Lake Conroe Release Rate at 90% of Harvey

5/2/24 at 4:30 PM – The San Jacinto River Authority (SJRA) is releasing water at the rate of 69,545 cubic feet per second (CFS from Lake Conroe. That’s down a couple thousand from the 71,835 they released earlier this afternoon, the second highest release rate ever – 90% of the all-time record of 79,000 CFS during Hurricane Harvey.

At that rate, NOAA predicted the San Jacinto West Fork at US59 would peak at 62.4 feet. Since then, they’ve reduced that back a bit to 62.2.

However, the level of Lake Conroe is still rising slightly. It stands at 205.13 MSL (mean feet above sea level) as of 4:30 PM.

And local leaders including Houston Mayor John Whitmire, State Rep. Charles Cunningham and City Council Member Fred Flickinger met in Kingwood to plan emergency response with first-responders.

More Rain on Way

The level of Lake Conroe is up significantly since this morning. And another rain storm is headed our way tonight. The National Weather Service predicts a 40% chance of more thunderstorms tonight. Anything that falls will be on top of almost 7 inches of rain received in the Kingwood area earlier today.

Flood watches and warnings remain in effect at the present time. Any new rain will fall onto already saturated soils, resulting in rapid runoff.

SJRA Pushing Up Against Limit

But the SJRA is running out of room. At 207, they flood Lake Conroe homes and endanger the dam, according to Mark Micheletti, an SJRA board member who lives in Kingwood.

Micheletti has demanded that SJRA operators throttle back releases as soon as they stabilize the Lake Conroe’s level. The SJRA hopes to keep a safety margin by not letting the lake level get above 206, but nature, not engineers will make that call.

Meanwhile, the uncertainty has many Kingwood people in panic mode wondering whether they should evacuate. I’ve been deluged (pardon the pun) with requests for information.

Whitmire Visits Kingwood to Plan Flood Response

Houston Mayor John Whitmire came to Kingwood this afternoon to meet with first responders and area leaders. He wanted to personally see the situation and assess what the area needs. He met with Fire Chief Samuel Peña, first responders, State Representative Charles Cunningham and City Council Member Fred Flickinger at Fire Station 102 on West Lake Houston Parkway.

CM Fred Flickinger (center) met with Mayor Whitmire (right), Chief Samuel Peña (left) and other first responders at Fire Station 102 this afternoon on West Lake Houston Parkway.

Peña emphasized the need for vehicles to stay out of high water. The fire department had already made numerous high water rescues today.

State Representative Charles Cunningham (left) also helped plan the emergency response.

At the meeting, Whitmire also said that he had discussed evacuation orders for certain subdivisions with Harris County Judge Lina Hidalgo. After Harvey, “communication with residents” and “warning time” were identified as two of the primary things officials needed to improve.

Current East Fork Predictions and Evacuation Orders

According to Harris County Meteorologist Jeff Lindner, the County has issued evacuation orders for the east side of the East Fork San Jacinto from FM1485 to Lake Houston. (Lake Houston Park is on the west side.) Forecasted water levels will rise 7-8 feet higher than earlier this week. Structures on the ground will be flooded to rooftop levels. Elevated structures will be flooded.

For reference, the forecasted East Fork water level is 3 ft below Harvey.

Impacted subdivisions: 
  • Idle Wilde
  • Idle Glen
  • Cypress Point
  • River Terrace
  • Magnolia Point
  • Northwood Country Estates

Current West Fork San Jacinto Predictions and Warnings

The West Fork is rapidly rising from upstream inflows. It will reach major flood levels and will rise to near 62 ft on Saturday. Widespread low-land flooding will occur impacting the following subdivisions:

  • Belleau Woods
  • Rivercrest
  • Northshore
  • Forest Cove
  • Kings Point
  • Atasocita Shores

In Kingwood, Lindner expects flooding of streets and the lowest structures nearest the river. He also predicts backwater impacts along the tributaries. That means high river levels could force water in channels and tributaries to back up.

The following areas will be completely flooded with several feet of water: Deerwood Country Club, Deer Ridge Park, and Kingwood Country Club.

Elevated residents near the river should be prepared to be cut-off through the weekend.

I have queried HCFCD about the list of subdivisions above. It seems incomplete. But I have not yet heard back.

San Jacinto River Below Lake Houston

Major flooding is expected at all locations along the lower portions of the river.

Rio Villa will be completely inundated and cut-off. 

High velocity flows may damage vessels and barges near I-10.

Flow may approach and potentially reach I-10 on the west side of the river.

Real Time Inundation Monitoring

To monitor what’s going on around you, Harris County Meteorologist Jeff Lindner suggests using the Real-Time Inundation Mapping Tool found in the Harris County Flood Warning System. From the home page, just click “Inundation Map” in the upper left tool bar, then zoom into the area of interest.

As of 4:22 PM on 5/2/24. Note large areas already inundated.

Easy Way to Find the Elevation of Your Home

Don’t know the elevation of your home? Consult this post about how to find it in the USGS National Map.

More updates later. SJRA may issue another statement at 8PM.

Posted by Bob Rehak at 4:30 PM, Thursday, May 2, 2024

2438 Days since Hurricane Harvey

Lake Conroe Increasing Release Rate After Torrential Rain

5/2/24 Noon Update: Since publishing this, Lake Conroe has continued to rise and the SJRA has increased the release rate to 66,100 CFS. – Heavy storms dumped 10-12 inches of rain in isolated areas north of Lake Conroe last night. Most areas experienced 5-7 inches. As a result, Lake Conroe has increased its release rate to 60,455 cubic feet per second and it could go higher.

The area north of Lake Conroe has received more than 17 inches in the last week.

Engineers are currently modeling several different scenarios. The current inflow is more than two times greater than the outflow. The current release rate is already the second highest in the history of Lake Conroe.

Source: SJRA as of 10:00 AM 5.2.24.

Current Situation

According to Jeff Lindner, Harris County meteorologist, significant flash flooding is ongoing from north of HWY 105 to southern Montgomery County and the northern portions of Harris County.

At 8:27 am, radar showed the storm had moved into northern Harris, and northern Liberty Counties.

RadarScope Pro Screen Capture at 8:23 AM, 5.2.24, Orange indicates 5″.

It dumped 6 inches of rain in my gauge in two hours. And the total is still climbing.

Such high hourly rainfall rates result in street flooding. Lindner warned people not to travel unless absolutely necessary.

According to Lindner, “There may be a break in the activity in the afternoon hours before another complex of storms arrives overnight into Friday morning with additional heavy rainfall. But confidence in the forecast is not high.”

Impact of Rains

“Significant rainfall has also occurred over the headwaters of the East Fork of the San Jacinto River. New flood waves will certainly be generated on both the East and West Forks of the San Jacinto River,” Lindner added. The same holds true for Lake Livingston and the Trinity River.

The heavy runoff over already saturated grounds will migrate downstream Friday into the weekend. 

The SJRA does not have a dam on the East Fork and can’t control it. Dam releases on the West Fork do not impact the East Fork, but do impact Lake Houston.

Lake Conroe Release Rate Increasing, Max Uncertain

Lake Conroe virtually quadrupled its release rate from 17,000 cubic feet per second (CFS) at 7 AM to 60,455 CFS at 9:45 AM.

The lake level at 10:48 AM had reached 204.4 – 3.4 feet above normal.

Mark Micheletti, San Jacinto River Authority (SJRA) board member, said that SJRA engineers are modeling several release scenarios. So the ultimate release rate is uncertain as of this writing.

The flowage easement at Lake Conroe is 207. That’s the elevation at which homes start to flood.

Some people will criticize the SJRA for not releasing more water sooner. However, it was not an easy call.

Lake Houston was already flooding from the East Fork. And a massive release coming down the West Fork could have flooded homes.

Micheletti added, “Hydrographs are useless in a situation like this because you don’t yet know what the release will be,” he added.

During Harvey, the SJRA released 79,000 CFS. So, they are already at 75 percent of the devastating Harvey release rate.

But even with that, the current release rate is only about one third of the estimated water coming into the lake. “So that’s our challenge,” said Micheletti. The release rate will almost certainly go higher.”

The Harris County Flood Warning system showed that the San Jacinto West Fork is still within banks, but that likely won’t last long.

Before the heavy rains moved south this morning, river gages on the East and West Forks were dropping slowly as floodwaters receded from earlier in the week. But we’re about to experience a second wave there.

If you’re in a place that has flooded before, the safest course of action is to start developing an action plan now.

River Predictions

At 10 AM, Lindner released new hydrographs for the West Fork, East Fork, and the area below Lake Houston.

West Fork

As of 10 AM, 5.2.24

A rise to flood stage will occur today with a rise above major flood levels on Friday. Widespread low land flooding near the river is expected. The forecast may need to be increased more because of the uncertainty over Lake Conroe releases.

While there will be widespread low land flooding, the lowest structures in Kingwood are not impacted until over 60-62ft. Expect this level of water in the river to create backwater in tributaries that could lead to additional flooding.

A reader sent in this photo of the new Northpark South development between the West Fork and Sorters-McClellan Road.

NorthPark South already underwater from rains. 5.2.24 at 11 AM. Photo by Jody Binnion.

East Fork

A significant rise on the East Fork is expected as the upstream flood wave moves downstream. Forecasted water levels will reach 6-8 ft higher than earlier this week. This expected flood level will be higher than TS Imelda and will be similar to October 1994. Even elevated structures may be flooded, according to Lindner.

Below Lake Houston

Other Flooding

As I write this, I have received word that Taylor Gully is flooding and parts of nearby streets are closed.

White Oak Creek is also flooding. Royal Pines, the new development on White Oak at the northern end of West Lake Houston Parkway, has also flooded neighbors’ yards and a garage.

Flash flooding is ongoing along Willow and Spring Creeks, which are rising rapidly. Flooding along these creeks is becoming likely. Widespread street flooding and some structure flooding is possible.

A training band of thunderstorms will produce another 2-4 inches of rainfall on top of the already 4-6 inches that has fallen in these watersheds.

Pardon the pun, but the situation is very fluid. Sometimes new information comes in faster than I can update it.

I will post updates including photos when the rain lets up.

Posted by Bob Rehak at 10:00 AM on 5/2/24

2438 Days since Hurricane Harvey

East Fork Homes Flooding, Another Flood Watch Issued

May 1, 2024 – Even as East Fork homes are flooding, the National Weather Service has issued another Flood Watch for the region.

Monday’s Storm Brings Wednesday’s Flood

The stormwater from last Sunday night/Monday morning that’s flooding homes near the East Fork San Jacinto could get reinforcements tonight. Another powerful storm is approaching and will collide with moisture laden air from the Gulf later day.

That caused the National Weather Service to issue another flood watch from 10 PM this evening until Thursday evening for Houston and Harris County.

That same NWS bulletin also says that a flood warning remains in effect for the East Fork San Jacinto near New Caney affecting Liberty, Montgomery and Harris Counties.

Jeff Lindner, Harris County’s meteorologist, warned in his midday report that “Widespread amounts of 2-5 inches are likely with isolated totals of 6-9 inches. High hourly rainfall rates will be likely on the order of 2-4 inches which will produce rapid onset flash flooding.”

Lake Conroe and Lake Livingston Already Taxed to Max

The additional rainfall could overburden already overtaxed watersheds. “There is no capacity at either Lake Livingston or Lake Conroe,” said Lindner. “Additional inflows and run-off will have to pass through the dams’ floodgates.”

Although Lindner expects the heaviest rains to stay north of Harris County, “There is some potential that some of the heavy rainfall reaches into northern Harris County overnight,” he added.

If so, the storm could impact Spring, Cypress, Little Cypress, and Willow Creeks as well as the tributaries in northern Waller and southwestern Montgomery Counties, such as Lake Creek.

Lindner says significant rises will be possible depending on the rainfall amounts and patterns. Flash flooding will be likely where heavy rains occur.

That could deal a devastating blow to homes already flooding along the East Fork.

East Fork Photos Taken Morning of Mayday Flood

Pictures taken this morning between 9 and noon showed roads flooded out and many homes and vehicles already underwater.

TXDoT closed FM1485 at the East Fork/Montgomery County line.
SH99 on left, FM1485 on right.

Streets close to the river also flooded.

Looking S. Casey Road on left flooding from East Fork on right.
Home with flooded vehicles and heavy equipment at Casey and Spaulding.
Flooded homes at Casey and Green.
Cypress Hollow just N of SH99.

I took more than a hundred photos like these this morning. Some people were lucky with the water stopping just feet from their homes. Other people were not so lucky. They will need help.

Colony Ridge, Plum Grove and FM2090

Farther north, I explored Colony Ridge and Plum Grove near FM2090.

One of the main entrances to Colony Ridge where it approaches Plum Grove Road

The water there was already starting to recede. But still, many roads were barely passable. Most smaller vehicles did not brave the water.

Opposite angle, same intersection. Unable to see the sides of the road, traffic tried to stay close to the centerline to stay out of the ditches.
Looking NW over East Fork. FM2090 was still passable, but water lapped at the bottom of the bridge. The East Fork completely flooded the abandoned sand mine (upper right) and swept sediment out of mine.

Ironically, even though I could see my way out of Colony Ridge (from the air), I could not get to FM2090 on the ground because of floodwaters. I had to drive south to SH99 to return home.

Dunnam Road Boat Launch

Back in Kingwood, I called a friend on Dunnam Road. She said her boat launch flooded and that water was lapping at the first house coming up the hill.

Dunnam Road boat launch.
Note water surrounding house adjacent to boat dock. Luckily it did not flood and water is receding as of 4PM.
This young man appeared to be making the most of the flood by giving his daughter a fishing lesson. A neighbor told me he’s been doing that since she was born!

Posted by Bob Rehak on May 1, 2024

2437 Days since Hurricane Harvey