The following is the forecast for the San Jacinto River basin including the West and East Forks and the mainstem below Lake Houston, as of about 8:30 p.m. Friday evening. Some forecasters believe rainfall, runoff and flooding could go higher. This post has already been updated once.
West Fork:
Major flooding forecast. Some uncertainty remains. Forecast could go a few feet higher. Jeff Lindner, Harris County meteorologist warns Northshore, Belleau Woods, Rivercrest, and Forest Cove will likely flood into early next week. Even elevated structures will be cut-off for several days.
Lake Conroe is currently releasing 2121 cfs as of 7 p.m. Friday. This is a small fraction of the expected flows along the West Fork.
The West Fork reached it’s low point around 4 p.m. this afternoon after the City lowered the Lake to 40.75 feet. Flood gates remain open at the Lake Houston dam. Regardless, the West Fork is now expected to crest at around 54 feet on Monday afternoon and not return to its banks for several days.Near Real Time Inundation Map from HarrisCountyFWS.org. Check the site periodically for latest updates.
This will be the inundation with a stage of 52.0 ft at US 59
East Fork:
NWS forecasts minor to moderate flooding along the East Fork at FM 1485. At 62 ft FM 1485 west of the river bridge will be impacted.
Mainstem below Lake Houston:
A rise to near flood stage is currently expected. A few low lying roads near the river could be flooded.
Overnight Rain Forecast
Lindner says, “Widespread rainfall of 1-2 inches has occurred over much of the area this afternoon with isolated totals of 3-4 inches over southern Walker and extreme northern Montgomery Counties.”
“Surface low is deepening northwest of Harris County and suggests increasing potential for heavier showers and thunderstorms. They will train from WSW and SW to the ENE and NE. Rainfall will continue to pile up at the rate of .5 to 1.5 inches per hour this evening and much of what is now falling is directly running off,” says Lindner.
The National Weather Service and Lindner expect areas along and NW of US 59 will receive the most sustained rainfall this evening.
Impact of Lake Lowering
Luckily for the Humble Kingwood Area, the City of Houston reduced the level of Lake Houston more than the 18″ they originally projected. As of this afternoon, the Lake was down to 40.5. That should give us some cushion against flooding.
Said City Council Member Dave Martin, “The gates at Lake Houston continue to remain open and will be adjusted as needed to allow for even more water to be released should that be necessary. In response to the lowering of Lake Houston, the West Fork of the San Jacinto River near Highway 59 has also lowered by 2 feet providing additional capacity in the river.
Expected SJRA Release Rates
According to Martin, the SJRA currently estimates that releases from Lake Conroe might peak at 9,000 to 11,000 cfs sometime over the weekend based on current forecasts. These amounts are relatively small in comparison to the rain events that our area saw during July 4, 2018 and Memorial Day 2016.
If you live in a low-lying area, monitor rainfall and water-level trends by visiting these web sites throughout the weekend.
Posted on 12/7/2018 by Bob Rehak based on info from Harris County & COH
465 Days since Hurricane Harvey.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2018/12/image001-1.png?fit=600%2C465&ssl=1465600adminadmin2018-12-07 20:01:502020-01-17 10:16:24West Fork Forecast to Flood up to 54 Feet
After Harvey, the SJRA, Harris County, National Weather Service and USGS added and upgraded stream gages throughout the region. Think of these gages as a distant early warning system. Looking at upstream conditions tells you what will soon happen in your area.
Here’s a list of handy web sites that display river, bayou and stream levels around Lake Houston and the state. Explore them before an emergency. Bookmark those that offer the best information for your area.
Reference Guide
Texas Water Development Board A one-stop shop for flood preparedness anywhere in Texas. Brings together local information from all over the state. Check everything from stream gages to the status of evacuation routes.
Harris County Flood Warning System. Real-time rainfall, and river-channel monitoring and forecasting. The Warning System also contains near-real-time inundation mapping. For instructions on how to use it and a discussion of its limitations, see this post.
Gages listed on the Harris County Flood Warning System in northern Harris and Montgomery Counties. This screen capture was made at 11:18 AM on 12/7/18. You can see that heavy rain is already falling at the top of the area shown in this map.
If you lose track of this post, you can always find these sites under the LINKS tab of this web site.
Posted by Bob Rehak on 12/7/2018
465 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2018/12/HCFWS.jpg?fit=1572%2C1210&ssl=112101572adminadmin2018-12-07 11:31:432018-12-07 15:20:34Handy Web Sites to Monitor Flooding
465 Days after Hurricane Harvey, the U.S. Army has finally liberated River Grove Park in Kingwood. They literally took the beach.
Drainage ditch at River Grove is now open to the San Jacinto River.
Actually, they took the giant sand bar that Harvey deposited one night. It had been blocking the drainage ditch that runs through the park and that caused excessive flooding. The two shots immediately below show what that sand bar looked like before dredging.
Sandbar deposited by Hurricane Harvey at River Grove forced water to make a 90 degree turn before it could reach the river. This slowed the velocity of runoff and backed up water into subdivisions, like the Barrington in the background. While the sandbar looks low from the air it was up to 15 feet high directly in front of the drainage ditch (middle left). See below.
The same dune in the previous image photographed from the boat dock.
Dredge Now Moves Downriver
Dredge is now moving downriver.
Work to Date
Dredge #1 is working alongside the West Lake Houston Parkway bridge. It has dredged approximately 135,000 cubic yards of sand and silt to date, according to the Corps’ project manager.
Dredge #2 is working on the upstream end of the project, still near River Grove. It has dredged approximately 226,000 cubic yards to date. After dredging the access channel to River Grove, surveys showed there were some areas that the dredge could not reach. Great Lakes, the contractor will use a barge-mounted excavator to perform final clean-up work. Updated surveys will then confirm achievement of plan goals.
Dredging plans for River Grove indicate a channel width of 50 feet and a depth of 15 feet near the boat ramp.
For all the people who live upstream from the drainage ditch that runs through River Grove, this is an early Christmas present. It will be interesting to see what happens to flood levels in the park now that the bar blocking the ditch has been removed…just in time for a major fall storm that could drop up to 10″ on the US59 corridor. However, we also need to remember that the City is dropping the level of the Lake by at least 18″.
Posted on December 7, 2018 by Bob Rehak
465 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2018/12/MH-CCC-NightDredge-RG-12.6_1_01.jpg?fit=1500%2C1000&ssl=110001500adminadmin2018-12-06 17:40:102018-12-06 17:57:44U.S. Army Liberates River Grove Park
West Fork Forecast to Flood up to 54 Feet
The following is the forecast for the San Jacinto River basin including the West and East Forks and the mainstem below Lake Houston, as of about 8:30 p.m. Friday evening. Some forecasters believe rainfall, runoff and flooding could go higher. This post has already been updated once.
West Fork:
Major flooding forecast. Some uncertainty remains. Forecast could go a few feet higher. Jeff Lindner, Harris County meteorologist warns Northshore, Belleau Woods, Rivercrest, and Forest Cove will likely flood into early next week. Even elevated structures will be cut-off for several days.
Lake Conroe is currently releasing 2121 cfs as of 7 p.m. Friday. This is a small fraction of the expected flows along the West Fork.
This will be the inundation with a stage of 52.0 ft at US 59
East Fork:
NWS forecasts minor to moderate flooding along the East Fork at FM 1485. At 62 ft FM 1485 west of the river bridge will be impacted.
Mainstem below Lake Houston:
A rise to near flood stage is currently expected. A few low lying roads near the river could be flooded.
Overnight Rain Forecast
Lindner says, “Widespread rainfall of 1-2 inches has occurred over much of the area this afternoon with isolated totals of 3-4 inches over southern Walker and extreme northern Montgomery Counties.”
“Surface low is deepening northwest of Harris County and suggests increasing potential for heavier showers and thunderstorms. They will train from WSW and SW to the ENE and NE. Rainfall will continue to pile up at the rate of .5 to 1.5 inches per hour this evening and much of what is now falling is directly running off,” says Lindner.
The National Weather Service and Lindner expect areas along and NW of US 59 will receive the most sustained rainfall this evening.
Impact of Lake Lowering
Luckily for the Humble Kingwood Area, the City of Houston reduced the level of Lake Houston more than the 18″ they originally projected. As of this afternoon, the Lake was down to 40.5. That should give us some cushion against flooding.
Said City Council Member Dave Martin, “The gates at Lake Houston continue to remain open and will be adjusted as needed to allow for even more water to be released should that be necessary. In response to the lowering of Lake Houston, the West Fork of the San Jacinto River near Highway 59 has also lowered by 2 feet providing additional capacity in the river.
Expected SJRA Release Rates
According to Martin, the SJRA currently estimates that releases from Lake Conroe might peak at 9,000 to 11,000 cfs sometime over the weekend based on current forecasts. These amounts are relatively small in comparison to the rain events that our area saw during July 4, 2018 and Memorial Day 2016.
If you live in a low-lying area, monitor rainfall and water-level trends by visiting these web sites throughout the weekend.
Posted on 12/7/2018 by Bob Rehak based on info from Harris County & COH
465 Days since Hurricane Harvey.
Handy Web Sites to Monitor Flooding
After Harvey, the SJRA, Harris County, National Weather Service and USGS added and upgraded stream gages throughout the region. Think of these gages as a distant early warning system. Looking at upstream conditions tells you what will soon happen in your area.
Here’s a list of handy web sites that display river, bayou and stream levels around Lake Houston and the state. Explore them before an emergency. Bookmark those that offer the best information for your area.
Reference Guide
Texas Water Development Board A one-stop shop for flood preparedness anywhere in Texas. Brings together local information from all over the state. Check everything from stream gages to the status of evacuation routes.
Advanced Hydrologic Prediction for Humble/Kingwood Area NOAA predictions for the West Fork at the 59 bridge. You can also navigate to predictions for the East Fork.
Harris County Flood Warning System. Real-time rainfall, and river-channel monitoring and forecasting. The Warning System also contains near-real-time inundation mapping. For instructions on how to use it and a discussion of its limitations, see this post.
National Weather Service Get current weather info and warnings for our area.
National Weather Service regional rainfall for the last 24 hours. Useful for looking at upstream and downstream rainfall when evaluating potential for flooding.
Water-On-The-Go App USGS stream-gage data surrounding you wherever you go in Texas. Location-aware app with historical information.
Weather.gov. Recommended by professionals.
Coastal Water Authority. For levels of Lake Houston at the dam and approaching weather.
SJRA. See the dashboard on their home page Lake Conroe levels and discharge rates. For other gages, dig further into their website.
If you lose track of this post, you can always find these sites under the LINKS tab of this web site.
Posted by Bob Rehak on 12/7/2018
465 Days since Hurricane Harvey
U.S. Army Liberates River Grove Park
465 Days after Hurricane Harvey, the U.S. Army has finally liberated River Grove Park in Kingwood. They literally took the beach.
Drainage ditch at River Grove is now open to the San Jacinto River.
Actually, they took the giant sand bar that Harvey deposited one night. It had been blocking the drainage ditch that runs through the park and that caused excessive flooding. The two shots immediately below show what that sand bar looked like before dredging.
Sandbar deposited by Hurricane Harvey at River Grove forced water to make a 90 degree turn before it could reach the river. This slowed the velocity of runoff and backed up water into subdivisions, like the Barrington in the background. While the sandbar looks low from the air it was up to 15 feet high directly in front of the drainage ditch (middle left). See below.
The same dune in the previous image photographed from the boat dock.
Dredge Now Moves Downriver
Dredge is now moving downriver.
Work to Date
Dredge #1 is working alongside the West Lake Houston Parkway bridge. It has dredged approximately 135,000 cubic yards of sand and silt to date, according to the Corps’ project manager.
Dredge #2 is working on the upstream end of the project, still near River Grove. It has dredged approximately 226,000 cubic yards to date. After dredging the access channel to River Grove, surveys showed there were some areas that the dredge could not reach. Great Lakes, the contractor will use a barge-mounted excavator to perform final clean-up work. Updated surveys will then confirm achievement of plan goals.
Dredging plans for River Grove indicate a channel width of 50 feet and a depth of 15 feet near the boat ramp.
For all the people who live upstream from the drainage ditch that runs through River Grove, this is an early Christmas present. It will be interesting to see what happens to flood levels in the park now that the bar blocking the ditch has been removed…just in time for a major fall storm that could drop up to 10″ on the US59 corridor. However, we also need to remember that the City is dropping the level of the Lake by at least 18″.
Posted on December 7, 2018 by Bob Rehak
465 Days since Hurricane Harvey