sensitive to Lake Conroe lifestyle considerations. But during Harvey, Lake Houston Area damages on the West Fork alone included:
After a year, only half the residents who flooded throughout the Lake Houston Area were fully back in their homes. Some still aren’t. Many homes have been abandoned.
City of Houston estimated Lake Houston area damages to be in the billions.
City of Houston estimated this area’s tax revenues were reduced 20-30 percent.
TIRZ funded expansion of Northpark Drive had to be delayed several years.
Humble ISD documented $97.5 million in damages to its facilities.
Kingwood High School closed for 7 months; 4000 students had to be bused to another high school more than an hour away the entire time.
More on this in future posts. Lake Houston Area residents need to gear up to fight the falsehoods and ensure that Lake Conroe seasonal lowering policy remains in place for another year.
Harvey knocked out the Union Pacific Railroad bridge over the San Jacinto River near I-69 and disrupted rail traffic for months. Photo taken 9/14/2017.
Posted by Bob Rehak on 11/22/2019
815 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2018/05/I69Damage-e1775243525276.jpg?fit=1100%2C733&ssl=17331100adminadmin2019-11-22 19:00:202020-01-23 11:28:50Lake Conroe Association Fighting Seasonal Lowering in Advance of SJRA Vote to Reconsider Policy
Note: This is the third in a five part series about What Went Wrong in Woodridge Village that may have contributed to flooding in Elm Grove and North Kingwood Forest.It focuses on Detention Ponds.
Section 7 of the Montgomery County Drainage Criteria Manual cautions, “The introduction of impervious cover and improved runoff conveyance serves in many cases to increase flood peaks quite dramatically over those for existing conditions.” And that’s exactly what happened in Elm Grove and North Kingwood Forest in May and September of this year. Two subdivisions that had never flooded before were inundated with several feet of water from Woodridge Village.
Perry Homes failed to observe numerous regulations in the Drainage Criteria Manual including provisions for:
Erosion control measures such as pond linings, revegetation, backslope swales
Maintenance roads
Increases in downstream flooding
Geotechnical reports for detention ponds
Drainage of detention ponds
Critically, they also failed to construct all the detention ponds they promised.
Less than a Quarter of Detention Ponds Built
When listing factors that contributed to the flooding, the absence of several promised detention ponds should rank near the top.
Before the September flood, contractors substantially completed a second detention pond (S2) that added another 16% of promised detention capacity.
Since then, no work has been done on additional excavation to protect against flooding.
While clearcutting ALL of the land, Perry Homes installed only PART of the detention.
According to LJA Engineering, Perry Homes was supposed to develop the project in two phases and clearcut only 30 acres in the northern section during Phase 1. However, something changed. Instead, Perry Homes clearcut the entire northern section. And they still haven’t excavated any of the three detention ponds there.
By May 2019, only S1 was substantially complete. By September, S2 was also substantially complete, but overwhelmed.
Had Perry Homes installed all the detention that it promised, the site should have detained a foot of rainfall. But it didn’t. When Imelda came along, it was like trying to pour 100 gallons of water into a 23 gallon jug. Water spilled out of the development into adjacent streets and homes.
Erosion Control Measures Missing for Detention Ponds
“The erosion potential for a detention basin is similar to that of an open channel. For this reason the same types of erosion protection are necessary, including the use of backslope swales and drainage systems (as outlined In SECTION 6), proper revegetation and pond surface lining where necessary. Proper protection must especially be provided at pipe outfalls into the facility, pond outlet structures and overflow spillways where excessive turbulence and velocities will cause erosion.” (See page page 123 of pdf, numbered 113 in doc.)
Revegetation?
Not much grass in S1 (right of the road) or the area that drains into it.All aerial photos below taken on 11/4/2019.Not much grass on the slopes of S2 either, although Perry Homes did make an ineffective attempt to hydromulch the south (right) border.
No Protection for Overflow Spillway
Perry Homes quality! This spillway from Taylor Gully (right) was supposed to have a grass lining, but still does not.Picture taken 11/4/2019.As of 11/21/19 work still had not started on the lining.Perry Homes has done virtually no work on this pond for three months.However, they did start lining the channel on the right today.
Backslope Interceptor Swales?
The northern edge of the S2 pond has no backslope interceptor swale. As a consequence, water from Taylor Gully at the top of this frame flows over the edge of the pond and erodes it. This may not be a sustainable solution. In the long run, the Gully could erode its way into the pond from the north (top of the frame).
Maintenance Road Missing at Critical Point
Section 7.2.8 talks about Maintenance of Detention Facilities. It states, “A 30-foot wide access and maintenance easement shall be provided around the entire detention pond.” The most critical place in the entire chain of detention ponds, the final outflow culvert into Taylor Gully, has no room for a maintenance road. That’s because when they installed the required backslope interceptor swale, the only place left for it was the maintenance road. That’s planning for you!
S2 has no maintenance easement or road at final outfall into Taylor Gully.The backslope interceptor swale takes up that space.
No Increase in Downstream Flood Levels Allowed
Section 7.3 talks about DETENTION DESIGN PROCEDURES. It clearly lays out the design goal when it says…
No increase in downstream flow rates or flood levels will be allowed.
Further down in this section, the regulations state: “The maximum 100-year water surface elevation in all detention facilities shall be a minimum of 1 foot below the minimum top of bank elevation of the basin.”
No Geotechnical Report for Groundwater Level at Pond Sites
Section 7.5 discusses GEOTECHNICAL INVESTIGATIONS. It says, “Before initiating final design of a detention pond, a detailed soils investigation by a geotechnical engineer should be undertaken.” Regulations state that the ground water investigation must be “at the proposed site.” Montgomery County has no record of such an investigation or report.
A company called Terracon prepared a Preliminary Geotechnical Report for Perry that addressed issues pertaining to utilities, road pavement and residential foundations. But it makes no mention of detention ponds.
The company took four widely spaced borings around the perimeter of the site that managed to miss all the detention pond locations. Significantly, they missed all the wetlands, too.
Page 17 of Terracon Report. Red lines added to improve visibility of locations.
MoCo Claims It Has No Further Geotechnical Reports
If Perry Homes did additional investigations into ground water on this site, Montgomery County says it doesn’t have them.
If no further investigations were conducted, this could be a fatal flaw affecting the economics of the entire development. Note the presence of standing water in the photo below.
S2 Pond (left), Taylor Gully (center), and area where N3 pond will go (right) all have standing water that will reduce their rated capacity.
The presence of standing water reduces the rated capacity of detention ponds and channels. Only the area above the standing water counts as capacity. Regulations say that these ponds should drain completely (see below).
Thus, S2 likely has lost a third of its designed capacity. N3, when eventually built, could fare worse. Note how close the water is to the surface in the small pond on the right.
If you can’t go deep to get your detention pond capacity, you have to go wide. And that will mean fewer homesites than the 896 they planned. This site might not even make economic sense for building homes.
Problems with Homes Built Over Wetlands
The presence of wetlands in the northern section, which the Terracon report never mentions, would also significantly reduce the site’s suitability for building homes.
This article describes the problems with homes built on wetlands. The title: “Caution: Building in a Wetland Can Be Hazardous to Your House.” A biologist for the US Fish and Wildlife service who investigated filled wetlands in Pennsylvania warned: “Build your house in a wetland, and you’ve got a hobby for the rest of your life. You will be fighting that water forever.” He discusses cracked foundations and also warns, “When wetlands are filled, the water that made them wet has to go somewhere. … the water likely is leaking into formerly dry homes of downstream property owners.”
I’m sure Perry Homes would divulge the presence of former wetlands to the future buyers of homes on this site. It’s the only ethical thing to do and Kathy Perry Britton, CEO, has standards to maintain.
Incomplete Drainage of Detention Ponds
Section 7.6 of the Drainage Criteria Manual addresses GENERAL REQUIREMENTS FOR DETENTION POND CONSTRUCTION. It states: “A pilot channel shall be provided in detention facilities to insure that proper and complete drainage of the storage facility will occur.” (Emphasis added.)
Complete drainage will likely never occur in S2 and N3 because of the high water table.
To excavate S2 to the required design depth, contractors had to continuously pump water out of it as they worked. It still retains water to this day.
Photo by Jeff Miller on June 2, three days after contractors started digging to the final depth.No surface linings were ever added to this portion of the pond per Section 7.2.7 of the MoCo Drainage Criteria Manual.Photo taken on June 3 shows contractors were pumping water out of pond as they continued excavating.
The new statistics would require 40% more capacity to ensure downstream safety.
Where Does Perry Homes Go from here?
After ignoring regulations, hundreds of homes flooded. And they will flood again. Owning this site is like hanging a millstone around one’s neck. It could drown the entire company in perpetual litigation and debt.
Future Posts in this series will look at:
Contradictions in Perry Homes’ Plans
The Dirt on Perry Homes’ Soil Test
The Floodplain that Wasn’t
Posted by Bob Rehak on 11/21/2019 with help from Jeff Miller
814 Days since Hurricane Harvey and 63 since Imelda
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/2019/11/RJR_4350-2.jpg?fit=1500%2C1089&ssl=110891500adminadmin2019-11-21 17:48:092019-11-21 18:26:13What Went Wrong, Part III: Perry Homes’ Woodridge Village Detention Pond Catastrophe
FAQs About Lowering Lake Conroe to Reduce Downstream Flood Risk
At its February 2020 board meeting, the San Jacinto River Authority (SJRA) Board of Directors will consider NOT lowering Lake Conroe during the spring and fall rainy seasons. Lake Conroe residents have mobilized to protest the lowering which they see as a costly inconvenience. They have started spreading disinformation about the policy. The SJRA Board has reportedly already received more than a hundred letters protesting the policy.
Reason for Lowering and Current Status
The strategy of lowering Lake Conroe on a seasonal basis reduces the risk of flooding downstream residents by increasing the capacity of Lake Conroe to store water. The SJRA Board of Directors and City of Houston review the strategy annually. Both entities own water rights in Lake Conroe.
After Hurricane Harvey, the State of Texas called on the SJRA Board of Directors and the City of Houston to participate in regional strategies to reduce flooding. The temporary lowering of Lake Conroe has reduced releases from Lake Conroe during storms. SJRA and downstream communities realize and understand the inconvenience that the strategy can create around Lake Conroe. We ask for understanding for the duration of this temporary mitigation strategy.
Seasonal Lake-Lowering FAQs
Who Decides?
The City of Houston and the SJRA collaborate on the decision to temporarily lower Lake Conroe for flood mitigation because it effects the water supply of both entities.
How Long Will It Continue?
Seasonal lake lowering is a temporary flood mitigation initiative to increase the capacity of Lake Conroe to catch rainfall and runoff while long-term and short-term flood mitigation strategies are implemented downstream.
The motion made by the SJRA Board states that the intent of the proposal is to provide “a near-term, temporary flood mitigation benefit while more permanent mitigation strategies, such as dredging of the lower West Fork, are completed.”
When Does It Happen?
Seasonal lake lowering occurs twice annually – first in April/May and second in August/September.
How Much is It Lowered and for How Long?
In the spring, releases begin on April 1st. SJRA gradually reduces the level of Lake Conroe to 200’ mean feet above sea level (msl)—one foot below the normal Lake Conroe pool level of 201’ msl. Starting on June 1st, SJRA recaptures flows to restore normal lake elevation to 201’ msl.
In the fall, releases begin on August 1st. SJRA gradually reduces the level of Lake Conroe with a goal of reaching 200’ msl by August 15th. After August 15th, gradual lowering continues with a goal of reaching (and maintaining) 199’ msl—two feet below normal pool—by August 31st. Starting October 1st, SJRA begins to capture flows to restore normal lake elevation to 201’ msl.
What If The Lake Is Already Down?
If the lake level has already dropped to the target elevation due to evaporation, no releases are made.
What if It Rains While the Lake is Already Lowered?
If a storm enters the forecast while seasonal releases are being made to lower the lake level, releases are stopped and the river is allowed to drain out until rainfall is out of the forecast.
Is There Science Behind This Policy?
Two engineering reports by Frees & Nichols from early 2018 show the benefits in terms of flood mitigation and the potential negative impacts to water supply. These reports as well as additional information about seasonal lowering can be found at: https://www.sjra.net/floodmanagement/.
Has it worked? Is there real value in terms of flood mitigation?
Yes. Looking at recent rainfall events, seasonal lowering resulted in both lower peak lake levels during storms and lower release rates from the dam.
For example, the spring 2019 seasonal lowering created an additional one foot of storage space to capture rainfall in early May 2019 when storms hit the Conroe and Lake Houston areas. Lake Conroe caught significant rainfall and runoff during the storms causing the lake to rise more than a foot. If Lake Conroe had entered this event at or near full, the peak release rate would have been higher thereby increasing the peak flow in the West Fork of the San Jacinto River.
Is There a Benefit to Lake Conroe?
Seasonal lowering also reduces the peak Lake Conroe level during storms, which reduces negative impacts around the lake such as damage to docks and other personal property. During Harvey, several hundred homes around Lake Conroe flooded.
Data for the May event, and for all releases from the dam, including those during seasonal lowering periods, can be monitored by visiting SJRA’s home page at www.sjra.net. Click on the “Lake Operations and Rainfall Dashboard.”
What is the cost of the release?
Lake Conroe was built as a water supply reservoir in the 1970s through a partnership between SJRA and the City of Houston. Two thirds of the water in Lake Conroe belongs to the City of Houston and one third to SJRA. The City of Houston can call for the release of its water at any time, and water supply reservoirs are built to fluctuate as demands or operational needs dictate.
Releases such as those made for dam repairs and seasonal lowering are not charged to any particular customer, therefore it is not possible to assign a value to the water released. In addition, temporary, non-customer releases do not reduce long-term water supplies, therefore they are not considered lost revenue.
To be considered as lost revenue, releases would have to happen at a time when the SJRA could not meet demand with water from Lake Conroe. But that has not happened.
And most important, if the water supply in Lake Conroe were ever threatened, say from drought, the SJRA would not be releasing water anyway. The lake level would already be far below the target level, making a release unnecessary.
Is This a Permanent Program?
No. Seasonal lowering is a temporary flood mitigation strategy that must be reconsidered each year by the City of Houston and the SJRA Board of Directors while more permanent mitigation strategies, such as dredging of the lower West Fork, are completed.
How Do I Make my Opinion Known to the Board?
The SJRA Board of Directors welcomes input regarding the seasonal lake lowering strategy. If you would like to contact the Board please visit: https://www.sjra.net/about/board/ or email floodmanagementdivision@sjra.net.
Posted by Bob Rehak on 11/23/2019
816 Days since Hurricane Harvey
Lake Conroe Association Fighting Seasonal Lowering in Advance of SJRA Vote to Reconsider Policy
Efforts have started already to lobby against the seasonal lowering of Lake Conroe again next year. They seem to be organized and inspired by the Lake Conroe Association again. I understand that the lowering inconveniences some Lake Conroe residents, especially boaters who live in areas like Grand Harbor where the water depth is shallow to start with. However, the inconvenience pales in comparison to the damages suffered in the Lake Houston Area. The lowering helps provide a buffer against downstream flooding during the wettest months of the year. The SJRA will vote on whether to extend the lowering policy at its February board meeting.
A Campaign of Misinformation
The Lake Conroe Association and its proxies are deliberately spreading falsehoods to rile up people against the lowering. The same misinformation contained in the Lake Conroe Association presentation on their news page, is repeated in the website Stop Draining Lake Conroe (https://www.stopdraininglakeconroe.com) and the Grand Harbor YouTube video below.
For the Record…
StopDrainingLakeConroe.com states that:
Lake Houston dredging is complete and completely out of funding. Four fifths of the mouth bar on the West Fork remains in place. Harris County Flood Control has allocated $10 million to help dredge it. See item CI-61. The State of Texas allocated $30 million in SB500. Plans for that project should be announced next week according to State Representative Dan Huberty. The City of Houston has also filed for another FEMA Grant for additional dredging.
Lake Conroe homes are being damaged by the lake lowering. Really? How does that work? Is it the same as 250,000 CFS coming through your living room? That’s what happened to 81 townhomes in Forest Cove. See below.
Lake lowering is damaging bulk-heading around Lake Conroe. How does that work? Does evaporation destroy the bulk-heading? See the bulk-heading along the West Fork above.
There is no science to support the original action by the board, or for continuing this action plan. See these engineering reports by Frees & Nichols.
Downstream residents are trying to turn this into a permanent plan. Please tell me who. I’m not aware of any organized effort. The plan has always been to reconsider the lowering every year until flood mitigation measures such as dredging were complete.
SJRA is throwing away $5.33 million of water revenue. It would only be throwing away the revenue if it could sell the water. But there’s no unfilled demand due to water shortages in the lake. And the water replenishes itself as rain falls from the sky.
Water level of Lake Conroe is at 198. That’s an exaggeration to rile up the people in Grand Harbor, who normally only have four feet of water. The lake level is normally at 201′ and currently at 198.82′. That’s 198 and ten inches. So those Grand Harbor people have half their normal water, not one quarter. Current release rate is 0.
Lake Conroe only provided 15% of the water that flooded Kingwood. Lake Conroe only affects the West Fork, but the statistic includes the East Fork. During Harvey, West Fork flooding caused the vast majority of the damage. The Lake Conroe release comprised ONE-THIRD of the water coming down the West Fork through the highly populated Humble/Kingwood corridor where virtually 100% of the businesses are located. Lake Conroe released 80,000 CFS of the 240,00 CFS coming down the West Fork. So the 15% statistic is extremely misleading.
Video Makes Many of Same False Claims And Some More
The video includes many of the same false claims and a few new ones. Let me focus on the new ones.
The video states or implies that:
Describing the lowering as Seasonal rather than Temporary implies we are trying to make it Permanent. I’m not sure how you get from either of those words to “permanent.” This is a logical fallacy. It’s a falsehood designed to inspire fear.
Recent events show that Lake Conroe is being unfairly blamed for downstream flooding. Kingwood still flooded during Imelda “even though we didn’t release anything” during Imelda. Please! The vast majority of all Kingwood flooding during Imelda was street flooding or related to Woodridge Village. Some homes did flood on the East Fork, but I can’t believe any of those residents would blame it on a fictional release from Lake Conroe that wasn’t coming down the West Fork.
There was an “organized effort” in Kingwood to send an unspecified number of “letters” to the SJRA board thanking them for not releasing during Imelda. So what is it? Are we allegedly blaming you for flooding us during Imelda or thanking you for not flooding us? Show me the letters. I’m not aware of any such organized effort. See the comment above.
Kingwood is trying to increase the lowering to 3 feet and Kingwood is winning that fight by a large margin. I’m aware of no effort to increase the lowering and no fight that we’re winning by a large margin.
Wading birds that require shallow areas are being destroyed. Duh! They’re saying birds need shallow water, but they want to make the lake deeper. So if water depth had something to do with destroying birds, who would be destroying them?
Boating Vs. Flooding
Let’s face it. The big reason Lake Conroe residents don’t want to see their lake lowered is that it makes boating more difficult. No argument there.
But the big reason Lake Houston area residents want more dredging is not boating. It’s to reduce flood risk. The mouth bar forms a sediment dam behind the dam that reduces the conveyance of the river through the heavily populated Humble/Kingwood corridor. And until it’s dredged, we need the help of Lake Conroe residents. The lake lowering strategy gives us the only effective way to mitigate flooding for now.
After the Army Corps removed 500,000 cubic yards of sediment from the West Fork mouth bar, Imelda promptly redeposited much of it. Here’s what it looked like after Imelda.
Compare These West Fork Damages
We are certainly sensitive to Lake Conroe lifestyle considerations. But during Harvey, Lake Houston Area damages on the West Fork alone included:
Gear Up for a Fight
More on this in future posts. Lake Houston Area residents need to gear up to fight the falsehoods and ensure that Lake Conroe seasonal lowering policy remains in place for another year.
Posted by Bob Rehak on 11/22/2019
815 Days since Hurricane Harvey
What Went Wrong, Part III: Perry Homes’ Woodridge Village Detention Pond Catastrophe
Note: This is the third in a five part series about What Went Wrong in Woodridge Village that may have contributed to flooding in Elm Grove and North Kingwood Forest. It focuses on Detention Ponds.
Section 7 of the Montgomery County Drainage Criteria Manual cautions, “The introduction of impervious cover and improved runoff conveyance serves in many cases to increase flood peaks quite dramatically over those for existing conditions.” And that’s exactly what happened in Elm Grove and North Kingwood Forest in May and September of this year. Two subdivisions that had never flooded before were inundated with several feet of water from Woodridge Village.
Perry Homes failed to observe numerous regulations in the Drainage Criteria Manual including provisions for:
Critically, they also failed to construct all the detention ponds they promised.
Less than a Quarter of Detention Ponds Built
When listing factors that contributed to the flooding, the absence of several promised detention ponds should rank near the top.
According to LJA Engineering, Perry Homes was supposed to develop the project in two phases and clearcut only 30 acres in the northern section during Phase 1. However, something changed. Instead, Perry Homes clearcut the entire northern section. And they still haven’t excavated any of the three detention ponds there.
Had Perry Homes installed all the detention that it promised, the site should have detained a foot of rainfall. But it didn’t. When Imelda came along, it was like trying to pour 100 gallons of water into a 23 gallon jug. Water spilled out of the development into adjacent streets and homes.
Erosion Control Measures Missing for Detention Ponds
Section 7.2.7 of the Montgomery County Drainage Criteria Manual details Erosion Control Measures for Detention Facilities. It states:
“The erosion potential for a detention basin is similar to that of an open channel. For this reason the same types of erosion protection are necessary, including the use of backslope swales and drainage systems (as outlined In SECTION 6), proper revegetation and pond surface lining where necessary. Proper protection must especially be provided at pipe outfalls into the facility, pond outlet structures and overflow spillways where excessive turbulence and velocities will cause erosion.” (See page page 123 of pdf, numbered 113 in doc.)
Revegetation?
No Protection for Overflow Spillway
Backslope Interceptor Swales?
Maintenance Road Missing at Critical Point
Section 7.2.8 talks about Maintenance of Detention Facilities. It states, “A 30-foot wide access and maintenance easement shall be provided around the entire detention pond.” The most critical place in the entire chain of detention ponds, the final outflow culvert into Taylor Gully, has no room for a maintenance road. That’s because when they installed the required backslope interceptor swale, the only place left for it was the maintenance road. That’s planning for you!
No Increase in Downstream Flood Levels Allowed
Section 7.3 talks about DETENTION DESIGN PROCEDURES. It clearly lays out the design goal when it says…
Further down in this section, the regulations state: “The maximum 100-year water surface elevation in all detention facilities shall be a minimum of 1 foot below the minimum top of bank elevation of the basin.”
Judging from this video shot by Edy and Ricki Cogdill during the May 7th storm, I would say Perry Homes didn’t meet that objective. It reminds me of that slime show on Nickelodeon, but in this case, the innocent bystanders got slimed.
No Geotechnical Report for Groundwater Level at Pond Sites
Section 7.5 discusses GEOTECHNICAL INVESTIGATIONS. It says, “Before initiating final design of a detention pond, a detailed soils investigation by a geotechnical engineer should be undertaken.” Regulations state that the ground water investigation must be “at the proposed site.” Montgomery County has no record of such an investigation or report.
A company called Terracon prepared a Preliminary Geotechnical Report for Perry that addressed issues pertaining to utilities, road pavement and residential foundations. But it makes no mention of detention ponds.
MoCo Claims It Has No Further Geotechnical Reports
If Perry Homes did additional investigations into ground water on this site, Montgomery County says it doesn’t have them.
If no further investigations were conducted, this could be a fatal flaw affecting the economics of the entire development. Note the presence of standing water in the photo below.
The presence of standing water reduces the rated capacity of detention ponds and channels. Only the area above the standing water counts as capacity. Regulations say that these ponds should drain completely (see below).
If you can’t go deep to get your detention pond capacity, you have to go wide. And that will mean fewer homesites than the 896 they planned. This site might not even make economic sense for building homes.
Problems with Homes Built Over Wetlands
The presence of wetlands in the northern section, which the Terracon report never mentions, would also significantly reduce the site’s suitability for building homes.
This article describes the problems with homes built on wetlands. The title: “Caution: Building in a Wetland Can Be Hazardous to Your House.” A biologist for the US Fish and Wildlife service who investigated filled wetlands in Pennsylvania warned: “Build your house in a wetland, and you’ve got a hobby for the rest of your life. You will be fighting that water forever.” He discusses cracked foundations and also warns, “When wetlands are filled, the water that made them wet has to go somewhere. … the water likely is leaking into formerly dry homes of downstream property owners.”
I’m sure Perry Homes would divulge the presence of former wetlands to the future buyers of homes on this site. It’s the only ethical thing to do and Kathy Perry Britton, CEO, has standards to maintain.
Incomplete Drainage of Detention Ponds
Section 7.6 of the Drainage Criteria Manual addresses GENERAL REQUIREMENTS FOR DETENTION POND CONSTRUCTION. It states:
“A pilot channel shall be provided in detention facilities to insure that proper and complete drainage of the storage facility will occur.” (Emphasis added.)
To excavate S2 to the required design depth, contractors had to continuously pump water out of it as they worked. It still retains water to this day.
If Perry Homes continues its Woodridge Village venture using its current plans, chances are, the company will never provide enough detention capacity for real world conditions. When modeling, their engineers did NOT use the current Atlas-14 rainfall statistics from NOAA.
Where Does Perry Homes Go from here?
After ignoring regulations, hundreds of homes flooded. And they will flood again. Owning this site is like hanging a millstone around one’s neck. It could drown the entire company in perpetual litigation and debt.
Future Posts in this series will look at:
Posted by Bob Rehak on 11/21/2019 with help from Jeff Miller
814 Days since Hurricane Harvey and 63 since Imelda
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.