The sign outside the abandoned Texas Concrete Sand and Gravel Mine in Plum Grove tells readers that an RV resort is coming soon. They might want to rethink that concept. Yesterday, rampaging floodwaters destroyed most of the mine except for a small area near the entry on FM1010.
Classic Example of Pit Capture
The East Fork rerouted itself right through the heart of the mine, sweeping away almost everything in its path. The river swelled to more than half a mile wide and ruptured dikes in at least four places when the river rose 10 feet in 24-hours.
The East Fork at this location rose 15 feet in three days, 10 of those in one day.
Normal course of river is red line on west side of mine. During flood, the river broke through the dike on the north side. Then floodwater filled the mine like a water balloon which burst in multiple places on the south side. Water now follows the yellow line.
This is a classic example of what geologists call pit or river capture. The East Fork entered the northern side of the mine and exited at multiple points on the south. Current coming out of the mine exceeded that in the river itself, carrying mud and muck downstream.
Flooding Based on Less than 10-Year Rain
The gage at this location indicated Plum Grove received only 3.36 inches of rain over a three-day period. However, up to 8 inches fell upstream from here, primarily during a two-day period. Jeff Lindner, Harris County’s meteorologist characterized the rains that produced the flood as, “Generally less than a 10-year event for the 48-hour time period.”
Pictures Taken on 5/3/2021
I took all of the shots below on 5/3/2021, three days after the major portion of the rain fell on April 30.
Looking north at the northernmost portion of the mine. The river appears to have entered the mine in this area.Note the dike in the far distance that’s not visible in the tree-line on the left.
Wider shot, still looking north toward entry point shows white water ripping through mine.
Looking south, you can see that the water in the mine is now higher and faster than the water in the river to the right.
Still looking south toward FM2090, now the only way in and out of Plum Grove. FM1485 is closed due to high water and FM1010 was washed out during Harvey by runoff from Colony Ridge to the southeast.
Looking north across FM2090. Where the water exits the mine, you can see that the force of the main flow is now misaligned with the bridge opening.
The width of the mine is now the width of the river…plus the river.Only the entry of the mine at the upper right remains above water at this time.
Looking east from over FM2090.
Danger of 2090 Washout in Next Big Flood?
Unless someone reroutes the river back to its original course and fixes the dikes, the current through the mine will continue to erode the banks of the roadway at the top of the image above.
These images dramatize the need for real sand-mining reform in Texas. There’s some evidence that Imelda did the same thing to this mine two years ago. But the TCEQ forced the company to repair the dikes. Now that the miners are gone, who will do that?
Plum Grove was lucky that upstream rains only amounted to a ten-year event. A larger storm could have cut the City and Colony Ridge off from the only viable evacuation route. More than 20,000 people would have been affected.
Posted by Bob Rehak on 5/3/2021
1343 Days since Hurricane Harvey and 592 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/2021/05/20210503-DJI_0661.jpg?fit=1200%2C900&ssl=19001200adminadmin2021-05-03 15:45:402021-05-04 07:53:21Rampaging East Fork Floodwaters Cut New Path Through Plum Grove Sand Mine
Last night’s storms in the Houston area did not drop as much rain as the previous night. As a result, the SJRA is holding the level of Lake Conroe steady by releasing 9270 cubic feet per second.
Level of Lake Conroe as of 9 a.m. 5/2/21, down from 203.07 last night.
However, the level of Lake Houston has risen from 42.85 last evening to 43.46 this morning. That’s a rise of .61 feet or 7.32 inches overnight. And it could get worse as more water works its way down the East Fork, Spring Creek and Cypress Creek.
From Coastal Water Authority as of 8:30 am., Sunday, May 2, 2021. Up .61 feet since last night.Data updated hourly.
To Get Whole Picture, Look Upstream in All Directions
Flooding upstream affects the level of Lake Houston. For instance, tributaries of Spring and Cypress Creeks have been flooding. So has Caney Creek. And the East Fork San Jacinto River is expected to crest above flood stage later today. This map from Harris County Flood Warning System shows the problem areas where people need to remain alert.
Observe the concentration of warning signs upstream from Lake Houston. They mean streams near or above flood stage.
For instance, look at this.
The hydrographic for the San Jacinto East Fork near FM2090 shows the river could rise 10 feet in the next 24 hours!
National Weather Service
The National Weather Service predicts moderate flooding on the East Fork near New Caney. We are at the stage where people close to the river need to take action.
Jeff Lindner, Harris County Meteorologist says, “The East Fork is rising quickly this morning and will exceed flood stage this afternoon and rise to moderate flood levels late tonight into early Monday. At the current forecast levels widespread low land flooding is expected downstream of the gages at both Plum Grove and FM 1485 (New Caney). At the forecasted levels FM 1485 is likely to be inundated with water west of the bridge crossing and become impassable. The river is forecast to fall below flood stage Wednesday or Thursday.
Hydrograph for the San Jacinto West Fork as of 10:45AM, 5/2/21.
About the West Fork San Jacinto, Lindner says, “The river is rising this morning mainly from inflow from both Spring and Lake Creeks. The river is forecasted to rise to near flood stage early Monday and hold around flood stage for a couple of days before falling around mid week.” Starting early Monday, Lindner expects minor low land flooding near the rise with possible impacts to roads on the north side of the river and east of US 59 as well as the US 59 turn-arounds.
Remain Cautious
Put it all together and the message is “Caution,” especially if you live near one of those gages colored red or yellow. But at this time, authorities have predicted no widespread flooding in the Lake Houston Area.
The SJRA posted a situational update for Lake Conroe as of 9 a.m. on Sunday morning, May 2, 2021. The SJRA notice says: “Water level at Lake Conroe is beginning to decrease. With no additional rain in the forecast today, SJRA and MoCo Constable Precinct 1 will continue to monitor lake level and open Lake Conroe as soon as it is safe to do so. Reservoir releases are holding steady and not expected to increase. The Constable’s office urges boaters to tie up their vessels to assist with boating safety. If you find your boat is missing, contact the Sheriff’s office non-emergency line 936-760-5800. We will provide another update Sunday afternoon. Real time lake conditions available below.”
The SJRA closed Lake Conroe to boaters Saturday, when the lake rose two feet overnight from Friday.
How Close Was It?
These pictures taken by a Lake Conroe resident on Sunday morning show what a close call some residents there had.
Picture taken Sunday, 5/2/21 at approximately 9:30 am. near the Walden boat ramp.
In reference to the fact that SJRA had lowered the lake one foot in April as part of its seasonal policy, the resident who took these pictures said…
“Think what an extra foot would have done to that homeowner.”
Lake Conroe resident
That extra foot gave the homeowner the buffer needed to avoid flooding.
Walden boat ramp on 5/2/21 at approximately 9:30 am. “Not usable really,” said the boater/photographer. “Water is just too high.”
Rainfall Totals for Last Two Waves of Thunderstorms
This rainfall map from the Harris County Flood Warning System shows the 9-day totals for all gages in the Houston region. The 9-days include the storm that wiped out the 1-foot buffer that the SJRA created when it lowered Lake Conroe beginning in April. Note how the northwest portion of the region received the most rain…two to four times the amounts shown on Lake Houston Area gages.
Nine day rainfall totals include the amount of rain received since Lake Conroe was at 200 feet (one foot below its normal target level during the seasonal lowering).
As wet as it has been for the last several days, we lucked out compared to our neighbors to the northwest.
Posted by Bob Rehak on 5/2/21 at 10am based on info provided by SJRA, HCFCD, Coastal Water Authority, NWS and Lake Conroe residents
1342 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/05/Close-Call.jpg?fit=1200%2C656&ssl=16561200adminadmin2021-05-02 11:05:122021-05-02 12:41:42Update: Lake Conroe Holding Steady, Lake Houston Rising, East Fork Expected to Rise 10 Feet in Next 24 Hours
In the last two weeks heavy rains have slammed the areas upstream from Lake Conroe leading to steady rises in the lake level. Had the lake not been lowered earlier, neighborhoods could be flooding now. Streets in several places are already cut off.
As of 7:30 pm Saturday night, 5/1/2021
More Than Three Foot Increase Above Lowered Level
The rain a week ago erased the one-foot seasonal lowering that SJRA started on April 1. Then yesterday’s rains increased the lake more than 2 feet above its normal level of 201 – despite increasing discharges by the SJRA. The lake is now threatening lakeside homes and businesses as you can see from the photos below.
If you’ve watched the dashboard at SJRA.net, the SJRA started discharging 450 cubic feet per second (CFS) before the most recent round of storms. Now the discharge rate has increased to 9275 CFS, which is close to the max rate that the antiquated flood gates on Lake Houston can handle. But even at 9275 CFS, Lake Conroe continued to rise this afternoon.
So did Lake Houston, despite the fact that the Coastal Water Authority has been trying to lower the lake a full foot for several days now.
As of 5:30PM Saturday.
Water Coming from Other Sources, Too
However, in addition to the water from Lake Conroe, Lake Houston is also picking up water from other sources, a number of which are in danger of coming out of their banks.
Yellow triangles indicate a stream could come out of its banks. Red exclamation points mean flooding is likely.
This is precisely the scenario that the SJRA designed its lake lowering policy to prevent – an ugly choice between flooding people upstream or downstream.
Water Creeping Closer to Homes and Businesses around Lake Conroe
A Lake Conroe resident who wishes to remain anonymous took the pictures below this afternoon. They show docks underwater, the lake invading shorelines, streets cut off, and homes and businesses being threatened by rising waters.
The docks at Papas on Lake Conroe are underwater.
Water is creeping closer to the Villas at Margaritaville.
This resident said water from the rising lake levels was keeping water from draining into the lake and backing it up into streets.
Docks in front of Monty’s Light House and Fajita Jacks. Those boats are in their slips. The docks are under water.
The marinas on 105 are closed for two reasons. First, the lake is closed to boat traffic because of dangerous conditions. Second, the water is high enough that you can’t get trailers in deep enough, according to one resident. The Walden marina looked like the one above, he said.
One More Round of Thunderstorms Tonight
Expect one more round of storms tonight. National Weather Service radar shows them already sweeping into the Lake Conroe area. They aren’t predicted to dump large amounts of rain, but they will put additional pressure on the homes and businesses around the lake, especially as runoff from previous storms continues to work its way to the lake.
And virtually the entire region remains under a flash flood watch through tomorrow morning. A Flash Flood Watch means that conditions may develop that lead to Flash Flooding. Flash Flooding is very dangerous. You should monitor forecasts and be prepared to take action should Flash Flood Warnings be issued.
From National Weather Service on 5/1/21
Posted by Bob Rehak on 5/1/2021 based on information from Lake Conroe residents and the NWS
Rampaging East Fork Floodwaters Cut New Path Through Plum Grove Sand Mine
The sign outside the abandoned Texas Concrete Sand and Gravel Mine in Plum Grove tells readers that an RV resort is coming soon. They might want to rethink that concept. Yesterday, rampaging floodwaters destroyed most of the mine except for a small area near the entry on FM1010.
Classic Example of Pit Capture
The East Fork rerouted itself right through the heart of the mine, sweeping away almost everything in its path. The river swelled to more than half a mile wide and ruptured dikes in at least four places when the river rose 10 feet in 24-hours.
This is a classic example of what geologists call pit or river capture. The East Fork entered the northern side of the mine and exited at multiple points on the south. Current coming out of the mine exceeded that in the river itself, carrying mud and muck downstream.
Flooding Based on Less than 10-Year Rain
The gage at this location indicated Plum Grove received only 3.36 inches of rain over a three-day period. However, up to 8 inches fell upstream from here, primarily during a two-day period. Jeff Lindner, Harris County’s meteorologist characterized the rains that produced the flood as, “Generally less than a 10-year event for the 48-hour time period.”
Pictures Taken on 5/3/2021
I took all of the shots below on 5/3/2021, three days after the major portion of the rain fell on April 30.
Danger of 2090 Washout in Next Big Flood?
Unless someone reroutes the river back to its original course and fixes the dikes, the current through the mine will continue to erode the banks of the roadway at the top of the image above.
These images dramatize the need for real sand-mining reform in Texas. There’s some evidence that Imelda did the same thing to this mine two years ago. But the TCEQ forced the company to repair the dikes. Now that the miners are gone, who will do that?
Plum Grove was lucky that upstream rains only amounted to a ten-year event. A larger storm could have cut the City and Colony Ridge off from the only viable evacuation route. More than 20,000 people would have been affected.
Posted by Bob Rehak on 5/3/2021
1343 Days since Hurricane Harvey and 592 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.
Update: Lake Conroe Holding Steady, Lake Houston Rising, East Fork Expected to Rise 10 Feet in Next 24 Hours
Last night’s storms in the Houston area did not drop as much rain as the previous night. As a result, the SJRA is holding the level of Lake Conroe steady by releasing 9270 cubic feet per second.
However, the level of Lake Houston has risen from 42.85 last evening to 43.46 this morning. That’s a rise of .61 feet or 7.32 inches overnight. And it could get worse as more water works its way down the East Fork, Spring Creek and Cypress Creek.
To Get Whole Picture, Look Upstream in All Directions
Flooding upstream affects the level of Lake Houston. For instance, tributaries of Spring and Cypress Creeks have been flooding. So has Caney Creek. And the East Fork San Jacinto River is expected to crest above flood stage later today. This map from Harris County Flood Warning System shows the problem areas where people need to remain alert.
For instance, look at this.
Jeff Lindner, Harris County Meteorologist says, “The East Fork is rising quickly this morning and will exceed flood stage this afternoon and rise to moderate flood levels late tonight into early Monday. At the current forecast levels widespread low land flooding is expected downstream of the gages at both Plum Grove and FM 1485 (New Caney). At the forecasted levels FM 1485 is likely to be inundated with water west of the bridge crossing and become impassable. The river is forecast to fall below flood stage Wednesday or Thursday.
About the West Fork San Jacinto, Lindner says, “The river is rising this morning mainly from inflow from both Spring and Lake Creeks. The river is forecasted to rise to near flood stage early Monday and hold around flood stage for a couple of days before falling around mid week.” Starting early Monday, Lindner expects minor low land flooding near the rise with possible impacts to roads on the north side of the river and east of US 59 as well as the US 59 turn-arounds.
Remain Cautious
Put it all together and the message is “Caution,” especially if you live near one of those gages colored red or yellow. But at this time, authorities have predicted no widespread flooding in the Lake Houston Area.
The SJRA posted a situational update for Lake Conroe as of 9 a.m. on Sunday morning, May 2, 2021. The SJRA notice says: “Water level at Lake Conroe is beginning to decrease. With no additional rain in the forecast today, SJRA and MoCo Constable Precinct 1 will continue to monitor lake level and open Lake Conroe as soon as it is safe to do so. Reservoir releases are holding steady and not expected to increase. The Constable’s office urges boaters to tie up their vessels to assist with boating safety. If you find your boat is missing, contact the Sheriff’s office non-emergency line 936-760-5800. We will provide another update Sunday afternoon. Real time lake conditions available below.”
The SJRA closed Lake Conroe to boaters Saturday, when the lake rose two feet overnight from Friday.
How Close Was It?
These pictures taken by a Lake Conroe resident on Sunday morning show what a close call some residents there had.
In reference to the fact that SJRA had lowered the lake one foot in April as part of its seasonal policy, the resident who took these pictures said…
That extra foot gave the homeowner the buffer needed to avoid flooding.
Rainfall Totals for Last Two Waves of Thunderstorms
This rainfall map from the Harris County Flood Warning System shows the 9-day totals for all gages in the Houston region. The 9-days include the storm that wiped out the 1-foot buffer that the SJRA created when it lowered Lake Conroe beginning in April. Note how the northwest portion of the region received the most rain…two to four times the amounts shown on Lake Houston Area gages.
As wet as it has been for the last several days, we lucked out compared to our neighbors to the northwest.
The sun is shining. At least for now. More thunderstorms predicted for Tuesday. I’m going out NOW to take my dog for a slosh. While I can.
Posted by Bob Rehak on 5/2/21 at 10am based on info provided by SJRA, HCFCD, Coastal Water Authority, NWS and Lake Conroe residents
1342 Days since Hurricane Harvey
Lake Conroe Keeps Rising Despite Increasing Discharges by SJRA
In the last two weeks heavy rains have slammed the areas upstream from Lake Conroe leading to steady rises in the lake level. Had the lake not been lowered earlier, neighborhoods could be flooding now. Streets in several places are already cut off.
More Than Three Foot Increase Above Lowered Level
The rain a week ago erased the one-foot seasonal lowering that SJRA started on April 1. Then yesterday’s rains increased the lake more than 2 feet above its normal level of 201 – despite increasing discharges by the SJRA. The lake is now threatening lakeside homes and businesses as you can see from the photos below.
If you’ve watched the dashboard at SJRA.net, the SJRA started discharging 450 cubic feet per second (CFS) before the most recent round of storms. Now the discharge rate has increased to 9275 CFS, which is close to the max rate that the antiquated flood gates on Lake Houston can handle. But even at 9275 CFS, Lake Conroe continued to rise this afternoon.
So did Lake Houston, despite the fact that the Coastal Water Authority has been trying to lower the lake a full foot for several days now.
Water Coming from Other Sources, Too
However, in addition to the water from Lake Conroe, Lake Houston is also picking up water from other sources, a number of which are in danger of coming out of their banks.
Yellow triangles indicate a stream could come out of its banks. Red exclamation points mean flooding is likely.
But the Lake Conroe Association has fought the lowering for the last two years both in a court of law and the court of public opinion. The Association mounted an expensive campaign including billboards, lawsuits, and a legislative offensive against the SJRA. Now, the rapid rise in lake levels may undermine LCA’s support; it certainly undercuts their arguments against seasonal lake lowering.
Water Creeping Closer to Homes and Businesses around Lake Conroe
A Lake Conroe resident who wishes to remain anonymous took the pictures below this afternoon. They show docks underwater, the lake invading shorelines, streets cut off, and homes and businesses being threatened by rising waters.
The marinas on 105 are closed for two reasons. First, the lake is closed to boat traffic because of dangerous conditions. Second, the water is high enough that you can’t get trailers in deep enough, according to one resident. The Walden marina looked like the one above, he said.
One More Round of Thunderstorms Tonight
Expect one more round of storms tonight. National Weather Service radar shows them already sweeping into the Lake Conroe area. They aren’t predicted to dump large amounts of rain, but they will put additional pressure on the homes and businesses around the lake, especially as runoff from previous storms continues to work its way to the lake.
The East Fork in southeast Montgomery County remains under a Flash Flood WARNING, especially areas around Caney and Peach Creeks.
And virtually the entire region remains under a flash flood watch through tomorrow morning. A Flash Flood Watch means that conditions may develop that lead to Flash Flooding. Flash Flooding is very dangerous. You should monitor forecasts and be prepared to take action should Flash Flood Warnings be issued.
Posted by Bob Rehak on 5/1/2021 based on information from Lake Conroe residents and the NWS
1341 Days since Hurricane Harvey