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
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.
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.
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.
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:
- Real-time rainfall and stream levels near you, visit the Harris County Flood Warning System.
- More about watersheds and channels, visit the Harris County Flood Education Mapping Tool.
- River forecasts, visit the National Weather Service Advance Hydrologic Prediction Service.
- Lake Conroe Levels and release rates, visit the SJRA.
- Lake Houston levels, visit the Coastal Water Authority.
- The elevation of a home, business or street, visit the USGS National Map.
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
