The Lake Houston Redevelopment Authority/TIRZ 10 (LHRA/TIRZ) Board Meeting on Thursday, Feb. 8, 2024, focused almost exclusively on issues that have delayed the Northpark expansion project. LHRA/TIRZ also announced lane closures beginning Feb. 19, 2024.
One Source of Hold Ups Resolved, Another Remains
The Northpark expansion project is designed to move more traffic faster and to create an all-weather evacuation route for 78,000 Kingwood residents in the event of another major flood, such as Hurricane Harvey.
Two major hold ups have been:
Reaching right-of-way agreements with Union Pacific Railroad (UP)
Getting utilities, such as CenterPoint and Entergy, to move gas and electric lines.
As of this week, all railroad agreements have been resolved.
Approval of the agreements by the Houston City Council should be a formality.
And CenterPoint should complete the relocation of their gas lines within a week or two.
However, Entergy has not even started relocating its equipment. They were given notice four years ago to do so.
The board discussed the possibility of condemning an existing Entergy easement within the limits of Northpark Drive right of way, but ultimately decided to defer action for one more month. The outcome is inevitable. Entergy must move its equipment. But members hope to avoid the expense and delays of litigation involved in a condemnation proceeding.
It is unclear what Entergy hopes to gain through delays. In the meantime, it is jeopardizing its public image in the most densely populated part of its Texas service area.
Entergy Must Resolve Three Problems
Entergy has:
Utility poles it must move out of the City’s right of way.
A transformer next to the Exxon station at US59 on LHRA/TIRZ property.
Underground electricity lines that would be paved over in several places.
The existing wood poles between 494 and the Kingwood Diversion Ditch are in the City’s right-of-way. Entergy has sought reimbursement to move those, however, they are on City property and not entitled to reimbursement.
The transformer next to the Exxon station now sits on property purchased from Exxon by the LHRA/TIRZ.
Entergy wants 52 weeks and more than a million dollars to move this transformer in the Exxon parking lot at US59 and Northpark Drive.
Regarding the third item, utilities commonly run electricity lines under streets in urban environments. But Entergy apparently does not want that in this case and has not made arrangements to move the lines.
To resolve such conflicts, LHRA agreed to pay Entergy $711,000 in July last year. But then a consultant for Entergy demanded $1.462 million – doubling the costs. LHRA balked. The extra money wasn’t and isn’t in the budget. Neither were the cost increases itemized. Said another way, Entergy didn’t break down what caused the price increases.
Itemized Costs Being Demanded
To make sure Entergy is not folding in un-reimbursable costs such as relocating poles in rights of way with allowable relocation costs for the transformer, Ralph De Leon, project manager for LHRA, said he has requested itemized costs and a schedule of values for each part of the job from Entergy.
A schedule of values includes such things as material costs as well as labor costs. For instance, one line item might read, “X people at $Y/hr times Z hours.” He also wants to see that schedule signed and stamped by a licensed PE, whose license could be revoked for falsifying information.
Entergy First Notified in 2020
The LHRA Board reviewed a history of attempts to resolve the Entergy conflict issues. They included 22 meetings/discussions between October 2020 and January 2024.
October 2020: Began coordinating utility impacts with Entergy and other utility companies (at 60% design stage). Held COH utility coordination meeting.
December 2020: Entergy reached out and asked if there were opportunities for relocation reimbursement. Held COH utility coordination meeting.
January 2021: Held COH utility coordination meeting.
February 2021: Held COH utility coordination meeting.
March 2021: Held COH utility coordination meeting.
June 2021: Began discussions regarding the ground transformer near Exxon gas station. M&S had preliminary plans prepared.
February 2022: Held COH utility coordination meeting.
March 2022: Held COH utility coordination meeting.
April 2022: Held COH utility coordination meeting.
July 2022: M&S determined that their preliminary plans were incorrect and had assumed overhead line relocations for crossing over Northpark Drive.
August 2022: M&S noted that their utilities were in an easement and would require reimbursement from LHRA.
September 2022: Additional correspondence regarding reimbursement for relocations. Teams meeting with M&S to discuss relocations.
October 21, 2022: M&S provided a draft cost estimate via email. Total estimated costs for the relocations were $1,218,000.
January 2023: Field meeting with M&S, AT&T and Exxon representative to discuss relocations on Exxon property. M&S provided easement documentation for their utilities and continued discussion about reimbursement. Wade Carpenter (Entergy attorney) began involvement in the conversations.
February 2023: Entergy attorneys reviewing the matter internally.
March 3, 2023: M&S noted that utility relocations in easement (primarily west of Loop 494) would cost $710,000 and would be seeking reimbursements for these relocations. For utility relocations east of Loop 494, those would cost approx. $500,000 and Entergy deemed these costs as non-reimbursable as they are not in easement.
May 17, 2023: M&S confirmed that relocation costs west or Loop 494 are reimbursable ($710,000) and relocation costs east of Loop 494 ($500,00) are non-reimbursable.
July 19, 2023: M&S provided draft agreement for relocations with relocation costs shown to be $711,186.26.
August 2023: Coordination with M&S on timeline of relocations.
October 2023: M&S noted that they are waiting for the go ahead to send plans to construction group.
December 2023: Coordination with M&S regarding fiber companies attached to their poles. M&S provided an update relocation cost estimate with a new total being $1,462,135.57.
January 2024: Coordination with M&S on timeline of relocations.
M&S is an Entergy consultant.
30-Day Deadline Given on Feb. 6, 2024
On February 6, 2024, Carol Haddock, Director of Houston Public Works, sent Entergy a letter giving the company 30-days to move its property. The letter included a request to submit a timeline for the relocations by Feb. 16.
Haddock’s letter parallels one sent by LHRA/TIRZ10 on Nov. 9, 2020, which the City says suffices as proper legal notification. That’s because the LHRA/TIRZ10 is acting as an agent of the City.
The City’s position is that Entergy is not moving into the City’s footprint. But the city is getting bigger and expanding into Entergy’s footprint. It appears that the City has the upper hand at the moment.
Impact of Delays
De Leon believes the City’s letter will resolve enough issues to keep crews busy for now. Next up:
Continuing excavation of two stormwater detention ponds at US59 and Northpark
Placement of box culverts in the middle ditch
Creation of some temporary lanes on the north side of Northpark.
However, he admits that the Entergy delays have caused problems. Instead of following the optimal critical path, his contractors are hopscotching around to keep crews busy.
If Entergy continues to delay, he could face contractual penalties, including costly demobilization.
Lane Closure Announced
LHRA/TIRZ posted this announcement on its project website. It affects westbound traffic.
“Beginning February 19th, Lake Houston Redevelopment Authority’s (LHRA’s) contractor, Harper Brothers Construction will be closing the right two lanes of westbound traffic near the Northpark/I-69 intersection. The first month of this closure will leave two westbound lanes open – the existing left turn lane and one through lane. The next 3 months of the closure will switch traffic onto the newly constructed lanes while construction of the existing left turn lane and through lane are completed. Westbound traffic should expect delays and alternative routes are encouraged. For this phase of work the contractor will be installing new storm sewer pipes and inlets along with new concrete roadway.”
Two westbound lane closures beginning Feb. 19circled in red.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/02/20240124-DJI_0271-Edit-copy.jpg?fit=1100%2C733&ssl=17331100adminadmin2024-02-10 19:16:172024-02-10 22:02:53Entergy in City’s Crosshairs, Northpark Lane Closures Announced
Just upstream from the blocked drainage ditch at Northpark Drive and the San Jacinto West Fork, Hallett Materials operates the biggest sand mine between I-69 and I-45. The mine complex sprawls across several square miles and has several leaks. During the last flood in January, those leaks likely contributed to sedimentation in the West Fork and a blocked drainage ditch immediately downriver from the mine.
Contrary to a popular narrative among miners, this sand did not come from Spring Creek. That’s another watershed.Picture taken on 2/5/2024.The Hallett Mine is to the left (upstream) of the channel. This picture of the blockage above shows the height of the sand relative to the top of the banks. Courtesy of a resident who prefers to remain anonymous.
Location of Mine Relative to Blockage
In late January, the West Fork experienced an estimated five-year flood after several days of nearly constant rains. Waking up after the flood was like a bad hangover. The blocked ditch above was just one of the problems. It is immediately downstream from the giant Hallett mine. See below.
Landsat image from Google Earth. Arrow shows direction of river’s flow. Circle shows location of blockage.Numbers show approximate location of leaks listed below.
Mine Leaks in Multiple Places
Let’s take a closer look at each of those three areas.
One pond was wide open to the river through a large gap in its dike. The gap appears to have remained open since at least July 2023 and enlarged.
A pipe was expelling water from a second pond straight into the river.
A bulldozer appeared to have helped a third pond overflow across a road. Wastewater from the settling pond then flowed through woods and neighboring properties on its way to the river.
Pictures Taken on Feb. 8, 2024
Leak #1
Notice the huge gap in the dike of the pond in the center of the image below. Also notice that pond’s elevation compared to the one on the right.
The dike breach (center of image) first showed up in Google Earth in July 2023.It now appears considerably larger, indicating severe erosion from the recent flood.
The drought last summer and fall certainly didn’t cause the breach to enlarge.
Historical images in Google Earth show that this pond frequently breaches its dikes in different places. Something’s going through there!
Leak #2
A little farther downstream on the west side of the river, a pipe drains another Hallet pond directly into the river.
Haven’t seen this before! On the east side of the river, in the woods next to Hallett’s main settling pond, a bulldozer apparently created a path for water to escape across a maintenance road. Water then flowed through woods 600-feet wide and onto neighboring properties before entering the river just above the blocked channel. See the series of images below.
Notice bulldozer tracks to left of perimeter road and wet area on road in the middle of the frame.
Flying closer, you can see that the bulldozer had pushed dirt from the road into the pond (see below, right side of frame).
Silty wastewater then escaped from the pondinto the woods on the left.The silty wastewater then migrated south (top of frame) through the woods.Along the way, it invaded neighboring properties.Then it drained back across the access road and into an abandoned mine (top of frame).
Hanover Estates now owns that abandoned mine. In the photo above, note the open path to the river in the upper right. It’s shown below in more detail.
Closer shot of wastewater exiting Hanover pond through another breach that leads straight to blockage (circled in red in the distance).
Apportioning the Relative Contribution of Different Sources
The Hallett mine owner told me that sand can’t escape his pits. I remain skeptical.
To be fair, some of the sediment in the channel blockage likely came from river-bank erosion and sand bars upstream.
Also, a new development called Northpark South, now in the clearing stage, likely also contributed to the blockage. Silty stormwater flows unchecked from it into a second abandoned mine (also owned by Hanover Estates) and then into the blocked drainage ditch.
Northpark South photo from January 24, 2024, looking south toward abandoned mine, blocked ditch and river in distance.
No one can say that Hallett and Northpark South contributed all of the material in the blockage. But it would be hard to pretend that none of it came from them.
The mine is still leaking two weeks after the flood!
And even before the flood, a giant ravine was sending stormwater from Northpark South into the second abandoned mine on the south side of the ditch.
Northpark South on December 28, 2023 before flood. Note ravine caused by erosion.
That mine drains into the blocked channel directly above the blockage. (See very first shot in this post.)
Now that the immediate danger has passed, we need to investigate the contribution of mining and floodplain development to sedimentation.
When rivers and ditches fill up with sludge, it reduces conveyance.
Then, when the next flood comes, instead of water staying within the riverbanks, it may back up or overflow into living rooms.
The greatest area of deposition will normally be where floodwater slows down as it reaches a standing body of water like Lake Houston. We’ve seen what that led to.
Corporate waste-disposal practices are matters of public safety and concern. We need to examine them more closely.
If Hallett and/or the Northpark South developer wish to respond to this editorial, I will be happy to post their points of view.
Posted by Bob Rehak on 2/9/24
2355 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/02/20240208-DJI_0797.jpg?fit=1100%2C733&ssl=17331100adminadmin2024-02-09 12:02:152024-02-22 08:51:35Sand Mine Leaks Upstream from Blocked Drainage Ditch
Yet another “RV Resort” is coming to the Kingwood/Porter area. This one will be at the north end of Woodland Hills Drive about a block north of Kingwood Park High School. Plans show parking for 43 RVs on the 4.4 acre property.
The Porter Strong RV Resort, which contains a recreation building, dumpsters, and concrete driveways, will back up to homes along Birchwood Springs Avenue in Woodridge Forest.
The drainage calculations look impressive…until you consider the way they estimated impervious cover.
Location map from construction plans obtained via a FOIA Request to MoCo Engineering.Note: High School is mislabeled. Should say, “Kingwood Park High School.”
Access from Porter For Now
Access to the RV resort – at least for now – will be via Needham Road and Collette Lane in Porter. However, plans show a dotted line for an extension of Woodland Hills Drive, which currently stops approximately 300 feet short of the development. It’s not immediately clear whether Montgomery County or the developer plans to extend Woodland Hills north at this time.
Drainage in this area flows south to Bens Branch. Note in the layout above that two 7-foot-deep, dry-bottom, stormwater-detention basins flanked by drainage swales will help intercept stormwater flowing south before it reaches adjoining properties.
FEMA shows no floodplains in the area and USGS shows no wetlands on the site.
The detention basins for the 4.4 acre site will hold 4.4 acre feet of stormwater before they start to overflow. That exceeds Harris County Flood Control District’s minimum recommendation for areas flowing into Harris County.
Moreover, the engineer claims the site only requires 3.4 acre feet in a 100-year storm. That calculation is based on Atlas-14 requirements adopted by Montgomery County.
The engineer indicates that the maximum discharge rate for the ponds, which will be pumped, is about 8 cubic feet per second less than the natural runoff rate for the site. So for everything up to the 100-year storm, runoff going into Bens Branch from this area should be reduced.
All that is good news. Now for the bad news.
The engineer seems to have based all those calculations on 29% impervious cover.
That seems unlikely for this type of project. The number of parking spots per acre is roughly equivalent to the Laurel Springs RV resort which claimed to have 66% impervious cover, but likely has much higher.
Best practices require excluding detention basins from impervious cover calculations. A quick glance at the construction diagram above suggests that concrete will cover much more than a third of the remaining property.
Also, the engineer says it will take 48 hours to drain the ponds after a 100-year rain. The ponds do not appear to empty by gravity, however. They will require pumps, which could present problems in a power outage. Such outages frequently occur in storms strong enough to create floods.
Pictures Taken on 2/1/24 Show Extent of Construction
Currently, the site is being cleared. Construction has not yet started. I took the shots below on 2/1/24. They show the extent of clearing as of last week.
Looking SW at construction site. Woodland Hills and Kingwood Park HS on left. Northpark Rec Area top center. Homes are in Woodridge Forest.
Looking W toward Woodridge Middle School at top of frame. Reverse Angle. Looking E toward Woodridge Village. Surrounding areas already include a number of mobil homes and RVs.
Bens Branch Getting Crowded
I hope contractors build what the plans indicate. Bens Branch has enough flooding problems of its own. The Kingwood Area Drainage Analysis showed that parts of the stream could flood in a two-year rain.
Since that study, several high-density developments have been built nearby in the watershed. They include The Preserve at Woodridge, which apparently understated the amount of impervious cover, and Brooklyn Trails, which was grandfathered under pre-Atlas-14 requirements.
And then there’s the Northpark Drive Expansion Project, which is seeking more room for another detention basin to mitigate its own increases in impervious cover.
For now, the best thing to do is remain vigilant.
Posted by Bob Rehak on Feb. 7, 2024
2353 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/02/20240201-DJI_0545.jpg?fit=1100%2C733&ssl=17331100adminadmin2024-02-07 15:34:072024-02-08 10:12:00Another RV Resort Coming Near North End of Woodland Hills Drive
Entergy in City’s Crosshairs, Northpark Lane Closures Announced
The Lake Houston Redevelopment Authority/TIRZ 10 (LHRA/TIRZ) Board Meeting on Thursday, Feb. 8, 2024, focused almost exclusively on issues that have delayed the Northpark expansion project. LHRA/TIRZ also announced lane closures beginning Feb. 19, 2024.
One Source of Hold Ups Resolved, Another Remains
The Northpark expansion project is designed to move more traffic faster and to create an all-weather evacuation route for 78,000 Kingwood residents in the event of another major flood, such as Hurricane Harvey.
Two major hold ups have been:
Approval of the agreements by the Houston City Council should be a formality.
And CenterPoint should complete the relocation of their gas lines within a week or two.
However, Entergy has not even started relocating its equipment. They were given notice four years ago to do so.
The board discussed the possibility of condemning an existing Entergy easement within the limits of Northpark Drive right of way, but ultimately decided to defer action for one more month. The outcome is inevitable. Entergy must move its equipment. But members hope to avoid the expense and delays of litigation involved in a condemnation proceeding.
It is unclear what Entergy hopes to gain through delays. In the meantime, it is jeopardizing its public image in the most densely populated part of its Texas service area.
Entergy Must Resolve Three Problems
Entergy has:
The existing wood poles between 494 and the Kingwood Diversion Ditch are in the City’s right-of-way. Entergy has sought reimbursement to move those, however, they are on City property and not entitled to reimbursement.
The transformer next to the Exxon station now sits on property purchased from Exxon by the LHRA/TIRZ.
Regarding the third item, utilities commonly run electricity lines under streets in urban environments. But Entergy apparently does not want that in this case and has not made arrangements to move the lines.
To resolve such conflicts, LHRA agreed to pay Entergy $711,000 in July last year. But then a consultant for Entergy demanded $1.462 million – doubling the costs. LHRA balked. The extra money wasn’t and isn’t in the budget. Neither were the cost increases itemized. Said another way, Entergy didn’t break down what caused the price increases.
Itemized Costs Being Demanded
To make sure Entergy is not folding in un-reimbursable costs such as relocating poles in rights of way with allowable relocation costs for the transformer, Ralph De Leon, project manager for LHRA, said he has requested itemized costs and a schedule of values for each part of the job from Entergy.
A schedule of values includes such things as material costs as well as labor costs. For instance, one line item might read, “X people at $Y/hr times Z hours.” He also wants to see that schedule signed and stamped by a licensed PE, whose license could be revoked for falsifying information.
Entergy First Notified in 2020
The LHRA Board reviewed a history of attempts to resolve the Entergy conflict issues. They included 22 meetings/discussions between October 2020 and January 2024.
M&S is an Entergy consultant.
30-Day Deadline Given on Feb. 6, 2024
On February 6, 2024, Carol Haddock, Director of Houston Public Works, sent Entergy a letter giving the company 30-days to move its property. The letter included a request to submit a timeline for the relocations by Feb. 16.
Haddock’s letter parallels one sent by LHRA/TIRZ10 on Nov. 9, 2020, which the City says suffices as proper legal notification. That’s because the LHRA/TIRZ10 is acting as an agent of the City.
The City’s position is that Entergy is not moving into the City’s footprint. But the city is getting bigger and expanding into Entergy’s footprint. It appears that the City has the upper hand at the moment.
Impact of Delays
De Leon believes the City’s letter will resolve enough issues to keep crews busy for now. Next up:
However, he admits that the Entergy delays have caused problems. Instead of following the optimal critical path, his contractors are hopscotching around to keep crews busy.
If Entergy continues to delay, he could face contractual penalties, including costly demobilization.
Lane Closure Announced
LHRA/TIRZ posted this announcement on its project website. It affects westbound traffic.
“Beginning February 19th, Lake Houston Redevelopment Authority’s (LHRA’s) contractor, Harper Brothers Construction will be closing the right two lanes of westbound traffic near the Northpark/I-69 intersection. The first month of this closure will leave two westbound lanes open – the existing left turn lane and one through lane. The next 3 months of the closure will switch traffic onto the newly constructed lanes while construction of the existing left turn lane and through lane are completed. Westbound traffic should expect delays and alternative routes are encouraged. For this phase of work the contractor will be installing new storm sewer pipes and inlets along with new concrete roadway.”
For More Information
For more information about the project including construction plans, visit the project pages of the LHRA/Tirz 10 website. Or see these posts on ReduceFlooding:
Posted by Bob Rehak on 2/10/2024
2356 Days since Hurricane Harvey
Sand Mine Leaks Upstream from Blocked Drainage Ditch
Just upstream from the blocked drainage ditch at Northpark Drive and the San Jacinto West Fork, Hallett Materials operates the biggest sand mine between I-69 and I-45. The mine complex sprawls across several square miles and has several leaks. During the last flood in January, those leaks likely contributed to sedimentation in the West Fork and a blocked drainage ditch immediately downriver from the mine.
Location of Mine Relative to Blockage
In late January, the West Fork experienced an estimated five-year flood after several days of nearly constant rains. Waking up after the flood was like a bad hangover. The blocked ditch above was just one of the problems. It is immediately downstream from the giant Hallett mine. See below.
Mine Leaks in Multiple Places
Let’s take a closer look at each of those three areas.
Pictures Taken on Feb. 8, 2024
Leak #1
Notice the huge gap in the dike of the pond in the center of the image below. Also notice that pond’s elevation compared to the one on the right.
The drought last summer and fall certainly didn’t cause the breach to enlarge.
Historical images in Google Earth show that this pond frequently breaches its dikes in different places. Something’s going through there!
Leak #2
A little farther downstream on the west side of the river, a pipe drains another Hallet pond directly into the river.
Leak #3:
Haven’t seen this before! On the east side of the river, in the woods next to Hallett’s main settling pond, a bulldozer apparently created a path for water to escape across a maintenance road. Water then flowed through woods 600-feet wide and onto neighboring properties before entering the river just above the blocked channel. See the series of images below.
Flying closer, you can see that the bulldozer had pushed dirt from the road into the pond (see below, right side of frame).
Hanover Estates now owns that abandoned mine. In the photo above, note the open path to the river in the upper right. It’s shown below in more detail.
Apportioning the Relative Contribution of Different Sources
The Hallett mine owner told me that sand can’t escape his pits. I remain skeptical.
To be fair, some of the sediment in the channel blockage likely came from river-bank erosion and sand bars upstream.
Also, a new development called Northpark South, now in the clearing stage, likely also contributed to the blockage. Silty stormwater flows unchecked from it into a second abandoned mine (also owned by Hanover Estates) and then into the blocked drainage ditch.
No one can say that Hallett and Northpark South contributed all of the material in the blockage. But it would be hard to pretend that none of it came from them.
The mine is still leaking two weeks after the flood!
And even before the flood, a giant ravine was sending stormwater from Northpark South into the second abandoned mine on the south side of the ditch.
That mine drains into the blocked channel directly above the blockage. (See very first shot in this post.)
The SJRA, which is investigating sedimentation in the river basin, relies on a sediment gauge at I-45 – upstream from the mines and most of the new developments along the river. So they can’t really help sort out this issue.
The Calm After the Storm
Now that the immediate danger has passed, we need to investigate the contribution of mining and floodplain development to sedimentation.
Then, when the next flood comes, instead of water staying within the riverbanks, it may back up or overflow into living rooms.
The greatest area of deposition will normally be where floodwater slows down as it reaches a standing body of water like Lake Houston. We’ve seen what that led to.
Corporate waste-disposal practices are matters of public safety and concern. We need to examine them more closely.
If Hallett and/or the Northpark South developer wish to respond to this editorial, I will be happy to post their points of view.
Posted by Bob Rehak on 2/9/24
2355 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.
Another RV Resort Coming Near North End of Woodland Hills Drive
Yet another “RV Resort” is coming to the Kingwood/Porter area. This one will be at the north end of Woodland Hills Drive about a block north of Kingwood Park High School. Plans show parking for 43 RVs on the 4.4 acre property.
The Porter Strong RV Resort, which contains a recreation building, dumpsters, and concrete driveways, will back up to homes along Birchwood Springs Avenue in Woodridge Forest.
The drainage calculations look impressive…until you consider the way they estimated impervious cover.
Access from Porter For Now
Access to the RV resort – at least for now – will be via Needham Road and Collette Lane in Porter. However, plans show a dotted line for an extension of Woodland Hills Drive, which currently stops approximately 300 feet short of the development. It’s not immediately clear whether Montgomery County or the developer plans to extend Woodland Hills north at this time.
Drainage and Detention Plans
Drainage in this area flows south to Bens Branch. Note in the layout above that two 7-foot-deep, dry-bottom, stormwater-detention basins flanked by drainage swales will help intercept stormwater flowing south before it reaches adjoining properties.
FEMA shows no floodplains in the area and USGS shows no wetlands on the site.
The detention basins for the 4.4 acre site will hold 4.4 acre feet of stormwater before they start to overflow. That exceeds Harris County Flood Control District’s minimum recommendation for areas flowing into Harris County.
Moreover, the engineer claims the site only requires 3.4 acre feet in a 100-year storm. That calculation is based on Atlas-14 requirements adopted by Montgomery County.
The engineer indicates that the maximum discharge rate for the ponds, which will be pumped, is about 8 cubic feet per second less than the natural runoff rate for the site. So for everything up to the 100-year storm, runoff going into Bens Branch from this area should be reduced.
All that is good news. Now for the bad news.
The engineer seems to have based all those calculations on 29% impervious cover.
That seems unlikely for this type of project. The number of parking spots per acre is roughly equivalent to the Laurel Springs RV resort which claimed to have 66% impervious cover, but likely has much higher.
Best practices require excluding detention basins from impervious cover calculations. A quick glance at the construction diagram above suggests that concrete will cover much more than a third of the remaining property.
Also, the engineer says it will take 48 hours to drain the ponds after a 100-year rain. The ponds do not appear to empty by gravity, however. They will require pumps, which could present problems in a power outage. Such outages frequently occur in storms strong enough to create floods.
Pictures Taken on 2/1/24 Show Extent of Construction
Currently, the site is being cleared. Construction has not yet started. I took the shots below on 2/1/24. They show the extent of clearing as of last week.
Looking SW at construction site. Woodland Hills and Kingwood Park HS on left. Northpark Rec Area top center. Homes are in Woodridge Forest.
Bens Branch Getting Crowded
I hope contractors build what the plans indicate. Bens Branch has enough flooding problems of its own. The Kingwood Area Drainage Analysis showed that parts of the stream could flood in a two-year rain.
Since that study, several high-density developments have been built nearby in the watershed. They include The Preserve at Woodridge, which apparently understated the amount of impervious cover, and Brooklyn Trails, which was grandfathered under pre-Atlas-14 requirements.
And then there’s the Northpark Drive Expansion Project, which is seeking more room for another detention basin to mitigate its own increases in impervious cover.
For now, the best thing to do is remain vigilant.
Posted by Bob Rehak on Feb. 7, 2024
2353 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.