When examining the floodwater detention pond capacity for the Kingwood Area’s first RV park at 1355 LAUREL SPRINGS LANE, it seemed impossibly low. The park will build a pond with 7.68 acre feet of stormwater detention. That’s more than the required 6.675 acre feet, but about half of what the City of Houston (COH) would require under new guidelines that went into effect within 90 days of the plan’s approval.
Because of that 90-day grandfathering loophole, the RV park will escape current City and County requirements for floodwater detention.
Current Regs Would Require 13 Acre-Feet of Detention Pond Capacity
Under today’s requirements, a 20.032-acre RV Park would require 13 acre-feet of detention pond capacity (20 acres x .65 = 13 acre feet). That’s because the COH 2021 infrastructure design manual makes properties larger than 20 acres follow HCFCD guidelines (see below).
New Harris County guidelines require a minimum rate of .65 acre-feet per acre.The RV Park is slightly larger than 20 acres.
This requirement is based on NOAA’s new, higher Atlas-14 rainfall probability tables adopted in the wake of Harvey.
COH 2021 Infrastructure Design Manual Defers to HCFCD Regs for Lots This Size
The City’s Infrastructure Design Manual imposed new criteria in July 2021 that would have required developments greater than 20 acres to follow the HCFCD standard for detention pond capacity. See screen capture below which bridges two pages.
Differences Between Old/New Versions of City/County Regs
Two primary differences exist between the City and County regs in 2020 and 2021.
The first is the basis for calculations. In both years:
The County bases required detention pond capacity on the total size of the site.
The City, except where it defers to HCFCD regs, bases detention pond capacity on the amount of impervious cover within the site.
The City also changed the minimum lot size required to follow HCFCD regulations between 2020 and 2021.
Sites larger than 50 acres had to follow HCFCD guidelines in 2020.
Sites larger than 20 acres had to follow HCFCD guidelines in 2021.
The 2020 requirements apply in this case because of when plans were first reviewed (January 2021). The 2020 Infrastructure Design Manual read as follows:
COH 2020 Infrastructure design manual requires 20- to 50-acre tracts to have detention volume (in acre feet) equal to half of the impervious cover.
Developer Applied Before Detention Pond Capacity Increased
Using that formula, the developer planned a detention pond that holds 7.68 acre feet of storm water detention, an acre foot more than required at the time the plans were first submitted, even though they were finally approved four months after the new regs went into effect. But that’s still far less than the 13 acre-feet required under today’s regulations.
I question whether the amount of impervious cover above is correct. That’s because the developer’s permit allows 182 RV spaces, but the plans show 226 – about a 24% increase. However, the impervious cover shown on the plans before and after the permit approval didnotincrease. That could also affect detention pond capacity requirements.
Timing, Impervious Cover Issues Raise Public Safety Questions
Assuming the impervious cover calculations above are correct, and that’s a big assumption, the developer is providing more than the minimum amount of required detention under 2020 requirements. But if they are not correct, the developer would be short.
And if the 2021 requirements applied, the developer would have to provide virtually twice as much detention.
A half-sized detention pond would require the RV Park to pump water into Lakewood Cove’s drainage system sooner and faster than with a larger pond. And under severe conditions, when Lakewood Cove’s drainage is already stressed, the extra water could over-stress it.
No Drainage Impact Analysis
I’ve requested a drainage impact analysis from the City for the RV Park on at least two occasions and have not received one. I therefore deduce that one does not exist. Such an analysis would quantify the impact on Lakewood Cove, Edgewater Park and surrounding roads.
Detail from most recent approved construction plan shows all water from detention pond going under Laurel Springs to Lakewood Cove storm sewer systemtoward homes below.
All the runoff from the 20 cleared acres will be funneled via a 24″ pipe toward the homes in the foreground.
Bottom Line: Park Will Provide Half of Today’s Detention Requirement
If this developer, LS RV Resort, LP, submitted plans today, it would have to provide almost twice as much detention pond capacity.
2021 requirements call for .65 acre feet per acre times 20 total acres. That equals 13 acre feet of detention.
2020 requirements call for .5 times the claimed 13.349 acres of impervious cover. That equals 6.675 acre feet of detention.
And we wonder how floods happen! Remember this the next time you see water rising toward your home.
I wonder if investors in the RV Park will be notified of the potential liability in a prospectus. Undersized detention ponds based on a similar grandfathering loophole in Montgomery County regulations became the central issue in lawsuits by hundreds of Elm Grove residents against Perry Homes, its subsidiaries and its contractors. The defendants recently settled those lawsuits.
Posted by Bob Rehak on 11/13/2021
1537 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/2021/11/20211111-DJI_0850.jpg?fit=1200%2C799&ssl=17991200adminadmin2021-11-13 17:18:552021-11-14 19:38:02Loophole Cuts RV Park Detention Pond Capacity Requirement in Half
Construction of the new Kingwood Middle School appears on schedule for opening with the next school year in 2022. Compared to my October update, no new major milestones have been reached. Everything just looks a little further along.
Kingwood Middle School Construction Sequencing
Construction started on the west and is moving toward the east. As subcontractors finish one phase such as foundations or structural , the next group picks up the baton and works on roofing, exterior walls, windows, etc.
The most visible change between October and November: progress on exterior walls and roofing.
I took all the pictures below on Saturday, November 6, 2021.
Looking W.Judging from the amount of erosion around the banks, the temporary detention pond appears to be getting a lot of use. This pond will be replaced with a larger permanent one after the old school is demolished to make room for it.Insulation, vapor barriers, brick and glass now surround more than half the site now. Roofing on the westernmost section looks complete. But many roofing materials remain stacked on other sections.Looking south with the old school visible in the top of the frame.Masons have completed the brickwork on large portions of the westernmost section. Shot taken from over Woodland Hills, looking east.Portions of the exterior at the west end still need work, but it’s more done than not.A view from the SE looking NW clearly shows the degree of finish evident in the left, middle and right sections.Low level shot shows middle section on left.
Next Steps for KMS
Next steps will be to dry-in the structure by completing the exterior walls, windows and roofs. The other trades will then start working on interior walls, electrical, wallboard, paint and flooring – all the things that could be destroyed by blowing rain.
I put two kids through the old Kingwood Middle School who became happy, healthy, successful adults. As I look at these pictures, fond memories of plays, recitals, teacher conferences, and athletic contests come to mind. Each month, as the old school comes closer to demolition, I become increasing nostalgic. We will soon witness the end of one era and the start of another in Kingwood.
And cross your fingers! Despite double the impervious cover now on the site, I have received no reports of flooding from neighbors.
Posted by Bob Rehak on 11/11/2021
1535 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/11/20211106-DJI_0804.jpg?fit=1200%2C799&ssl=17991200adminadmin2021-11-10 14:34:542021-11-10 14:34:57Kingwood Middle School: November Construction Update
Future site of Preserve At Woodridge. Looking W toward St. Martha Church across a drainage ditch that empties into Bens Branch.
Nine Homes Per Acre with 65% Impervious Cover
Guefen will build 131 units on 14.65 acres. The rest of the 17 acres will contain a detention pond. That works out to nine homes per acre. RG Miller, the firm that engineered the “Preserve at Woodridge” estimates the development will have 65% impervious cover. See the Plans here. (Caution: large file, 21 mb download.)
Grass will definitely be in the minority. I’m not sure what the Preserve is preserving. The site certainly preserves no trees.
Pictures Taken This Week
Here’s what Guefen’s land looks like as of this week.
Looking E. Cleared area between St. Martha and Kingwood Park High School baseball fields will hold 131 homes and a detention pond.Guefen’s detention pond will border the drainage ditch that empties into Bens Branch about a block south.
With other high-density developments going in upstream along Bens Branch, I hope Guefen’s detention pond capacity will suffice. Brooklyn Trails, several blocks upstream on another tributary of Bens Branch, lacks about 30% of the capacity needed to meet Atlas-14 requirements according to my calculations.
Montgomery County’s Subdivision Rules and Regulations specify that outfall ditches, such as the one in the first photo above only need to carry a 25 year rain. (See page 9.) With that in mind, it seems like Guefen’s detention pond so near a ditch would fill up quickly from ditch overflow in a 25-year rain and provide little detention benefit for anything heavier, for instance, 50-100 year rains.
If that ditch ever needs to be widened, like Hall’s Bayou, the fact that so many homes are built so close to it will severely limit mitigation options.
You can’t build mitigation projects if you don’t have the land.
668 SF Homes with “Interior Garages” and “Luxury Vinyl” Flooring
The 131 single-family detached homes will range in size from 668 square feet to 1,255 square feet and feature “luxury vinyl” flooring. The press release boasts of an “amenity suite” including interior garages. It’s hard to imagine how much living space would be left in 668-SF homes with “interior garages.”
So I checked the plans. I found 29 parking spots labeled “garage spcs.” Many more exterior parking spaces exist. But no one, it appears, will be unloading groceries from his/her car directly into a kitchen. Your “interior garage” could be several homes away.
Nor do all the homes front on a street. That’s going to make moving day hard for your college buddies. You know who your real friends are when they’ll go the distance for you.
Speaking of going the distance, in case of an emergency, that firetruck may be parking 250 feet away from some homes. That’s almost the length of a football field.
Build-to-Rent
According to Guefen’s website and press release, the company sees a niche market for this type of housing in the Kingwood area. They are building these homes to rent them, not sell them. The company normally specializes in multifamily and student housing.
While plans show detached homes, they also show five to six feet of separation. That should be enough to dampen most stereos. So party on, Wayne!
Posted by Bob Rehak on 11/10/2021
1534 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/11/20211105-DJI_0700.jpg?fit=1200%2C799&ssl=17991200adminadmin2021-11-09 17:24:492021-11-09 17:33:57Guefen Clears 17 Acres Between KPHS, St. Martha for 131 High-Density Homes. Will Detention Pond Be Enough?
Loophole Cuts RV Park Detention Pond Capacity Requirement in Half
When examining the floodwater detention pond capacity for the Kingwood Area’s first RV park at 1355 LAUREL SPRINGS LANE, it seemed impossibly low. The park will build a pond with 7.68 acre feet of stormwater detention. That’s more than the required 6.675 acre feet, but about half of what the City of Houston (COH) would require under new guidelines that went into effect within 90 days of the plan’s approval.
Current Regs Would Require 13 Acre-Feet of Detention Pond Capacity
Under today’s requirements, a 20.032-acre RV Park would require 13 acre-feet of detention pond capacity (20 acres x .65 = 13 acre feet). That’s because the COH 2021 infrastructure design manual makes properties larger than 20 acres follow HCFCD guidelines (see below).
This requirement is based on NOAA’s new, higher Atlas-14 rainfall probability tables adopted in the wake of Harvey.
COH 2021 Infrastructure Design Manual Defers to HCFCD Regs for Lots This Size
The City’s Infrastructure Design Manual imposed new criteria in July 2021 that would have required developments greater than 20 acres to follow the HCFCD standard for detention pond capacity. See screen capture below which bridges two pages.
City’s 2020 Regulations Required Far Less Detention
However, the City’s 2021 standards also provided a 90-day grace period for plans initially submitted before July. That meant the City’s 2020 Infrastructure Design Manual applied. And those standards only required following HCFCD’s higher standards if the lot was larger than 50 acres – which this is not. It’s 20.032 acres. So the RV Park developer will get away with installing far less detention than current regs require.
Differences Between Old/New Versions of City/County Regs
Two primary differences exist between the City and County regs in 2020 and 2021.
The first is the basis for calculations. In both years:
The City also changed the minimum lot size required to follow HCFCD regulations between 2020 and 2021.
The 2020 requirements apply in this case because of when plans were first reviewed (January 2021). The 2020 Infrastructure Design Manual read as follows:
Developer Applied Before Detention Pond Capacity Increased
Using that formula, the developer planned a detention pond that holds 7.68 acre feet of storm water detention, an acre foot more than required at the time the plans were first submitted, even though they were finally approved four months after the new regs went into effect. But that’s still far less than the 13 acre-feet required under today’s regulations.
The City previously reviewed a version of the plans on 1/21/21 which were originally submitted in 12/20.
Impervious Cover Calculations Need Further Review
I question whether the amount of impervious cover above is correct. That’s because the developer’s permit allows 182 RV spaces, but the plans show 226 – about a 24% increase. However, the impervious cover shown on the plans before and after the permit approval did not increase. That could also affect detention pond capacity requirements.
Timing, Impervious Cover Issues Raise Public Safety Questions
Assuming the impervious cover calculations above are correct, and that’s a big assumption, the developer is providing more than the minimum amount of required detention under 2020 requirements. But if they are not correct, the developer would be short.
A half-sized detention pond would require the RV Park to pump water into Lakewood Cove’s drainage system sooner and faster than with a larger pond. And under severe conditions, when Lakewood Cove’s drainage is already stressed, the extra water could over-stress it.
No Drainage Impact Analysis
I’ve requested a drainage impact analysis from the City for the RV Park on at least two occasions and have not received one. I therefore deduce that one does not exist. Such an analysis would quantify the impact on Lakewood Cove, Edgewater Park and surrounding roads.
Bottom Line: Park Will Provide Half of Today’s Detention Requirement
If this developer, LS RV Resort, LP, submitted plans today, it would have to provide almost twice as much detention pond capacity.
And we wonder how floods happen! Remember this the next time you see water rising toward your home.
I wonder if investors in the RV Park will be notified of the potential liability in a prospectus. Undersized detention ponds based on a similar grandfathering loophole in Montgomery County regulations became the central issue in lawsuits by hundreds of Elm Grove residents against Perry Homes, its subsidiaries and its contractors. The defendants recently settled those lawsuits.
Posted by Bob Rehak on 11/13/2021
1537 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.
Kingwood Middle School: November Construction Update
Construction of the new Kingwood Middle School appears on schedule for opening with the next school year in 2022. Compared to my October update, no new major milestones have been reached. Everything just looks a little further along.
Kingwood Middle School Construction Sequencing
Construction started on the west and is moving toward the east. As subcontractors finish one phase such as foundations or structural , the next group picks up the baton and works on roofing, exterior walls, windows, etc.
The most visible change between October and November: progress on exterior walls and roofing.
I took all the pictures below on Saturday, November 6, 2021.
Next Steps for KMS
Next steps will be to dry-in the structure by completing the exterior walls, windows and roofs. The other trades will then start working on interior walls, electrical, wallboard, paint and flooring – all the things that could be destroyed by blowing rain.
I put two kids through the old Kingwood Middle School who became happy, healthy, successful adults. As I look at these pictures, fond memories of plays, recitals, teacher conferences, and athletic contests come to mind. Each month, as the old school comes closer to demolition, I become increasing nostalgic. We will soon witness the end of one era and the start of another in Kingwood.
Architectural renderings on the Humble ISD site inspire confidence that the next generation of Kingwood Middle School students will have an even better learning environment than the last.
And cross your fingers! Despite double the impervious cover now on the site, I have received no reports of flooding from neighbors.
Posted by Bob Rehak on 11/11/2021
1535 Days since Hurricane Harvey
Guefen Clears 17 Acres Between KPHS, St. Martha for 131 High-Density Homes. Will Detention Pond Be Enough?
Guefen Development Partners has announced that it will build a “luxury single family build to rent multifamily community” [sic] on 17 acres between Kingwood Park High School and the St. Martha Church on Woodridge Parkway.
Nine Homes Per Acre with 65% Impervious Cover
Guefen will build 131 units on 14.65 acres. The rest of the 17 acres will contain a detention pond. That works out to nine homes per acre. RG Miller, the firm that engineered the “Preserve at Woodridge” estimates the development will have 65% impervious cover. See the Plans here. (Caution: large file, 21 mb download.)
Grass will definitely be in the minority. I’m not sure what the Preserve is preserving. The site certainly preserves no trees.
Pictures Taken This Week
Here’s what Guefen’s land looks like as of this week.
Basis of Detention-Basin Calculations
The technically inclined reader may appreciate the detention calculations below. The basis for the calculations is a 16.1 inch rain in 24-hours which is the Atlas-14 amount used throughout Montgomery County. MoCo specifies an average to keep things simple for developers. Their average is slightly less than the 17.3 inches specified by NOAA for the Kingwood area.
Will the Detention Pond Be Enough?
With other high-density developments going in upstream along Bens Branch, I hope Guefen’s detention pond capacity will suffice. Brooklyn Trails, several blocks upstream on another tributary of Bens Branch, lacks about 30% of the capacity needed to meet Atlas-14 requirements according to my calculations.
Montgomery County’s Subdivision Rules and Regulations specify that outfall ditches, such as the one in the first photo above only need to carry a 25 year rain. (See page 9.) With that in mind, it seems like Guefen’s detention pond so near a ditch would fill up quickly from ditch overflow in a 25-year rain and provide little detention benefit for anything heavier, for instance, 50-100 year rains.
If that ditch ever needs to be widened, like Hall’s Bayou, the fact that so many homes are built so close to it will severely limit mitigation options.
668 SF Homes with “Interior Garages” and “Luxury Vinyl” Flooring
The 131 single-family detached homes will range in size from 668 square feet to 1,255 square feet and feature “luxury vinyl” flooring. The press release boasts of an “amenity suite” including interior garages. It’s hard to imagine how much living space would be left in 668-SF homes with “interior garages.”
So I checked the plans. I found 29 parking spots labeled “garage spcs.” Many more exterior parking spaces exist. But no one, it appears, will be unloading groceries from his/her car directly into a kitchen. Your “interior garage” could be several homes away.
Nor do all the homes front on a street. That’s going to make moving day hard for your college buddies. You know who your real friends are when they’ll go the distance for you.
Speaking of going the distance, in case of an emergency, that firetruck may be parking 250 feet away from some homes. That’s almost the length of a football field.
Build-to-Rent
According to Guefen’s website and press release, the company sees a niche market for this type of housing in the Kingwood area. They are building these homes to rent them, not sell them. The company normally specializes in multifamily and student housing.
While plans show detached homes, they also show five to six feet of separation. That should be enough to dampen most stereos. So party on, Wayne!
Posted by Bob Rehak on 11/10/2021
1534 Days since Hurricane Harvey