Tag Archive for: east fork

West and East Forks of San Jacinto Flooding Again

May 19, 2024 – For the second time this month, the West and East Forks of the San Jacinto River are flooding. The East Fork crested last night about 1.5 feet below the prediction. However, the West Fork is still rising at US59. Parts of River Grove Park and the turnaround under US59 are already flooded. And the National Weather Service predicts floodwaters will go even higher.

Meanwhile, the West Fork continues to run through an old Hallett sand pit that was sold in January.

Here’s what you can expect if you live near the rivers.

East Fork Crest Moving Toward Lake Houston

Low-lying areas along the East Fork began flooding yesterday at FM1485. Earlier, the East Fork flooded near Cleveland and Plum Grove. As the crest moves downriver, it is affecting communities differently. Exactly how depends on many factors, such as the conveyance of the river at different points, sediment accumulations, proximity of homes to the river and more.

Yesterday, water was coming across part of FM1485 where it crosses the East Fork and parallels SH99. Today, the entire east bound section of FM1485 was blocked by floodwaters.

East Fork San Jacinto at approximately 4:30 PM on 5.16.24
East Fork San Jacinto at approximately 4:30 PM on 5.16.24

As of 6 PM, May 19, floodwaters are declining in this reach of the river. The crest has moved downstream toward Lake Houston.

Harris County’s Flood Warning System shows the river crested last night but was still well above flood stage as of noon today.

Farther upstream, at FM2090, the river has already returned to its banks.

All this is the result of another 3-5″ of rain falling earlier in the week upstream in the watershed on grounds that were already saturated from torrential rains and flooding earlier this month.

NWS Issues Flood Warning for West Fork until Tuesday Morning

While the East Fork is falling at this hour, the West Fork is still rising. At 1:34 PM Sunday, the National Weather Service issued a flood warning for the West Fork near Humble affecting Harris and Montgomery Counties.

Communities affected include: Porter, Sendera Ranch Road, Conroe, Kingwood, Humble, Sheldon.

Only minor flooding is forecast.

National Weather Service Flood Warning

NWS will issue its next statement Monday morning at 7:45 AM CDT.

The FLOOD WARNING WILL REMAIN IN EFFECT UNTIL LATE TUESDAY MORNING.

IMPACTS: At 49.3 feet, minor lowland flooding begins in the vicinity of the gauge at US59. The north side turnaround at US 59 begins to flood. Low points in surrounding areas also begin to flood.

At 12:45 PM CDT Sunday, the river had risen to 49.2 feet.

 Bankfull stage is 45.3 feet.

The river will crest at 49.7 feet just after midnight tonight. It will then fall below flood stage late tomorrow evening.

Flood stage is 49.3 feet.

This afternoon, the turnaround under US59 was just beginning to flood. The parking lots and part of the roadway were already underwater.

Far side of sandbar in middle is normally the river bank.

At 5 PM, the soccer fields, picnic area and boat launch at River Grove Park were also partially underwater. And water was rising quickly.

Picnic area and boat docks at River Grove underwater and going deeper tonight.
Soccer fields, also at around 5PM
River still rising. Minor flooding expected through Tuesday.
Sand Mine Area Upstream

Farther upstream, the West Fork was still ripping a hole through an abandoned Hallett sand pit that the company sold to a real estate developer in January.

River is now flowing through the abandoned pit (right) instead of following the normal arc of the river (left) around the pit. Note trail of foam. It moved at around 5 mph.

This breach appears to have widened significantly in recent days. If it remains open and this pit becomes the new course of the river, it’s possible that the entire pit could become public property, just like the river is now.

On the other side of the river, Hallett filled in the trench that was releasing sludge from its settling pond last Friday afternoon.

Trench on perimeter of Hallett Mine that was releasing sludge into river on Friday afternoon has been filled in.

Lake Report

As of 7 PM, the SJRA is releasing 5,325 Cubic Feet per Second (CFS) from Lake Conroe. The lake is almost back to its normal level – within .67 feet of 201. And no rain is in sight. That’s good news. Releases should continue to go down.

Screen capture from SJRA website at 7:15PM.

Throughout this event, SJRA has balanced inflows and outflows to the degree that it can. The rate they show above is about half of what they released earlier in the weekend.

Lake Houston, however, is getting more, not less water. It is still about two feet above normal and discharging water via its gates and spillway. Total discharge is 34,015 CFS. Of that, the gates can release only 10,000 CFS. The other 24,000 CFS goes over the spillway.

Screen capture from Coastal Water Authority as of 7:15 PM.

Comparing the two numbers on the right, shows us that the flood risk is shifting to the Lake Houston Area now.

Of the 11 watersheds that send water into Lake Houston, SJRA controls only Lake Conroe. The East Fork has no flood control. But that’s a story for another time.

Posted by Bob Rehak on 5/19/24 at 8PM

2455 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.

Tornado Watch, Flood Warning, Flood Watch In Effect

4:30 PM May 16, 2024 – The National Weather Service has issued a trio of alerts that affect the Lake Houston Area. A tornado watch, flood warning, and flood watch are all simultaneously in effect.

Scene Capture from RadarScope Pro at 4:12PM 5/16/24

Tornado Watch

The three include a tornado watch until 10 PM tonight. The watch includes all counties in the Houston Region and then some. 

AUSTIN               BRAZORIA            BRAZOS
BURLESON             CHAMBERS            COLORADO
FORT BEND            GALVESTON           GRIMES
HARDIN               HARRIS              HOUSTON
JASPER               JEFFERSON           LIBERTY
MADISON              MONTGOMERY          NEWTON
ORANGE               POLK                SAN JACINTO
TRINITY              TYLER               WALKER
WALLER               WASHINGTON          WHARTON

Update: At 5:50 PM, issued a tornado warning for NW Harris, Austin and Waller Counties. They spotted rotation on radar. The warning will expire at 6PM, but it speaks to the severity of these storms.

Flood Warning

The Weather Service has also issued a flood warning for the San Jacinto East Fork. Predicted crests are increasing from minor to moderate levels near FM1485. This could affect people in Harris, Montgomery and Liberty Counties. Some are still cleaning up from the flood two weeks ago.

Flood Watch in Wider Area

Finally, a flood watch has been issued due to excessive rainfall across the region. This one could trigger flooding on other creeks, streams and bayous. The watch area includes:

Houston-Trinity-Madison-Walker-San Jacinto-Polk-Burleson-Brazos-
Washington-Grimes-Montgomery-Northern Liberty-Austin-Waller-
Inland Harris-Southern Liberty-Coastal Harris Counties

This watch is primarily due to excessive rainfall associated with the approaching storm. It could drop 2-4″ across a wide area, with isolated totals up to 6-8″.

Lake Houston is in the area of highest risk – Level 4 – for excessive rainfall.

National Weather Service (See below.)

Flash Flooding Possible

High intensity rains could produce flash flooding that makes driving dangerous.

The ground is already super saturated from previous rains. “There is just nowhere for the water to go,” said Harris County Meteorologist Jeff Lindner.

According to Lindner, “Widespread rainfall amounts of 2-4″ will be likely north of HWY 105. Isolated totals could reach upwards to 6-8 inches. Amounts will decrease toward the south with totals near the coast less than 1 inch. This will virtually be a carbon copy of the last several rainfall events in terms of location and amounts.”

Lake Report

Lake Conroe was releasing 1590 cubic feet per second until the noon hour today. Then, the SJRA stopped releasing water give the Coastal Water Authority a chance to reduce the level of Lake Houston. Lake Houston continues to release water.

Lake Conroe operators hoped they had enough capacity in the Lake to absorb the expected influx of water. But at 4:30PM, the resumed releasing 1587 CFS.

They also announced that they will “pass through storm water and runoff received in the Upper San Jacinto River Basin until Lake Conroe returns to conservation pool.” (201 feet)

Both lakes just returned close to their normal levels from the floods in early May. However, Lake Houston is still a few inches above normal.

Total inflows into Lake Houston are at 6,627 cfs and outflows are at 8,960 cfs. Lake Houston gates have and will remain open until the gate that is stuck partially open is repaired.

Impact on Sedimentation

Most sediment moves during floods. And the West Fork sure has been piling up sediment lately. KSA just completed a sonar survey in River Grove Park where the Kingwood Diversion Ditch enters the West Fork.

Before the last storm, sand had built up at the mouth so that only about two feet of clearance was available for boats. After the last storm, sand is poking up even closer to the surface…and the river is still about a half foot above normal.

Even with water up about a half foot, you can see sand bars lurking just below surface at the River Grove boat launch.

The City of Houston is getting ready to launch a new $34 million dredging program between Kings Point and FM1960.

DRC/Callan Marine mobilizing for new dredging program south of Forest Cove Pool.

Unfortunately, the new City program won’t include the mouth of the Diversion Ditch. KSA will have to hire its own dredger to keep the boat docks open.

KSA’s dredging interval has gone from 8 to 4 to 2 years. It sure seems as though it would be less expensive if we didn’t have West Fork floods flowing through sand pits.

Sand mine on San Jacinto West Fork near Kingwood

For Real-Time Information

To monitor:

Posted by Bob Rehak on 5/16/24 at 4:30 PM

2452 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.

SJRA Reducing Lake Conroe Release Rate

May 3, 2024 – As of 10 PM last night, the level of Lake Conroe had declined slightly for several hours. That indicates inflows are now less than outflows. Accordingly, San Jacinto River Authority Board Member Mark Micheletti worked out an agreement with the SJRA General Manager to start reducing the lake’s release rate.

By midnight the release rate was down from 69,585 cubic feet per second (CFS) to 64,797. And the lake level was down from 205.13 to 204.79.

This post contains information about the new release strategy, updated river and weather forecasts, plus a list of stunning rainfall totals from yesterday.

New Lake Conroe Release Strategy

During Harvey, many downstream residents felt the SJRA released too much for too long to return the lake to normal as quickly as possible.

The new agreement reached late tonight will have dam operators lowering the release rate in 2500 CFS increments. They will then wait two hours to see if the water level is increasing or decreasing, and adjust the next increment accordingly.

This strategy lets them delay additional decreases if necessary. For instance, if new heavy rainfalls increase inflows.

Dam operators still have the flexibility to release more if necessary. But it avoids leaving the release rate too high for too long when unnecessary.

All things considered, this strategy should protect downstream residents as much as possible. It also gives Lake Conroe operators a safety margin.

No Significant Changes to Flood Forecasts Since This Afternoon

As of 9:31 PM, Harris County Meteorologist Jeff Lindner had no changes to ongoing river forecasts. He emphasized that significant flood waves will continue moving down the East and West Forks of the San Jacinto into the weekend.

New Weather Forecast Reduces Rainfall Risk

Compared to yesterday’s weather forecast, however, Lindner also revised the expected overnight rainfall downward.

“Expect a mostly calm night with a low-end chance of a few showers toward morning. With heating on Friday and the approach of another thunderstorm complex from North Texas, there will be an increasing chance of rainfall during the day,” he said. “At this time. this complex of storms looks fairly progressive during the afternoon hours, but there is some uncertainty on how the storms evolve and how fast they cross the area.”

He says that additional rainfall amounts of 1-2 inches with slightly higher isolated totals can be expected on Friday. This additional rainfall is included in the river forecast models and should not greatly alter the current river forecast.

See river forecast summaries below.

East Fork San Jacinto River at New Caney (FM 1485)

Mandatory evacuation is still in effect for the eastern side of the river from FM 1485 to Lake Houston.

“Forecasted water levels will rise 7 feet higher than earlier this week. Structures on the ground will be flooded to rooftops levels,” says Lindner. “Elevated structures will be flooded. For reference, the forecasted water level is 4 ft below Harvey.” Similar to earlier this week, the rapid rise of several feet is expected late Friday into Saturday.

Impacted subdivisions: 
  • Idle Wilde
  • Idle Glen
  • Cypress Point
  • River Terrace
  • Magnolia Point
  • Northwood Country Ests
  • Low-lying eastern portions of Kingwood, such as:
    • Riverchase
    • Woodstream
    • Woodspring Forest
As of Thursday at 9 PM

West Fork San Jacinto River at Humble (US 59)

The river will rapidly rise from upstream inflows. It will reach major flood levels and peak near 62 ft on Saturday. Widespread low-land flooding will occur. It will likely impact lower areas in West Fork subdivisions such as:

  • Belleau Woods
  • Rivercrest
  • Northshore
  • Forest Cove 
  • Kings River Estates
  • Atascocita Shores
  • Kings Point
  • Kings Harbor
  • Kings River
  • Kingwood Greens
  • Fosters Mill
  • Kingwood Lakes
  • Barrington
  • Trailwood
  • Deer Ridge Estates

Kingwood residents should expect flooding of streets and structures near the East Fork, West Fork, and their tributaries.

Harris County is revising a potential inundation map that circulated Thursday on Facebook. Lindner says to expect the type of flooding we saw during the Memorial Days storm in 2016.

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

Elevated residents near the river should be prepared to be cut-off through the weekend if they don’t evacuate.

As of Thursday at 9 PM

West Fork of the San Jacinto River at I-45 

Major flooding is imminent upstream and downstream of I-45 including large portions of River Plantation and portions of Woodloch downstream to SH 242 and SH 99. Flows may approach the I-45 bridge deck. The current forecast is about 1 ft below Harvey recorded levels.

As of Thursday at 9 PM

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 and well as low lying in the river bottom around Highlands and HWY 90.

High velocity flows may damage vessels and barges near I-10 and result in loss of mooring.  

Flow may approach the I-10 river bridge west of the river crossing. Additionally, high flows will result in the suspension of Ferry service.

As of Thursday at 9 PM

Spring Creek

According to Lindner, the creek is rising on the upper end due to flows from Waller and Montgomery Counties. Minor flooding is in progress along the upper portions of Spring Creek at Hegar Rd. Water levels along the creek are high, but any flooding is minor and to rural areas near the creek. 

Willow Creek 

Willow Creek has crested and is slowly falling.

Yesterday’s Storm: Gage Readings

The storm that swept through southern Montgomery and northern Harris Counties yesterday dropped impressive amounts of rainfall.

Harris County Flood Control District released the following totals at 7 PM Thursday.

  • 8.24 in. – 1050 Spring Creek @ I-45
  • 8.2 in. – 1320 Willow Creek @ Kuykendahl Road
  • 7.76 in. – 755 San Jacinto River @ Lake Houston Pkwy
  • 7.2 in. – 785 Peach Creek @ FM 2090
  • 7.12 in. – 790 East Fork San Jacinto @ FM 1485
  • 6.92 in. – 795 East Fork San Jacinto @ FM 2090
  • 6.8 in. – 765 San Jacinto River @ SH 99
  • 6.64 in. – 1745 Cedar Bayou @ FM 1960
  • 6.6 in. – 1960 Luce Bayou @ SH 321
  • 6.12 in. – 770 San Jacinto River @ SH 242
  • 5.88 in. – 780 Caney Creek @ FM 2090
  • 5.76 in. – 1040 Spring Creek @ FM 2978
  • 5.64 in. – 1940 Luce Bayou @ FM 2100
  • 5.48 in. – 1340 Willow Creek @ SH 249
  • 5.12 in. – 1056 Mill Creek @ FM 1774
  • 5.04 in. – 1950 Luce Bayou @ SH 99
  • 5.0 in. – 1080 Spring Creek @ Decker Prairie-Rosehill Road
  • 4.96 in. – 760 San Jacinto River @ US 59

Locations Out of Banks, Flooding Likely

    HCFCD also reported that the following streams/channels were out of their banks and flooding was likely.

    • 710    San Jacinto River @ Rio Villa
    • 720    San Jacinto River @ US 90
    • 740    Lake Houston @ FM 1960
    • 760    San Jacinto River @ US 59
    • 780    Caney Creek @ FM 2090
    • 785    Peach Creek @ FM 2090
    • 790    East Fork San Jacinto @ FM 1485
    • 795    East Fork San Jacinto @ FM 2090
    • 1054    Mill Creek @ FM 1486
    • 1074    Walnut Creek @ Joseph Road
    • 1084    Threemile Creek @ Joseph Road
    • 1090    Spring Creek @ Hegar Road
    • 1195    Mound Creek @ FM 362
    • 1950    Luce Bayou @ SH 99

    Flooding Possible

    The following streams were still in banks, but flooding was possible.

    • 755    San Jacinto River @ Lake Houston Pkwy
    • 765    San Jacinto River @ SH 99
    • 770    San Jacinto River @ SH 242
    • 796    East Fork San Jacinto @ SH 105
    • 1050    Spring Creek @ I-45
    • 1055    Bear Branch @ Kuykendahl
    • 1076    Birch Creek @ Riley Road
    • 1086    Threemile Creek @ FM 362
    • 1110    Cypress Creek @ Cypresswood Drive
    • 1186    Live Oak Creek @ Penick Road
    • 1190    Little Mound Creek @ Mathis Road
    • 1320    Willow Creek @ Kuykendahl Road
    • 1340    Willow Creek @ SH 249
    • 1740    Cedar Bayou @ US 90
    • 1745    Cedar Bayou @ FM 1960
    • 1960    Luce Bayou @ SH 321
    • 2200    Houston Ship Channel @ Juan Seguin Park

    Resources for More Information

    To see:

    If in doubt about whether you will flood, remember. Better safe than sorry. If you evacuate needlessly, the most you lose is a day or two. But if you don’t and you flood, you could lose everything.

    Posted by Bob Rehak on 5/3/24

    2439 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 Predicted to Rise 15 Feet in Next 24 Hours

    (Updated with more Subdivisions/Streets at 9PM Tuesday) As yesterday’s heavy rains work their way downstream, the National Weather Service’s (NWS) Advanced Hydrologic Prediction Service forecasts that the East Fork at FM1485 will rise 15 feet in the next 24 hours.

    As of noon Tuesday, NWS said the river had already reached the “Action Stage” at 56.85 feet. NWS predicts it will reach 71.9 feet by tomorrow at noon. “Major flooding” at that location begins at 69 feet.

    From NWS Advanced Hydrologic Prediction Service at noon on 4/30/24

    Jeff Lindner, Harris County’s meteorologist, says, “Many of the structures in this area have been elevated, however isolated homes that remain on the ground will be subject to flooding at these levels.”

    “Flooding similar to TS Imelda in 2019 is expected.”

    Jeff Lindner, Harris County Meteorologist

    FM1485 will be under several feet of water. Flows may even approach the deck of the Highway 99 bridge!

    Subdivisions and Streets that Could Be Affected

    Lindner specifically warned about flooding that could affect the following subdivisions and streets.

    Magnolia Point (West end of Commons of Lake Houston)
    • Opal Way
    • Diamond
    • Mendencino
    • Lassen Villa
    • Glen
    • Magnolia
    • Hill
    • Calvins
    • Collins
    • Calaveras Creek

    Flooding of streets is likely. Elevated homes will be cut-offSome structure flooding is possible for any homes on the ground in this area.

    South of FM 1485 (east side of the river): 
    • Spalding
    • Green
    • Jett
    • Casey

    Some structure flooding is possible for any homes on the ground in this area.  

    Idle Glen subdivision: 
    • Brookside
    • Chinquapin
    • River Side
    • E. San Jacinto
    • Glenwood
    • Dipping
    • Idlewild
    • Lazy Creek

    Almost all of the homes in this area are elevated, but will be cut-off. Any homes on the ground will be flooded.

    Northwood Country Estates: 
    • Flooding of streets is likely. Elevated homes will be cut-off.
    • Disher
    • Bounds
    • Thomas
    • Davidson
    • A new 553-acre Friendswood development called Sila is in this area.
    River Terrace: 
    • Flooding of the following streets is likely. Elevated homes will be cut-off.
    • River Terrace
    • Elm
    • Pine
    • Cherry Laurel
    • Holly 
    • Cypress 
    Cypress Point:
    • The following streets will be flooded (closest to the river). Elevated homes will be cut-off.
    • Blue Lake
    • Oak Knoll
    • Wild Oak
    • Birchwood

    The East Fork should also rise 10-15 feet at FM2090.

    East Fork at Cleveland

    Farther upstream at Cleveland, the East Fork has already peaked and is beginning to recede after only reaching a moderate level of flooding.

    As of noon 4/30/24, the East Fork at Cleveland was at a moderate flood stage.

    Structure Flooding In Kingwood NOT Expected

    Lindner added that, “Flooding will occur in the low lying areas of Kingwood that back up to the East Fork of the San Jacinto River. This is mostly all non-developed lands near the river or back yards with bulkhead that front the river. Structure flooding is NOT expected in Kingwood.”

    Meanwhile, at as of noon on 4/30/24, NWS predicts the West Fork will not flood.

    Noon, 4/30/24

    View Real-Time Inundation Mapping

    To view Real-Time Inundation Mapping, go to www.harriscountyfws.org and click “inundation map” on the left side.

    Trinity River Also Flooding Badly

    The Trinity River at Liberty is about to see major flooding through Sunday. The Trinity is a separate watershed. It will not affect Harris County.

    As of noon, 4/30/2024

    Other Flooding

    Fourteen gages show various streams and creeks in the region are at or near flood stage.

    To see gage levels and predictions for a stream near you, go to the NWS Advanced Hydrologic Prediction Service.

    The Harris County Flood Warning System offers many of the same features plus more, such as historical flood heights.

    Posted by Bob Rehak on 4/30/24 at 2PM

    2436 Days since Hurricane Harvey

    Swollen San Jacinto East and West Forks Sweep Through Sand Mines

    As floodwaters worked their way down the East and West Forks of the San Jacinto from last week’s heavy rains, they invaded sand mines on both rivers on Easter Sunday, 2023.

    Up to 9 inches of rain fell in the headwaters of both rivers during 3 days from 4/5 to 4/7. Atlas-14 rainfall probability statistics indicate that equals a 5-year rain.

    The Lake Conroe Dam intercepted much of the West Fork rain and is now releasing it at about 6400 cubic feet per second. There are no dams on the East Fork and the flooding there appears much worse.

    West Fork Near Northpark South Development

    Near the Northpark South Development on Sorters Road, the West Fork snakes its way through four square miles of sand mines. In the image below, the Hallett Mine on the right seemed secure. But the abandoned sand mines on the left and top center both opened to the river.

    Photo taken 4/9/2023 two days after rain stopped.

    East Fork Near FM2090 on 4/9/2023

    Normally, the East Fork at 2090 is about 30-40 feet wide – the size of the opening in the woods circled in red below. But today, the river swelled to about 2000 feet wide.

    Looking south from over East Fork San Jacinto toward FM2090.
    Looking East along FM2090 across the East Fork.

    As the East Fork rose, it invaded the abandoned Texas Concrete Sand and Gravel Mine in Plum Grove.

    Abandoned Texas Concrete Sand and Gravel Plum Grove Mine north of FM2090 between East Fork and FM1010

    Water entered the northern end, swept through the mine, and punched through the dikes on the southern end, carrying silt and sand with it. See sequence of pictures below.

    Looking N toward northern end of mine. Water entered mine in upper left and cut off house.
    Water then swept under and around house moving south.
    Looking S. The water then exited back into the river through several breaches in dikes.
    Rushing water carrying silt and sand found two more breaches close to 2090. Left unchecked, the force of this water will eventually erode the banks of FM2090.
    Baptist Church Loop Road south of FM2090 was also underwater.

    Mine Fails to Meet Guidelines for Abandonment

    This mine does not meet TCEQ guidelines for abandonment. The miners left equipment, including a dredge. They also failed to grade stockpiles, remove buildings, and plant grass. Yet somehow, the TCEQ gave them a pass.

    This is the second time in less than two years that this mine has been inundated. The public will bear the cost of dredging all the sand carried downriver.

    Ironically, a bill introduced by State Rep. Charles Cunningham requiring financial surety for sand mine reclamation remains bottled up in the House Natural Resources Committee. See HB1093.

    I guess the miners need the money more than you do.

    Posted by Bob Rehak on 4/9/2023

    2049 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.

    February East Fork Mouth Bar Dredging Update

    Since last month, dredgers have removed one island and have started on another in the massive complex of sand bars laid down during Harvey and Imelda on the San Jacinto East Fork where it meets Lake Houston.

    Current Location

    Another island in the San Jacinto East Fork Mouth Bar complex.
    Another island in the San Jacinto East Fork Mouth Bar complex is being dredged away. Photo taken on Sunday afternoon, 2/20/22. Looking downstream toward Lake Houston.

    The sand bar already eliminated was toward the top and left side of the frame above. It stretched almost 2000 feet.

    Now dredgers are focusing on the giant bar in the middle above.

    Mouth Bar Complex in 2020 Before Start of Dredging

    The shot below, taken from the opposite direction, helps put things in perspective.

    East Fork Mouth Bar
    Looking upstream at the East Fork Mouth Bar complex in March 2020 before dredging. The bar dredgers already eliminated is the bright white one in the foreground. Now they’re working on the one farther upriver and to the left.

    More Current Shots Taken Today

    East Fork Mouth Bar Complex
    Looking NE at dredging in the East Fork Mouth Bar Complex. It looks like they may have started here and moved elsewhere for some reason. Photo taken 2/20/22.
    This shot more than the others, gives one a feeling for the immensity of the task.

    Long Range Dredging Plan

    The City of Houston’s purchasing website does not indicate whether the City has yet awarded the project to develop a long range dredging plan. Last month, the purchasing agent for the City, Bridget Cormier, stated that “The City has not yet made a decision, nor a recommendation for award yet.” She explained, “We are still in the evaluation phase and have requested additional information from suppliers that moved forward in the process.” 

    It took three months just for contractors to dredge their way through the Royal Shores channel to get to East Fork (July, August, September 2021). East Fork dredging started in October last year. Spoils are currently being ferried back to land south of the West Fork, opposite River Grove Park. There it dries before TexDoT hauls it away for use in roadbuilding.

    Posted by Bob Rehak on 2/20/2022

    1636 Days since Hurricane Harvey

    San Jacinto East Fork Dredging Begins

    This morning, for the first time, I photographed dredging on the San Jacinto East Fork. It was a welcome site and one that hundreds of East Fork residents who flooded will appreciate.

    Three Months After Plans Unveiled

    It was back on July 9, 2021, that Stephen Costello, the City’s Chief Recovery Officer, unveiled the City’s plans to begin East Fork dredging. At the time, Costello said crews would have to dredge their way there through a shallow channel south of Royal Shores in Kingwood.

    On July 11, I first photographed dredging in the channel.

    On September 23rd, I photographed crews about three quarters of the way through the channel.

    Finally, today, October 12, three months later, I photographed a barge moving straight through the channel and into the East Fork. I even had to move locations a couple time to keep the drone within range.

    Drone Photos of East Fork Dredging from 10/12/2021

    Two mechanical dredges on East Fork, just upstream from the entrance to Luce Bayou.
    Today’s dredging location circled in red. Arrow points way back to where crews are depositing the spoils on the West Fork just south of River Grove Park.
    Tug pushing empty pontoon through Royal Shores Channel toward East Fork (top). Looking SE. Note FM1960 Causeway in upper right.
    Looking NE toward Luce Bayou on opposite shore to begin Dredging
    Empty barge turns NNE. East Fork dredging location is around the finger that sticks out into the river from the upper left. After loading up with silt and sediment, the barge will return to the West Fork to deposit the spoils.

    More Dredging $$$ Voted by Commissioners Today

    This morning, in Harris County Commissioners Court, Agenda Item 102 passed unanimously without discussion. The motion will contribute $10 million from the Harris County 2018 flood bond funds to extend the dredging on the East Fork, West Fork, and Lake Houston, including the entrance to Rogers Gully.

    Posted by Bob Rehak on 10/12/2021

    1505 Days since Hurricane Harvey and 756 since Imelda

    FM1485: What’s Wrong With This Picture?

    I took this picture on May 26, 2021. It shows TxDOT construction of the new State Highway 99 (Grand Parkway) next to FM1485 in New Caney. The picture looks northeast toward Colony Ridge in Liberty County. The East Fork of the San Jacinto River flows under both bridges toward Lake Houston on the right.

    Looking east toward Colony Ridge across FM1485 and the East Fork. Water flows left to right.

    Note the huge backup of water trying to get under the FM1485 bridge. Also note how much taller and wider the new bridge is compared to the old one.

    How Much Rainfall Caused This?

    Here is rainfall for the month of May as measured by the Harris County Flood Control District Gage at this location.

    The Harris County Flood Warning System shows that the largest rainfall for the month was 2.28 inches TWO days before the photo. But the ground was clearly saturated from steady, moderate rains the week before.

    The gage upstream at FM2090 shows slightly more rain. It reported 14 inches for the month instead of 11, but it received exactly 2.28 inches on the same day this gage did. While 2+ inches in a day is substantial, few in this part of the world would consider it excessive – especially since it was spread out over 5 hours.

    Likewise, according to Atlas-14 standards, the rain that fell in the week before would qualify as a 1- to 2-year rain – notable, but not historic.

    Note the 7-day rainfall totals in columns 1 and 2.

    Submerged 41 Times in 32 years

    And after consulting Harris County Flood Control District records, I learned that FM1485 has gone under water 41 times since 1990 – an average of 1.32 times per year.

    The East Fork came out of its banks and flooded this area twice in the week before the picture was taken.

    Rainfall data, road flooding frequency and the photo all suggest that a 1- to 2-year rain is enough to flood FM1485.

    What Should a Roadway over a Major River Withstand?

    Yet the TxDOT standard suggests that such minor arterials and bridges over a major river crossing be built to withstand 25- to 50-year floods. Oops!

    Obviously TxDOT built a much higher road and a much wider, taller bridge for its new highway. The new one is approximately five times wider than the old one. Construction standards for major highways could account for that. But so could TxDOT’s experience with FM1485.

    So What’s Going on Here?

    Why did TxDOT make the new bridge so much wider and taller?

    • Did TxDOT just get the engineering wrong on the old bridge?
    • Did bridge standards change over time?
    • Do state highways have higher standards than farm-to-market roads?
    • Did Atlas-14 increase the risk?
    • Did upstream development, such as Colony Ridge, alter the hydraulics of the watershed when the developer paved over wetlands and deforested thousands of acres while providing little detention-pond capacity?
    • Did the mischaracterization of soil types in Colony Ridge lead to more runoff than anticipated?
    • All of the above?
    • Some of the above?

    Jeff Lindner, Harris County’s meteorologist, cautions that, “Water surface elevations depend on many variables…rainfall patterns, intensity, soil conditions, water level in the river when the rain started, ect. It is usually difficult to compare events as no two are exactly alike. You really need a hydrological analysis of the location to determine the amount of run-off from that site into the river per an amount of rainfall.”

    Good luck with that! More than six months after the Liberty County Attorney launched an investigation into Colony Ridge drainage reports, we still are waiting for answers.

    Posted by Bob Rehak on 7/15/2021

    1415 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.

    Floodgate, Dredging Plans Unveiled

    At one of the first large public meetings since Covid began, several hundred people crowded into the Kingwood Community Center last night. They came to see the City unveil floodgate and dredging plans for Lake Houston. Stephen Costello, PE, the City’s Chief Recovery Officer, addressed dredging. And Chris Mueller, PhD, PE, of engineering firm Black & Veatch discussed adding more floodgates to the Lake Houston Dam. Mayor Pro Tem Dave Martin coordinated the meeting.

    To see both presentations, click here. Or see the summaries below.

    Dredging: About Half Done

    In late 2019, the Army Corps finished hydraulic dredging in the area south of the West Fork mouth bar. Then in early 2020, the City of Houston began mechanical dredging to extend the effort. In terms of the estimated dollars designated for dredging, the effort is about halfway done.

    The first four rows on this chart are done or almost done. They total $114 million out of a projected total of $222 million.

    The last two rows on the chart above are estimates because they depend on bids currently in progress and a long-range plan not yet complete. The need for a long-term plan and maintenance dredging were identified early on by the Army Corps so that any benefits of dredging were not immediately wiped out by future sedimentation.

    Scope of Long-Range Dredging Plan Still in Development

    A long-range dredging plan for Lake Houston is critical. We must understand where the sediment comes from, how fast it builds up, where it builds up, and the consequences of not removing it periodically.

    The numbered dots in the photo above show channels south of the East and West Forks draining into Lake Houston where sediment can also build up.

    Costello says the City is currently working with affected homeowner associations to discuss cost-sharing arrangements.

    He also says that the City must identify a long-range site for depositing the spoils that is suitable for hydraulic dredging. He called the mechanical dredging now in progress “not sustainable.” Currently, the City is using Berry Madden’s property on the West Fork south of Kingwood’s River Grove Park to deposit the mechanical dredging spoils. That’s a long haul for barges on the East Fork.

    Next Dredging Steps: Channel to East Fork and East Fork Itself

    Contractors must next deepen the channel between the West and East Forks of the San Jacinto to move dredging equipment and spoils back and forth (see below).

    Current location of dredging is near yellow dot.

    From there, dredgers will move slightly north of where Luce Bayou (far right) enters the East Fork and begin dredging the East Fork mouth bar. See large circle above. The map shows that area grew shallower by up to nine feet between 2011 and 2018. Imelda, in September 2019, made it grow even shallower. Note the fresh deposits of sand in the photo below now poking up above the water.

    Growth of East Fork Mouth Bar after Imelda in September 2019. Photo taken in November 2019.

    Additional Floodgates for Lake Houston Dam

    Chris Mueller of Black & Veatch then discussed the reasons for adding additional floodgates to Lake Houston, preliminary engineering findings, and an implementation schedule.

    The primary objective: to increase the outflow capacity of the dam to reduce the risk of future flooding. However, he emphasized that reducing the risk for people upstream of the dam cannot have an adverse impact on people below it. See below.

    He emphasized that Lake Houston is, first and foremost, a drinking water reservoir. He also emphasized that the dam is almost seventy years old and near the end of its useful life. Significant safety issues exist in working with such old concrete.

    Calculating the Benefit/Cost Ratio of Additional Floodgates

    Mueller then explained how FEMA calculates the benefit/cost ratio of additional floodgates.

    • On the benefit side, it considers: the reduction in water surface level; how many buildings and streets that will prevent from flooding; reduced societal impacts; and reduced impacts to business revenues. These are primarily damage costs avoided.
    • On the cost side of the equation, FEMA factors in construction costs and annual operation and maintenance costs.

    To win project approval, the City must show that the benefits of additional floodgates exceed the costs in a 100-year storm, similar to Imelda. Such a storm elevates the lake 10 feet.

    The peak inflow to Lake Houston in a 100-year storm: 286,000 cubic feet per second (CFS), enough to fill the Astrodome in 3 minutes! However, during Harvey, SJRA estimated the peak inflow at 400,000 cfs.

    Proposed Alternative Produces 11-Inch Benefit Nearest Dam

    A hydrologic and hydraulic analysis conducted by Black & Veatch will help prove up the benefit/cost analysis. The San Jacinto Watershed (including Buffalo Bayou) includes flow from eight counties.

    In evaluating about ten alternatives for adding floodgates, Black & Veatch considered both cost and non-cost factors listed below.

    The company’s first choice was to install additional gates on the earthen portion of the dam on the east side. But environmental considerations there would have delayed the project by a decade or more.

    So they decided to recommend a 1,000 feet of crest gates on the west side of the spillway instead. See example of crest gates in operation below.

    An air bladder near a bottom hinge raises or lowers the floodgates to let water in/out

    Such gates would increase the discharge capacity to 45,000 cfs, more than four times the current capacity of 10,000 cfs. That’s still only about a third of the discharge capacity of the floodgates on Lake Conroe. But according to Martin, that would still be enough to lower the level of the lake 4 feet in 24 hours.

    However, before floodgate construction can begin, engineers must evaluate:

    • Downstream impacts and how to mitigate them
    • Impact to the stability of the existing concrete dam

    Back in the 1950s when the Lake Houston dam was built, engineers did not use rebar. So this will be a delicate operation. Contractors must cut 6 feet into the existing spillway; cap the remaining concrete with a slab; and install the crest gates on top of the slab.

    Black & Veatch must also develop an operations protocol for new floodgates that maximizes upstream benefits and limits downstream impacts. Mueller shared this schedule with attendees.

    Best-Case Project Timeline Shows Completion in 2024

    Schedule as of 7/8/2021. Detailed engineering could take another year.

    A best-case scenario shows construction starting at the end of 2022 and finishing before the start of hurricane season in 2024. So, at least three more hurricane seasons to get through before seeing any benefit from additional gates.

    Posted by Bob Rehak on 7/9/2021

    1410 Days since Hurricane Harvey