Perry Home’s new contractors have excavated the vast majority of virtually all three detention ponds on the north section of Woodridge Village. That means they have almost completed 77% of the detention pond capacity for the whole site in two months. The previous contractors completed only 23% in approximately twenty months.
That represents approximately a 30x increase in productivity.
Overview of Woodridge Village Detention Pond Capacity
The pie chart below shows how that capacity breaks down. And the map shows where it is.
Percentage of detention pond capacity in acre feet for each of the five Woodridge Village ponds.Source: LJA Drainage Addendum.General layout of detention ponds on Perry Homes’ property.
Cristobal has the potential to create massive erosion and set the work schedule back. The aerial photos below taken on 6/2/2020 show the current “pre-storm” status of construction for the three northern detention ponds. The two southern detention ponds were completed earlier this year.
N1 Nearing Completion of Excavation
N1 Starts at the northern boundary of the site and runs halfway down the western edge to Mace Street.
Looking north at N1 from Mace Street in Porter to the northern boundary. The area between the culverts will eventually become an extension of Mace Street (top of photo) which will traverse the entire subdivision to Ford Road on the eastern side.While some contractors continue excavating, others work on installing concrete pilot channels. Shown here, the pilot channel near Ivy Ridge in Porter.The northern part of N1 is not yet complete. Contractors still use the Webb Street entrance (upper left as their main access point to the site.Note how height of road dwarfs excavator in pit.
Still Widening and Deepening N2 Pond
The area left of the diagonal road is the expansion of N2. The area near the diagonal embankment is deep enough to conceal trucks and excavators. However, the grassy triangle in the middle left was a previous detention pond constructed my Montgomery County in the early 2000s. Contractors are deepening the MoCo pond a small amount to create additional storage capacity.The dirt is being used to build up other portions of the site.Looking north along the western boundary from the southern part of the grassy triangle. Much work remains to extend the N1 channel south to N2. Jeff Miller reported today that contractors started working on thisthis morning.On 6.3.20, contractors were removing dirt from the northward extention of N2 with three dump trucks running in a relay fashion. Photo courtesy of Jeff Miller.Twin culverts installed in Taylor Gully will control outflow rates from N1 and N2.
N3 All Excavated
N3 cuts down the eastern side of Woodridge Village and joins Taylor Gully right above S2.
Looking north. Excavation of N3 appears complete although few of the finishing touches have yet been installed.Looking south at the main body of N3. N3 widens out about halfway down the eastern border.Then it narrows down again to help control outflow speedas it approaches the junction with Taylor Gully.Water from the entire site converges here. Erosion patterns, fence damage and grass matting show this is where the overflow started that contributed to the flooding of Elm Grove (right) and North Kingwood Forest (left) twice last year.
The pile of dirt in the picture above could be shoved into the connecting channel in the event that Cristobal should strike Houston. That would then help retain water in N3 until after the storm.
All the runoff from the approximately 200-acre northern portion of the site converges here and tries to make its way through a 3-foot culvert at the end of the concrete channel.
Uncertain Still Surrounds Corner of Chaos
Some Elm Grove and North Kingwood Forest residents have called the complex flow patterns in the photo above “The Corner of Chaos.”
Overflow from the concrete lined channel is supposed to go into the kite-shaped S2 pond, and then through the twin culverts into Taylor Gully. However, a hydrology consultant for the plaintiffs in flooding lawsuits contends that floodwaters went the other way.They escaped out of the inflow channel, he says. He further claims that LJA Engineering failed to model the performance of that connecting channel.
If the design of the flow at this “Corner of Chaos” is flawed, there’s little contractors can do to fix that at this point without some major re-engineering.
In that regard, we should also remember that LJA designed these ponds before Atlas 14, so they will only hold approximately 60% of a 100-year rainfall as defined by Atlas 14 standards adopted in Harris County.
How Contractors are Temporarily Funneling Water into Ponds
Because storm drains are not yet installed, contractors are relying on temporary channels to intercept runoff and direct it to detention ponds.
Small ditches like one on right catch runoff and direct it to ponds for the time being.
Next Steps in Completing Detention Ponds
A modest amount of excavation remains to complete the full detention pond capacity.
But the capacity already in place should reduce flood risk compared to last year by more than 3X for storms equivalent to May 7 and September 19, 2019.
As some crews focus on completing excavation, others are putting the finishing touches on ponds. Those include concrete pilot channels, backslope interceptor swales, drain pipes, and culverts to control the rate of outflow.
Posted by Bob Rehak on 6/4/2020with thanks to Jeff Miller
1010 Days after Hurricane Harvey and 258 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/2020/06/20200602-DJI_0058.jpg?fit=1200%2C900&ssl=19001200adminadmin2020-06-03 22:02:292020-06-04 09:07:38Woodridge Village Pre-Cristobal Detention Pond Update
Cristobal should approach the northern Gulf coast within 4 days. The latest predictions from the National Hurricane Center (NHC) suggest it should reach Louisiana Sunday morning by 8 a.m. Houston remains within the cone of uncertainty. The storm has already dumped torrential rains on Mexico and Central America and produced life-threatening flash flooding.
NHC forecast track of TS Christobal shows the center of the storm arriving in Louisiana sometime between Sunday and Monday.
No one is yet predicting the exact point of impact, the intensity at landfall, or the potential rainfall. Note, however, that the storm is significantly bigger than the center. Areas far away from the track may still experience significant impacts.
So far, this storm appears to be Mexico’s and Central America’s version of Harvey in that it has stalled in one location and dropped heavy rainfall for 4-5 days.
Current Location and Conditions
Here’s what’s happening at this hour.
Cristobal dipped inland this morning in the Mexican State of Campeche around around 8 a.m. CDT. Aircraft and surface reports indicate intensity at about 50 kt. (57.5 mph).
Now that the center of circulation has moved inland, a gradual weakening trend should commence. The NHC anticipates Cristobal will weaken to a topical depression by tomorrow evening. However, they also predict the system will re-emerge into the Gulf of Mexico.
Sheer Expected in Northern Gulf
NHC says global models show increased southwesterly shear influencing the cyclone over the northern Gulf of Mexico and this should limit intensification. However, there is significant uncertainty as to how strong a cyclone we will be dealing with near the northern Gulf coast this weekend.
Impacts to Date
Damaging and deadly flooding has occurred in portions of Mexico and Central America. Cristobal is expected to produce additional extreme rainfall amounts through the end of the week. The heaviest additional rainfall is expected over far southern Mexico and portions of the Yucatan Peninsula, while also extending along the Pacific coast from Chiapas to Guatemala and El Salvador. This rainfall could cause widespread life-threatening flash floods and mudslides. Up to 35 inches of rain has already fallen in some locations since May 30.
Even though Cristobal has made landfall, tropical storm conditions will continue along and near the coast of Mexico through Thursday, especially over western Campeche, eastern Tabasco, and northern Chiapas states.
Rainfall in Mexico and Central America Through Friday
NHC predicts Cristobal will produce the following rain accumulations through Friday night:
Mexican states of Campeche, northern Chiapas, Quintana Roo, Tabasco, and Yucatan…10 to 20 inches, isolated 25 inches.
Mexican state of southern Chiapas…15 to 20 inches, isolated 25 inches. Mexican states of Veracruz and Oaxaca…5 to 10 inches.
Southern Guatemala…Additional 15 to 20 inches, isolated storm total amounts of 35 inches dating back to Saturday, May 30th.
El Salvador…Additional 10 to 15 inches, isolated storm total amounts of 35 inches dating back to Saturday, May 30th.
Belize and Honduras…3 to 6 inches, isolated 10 inches.
Rainfall in all of these areas may produce life-threatening flash floods and mudslides.
Threat to U.S. by Sunday
NHC forecasts Cristobal to re-emerge over the southern Gulf of Mexico Friday or Friday night.
Christobal should then move northward over the central and northern Gulf over the weekend. Risks to the US Gulf coast from Texas to the Florida Panhandle include storm surge, heavy rainfall, and wind impacts beginning this weekend.
While it is too soon to determine the exact location, timing, and magnitude of these impacts, people and businesses in these areas should monitor the progress of Cristobal and ensure they have their hurricane plan in place.
Earliest Arrival Times of Tropical Storm Force Winds. NHC prediction as of 6/3/2020 at 10AM CDT.
Posted by Bob Rehak on 6/3/2020 at 11:30 a.m.
1009 days after Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/06/145637_earliest_reasonable_toa_no_wsp_34.png?fit=897%2C736&ssl=1736897adminadmin2020-06-03 11:30:192020-06-03 11:40:59NHC Predicts Christobal to Hit Louisiana by Sunday Morning, Houston Still Within Cone
It’s hard to get a feeling for the enormity of the West Fork mouth bar in a still photo. Something more than half a mile long is reduced to 1200 pixels. That fundamentally alters the scale between nature and humans. Instead of being a thousand times bigger, it’s a hundred times smaller. That does not produce the same emotional impact. It’s like looking at a picture of a mountain instead of standing at the base of one and feeling dwarfed as you look up.
Video Comes Closer to Capturing Imensity
However, tonight, at sunset, I flew a drone over mouth bar and captured the entire flight on video. At 30 miles per hour, it took 1 minute and 9 seconds to get from one end to the other.
The rapidly vanishing San Jacinto West Fork mouth bar. Mechanical dredging reduces the size a little more every day.Looking south from Scenic Shores in King’s Point across mouth bar toward FM1960 Causeway downriver.Looking west toward West Lake Houston Parkway.Excavators working western tip of mouth bar. They shaver one row after another off, as if they are nibbling an ear of corn.From the upstream to downstream tip measures more than half a mile.At the eastern end, it almost look as if a bored dredging is carving his initials in the bar so that they can be seen from outer space.Looking south across the eastern edge toward the FM1960 bridge again.
Tonight, as we watch Tropical Storm Cristobal dump torrential rains on Mexico, it’s hard to escape thinking of Hurricane Harvey. It dumped torrential rains on Houston and formed this monster mouth bar almost overnight. Remember, like an ice berg, the part you see above water is only a tiny percentage of what you can’t see below water.
Thinking of Cristobal, Remembering Harvey
As I look at the cloudless skies and soft sunset, I can’t help but wonder. Will Cristobal miss us. Or is this just the calm before the storm?
Cristobal has produced life-threatening flash flooding in Mexico and Central America. The National Hurricane Center forecasts it to move northward across the Gulf of Mexico on Friday. Risks include storm surge, rainfall and wind impacts this coming weekend across the US Gulf Coast from Texas to Florida. NHC reiterates that it’s too soon predict the exact location, timing and magnitude of these impacts.
Posted by Bob Rehak on 6/3/2020
1009 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/06/20200602-DJI_0005.jpg?fit=1200%2C900&ssl=19001200adminadmin2020-06-02 22:27:092020-06-02 22:52:41Buzzing The Mouth Bar: Low Altitude Flyover at 30 MPH Takes 1 Minute 9 Seconds
Woodridge Village Pre-Cristobal Detention Pond Update
Perry Home’s new contractors have excavated the vast majority of virtually all three detention ponds on the north section of Woodridge Village. That means they have almost completed 77% of the detention pond capacity for the whole site in two months. The previous contractors completed only 23% in approximately twenty months.
Overview of Woodridge Village Detention Pond Capacity
The pie chart below shows how that capacity breaks down. And the map shows where it is.
Contractors Scurry as Cristobal Churns in Gulf
Tropical Storm Cristobal could be a game changer next week if it hits Houston. It’s track is far from certain at this point, but the National Hurricane Center still puts Houston within the cone of uncertainty.
Cristobal has the potential to create massive erosion and set the work schedule back. The aerial photos below taken on 6/2/2020 show the current “pre-storm” status of construction for the three northern detention ponds. The two southern detention ponds were completed earlier this year.
N1 Nearing Completion of Excavation
N1 Starts at the northern boundary of the site and runs halfway down the western edge to Mace Street.
Still Widening and Deepening N2 Pond
N3 All Excavated
N3 cuts down the eastern side of Woodridge Village and joins Taylor Gully right above S2.
The pile of dirt in the picture above could be shoved into the connecting channel in the event that Cristobal should strike Houston. That would then help retain water in N3 until after the storm.
All the runoff from the approximately 200-acre northern portion of the site converges here and tries to make its way through a 3-foot culvert at the end of the concrete channel.
Uncertain Still Surrounds Corner of Chaos
Some Elm Grove and North Kingwood Forest residents have called the complex flow patterns in the photo above “The Corner of Chaos.”
Overflow from the concrete lined channel is supposed to go into the kite-shaped S2 pond, and then through the twin culverts into Taylor Gully. However, a hydrology consultant for the plaintiffs in flooding lawsuits contends that floodwaters went the other way. They escaped out of the inflow channel, he says. He further claims that LJA Engineering failed to model the performance of that connecting channel.
If the design of the flow at this “Corner of Chaos” is flawed, there’s little contractors can do to fix that at this point without some major re-engineering.
In that regard, we should also remember that LJA designed these ponds before Atlas 14, so they will only hold approximately 60% of a 100-year rainfall as defined by Atlas 14 standards adopted in Harris County.
How Contractors are Temporarily Funneling Water into Ponds
Because storm drains are not yet installed, contractors are relying on temporary channels to intercept runoff and direct it to detention ponds.
Next Steps in Completing Detention Ponds
A modest amount of excavation remains to complete the full detention pond capacity.
As some crews focus on completing excavation, others are putting the finishing touches on ponds. Those include concrete pilot channels, backslope interceptor swales, drain pipes, and culverts to control the rate of outflow.
Racing Against Hurricane Season
At this point, contractors are racing against time and the hurricane season. Cristobal underscores the risk of having waited for months to begin the three northern detention ponds in April. Had they begun them immediately after J. Carey Gray’s letter to Mayor Turn in October, they could easily have finished by now.
Posted by Bob Rehak on 6/4/2020 with thanks to Jeff Miller
1010 Days after Hurricane Harvey and 258 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.
NHC Predicts Christobal to Hit Louisiana by Sunday Morning, Houston Still Within Cone
Cristobal should approach the northern Gulf coast within 4 days. The latest predictions from the National Hurricane Center (NHC) suggest it should reach Louisiana Sunday morning by 8 a.m. Houston remains within the cone of uncertainty. The storm has already dumped torrential rains on Mexico and Central America and produced life-threatening flash flooding.
No one is yet predicting the exact point of impact, the intensity at landfall, or the potential rainfall. Note, however, that the storm is significantly bigger than the center. Areas far away from the track may still experience significant impacts.
So far, this storm appears to be Mexico’s and Central America’s version of Harvey in that it has stalled in one location and dropped heavy rainfall for 4-5 days.
Current Location and Conditions
Here’s what’s happening at this hour.
Cristobal dipped inland this morning in the Mexican State of Campeche around around 8 a.m. CDT. Aircraft and surface reports indicate intensity at about 50 kt. (57.5 mph).
Now that the center of circulation has moved inland, a gradual weakening trend should commence. The NHC anticipates Cristobal will weaken to a topical depression by tomorrow evening. However, they also predict the system will re-emerge into the Gulf of Mexico.
Sheer Expected in Northern Gulf
NHC says global models show increased southwesterly shear influencing the cyclone over the northern Gulf of Mexico and this should limit intensification. However, there is significant uncertainty as to how strong a cyclone we will be dealing with near the northern Gulf coast this weekend.
Impacts to Date
Damaging and deadly flooding has occurred in portions of Mexico and Central America. Cristobal is expected to produce additional extreme rainfall amounts through the end of the week. The heaviest additional rainfall is expected over far southern Mexico and portions of the Yucatan Peninsula, while also extending along the Pacific coast from Chiapas to Guatemala and El Salvador. This rainfall could cause widespread life-threatening flash floods and mudslides. Up to 35 inches of rain has already fallen in some locations since May 30.
Even though Cristobal has made landfall, tropical storm conditions will continue along and near the coast of Mexico through Thursday, especially over western Campeche, eastern Tabasco, and northern Chiapas states.
Rainfall in Mexico and Central America Through Friday
NHC predicts Cristobal will produce the following rain accumulations through Friday night:
Threat to U.S. by Sunday
NHC forecasts Cristobal to re-emerge over the southern Gulf of Mexico Friday or Friday night.
While it is too soon to determine the exact location, timing, and magnitude of these impacts, people and businesses in these areas should monitor the progress of Cristobal and ensure they have their hurricane plan in place.
Posted by Bob Rehak on 6/3/2020 at 11:30 a.m.
1009 days after Hurricane Harvey
Buzzing The Mouth Bar: Low Altitude Flyover at 30 MPH Takes 1 Minute 9 Seconds
It’s hard to get a feeling for the enormity of the West Fork mouth bar in a still photo. Something more than half a mile long is reduced to 1200 pixels. That fundamentally alters the scale between nature and humans. Instead of being a thousand times bigger, it’s a hundred times smaller. That does not produce the same emotional impact. It’s like looking at a picture of a mountain instead of standing at the base of one and feeling dwarfed as you look up.
Video Comes Closer to Capturing Imensity
However, tonight, at sunset, I flew a drone over mouth bar and captured the entire flight on video. At 30 miles per hour, it took 1 minute and 9 seconds to get from one end to the other.
Tonight, as we watch Tropical Storm Cristobal dump torrential rains on Mexico, it’s hard to escape thinking of Hurricane Harvey. It dumped torrential rains on Houston and formed this monster mouth bar almost overnight. Remember, like an ice berg, the part you see above water is only a tiny percentage of what you can’t see below water.
Thinking of Cristobal, Remembering Harvey
As I look at the cloudless skies and soft sunset, I can’t help but wonder. Will Cristobal miss us. Or is this just the calm before the storm?
Cristobal has produced life-threatening flash flooding in Mexico and Central America. The National Hurricane Center forecasts it to move northward across the Gulf of Mexico on Friday. Risks include storm surge, rainfall and wind impacts this coming weekend across the US Gulf Coast from Texas to Florida. NHC reiterates that it’s too soon predict the exact location, timing and magnitude of these impacts.
Posted by Bob Rehak on 6/3/2020
1009 Days since Hurricane Harvey