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Drought Comparison – 2011 to 2023

By Jeff Lindner, Harris County Flood Control District’s Director Hydrologic Operations Division/Meteorologist, with a few minor edits for a non-technical audience.

There have been many comparisons of this summer to that of 2011 with respect to the heat and drought. Below, see the comparison of drought, water supply storage, and heat between 2011 and 2023.

Rainfall (Jan 1 to Aug 23)

	2023 Rainfall	2023 Departure	2011 Rainfall	2011 Departure
BUSH IAH	29.97	-2.29	10.93	-21.33
Hobby	22.20	-11.83	10.47	-23.56
Conroe	28.41	-3.25	17.54	-14.69
College Station	21.47	-3.79	10.57	-14.12

As the table above shows, the rainfall departures in 2011 were significantly greater at all sites. That indicates a much more significant drought in 2011 than in 2023.

Rainfall departures in 2023 were tempered by a wet April and May over much of the area, while in 2011 drought conditions in the spring were some of the worst ever recorded with many areas recording their driest spring ever. 2011 was also preceded by dryness in late 2010 that helped to worsen the 2011 drought conditions and water supply concerns.

Rainfall at Hobby Airport in 2011 (Feb-May) was only 1.31 inches compared to 2023 of 11.85 inches.

While it is clear that 2011 was worse with respect to lack of rainfall, the abrupt change in rainfall from late spring into the summer of 2023 has “shocked” vegetation across the region.

Additionally, it has been hotter to some degree (especially overnight) in 2023 and the flash drought has been severe with nearly the entire area drought free in early June to all of the area in severe to extreme drought as of August 15^th.

The very warm maximum temperatures and record “high” low temperatures over the region have resulted in rapid degradation of vegetation health. Tree losses were staggering in 2011 and the area is starting to see losses mounting in 2023, but far below what was experienced at this point in 2011.

Comparison of Drought Conditions, Extents

In 2011, exceptional drought covered most of the state.

In 2023, exceptional drought is minuscule by comparison.

Reservoir Storage

2011 also featured significant drawdown on area lakes and water supply reservoirs as the longer duration “hydrological” drought resulted in record or near record low inflows to several lakes.

As of this afternoon, statewide reservoir storage is at 69.8% of capacity compared to 65.4% on this date in 2011. A low of 58.5% was recorded on 11-18-2011.

The table below summarizes storage capacities for the first 2 weeks of August 2023 compared to 2011:

	2023 Capacity	2023 Departure	2011 Capacity	2011 Departure
Conroe	92.5%	-1.60	82.0%	-4.05
Houston	96.4%	-.42	81.0%	-6.50
Livingston	89.0%	-2.38	90.0%	-2.08
Texanna	77.2%	-3.83	52.0%	-9.62
Somerville	79.0%	-2.90	49.0%	-8.06
Travis	39.4%	-47.96	43.0%	-44.50
Buchanan	49.7%	-22.55	51.0%	-23.00

Lake Conroe and Houston are much better off than in 2011 with Lake Livingston being nearly the same and both Somerville and Texanna significantly better off in 2023 versus 2011. This matches well with the rainfall trends experienced in late Spring over the area which for the most part filled Houston, Conroe, Somerville, and Texanna to near capacity, allowing the recent dryness to be well handled.

This was not the case in 2011 when a very dry spring and dryness from late 2010 was already depleting capacities prior to the summer increased demand and evaporation losses.

Central Texas Lake Levels Lower in 2023

However, across central Texas at Travis and Buchanan, conditions are worse at this point than in 2011. Travis is 3.46 ft lower in 2023 than in 2011 and Buchanan is 0.45 ft lower.

Central Texas and the highland lakes chain have been in drought conditions since the summer of 2022 and rainfall this spring was not as significant in this area compared to coastal areas of the state and SE TX, so lake inflows have been very low and evaporation and demand maximized.

Heat Comparison

In addition to the drought conditions, it has been brutally hot. But how does 2023 compare to 2011 with respect to 100 degree or hotter afternoons? This is only part of the story of the heat of 2023, as overnight low temperatures have also been warm.

College Station has recorded 42 days with a morning low at or above 80 degrees, BUSH IAH 41, and Hobby 44. However, Galveston has recorded 64 days this summer at or above 80 degrees for a morning low.

The above average Gulf of Mexico waters are resulting in exceptional overnight heat along the coast.
Jeff Lindner, Harris County Meteorologist

	Days At or Above 100		Days At or Above 105
	2023	2011	2023	2011
BUSH IAH	33	34	3	2
Hobby	28	14	1	0
Conroe	38	38	5	0
College Station	52	51	22	9

With the exception of Hobby Airport, 2011 and 2023 are nearly tied for the number of 100 degrees days up to 8-23. Hobby Airport has surpassed 2011 by 14 days.

More significant is the number of days at or above 105 with College Station crushing 2011 by 13 days. All sites have recorded more 105+ degree days in 2023 compared to 2011. The afternoon high temperatures have been higher in 2023 than in 2011 especially at Conroe and College Station.

Most of this has occurred in the last 3-4 weeks as the ground has dried and the influence of high dewpoints from the Gulf has become less. That has let afternoon temperatures spike higher compared to June and July.

By Jeff Lindner, Director Hydrologic Operations Division/Meteorologist, Harris County Flood Control District, on 8/23/2023

2185 Days since Hurricane Harvey

Northeast Water Purification Plant Expansion Now in Last Phase

The massive $1.77 billion expansion of the 120-acre Northeast Water Purification Plant near Summerwood is now well into its last phase. The last update to the expansion website is dated May 23, 2023 and estimates completion in 2025. Contractors have made considerable progress since May. This satellite image is dated 6/14/23. Note the area on the far right at the eastern side of the plant. That area contains most of the new construction activity.

*Landsat Photo in Google Earth from June 2023*

Aerial Photos Taken 8/12/23

Compare the photos below of the Northeast Water Purification Plant taken just two months later. They were all taken on 8/12/23.

*Wider shot looking N from SE corner of plant*. *White circle will contain a giant water storage tank.*

*Looking W at entire plant. Note NE corner of Beltway 8 beyond plant and Atasocita Landfill in upper right.*

5X Capacity Increase Will Help Reduce Subsidence

The Northeast Water Purification Plant is designed to help ensure Houston’s water supply while reducing groundwater usage. Pumping groundwater at a rate greater than nature replaces it can cause irreversible subsidence. Subsidence has been linked to increased risk of flooding and structural damage.

The physical site above contains three major sections.

The original plant which can treat 80 million gallons per day (foreground)
First expansion phase (middle)
Second expansion phase (far end).

In May, Phase One was nearing completion and expected to be ready soon. Phase Two is the major focus of efforts now.

Together the first and second expansions will produce 320 million gallons per day, bringing the total treatment capacity to 400 million gallons.

Plant Will Handle Wide Range of Turbidity

Because Lake Houston is so shallow, turbidity increases rapidly during rainfall events. Accordingly, the partners have incorporated both wet- and dry-weather technologies into the treatment plant, so operators can switch nimbly as needed.

Innovative treatment strategies like chlorine dioxide, ozonation and biological filtration have been proven at other Texas facilities using similar source waters. Given the broad range of raw water qualities, they will help the City preserve high-quality finished water and deliver more of it.

Majority of Water Used by Industry

Houston Public Works Drinking Water Operations (DWO) currently serves about 2.2 million people. And Harris County’s population alone is projected to expand to 5.5 million people by 2050. But serving all those extra people is only half the battle.

Industrial and manufacturing operations use a MAJORITY of the City’s water.
Venus Price, P.E., Interim Senior Assistant Director, DWO

Many Sources Help Meet Demand, Protect from Drought

To meet demand DWO has three water treatment plants and 49 groundwater production facilities. They span four counties and 600 square miles, making Houston’s system one of the most complex in the nation.

And to feed those plants, the City of Houston owns a 70% share of Lake Livingston, a 70% share of Lake Conroe, 100% of Lake Houston and a 70% share of the future Allen’s Creek Reservoir on the Brazos River.

Lake Livingston supplies water to Lake Houston and the Northeast Water Purification Plant through the Luce Bayou Inter-Basin Transfer Project.

The variety of sources help sustain a growing population through droughts, such as the one we are in now. Corporations evaluate such factors when choosing where to expand. For more information about Houston’s water supply, check this informative history, written by Susan Smyer in 2008.

Posted by Bob Rehak on 8/22/2023

2184 Days since Hurricane Harvey

Three Named Storms in Atlantic in Two Days, Could Get Fourth

8/21/23 (9 AM CDT) – Three named storms have formed in the Atlantic in two days and we will likely get fourth (in the Gulf of Mexico) today or tomorrow.

Tropical storms Emily and Gert formed in the Atlantic yesterday (8/20/23). Gert formed overnight. And a fourth disturbance barreling across the Gulf of Mexico toward the lower Texas Coast could reach tropical storm intensity today or tomorrow, according to the National Hurricane Center (NHC).

2023 Summary Compared to 30-Year Average

So far this year, the Atlantic Basin has had:

An unnamed sub-tropical storm in January, that was later determined to have 70 mph max winds
Tropical Storms Arlene, Bret and Cindy in June
Hurricane Don in July
Emily, Franklin and Gert in August

If the disturbance currently in the Gulf turns into a named storm, it will become Harold – the ninth storm of the year to reach tropical storm intensity.

Normally, by this week in the hurricane season, the Atlantic Basin has five named storms. See the table below from the NHC’s Climatology page.

Progress of the average Atlantic season (1991-2020). Date upon which the following number of events would normally have occurred.
Number	Named systems	Hurricanes	Major Hurricanes
1	Jun 20	Aug 11	Sep 1
2	Jul 17	Aug 26	Sep 19
3	Aug 3	Sep 7	Oct 28
4	Aug 15	Sep 16	–
5	Aug 22	Sep 28	–
6	Aug 29	Oct 15	–
7	Sep 3	Nov 15	–
8	Sep 9	–	–
9	Sep 16	–	–
10	Sep 22	–	–
11	Oct 2	–	–
12	Oct 11	–	–
13	Oct 25	–	–
14	Nov 19	–	–

Greatest Threat to Houston is Fire

None of the current disturbances in the Gulf, Caribbean or Atlantic represent a threat to Houston.

The closest storm to Houston is south of Mississippi as of 9AM Tuesday morning. It will miss the upper Texas Coast and likely come ashore between Corpus Christi and Brownsville tomorrow.

NHC says that showers and thunderstorms are showing signs of organization and banding. Environmental conditions appear conducive for development. And a tropical depression or tropical storm is likely to form before it reaches the coastline on Tuesday. Formation chance is high…80 percent.

The greatest threat to the Houston area is not rain or flooding; north of I-10, we should see only about a tenth of an inch from the storm. But hot, dry conditions combined with a long-term drought have created critical fire weather conditions. A burn ban is in effect. High winds associated with the storm could spread fire quickly. So be careful. Several fires are already burning in other parts of East Texas.

Discussion of Other Disturbances

Unnamed Storm off African Coast

NHC gives the other unnamed storm off the coast of Africa a formation chance of 70% in the next 7 days.

Emily

Emily will also turn north. Its intensity will lessen into a tropical depression by Tuesday morning.

Franklin

NHC predicts Franklin will turn north and cross Puerto Rico, the Dominican Republic and Haiti through the middle of the week. It could produce heavy rainfall; life-threatening flash and urban flooding; and mudslides through Wednesday.

Gert

Gert is quickly unraveling. NHC expects to downgrade it into a tropical depression by Monday at 2PM.

A Record?

Is three or four named storms in two or three days a record? According to Harris County Meteorologist Jeff Lindner, it’s not. The record is closer to five or six at one time, he says. Regardless, tropical activity is heating up. The peak of hurricane season is still three weeks away – September 10th. It looks like earlier predictions of an above-average season were accurate.

In the meantime, watch out for that heat! Here’s a summary put together by Lindner of record highs on 8/20/23.

College Station: 112 (tied all time record high from 9-4-2000, broke the all-time August record high of 110 from 8-17-1903, and shattered the daily record high of 107)

BUSH IAH: 108 (broke the daily record high of 107 from 1909). This is only the 5^th time since the 1880’s that Houston has reached 108. 1 degree shy of the all-time record high of 109.
Hobby: 107 (broke the daily record high of 101 in 1999).
Galveston: 97 (tied record high from 1995)
Huntsville: 112 (shattered the daily record high of 106 from 1909)
Madisonville: 108 (broke daily record high of 105 from 1948)
Sugar Land: 107 (broke daily record of 101 from 2018)
Conroe: 109 (tied all time record high from 2000 and 1925)
Tomball: 110 (shattered daily record of 101 from 1999) All time record high surpassing 108 in 2000
Wharton: 106 (broke daily record of 100 from 1911)
Brenham: 108 (broke daily record of 105 from 1948)

Posted by Bob Rehak on 8/21/23

2183 Days since Hurricane Harvey

Gulf Disturbance Could Increase Fire Danger

(11AM 8/20/23 and updated at 7PM) Here’s something you don’t often see – a tropical disturbance that could increase fire danger more than flood risk.

The 8am 7-day tropical outlook from the National Hurricane Center shows that Tropical Storm Emily has formed in the Atlantic. Separately, a disturbance lingering over the Bahamas has finally crossed over Florida and moved into the Gulf. However, the latter storm will likely miss Houston as it veers south into the lower Texas Coast and northern Mexico. That means…

Twelve hours later, another tropical storm formed in the Atlantic – Franklin. And NHC increased the chances for formation for the two orange disturbances to 70%.

High winds from the storm combined with the lack of rain and dry vegetation could actually increase fire danger north of I-10.
Jeff Lindner, Harris County Meteorologist

Rainfall Chances for North Houston Area Slight

Unfortunately, the still unnamed Gulf disturbance will likely bring little rain to the Houston area. The 72-hour cumulative prediction from the National Weather Service shows about a quarter inch of rain south of I-10 and a tenth of an inch north of it.

As of Sunday morning, the disturbance is centered south of the Florida panhandle.

That big clear area over the southern plains and Texas is the high pressure system that has dominated our weather for the last month. It forms a barrier that will likely block the lower pressure system in the Gulf from moving north toward Houston.

High Winds, but Little Chance of Flooding

Jeff Lindner, Harris County meteorologist predicts that tropical moisture will begin to arrive along the Texas coast on Monday with offshore scattered activity increasing through the day.”

Lindner believes that I-10 will be a good dividing line between higher coastal rain chances and lower inland chances late Monday into Tuesday.

Said Lindner, “There will likely be a strong south to north rainfall gradient over the region … with rain chances in the 50-60% range near the coast, 30-40% along I-10, and generally less than 30% north of I-10.

Lindner expects wind gusts up to 30 knots on Monday and Tuesday as the storm passes. He also predicts that seas will build 5-9 feet for most offshore waters. He also predicts that tides will be elevated late Monday into Tuesday, but he doesn’t expect them to reach critical thresholds or cause any issues along the coast or in the inland bays.

Inland winds will increase Monday into the 15-20 mph range with higher gusts. Ironically, the biggest threat from this storm may be fire.

Lindner predicts that the high winds inland along with low humidity and critically dry vegetation will support an enhanced fire danger for those areas along and north of I-10. “Fires could quickly spread in these conditions,” warns Lindner.

Red Flag Warnings

At 2:39 PM, Lindner announced that red flag warnings had been issued for most counties in SE Texas including Harris, Montgomery and Liberty.

Potentially dangerous fire weather conditions will exist on Monday as the tropical system approaches. It will increase the pressure gradient across much of SE TX. Humidity values will decrease through Monday and reach below 30% during the afternoon and early evening hours.

Fuels loads are critically dry over the region, said Lindner. “Small fire will grow rapidly. Fires continue to exhibit aggressive behavior in pine areas and winds on Monday.Ccanopy crown runs will make containment lines challenging.

Fire conditions have deteriorated to those similar to August and September 2011 when several large devastating fires occurred over portions of SE and central Texas.

Extreme Drought Conditions Persist

In fact, the U.S. Drought Monitor shows that the Lake Houston Area is in Extreme Drought.

What have temperatures and rainfall been compared to the 30-year average?

Temperatures so far this year have been consistently above the average for the last thirty years (green line compared to yellow line). Rainfall (blue and red bars) has been both above and below average. April and May were both above average. But June, July and August have been far below.

According to the Harris County Flood Warning System, the West Fork San Jacinto gage at US59 last received rain on July 23rd – four one-hundredths of an inch!

Obviously, this is not the time for outdoor burning! In fact, the Texas A&M Forest Service shows that most Texas counties currently have burn bans.

Posted by Bob Rehak on 8/20/2023

2182 Days since Hurricane Harvey

Tropics Show More Activity, Higher Probabilities since Yesterday

What a difference a day makes! Yesterday, the Atlantic Basin had four areas of concern. Today, it has five. And, according to the National Hurricane Center (NHC), the chances of tropical development have increased for all of them since yesterday. See the seven-day outlook for the Atlantic Basin below and note the time: Saturday, August 19, 2023 at 3:35 Eastern time.

The NHC diagram below shows a veritable parade of potential storms marching from Africa toward the Americas.

Lowdown on the Lows

Starting with the yellow area moving off the coast of Western Africa:

Yellow Area on Right

A tropical wave located near the western coast of Africa is producing a large area of disorganized showers and thunderstorms. Some slow development is possible while it moves generally west-northwestward across the tropical eastern Atlantic during the next several days. Formation chance through 7 days…still low…20 percent.

Red Area with X

The red cross-hatched area to the left of the yellow is a broad area of low pressure located several hundred miles west of the Cabo Verde Islands. Shower and thunderstorm activity continues. Environmental conditions appear generally favorable for further development. A short-lived tropical depression will likely form this weekend and move west-northwestward at about 10 mph across the eastern tropical Atlantic. By early next week, upper-level winds over the system are forecast to increase, and further development is not expected. Formation chance through 7 days…high…70 percent.

TD #6

Tropical Depression #6 formed in the central, tropical Atlantic this afternoon. The system will move west-northwestward at 10 to 15 mph. However, upper-level winds will become increasingly unfavorable by late this weekend, so NHC does not anticipate any further development.

Orange Area Entering Caribbean

A broad area of low pressure has formed near the Windward Islands. Shower and thunderstorm activity has become better organized since yesterday. Some additional development of this system is likely and a tropical depression could form by early next week when the system moves into the eastern and central Caribbean Sea. Formation chance through 7 days…medium…60 percent.

Orange Area Entering Gulf

An area of disturbed weather located near the Bahamas will move into the Gulf of Mexico by early next week where a broad area of low pressure will form. Some slow development is possible thereafter. A tropical depression could form as it moves westward and approaches the western Gulf of Mexico coastline by the middle of next week. The storm will likely make landfall in South Texas and bring little rainfall to the Houston area north of I-10. Formation chance through 7 days…medium…50 percent.

Satellite Image Shows Current Conditions in Gulf and Eastern Pacific

The last area represents the most imminent threat to Texas. Here’s what it looks like in a satellite image. Not very impressive at the moment, especially compared to Hurricane Hilary in the Pacific (on the left).

Conditions can change rapidly so prepare and stay aware.

Posted by Bob Rehak on 8/19/23 based on information from the NHC

2181 Days since Hurricane Harvey

Pack Your Patience: Accident Closes Northpark in Both Directions

Update as of 6:30 PM: Outbound lanes have opened. One inbound lane open. Utility crews onsite.

Northpark Drive is closed in the worst possible place at the worst possible time – Friday night during rush hour in a construction zone. However, the accident that caused the closure is not related to construction.

A little before 3 PM, I got a tip about an accident at Russell-Palmer Road from Ralph De Leon, the project manager for the Lake Houston Redevelopment Authority’s Northpark Drive expansion project. He said that a truck had clipped a power pole and wires were down.

By the time I got there with my drone, police and fire trucks had Northpark closed off in both directions between Woodridge Drive and Russell-Palmer. However, I got my drone up from the parking lot of St. Martha’s Catholic Church to get the shots below. That was the easy part.

Getting home (about 2 miles away) took almost 45 minutes.
Bob Rehak

If you have a family member coming into Kingwood during the Friday evening rush hour, warn them to pack their patience. Utility lines are down across the road in BOTH directions.

According to De Leon, Northpark will be closed until the utility company can assess and repair the problem. That could take hours. It will be difficult just to get to the area. Avoid it at all costs.

Photos Taken at 3PM

*Looking east along Northpark over Russell-Palmer.* *Note emergency vehicles blocking inbound traffic.*

*One utility pole has snapped and another one across Northpark appears to be leaning. However, that could be a shadow.*

It’s not clear whether the utility lines carry communications or electricity. The downed line in the photo below is next to a power pole; you can tell by the transformer. So it may be a communications line.

*The utility line appears to be caught on an eighteen wheeler blocking the inbound lanes.*

*The downed lines stretch from the truck to a snapped pole, across the ditch and then across the outbound lanes.*

The inbound traffic was being funneled south on Russell-Palmer toward Kingwood Drive. See below.

*Here you can see the lines tangled on the truck.* *It’s unclear whether the truck struck the pole.*

*West of Russell-Palmer Traffic is backed up to 59 and maybe beyond.*

People trying to enter Kingwood through back streets will find the slogging tough. Everyone who normally uses Northpark is trying to squeeze through stop signs not designed to handle this volume of traffic.

Stay away. If you simply can’t, pack your patience.

Posted by Bob Rehak on 4:30pm on 8/18/23

2180 Days after Hurricane Harvey

Tropical Forecast Suddenly More Active

Still three weeks from the peak of hurricane season (September 10), the tropical forecast has suddenly become more active. The latest seven-day outlook from the National Hurricane Center (NHC) shows four areas of concern. Two will not affect the Texas Gulf Coast. Eventually, the other two could get close.

Chances of Tropical Formation

According to the NHC 8 a.m. update:

The red area at the right currently has a 70% chance of tropical formation in the next seven days.
The orange area has a 40% chance. Environmental conditions are only marginally conducive for further development of this system, but a tropical depression could still form during the next couple of days while it moves west-northwestward at 10 to 15 mph across the central tropical Atlantic.
Neither of those systems poses a threat to Texas.
The yellow area in the middle approaching the Lesser Antilles has a 30% chance of formation.
The yellow area on the left will move toward the Gulf of Mexico by early next week. It also has a 30% chance of tropical formation.

The NHC updates its website several times a day during hurricane season. So bookmark it and check back often for the latest forecasts.

Local Impact Felt by Next Tuesday

Jeff Lindner, Harris County’s meteorologist, has been sending out updates all week long on the last system. Here’s what he had to say on Friday morning, 8/18/23. “A low chance of tropical cyclone formation remains possible over the western Gulf early to mid next week.”

“A tropical wave will reach the eastern Gulf of Mexico late this weekend. As high pressure over Texas lifts northward and centers over the Midwest early next week, this wave will continue westward and approach the Texas coast by Tuesday or Wednesday,” said Lindner.

Possibilities include a tropical wave, tropical depression, or weak tropical storm moving inland along the lower or middle Texas coast. Conditions appear to be generally favorable for some slow development, but dry air is lurking along the U.S. Gulf coast that could wrap into any developing system. Also any developing system could encounter wind shear over the western Gulf from the outflow of powerful Hurricane Hilary in the eastern Pacific Ocean.

Any Development Most Likely Near Coast

“With that said, the system will be moving over warm sea surface temperatures and systems, especially in the NW Gulf under the right conditions can tighten up just prior to landfall. This may be a situation where whatever is going to happen with any development occurs very near the coast,” said Lindner.

Most Moisture Near Coast and West of Houston

Lindner concludes, “Regardless of development, tropical moisture will surge into the Texas coast as early as late Monday, but more likely Tuesday or Wednesday. For now, the greatest moisture looks to remain along and south of the I-10 corridor with areas north of I-10 still under the influence of the high pressure ridge over the Midwest. There will likely be a strong gradient in rain chances from south to north over the area next week with the potential for some desperately needed rainfall across the coastal locations.”

Subsiding air from the high to the north will determine how far inland the moisture and rain/bands reach. This map from the National Weather Service (NWS) helps visualize what the situation will look like by Monday, August 21.

Flood Risk Less than 5%

The risk of excessive rainfall that could cause flash flooding is less than 5% according to the NWS.

It’s pretty sad when you start wishing for a tropical storm. But we sure could use something to break the drought and cool us off. Yesterday’s high of 105 was the highest temp recorded in Houston since 1909, according to ABC13. And it could get close to that again today.

Posted by Bob Rehak on 8/18/23

2180 Days since Hurricane Harvey

More Drainage for Northpark Drive Expansion Project

The drainage project currently underway down the median of Northpark Drive represents only part of the drainage improvements for the expansion project. Another parallel drainage system about 250 yards north of Northpark will carry additional stormwater all the way from U.S. 59 to the Kingwood Diversion Ditch and Bens Branch. Project engineers call it “Ditch One.”

Additional Parallel Drainage Route North of Northpark

In the satellite image below, the two triangles at 59 surround the wooded areas at the Northpark entrance to Kingwood. Detention ponds similar to those at the Kingwood Drive entry will replace those wooded areas.

*Northpark Drive cuts left to right through the frame just above the center. Red line shows route for supplementary drainage* *and where flow splits in two* *at Diversion Ditch.*

The water surface elevation of the Northpark ponds will be several feet below grade, as you can see in this video.

The difference between the surface of the ponds and ground level will provide storage capacity to offset the increase in impervious cover created by the expansion of the roadway.

When the south pond fills up, it will overflow to the north pond. And when the north pond fills up, it will drain to the east via an eight-foot culvert. The eight-foot culvert by itself provides additional underground water storage before it reaches the eastbound ditch.

That culvert will go under Loop 494 and the UnionPacific railroad tracks, then turn left (north) until it gets past the businesses on the north side of Northpark. From there, it will empty into a ditch that heads back east again. See below.

*Looking East from over 494 toward St. Martha Catholic Church. Arrows in distance show where Diversion Ditch splits off from Bens Branch.* *Note part of Northpark Drive in upper right.*

Ditch One is barely visible in the photo above for two reasons.

The tree canopy is dense this time of year.
Due to lack of maintenance over the years, trees have grown up in the ditch. Contractors will have to clear them out to restore conveyance before completion of the project.

The Big Split

Once water in the ditch reaches the detention basins south of St. Martha Catholic Church, part of the water will enter the Kingwood Diversion Ditch and head south along the western edge of Woodland Hills. The rest will continue east and go down Bens Branch which angles diagonally toward Town Center and eventually empties into Lake Houston near Kings Harbor.

*Looking N toward St. Martha in upper left at where flow in Ditch One splits into Diversion Ditch (foreground) and Bens Branch (right)*

Why Diversion Ditch is Called Diversion Ditch

The split you see in the red line below is why the Diversion Ditch is called the Diversion Ditch. It is a man-made channel designed to take stormwater out of the natural channel (Bens Branch) to reduce flood risk for homes in the center of Kingwood.

*Reverse angle looking S* *toward Diversion Ditch.*

In the photo above, Bens Branch flows R to L. The Diversion Ditch flows south toward Kingwood Drive and Lake Houston. The blue water towers in background are near the firehouse on Kingwood Drive and Deer Ridge Park.

The City just finished cleaning out under the Northpark bridges at the Diversion Ditch. See results below.

*Looking north at recent CoH excavation under North Park at Diversion Ditch.*

Eventually, the Diversion Ditch itself will expand to match the increased conveyance you see under the bridges. Some engineers feel that constrictions like you see above contributed more to flooding than lack of capacity in the ditch itself.

Kingwood Drainage Priorities

Regardless, expansion of the Diversion Ditch was one of the top two priorities of the Kingwood Area Drainage Analysis. That project has not yet started.

Bens Branch has already gone through four phases of de-silting and de-snagging to help restore its conveyance. That was part of a major maintenance program by HCFCD after Harvey.

The route that Bens Branch will take to get under Northpark Drive east of the diversion ditch has yet to be determined. However, that phase of the project is still at least three years away. TxDoT is currently evaluating multiple alternatives suggested by engineers for the Lake Houston Redevelopment Authority. For more videos of the project, drainage studies and construction plans, see the LHRA website.

To see how ALL the ditches and streams in Kingwood connect, visit the Harris County Flood Education Mapping Tool. If you see a blockage in a Harris County Ditch, you can request service at HCFCD.

Posted by Bob Rehak on 8/17/2023

2189 Days since Hurricane Harvey

Colony Ridge Stormwater Detention Basins, Ditches Fail to Meet Liberty County Standards

Colony Ridge, the world’s largest trailer park, fails to meet Liberty County regulations for the construction of stormwater detention basins and ditches. The development’s basins and ditches routinely lack erosion controls such as grass and backslope interceptor swales. The resulting erosion can reduce the conveyance of streams, increase flood risk and threaten property both inside the development and downstream. The failure to follow those regulations imposes a hidden tax on residents of Liberty and surrounding counties.

No Bare, Earthen Slopes Allowed

Page 100 of the Liberty County Subdivision and Development Regulations updated in 2019 states that, “All drainage facilities must be designed and maintained in a manner which minimizes the potential for damage due to erosion. No bare earthen slopes will be allowed.“

Backslope Drain Systems Required

Pages 152 and 153 of the regulations also require backslope drain systems to “intercept sheet flow which otherwise would flow over the banks of drainage channels leading to erosion of the side slopes.” Swales behind the edges of basins and channels trap stormwater. Pipes then carry it to the bottom of the ditch or basin so that it won’t erode side slopes.

What Ditches/Detention Basins Should Look Like

The photo below shows a Harris County ditch with grass on the side slopes and pipes that lead from backslope swales to the bottom of the channel. Note how they reduce erosion and sedimentation.

*Harris County ditch which follows regulations similar to Liberty County’s. Compare the Colony Ridge ditches below.*

Compare Requirements to Photos

I took the pictures below on 8/12/23 from a helicopter while flying over Colony Ridge in Liberty County. Note the lack of grass and interceptor inlets/outlets. Also note the severe erosion that results.

*Note severe erosion on banks of pond. Also note lack of backslope swales, inlets*, *and outlets in base of pond.*

*No backslope interceptor system. No grass.*

*No backslope interceptor system. No grass* *on sides of ditch.*

In some cases, the ditches and detention basins don’t even have perimeter maintenance roads and the erosion is cutting into people’s back yards.

Colony Ridge Household slipping into drainage ditch — *Colony Ridge resident losing back of property due to ditch erosion.*

The Largest Development Few Know About

Colony Ridge is large and growing rapidly. The satellite image below shows how it has virtually doubled in size within the last two years as it has grown from left to right and bottom to top. The large area in the lower left began developing around 2011. Those lines that look like hashmarks are thousands of mobile homes.

Colony Ridge Expansion — *This satellite image taken in July 2023 does not even show the development’s current extent. Much of the area in the upper right below the clouds was cleared since then.* *See below.*

*Portion of Colony Ridge in upper right of satellite photo has now been cleared.*

Colony Ridge already comprises more than 30 square miles. That makes it approximately one third the size of the area inside Houston’s 610 loop.

*Mostly mobile homes and rivers of mud as far as the eye can see.*

Erosion a Major Issue

Colony Ridge drains into three watersheds: the East Fork San Jacinto, Luce Bayou and Tarkington Bayou. And all of them drain into Lake Houston. That will make erosion from Colony Ridge Harris and Liberty County’s problem forever.

During floods, erosion will reduce the conveyance of downstream channels and rivers. Page 148 of the Liberty County Subdivision and Development Regulations has this to say about the effects of erosion and sedimentation.

“Erosion and sedimentation can have very serious effects on storm water drainage.”
“Erosion can cause slope failures, increase roughness coefficients, and generally reduce the efficiency of drainage channels. However, sediment deposition can clog drainage culverts and reduce the available conveyance in open channels.”
“Erosion can significantly reduce the maintainability of drainage facilities and increase the cost of maintenance by increasing the frequency with which repairs are required.”

LJA engineering wrote a letter to the Liberty County Engineer that underscores the need to plan ahead as the county transitions from rural to urban. “While limited regulation of development in a rural area may not significantly impact drainage issues, Liberty County is now challenged with explosive population growth and a particularly high percentage of socially vulnerable residents…” said the letter.

Hidden Cost to Downstream Residents

Most people in Harris County don’t even know that Colony Ridge exists. Yet the drainage practices there affect dredging costs downstream. The City of Houston, Harris County and Army Corps spent almost a quarter billion dollars dredging the headwaters of Lake Houston between Harvey and mid-2021.

Clearly, not all of that sediment came from Colony Ridge. However, the development practices in Colony Ridge and other developments like it will set the pattern for the future.

Developments are virtually impossible to change after people start building next to undersized basins and ditches that erode more with every substantial rain.

What You See Makes You Question What You Don’t See

Substandard construction practices make you wonder about engineering practices. Did Colony Ridge engineers produce reliable, accurate estimates of drainage needs? Are those ditches and detention basins sized properly? Will they hold enough runoff to protect residents?

Probably not. Even assuming engineers and contractors did their jobs properly (a big assumption), Liberty County still defines a 100 year/24 hour rainfall as 13.5 inches (see page 108), a rate associated with pre-Atlas 14 days.

Atlas 14 catalogs the current national precipitation frequency standards for every community in the U.S.

However, the phrase “Atlas 14” appears nowhere in the 2019 Liberty County Subdivision and Development Regulations.

But NOAA now defines a 100 year/24 hour rainfall for nearby Cleveland, TX, as 17.1 inches – a 27% increase above the current Liberty County standard. So in a hundred-year rainfall, everything you see in Colony Ridge will be 27% short of capacity. Few people likely understand this.

Consider also that NOAA is already working on replacing Atlas 14 with Atlas 15!

Posted by Bob Rehak on 8/16/23

2178 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.

HCFCD Spending Shows Slight Rebound

After a sharp decline in the first quarter of 2023, Harris County Flood Control District (HCFCD) spending rebounded slightly in the second quarter. Second quarter spending did not recover to recent peaks, but at least exceeded pre-2018 Flood Bond levels.

*Data obtained via FOIA Request from HCFCD on 8/14/23*

One Third of Bond Money Spent in Half the Projected Time

However, HCFCD is still behind schedule with mitigation related to the 2018 flood bond. HCFCD has not issued a flood-bond update since last December. But you can calculate progress yourself by looking at the charts in this post.

Six years after Harvey and five years after the flood bond, HCFCD and its partners have spent approximately $1.6 billion to improve Harris County drainage.

Taxpayers approved $2.5 billion in the 2018 flood bond. Approximately a third of that was designated for matching funds to attract another $2.5 billion from Federal, State and local sources.

That means five years after the bond (and six years after Harvey) we are are roughly one third of the way through the bond, which was intended to be a ten-year program. And that one third is likely overstated due to inflation.

Spending Inequities

The County has not spent the money to benefit all people equally, thanks to the so-called Equity Plan approved by Commissioners Ellis, Garcia, and Judge Hidalgo. They argue that people with low incomes should enjoy a higher level of flood protection because they are less able to fix their homes after disasters.

Harris County tracks spending by watershed. Eight watersheds have a populations where Low-to-Moderate Income (LMI) residents comprise a majority of the population. Those same watersheds also tend to have high social vulnerability indexes based on the CDC’s ranking criteria.

The eight LMI watersheds include:

Halls (72.5% LMI)
Hunting (67.8%)
Vince (64.9%)
Sims (60.8%)
Greens (59.8%)
Goose Creek (56.9%)
White Oak (51.9%)
Brays (51%).

HCFCD updated those LMI percentages at the end of 2022 to reflect the latest census data.

Actual Flood Damage No Longer Considered

Harris County no longer weighs damage in ranking flood-mitigation priorities.

Here’s how LMI-majority watersheds line up versus the county’s 15 other watersheds in terms of the money received since Hurricane Harvey.

Here’s how all watersheds ranked last quarter.

The San Jacinto declined a place in spending among the watersheds last quarter compared to “Since Harvey” (14th vs 13th). For the exact amounts each watershed received last quarter, see the table below.

Some readers might notice slight changes in the totals from past time periods. That has to do with ongoing transition of project and invoice coding in the county’s accounting systems. But they affect only about $2 million out of $1.6 billion. And most of those have to do with first quarter invoices received after my first quarter FOIA Request.

For those unfamiliar with the locations of various watersheds, see the map below.

watershed map of Harris County — *From HCFCD 2019 Federal Briefing*

Now compare spending to the actual flood damage during the last 44 years.

*This map from MAAPnext, totals damage since 1979. Dark areas represent more damage. Compare the spending priorities above with actual damage in your watershed.*

Flood control money used to flow to damage. But that’s no longer always the case.

Come back soon for more analysis of the latest data.

Posted by Bob Rehak on 8/15/23

2177 Days since Hurricane Harvey