The primary audience for the regulations is developers. However, neighbors near new developments may wish to study the regs, too, to ensure developers follow the rules.
On a separate but related note, MoCo’s new Drainage Criteria Manual is still on hold.
Changes
Montgomery County Subdivision Regulations were adopted in 1984 with an update in 2021. This rewrite includes many significant updates, such as:
Privacy fences at least 6-feet high between new commercial developments and existing single-family homes.
An entire section related to Traffic Engineering Study requirements.
Planting requirements along curbs
A new minimum lot width standard of 40′ for concrete curb and gutter and 65′ for asphalt open ditch lots
Commercial Drainage Plans will now be reviewed before acceptance of the entire permit submittal
A modified “impervious cover” threshold
New requirements for Stormwater Pollution Protection Plans.
What Developers Must Submit
Section Three outlines what developers must submit to Commissioners’ offices. This could come in handy if you ever need to submit a FOIA request. Requirements include:
Timelines
Maps
Construction traffic routing/access points
Drainage Reports and Studies
Spreadsheets used in calculations contained in those reports
Construction Plans including a Drainage Impact Analysis
Separate plans must be prepared for each subdivision.
Section 4 covers drainage plan requirements. Among other things, a drainage plan must provide for the disposition of runoff entering the development from adjacent property, runoff within the development and runoff leaving the development to an acceptable outfall.
Floodplain and Floodway Development
Section 5 specifies additional requirements for drainage studies when developers build in floodplains and floodways. For instance, they must obtain a Conditional Letter of Map Revision (CLOMR) from FEMA prior to the County’s approval of a drainage plan or study when:
Proposing to construct a detention pond or alter the floodway landscape
Relocating a stream
If Northpark Woods were being built today, the developer would have to comply with the new development regs because part of it is in the floodplain of the West Fork.
A CLOMR is a FEMA comment on a proposed project that could impact flood-hazard areas. And it indicates whether the project, if built as proposed, would meet National Flood Insurance Program (NFIP) standards and warrant a change to the Flood Insurance Rate Map (FIRM).
Alteration of a stream or river also requires TCEQ approval and the approval of any governing entities within 1,000 feet.
In February 2024, Montgomery County finally published a draft of a comprehensive new DCM. The draft brought the County’s standards up to date and in line with surrounding areas’.
Major changes included, but were not limited to:
Use of industry-standard modeling software by engineering companies submitting plans
A requirement that new developments produce “no adverse impact” on downstream areas
Mandates to use certain “roughness coefficient standards” when calculating flood peaks.
Stipulations that all projects shall mitigate and attenuate runoff for 5-, 10-, and 100-year storm events
Stormwater detention for all developments regardless of size
A discussion of flood mitigation measures
Identification of entities responsible for maintenance of stormwater detention facilities, channels, etc.
Adoption of Atlas-14 rainfall rates
A minimum detention rate of .55 acre-feet per acre (almost up to Harris County’s rate)
Prohibition of hydrologic-timing surveys (also known as flood-routing or beat-the-peak studies).
I’ll let you know when/if MOCO adopts these new drainage standards.
By the way, people always ask me why I list “days since Harvey,” on all my posts. I want to dramatize how long political change takes. And this is a prime example.
Posted by Bob Rehak on 3/14/25
2754 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/01/20211231-DJI_0298.jpg?fit=1200%2C799&ssl=17991200adminadmin2025-03-14 16:43:022025-07-21 11:31:54Montgomery County Development Regs Revised, New Drainage Criteria on Hold
3/13/25 – Just how wide will Northpark be when construction is complete? After the UnionPacific Railroad finished installing concrete road crossing panels last week we now have a visual cue. It’s going to be WIDE! With a capital W! Approximately three times wider than it currently is. See the pictures below taken this morning.
Looking E.See concrete panels in railroad tracks.
Northpark will expand from its current four lanes to 10 with two 10-foot-wide sidewalks.
In addition to accommodating extra traffic, one of the main reasons for expanding Northpark is to create an all-weather evacuation route from Kingwood for 78,000 people.
Why So Many Lanes?
The 10 lanes will include:
Six lanes over a bridge that spans the tracks and Loop 494. It has yet to be built. The bridge will carry three lanes in each direction.
Two surface lanes on the north/outbound side of Northpark will let traffic turn left or right onto Loop 494.
Two surface lanes on the south/inbound side of Northpark will let Loop 494 traffic from the north and south turn onto Northpark.
Two sidewalks (one on each side of Northpark) will accommodate both pedestrians and bicyclists.
Northpark looking W toward 59. Again, concrete panels in UPRR tracks indicate eventual width of traffic corridor.
Loop 494 Width
Loop 494 will also expand to accommodate more traffic.
Looking North along Loop 494 at Northpark. The old road will expand to 5 lanes, two in each direction plus one dedicated turn lane from each direction.Looking S at Loop 494 from opposite direction.
The schematic below shows how the intersection will eventually look.
Between Russell Palmer Road and Loop 494, contractors are making good progress with the drainage that goes under the expanded roadway. On the North/Outbound side, the underground work is almost complete. And this morning, they were stabilizing the road bed.
Stabilizing road bed on outbound Northpark (north side).
At this morning’s Lake Houston Redevelopment Authority/TIRZ 10 Board Meeting, project manager Ralph De Leon stated that contractors would soon bore underneath the railroad tracks. Once they connect the drainage on the east and west sides, they can begin paving. So you should see the pace of progress accelerate soon.
Spreading more road base and compacting it.
On the inbound/south side of Northpark, contractors are also making excellent progress with the drainage after resolving more utility conflicts.
Looking W at inbound side (left). The old concrete has been removed and drainage work is in full swing.Closer shot of new drainage on inbound Northpark.
Part of Phase II May Be Accelerated
Also at the board meeting this morning, De Leon introduced the idea of moving Phase II stormwater detention work forward. Phase II of Northpark expansion covers the area from Woodland Hills Drive to a block west of the Kingwood Diversion Ditch.
Phase II calls for building a detention basin to compensate for extra runoff caused by the road expansion. Just as the entry ponds at US 59 compensate for much of the extra runoff in Phase I.
De Leon discussed a combination of two types of detention. Together, they could add as much as 100 acre-feet of stormwater detention capacity to the project. They include:
In-line detention within the Diversion Ditch itself, down to the first bend south of Northpark.
A large, regional detention basin near where the Diversion Ditch and Bens Branch come together.
He stated that, right now, much of the water coming down Bens Branch shoots past the Diversion Ditch. That’s because the Diversion Ditch splits off the main part of Bens Branch at almost 90 degrees.
Diversion Ditch = white. Bens Branch = red.
Partially as a consequence, during Harvey, 100% of the businesses along Bens Branch in Town Center, dozens of homes, and Kingwood High School flooded badly and still have elevated flood risk.
For instance, during Harvey, large parts of Town Center had 4- to 8-feet of water. Moreover, 12 people died at a retirement home in Town Center as a result of evacuation or immediately after it.
A detention basin at the junction of Bens Branch and the Diversion Ditch would slow incoming water down. That would give the stormwater a chance to drain into each channel the way it was originally designed to.
The volume of stormwater detention that De Leon discussed would provide enough to accommodate Phase II, insufficiently mitigated upstream development, future expansion, and part of HCFCD’s plans for the Diversion Ditch.
The community will need it eventually, especially when Northpark Drive bridges over the two channels are raised. The higher roadway will eliminate chokepoints that let more floodwater flow downstream. So, building more detention now could protect people along both channels – and sooner rather than later.
Engineering details are still being worked out. The board took no action on it this morning, nor were they asked to.
Note: Corrected volume of stormwater detention on 3/15/25. 300 acre-feet changed to 100 per Ralph De Leon
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2025/03/20250313-DJI_20250313112934_0246_D.jpg?fit=1100%2C619&ssl=16191100adminadmin2025-03-13 16:24:402025-03-15 08:44:43How Wide Will Northpark Be When Done?
3/12/25 – The National Hurricane Center (NHC) has announced a series of changes to 2025 hurricane forecasts. The changes affect cone graphics, risk maps, prediction periods, forecast uncertainty, and forecast frequency. Let me attempt to summarize and simplify a highly complex announcement.
Experimental Cone Graphic with Depiction of Inland Watches/Warnings
Along with its normal cone graphics, NHC will offer experimental cone graphics that feature inland watches and warnings. The new experimental graphics will now contain diagonal pink and blue lines in areas where hurricane watches and tropical storm warnings are in effect simultaneously.
The current cone graphic that only shows coastal watches and warnings will remain. But research showed that adding inland watches and warnings could help communicate wind risk for those who live away from coasts.
The new, experimental graphics take longer to produce. So, they may appear online up to 30 minutes later than the regular graphics. Here’s an example.
Blue = TS Warning, Red = Hurricane Warning, Yellow = TS Watch, Striped = Simultaneous Hurricane Watch and TS Warning
Rip-Current Risk Maps
An increase in fatalities from rip currents during the past decade prompted this innovation. NHC will compile a national rip current risk map from data provided by local National Weather Service offices. It will cover the current day, the next day, and a composite showing the highest risk for both days. However, it will not contain information on surf height.
NHC will now issue potential tropical cyclone advisories up to 72 before the anticipated arrival of a storm. That’s up from 48 hours for watches and 36 hours for warnings. The longer lead times will give people more time to prepare when there is a high risk of significant damage.
Earlier Forecasts for Hurricane Wind Radii Forecasts
Until now, NHC has issued forecasts of storm widths two days in advance. They will now provide those forecasts three days in advance.
Those same forecasts (which also include wave height), will now show the height in meters instead of feet, based on requests from the public.
The forecast wind radii are available in real-time in a geographic information system (GIS) friendly format at the following link: https://www.nhc.noaa.gov/gis/.
Error-Cone Forecasts
As storm forecasting becomes more accurate, error cones are shrinking. This year’s error cones will be 3-5% smaller than last year’s, based on a 36-hour forecast period. 96-hour cones could shrink as much as 9%.
However, this may fool some people who misunderstand what the cones mean. The cone represents the probable track of the center of a storm, not its width.
A storm’s center has an equal chance of tracking along any point within the cone. If people think the cone indicates a storm’s width, they might be lulled into a false sense of security if they are outside a smaller cone.
Frequency of Watch/Warning Updates
NHC will now issue storm watch/warning updates eight times a day instead of four whenever coastal watches or warnings are already in effect. They actually instituted this change last year. So, this is a reminder. You can check for full updates every three hours.
That’s it for the summary of NHC’s changes to 2025 hurricane forecasts. Here also are some helpful links to use throughout the upcoming hurricane season.
Where to Find NHC Information
Live Stream
NHC will livestream forecast updates simultaneously on YouTube and Facebook whenever an area of interest exists that may pose a threat to land. NHC will generally provide these updates around 10:30 AM 4:30 PM CDT.
It’s getting to be that time of year again. Early predictions from Colorado State University indicate this should be an average hurricane season based on sea surface temperatures, the El Niño cycle, and accumulated cyclone energy.
But don’t take anything for granted. The I-storm this year will be named Imelda. Remember that one! Names recycle every six years. So prepare for a rerun.
Posted by Bob Rehak on 3/12/25
2752 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2025/03/20250312-New-Cone-Graphic.jpg?fit=1100%2C706&ssl=17061100adminadmin2025-03-12 12:31:492025-03-12 18:18:36NHC Announces Changes to 2025 Hurricane Forecasts
Montgomery County Development Regs Revised, New Drainage Criteria on Hold
3/14/25 – Montgomery County Development Regs have been revised and became effective on 3/4/25.
The MoCo Engineer has posted them online. For convenience, I have also posted them under the Regulations Tab on the ReduceFlooding Reports Page.
The primary audience for the regulations is developers. However, neighbors near new developments may wish to study the regs, too, to ensure developers follow the rules.
On a separate but related note, MoCo’s new Drainage Criteria Manual is still on hold.
Changes
Montgomery County Subdivision Regulations were adopted in 1984 with an update in 2021. This rewrite includes many significant updates, such as:
What Developers Must Submit
Section Three outlines what developers must submit to Commissioners’ offices. This could come in handy if you ever need to submit a FOIA request. Requirements include:
Separate plans must be prepared for each subdivision.
Section 4 covers drainage plan requirements. Among other things, a drainage plan must provide for the disposition of runoff entering the development from adjacent property, runoff within the development and runoff leaving the development to an acceptable outfall.
Floodplain and Floodway Development
Section 5 specifies additional requirements for drainage studies when developers build in floodplains and floodways. For instance, they must obtain a Conditional Letter of Map Revision (CLOMR) from FEMA prior to the County’s approval of a drainage plan or study when:
A CLOMR is a FEMA comment on a proposed project that could impact flood-hazard areas. And it indicates whether the project, if built as proposed, would meet National Flood Insurance Program (NFIP) standards and warrant a change to the Flood Insurance Rate Map (FIRM).
Alteration of a stream or river also requires TCEQ approval and the approval of any governing entities within 1,000 feet.
Status of Updated Drainage Criteria Manual
On a separate note: MoCo will soon update its Drainage Criteria Manual (DCM). The county is still working off an old DCM from 2019 that was a minor revision of a 1989 document.
In February 2024, Montgomery County finally published a draft of a comprehensive new DCM. The draft brought the County’s standards up to date and in line with surrounding areas’.
Major changes included, but were not limited to:
I’ll let you know when/if MOCO adopts these new drainage standards.
By the way, people always ask me why I list “days since Harvey,” on all my posts. I want to dramatize how long political change takes. And this is a prime example.
Posted by Bob Rehak on 3/14/25
2754 Days since Hurricane Harvey
How Wide Will Northpark Be When Done?
3/13/25 – Just how wide will Northpark be when construction is complete? After the UnionPacific Railroad finished installing concrete road crossing panels last week we now have a visual cue. It’s going to be WIDE! With a capital W! Approximately three times wider than it currently is. See the pictures below taken this morning.
Northpark will expand from its current four lanes to 10 with two 10-foot-wide sidewalks.
In addition to accommodating extra traffic, one of the main reasons for expanding Northpark is to create an all-weather evacuation route from Kingwood for 78,000 people.
Why So Many Lanes?
The 10 lanes will include:
Loop 494 Width
Loop 494 will also expand to accommodate more traffic.
The schematic below shows how the intersection will eventually look.
Elsewhere on Northpark
Between Russell Palmer Road and Loop 494, contractors are making good progress with the drainage that goes under the expanded roadway. On the North/Outbound side, the underground work is almost complete. And this morning, they were stabilizing the road bed.
At this morning’s Lake Houston Redevelopment Authority/TIRZ 10 Board Meeting, project manager Ralph De Leon stated that contractors would soon bore underneath the railroad tracks. Once they connect the drainage on the east and west sides, they can begin paving. So you should see the pace of progress accelerate soon.
On the inbound/south side of Northpark, contractors are also making excellent progress with the drainage after resolving more utility conflicts.
Part of Phase II May Be Accelerated
Also at the board meeting this morning, De Leon introduced the idea of moving Phase II stormwater detention work forward. Phase II of Northpark expansion covers the area from Woodland Hills Drive to a block west of the Kingwood Diversion Ditch.
Phase II calls for building a detention basin to compensate for extra runoff caused by the road expansion. Just as the entry ponds at US 59 compensate for much of the extra runoff in Phase I.
De Leon discussed a combination of two types of detention. Together, they could add as much as 100 acre-feet of stormwater detention capacity to the project. They include:
He stated that, right now, much of the water coming down Bens Branch shoots past the Diversion Ditch. That’s because the Diversion Ditch splits off the main part of Bens Branch at almost 90 degrees.
Partially as a consequence, during Harvey, 100% of the businesses along Bens Branch in Town Center, dozens of homes, and Kingwood High School flooded badly and still have elevated flood risk.
For instance, during Harvey, large parts of Town Center had 4- to 8-feet of water. Moreover, 12 people died at a retirement home in Town Center as a result of evacuation or immediately after it.
A detention basin at the junction of Bens Branch and the Diversion Ditch would slow incoming water down. That would give the stormwater a chance to drain into each channel the way it was originally designed to.
The volume of stormwater detention that De Leon discussed would provide enough to accommodate Phase II, insufficiently mitigated upstream development, future expansion, and part of HCFCD’s plans for the Diversion Ditch.
The community will need it eventually, especially when Northpark Drive bridges over the two channels are raised. The higher roadway will eliminate chokepoints that let more floodwater flow downstream. So, building more detention now could protect people along both channels – and sooner rather than later.
Engineering details are still being worked out. The board took no action on it this morning, nor were they asked to.
For More Information
See the Lake Houston Redevelopment Authority project web pages. For more about topics raised in this post, see:
UPRR:
Evacuation Route:
Plan Details:
Phase II:
Posted by Bob Rehak on 3/13/24
2753 Days since Hurricane Harvey
Note: Corrected volume of stormwater detention on 3/15/25. 300 acre-feet changed to 100 per Ralph De Leon
NHC Announces Changes to 2025 Hurricane Forecasts
3/12/25 – The National Hurricane Center (NHC) has announced a series of changes to 2025 hurricane forecasts. The changes affect cone graphics, risk maps, prediction periods, forecast uncertainty, and forecast frequency. Let me attempt to summarize and simplify a highly complex announcement.
Experimental Cone Graphic with Depiction of Inland Watches/Warnings
Along with its normal cone graphics, NHC will offer experimental cone graphics that feature inland watches and warnings. The new experimental graphics will now contain diagonal pink and blue lines in areas where hurricane watches and tropical storm warnings are in effect simultaneously.
The current cone graphic that only shows coastal watches and warnings will remain. But research showed that adding inland watches and warnings could help communicate wind risk for those who live away from coasts.
The new, experimental graphics take longer to produce. So, they may appear online up to 30 minutes later than the regular graphics. Here’s an example.
Rip-Current Risk Maps
An increase in fatalities from rip currents during the past decade prompted this innovation. NHC will compile a national rip current risk map from data provided by local National Weather Service offices. It will cover the current day, the next day, and a composite showing the highest risk for both days. However, it will not contain information on surf height.
For more information on NWS surf zone forecasts, rip current risk categories, and rip current safety, visit https://www.weather.gov/safety/ripcurrent-forecasts.
Earlier Warnings for Potential Tropical Cyclones
NHC will now issue potential tropical cyclone advisories up to 72 before the anticipated arrival of a storm. That’s up from 48 hours for watches and 36 hours for warnings. The longer lead times will give people more time to prepare when there is a high risk of significant damage.
Earlier Forecasts for Hurricane Wind Radii Forecasts
Until now, NHC has issued forecasts of storm widths two days in advance. They will now provide those forecasts three days in advance.
Those same forecasts (which also include wave height), will now show the height in meters instead of feet, based on requests from the public.
The forecast wind radii are available in real-time in a geographic information system (GIS) friendly format at the following link: https://www.nhc.noaa.gov/gis/.
Error-Cone Forecasts
As storm forecasting becomes more accurate, error cones are shrinking. This year’s error cones will be 3-5% smaller than last year’s, based on a 36-hour forecast period. 96-hour cones could shrink as much as 9%.
However, this may fool some people who misunderstand what the cones mean. The cone represents the probable track of the center of a storm, not its width.
A storm’s center has an equal chance of tracking along any point within the cone. If people think the cone indicates a storm’s width, they might be lulled into a false sense of security if they are outside a smaller cone.
Frequency of Watch/Warning Updates
NHC will now issue storm watch/warning updates eight times a day instead of four whenever coastal watches or warnings are already in effect. They actually instituted this change last year. So, this is a reminder. You can check for full updates every three hours.
That’s it for the summary of NHC’s changes to 2025 hurricane forecasts. Here also are some helpful links to use throughout the upcoming hurricane season.
Where to Find NHC Information
Live Stream
NHC will livestream forecast updates simultaneously on YouTube and Facebook whenever an area of interest exists that may pose a threat to land. NHC will generally provide these updates around 10:30 AM 4:30 PM CDT.
Outreach
NHC provides outreach and education throughout the year on Facebook at https://www.facebook.com/NWSNHC.
Real-Time Updates on X
For the Atlantic basin (which includes the Gulf and Caribbean), see @NHC_Atlantic.
For storm surge reports, see @NHC_Surge.
Web
National Hurricane Center: www.hurricanes.gov or https://www.nhc.noaa.gov
Explanation of Tropical Weather Outlook Graphics: www.nhc.noaa.gov/aboutnhcgraphics.shtml#GTWO
National Hurricane Preparedness Week: www.hurricanes.gov/prepare.
Hurricane Season Starts June 1
It’s getting to be that time of year again. Early predictions from Colorado State University indicate this should be an average hurricane season based on sea surface temperatures, the El Niño cycle, and accumulated cyclone energy.
But don’t take anything for granted. The I-storm this year will be named Imelda. Remember that one! Names recycle every six years. So prepare for a rerun.
Posted by Bob Rehak on 3/12/25
2752 Days since Hurricane Harvey