Houston in Bullseye: NWS Predicting Another 4-6 Inches of Rain in Next 5 Days

The National Weather Service released this map around 7 a.m. Houston time this morning. It shows Houston in the bullseye with another 4 to 6 inches of rain predicted in the next five days. Jeff Lindner, Harris County Meteorologist, warns that flash flood watches may be needed by Friday into the weekend.

Houston Area is in the Bullseye and could receive another 4-6 inches of rain in the next five days.

Atmosphere Moisture Levels Support 1-3 Inches Per Hour Later Today

Yesterday’s active weather pushed down toward the coast overnight. The local air mass stabilized by Thursday morning. But afternoon heating and a rapid influx of Gulf moisture favor the development of numerous thunderstorms later today over the region.

Moisture levels in the atmosphere support heavy rainfall with hourly rainfall rates of 1-3 inches per hour possible under the strongest cells. Lindner notes that we saw this yesterday evening throughout the Lake Houston area.

Heaviest Rains Expected Friday

However, the main storm system will begin to move slowly into southwest and west TX on Friday. It will dominate local weather through the weekend, according to Lindner, as several disturbances rotate around around it and feed off the near-continuous stream of rich Gulf moisture over the area.

Expect widespread showers and thunderstorms Friday through the weekend with frequent rounds of heavy rainfall.

Jeff Lindner, Harris County meteorologist

Upper level winds will support cell training over the area this weekend. Flash flooding will be a concern. 

Rainfall Amounts, Impacts

Additional rainfall amounts of 4-6 inches will be possible over the next 5 days. Much of this will fall during periods of heavy rainfall. Isolated totals could be significantly higher under any areas of sustained training. Hourly rainfall rates of 1-3 inches will be possible, which could support rapid street flooding.

Ground Still Saturated

Grounds are still saturated from heavy rainfall in May. And some watersheds are still elevated from the rainfall yesterday evening. Rainfall over the next several days will likely generate run-off into local watersheds resulting in rises. Any areas of sustained heavy rainfall will increase the threat for channel flooding given the delicate groundwater situation currently in the area.

Posted by Bob Rehak on June 3, 2021, based on info from the NWS and HCFCD

1074 Days since Hurricane Harvey

Brays Bayou Received Approximately Half Billion in Flood Mitigation Funding In Last 23 Years

Since 1998, the Brays Bayou watershed has received approximately a half billion dollars in flood-mitigation funding. To compile that estimate, I consulted Harris County Flood Control District’s (HCFCD) 2019 Federal Briefing (see page 45) and HCFCD’s “active construction projects” page for May 2021.

Map of Improvements

From page 57 of HCFCD 2019 Federal Briefing. Note all of the projects recently funded, completed or under construction.

Nature of Improvements

The 2019 Federal Briefing (page 56) separates Brays improvements into two areas:

  • Upstream (west of Sam Houston Tollway)
    • 3 detention basins: 595 surface acres; 9,623 acre-feet of storage – enough to hold a foot of water falling over 15 square miles (13% of entire watershed)
    • 3.7 miles of channel conveyance improvements, including control structures, from Old Westheimer Rd. to SH 6
  • Downstream (east of Sam Houston Tollway)
    • 17.5 miles of channel conveyance improvements from the mouth to Fondren Rd.
    • 1 detention basin: 252 surface acres; 1,865 acre-feet of storage – enough to hold a foot of water falling over 3 square miles
    • 30 bridge replacements/modifications, and/or channel conveyance improvements under bridges (16 due for completion this year)

Harris County Flood Control District (HCFCD) manages, designs, and builds the projects; buys land, easements, rights-of-way; relocates utilities; adjusts bridges (except for railroads); and operates and maintains the channel after construction.

Benefits and Costs

After completion, upstream improvements should give residents a 100-yr. level of flood protection (1% annual chance).

Likewise, downstream improvements should reduce the number of structures:

  • In the 4% or 25-year flood plain from 3,520 to 50.
  • In the 100-year flood plain from 16,800 to 1,800.

Total Cost Estimate: $480M though 2019 (Source: 2019 HCFCD Federal Briefing, Page 45)

Benefit-Cost Ratio: 7.0 (Source: 2019 HCFCD Federal Briefing, Page 56)

The size of the cost in conjunction with the benefit-cost ratio makes these numbers impressive. The primary requirement for the ratio is that it exceeds 1.0, i.e., that the benefits exceed the costs.

Brays’ watershed includes 114 square miles. That makes the cost per square mile a whopping $4.4 million throughout the watershed. However, one must also consider that the population of Brays is the largest of any watershed in Harris County – more than 700,000 of which (57.5%) qualifies as low-to-moderate income.

The map below, taken from a 2020 HCFCD grant application to the US Department of Housing and Urban Development (HUD), shows the distribution of income throughout the watershed. Areas such as West University and the Medical Center in the middle (blue) rank higher in income than areas east and west (tan/red).

LMI quartiles within Brays Bayou Watershed as of 2020. Source: HCFCD HUD grant application.

Possible Reasons for Large Investment

You could justify this extraordinary level of investment any number of ways. By the:

  1. Large population
  2. High population density
  3. High benefit/cost ratio
  4. Protection of critical infrastructure, such as the Texas Medical Center
  5. Number of homes and businesses flooded historically – also the largest in Harris County: 32,194 structures since Allison (Source: 2019 Federal Briefing: Pages 16-21)
  6. Length of time projects have been in the pipeline (most before Harvey and some even before Allison)
  7. Proximity to older, central part of county

Do not underestimate the last two points. Funding for many flood-mitigation projects can take decades.

Disproven Theories

Regardless of the reasons why Brays has received so much investment, one can also look at what this example does not show. It does not support the “equity” narrative propounded by some. That narrative asserts low-to-moderate-income neighborhoods receive less flood-mitigation funding because of lower home values compared to more affluent neighborhoods. Those affluent neighborhoods theoretically get more flood-mitigation funding because they allegedly support higher benefit-cost ratios (BCRs).

Home Value Alone Does Not Determine Benefit/Cost Ratio

The 7.0 BCR in Brays proves that low-to-moderate income neighborhoods are not automatically disadvantaged. Population density can offset lower property values. A whole apartment complex can sit on the same amount of land as one suburban home, yet the apartments would have higher value.

Experts also point out that many other elements affect calculation of BCRs. This study from the William & Mary Law School summarizes the approaches of HUD, FEMA, the Corps and others in determining BCRs. Table I.1 on page 11 shows many of the factors considered:

  • Resiliency benefits
    • Direct Physical Damages to Buildings, Contents and Inventory
    • Essential Facility and Critical Infrastructure Serivce Loss
    • Human Impacts
    • Economic Losses
  • Environmental Benefits
    • Provisioning Services
    • Regulating Services
    • Supporting Services
    • Cultural Services
  • Social Benefits
    • Recreational Benefits
    • Health Benefits
    • Aesthetic Benefits
  • Economic Revitalization
Brays Watershed Investment Not Suffering From Discrimination

The Brays watershed cuts across racial, ethnic and socio-economic boundaries. Flooding has been recognized as a problem here for decades and HCFCD has successfully obtained many grants during that time. HCFCD has also invested more in Brays than any other watershed. Like Halls Bayou and Greens Bayou, the narrative re: Brays is far more complex than some acknowledge.

Photos of Improvements in Bray’s Bayou Watershed

On May 26, I flew from Beltway 8 West to the Ship Canal east of downtown along Brays Bayou. Out of more than 1100 images, here are 16 that represent what you see along the way. Lots of detention ponds, channel improvements, and new bridges. The bridges are higher and often wider, with wider supports to avoid constrictions and blockages. New bridges never have more than two supports in the water flow; some old ones had seven.

Arthur Storey Park at Beltway 8 West and Bellaire Blvd. Looking N toward Westchase District.
Southern part of same park. Looking NE across BW8 West.
Looking NNE at Hilcroft and North Braeswood Blvd.
Looking WSW across same new bridge at Hillcroft. Note wide spans and wings designed to prevent erosion.
Looking north at new bridge over Brays at Chimney Rock
SW Corner of Loop 610 looking toward downtown in upper right.
Same intersection south of Galleria area. Note complexity where seven streams of traffic intersect.
Looking east toward downtown along Brays just inside of Loop 610 at detention pond. Note sewage treatment plant across bayou.
Looking north across new bridge over Brays along Buffalo Speedway toward Greenway Plaza in background.
Looking NE toward downtown in background along Main Street. Medical Center is in middle of frame.
Looking NE toward downtown where Fannin St. crosses Brays at UT Health Science Center.
Looking NE toward Med Center and downtown in background across another new bridge over Brays. Note the electrical infrastructure next to the bayou.
288 and Brays. Bridge construction on Almeda.
New Bridge over Brays at South 75th.
Looking NE across Brays at new railroad bridge near Tipps Street.
Downstream end of Brays near Buffalo Bayou. The ship canal and Port of Houston are in background.

As these pictures show, flood mitigation funding isn’t all about home value. Brays traverses some of Houston’s most critical infrastructure, job centers, rail lines, diverse neighborhoods and employment centers.

HCFCD describes Project Brays as the largest it has ever managed. To learn more more and see before/after pictures of many improvements, visit Project Brays’ own website.

Posted by Bob Rehak on 6/3/2021

1374 Days since Hurricane Harvey

I-45 Feeder Over Cypress Creek Is Cattywumpus

Ever since Harvey, Cypress Creek residents near I-45 have been caterwauling that the southbound feeder road is cattywumpus. For those who may not speak fluent Texan, that first word means “screaming” and the second means “skewed” or “out of alignment.”

So on my latest helicopter flight, I flew over the bridge to see what was up. Or down. Actually, the road bed appears level. And nothing has yet fallen into the creek.

However, aerial photos indicate that the bridge panels are indeed cattywumpus. Note how the side guardrails seem to be out of alignment. Also note uneven gaps in the bridge panels (tight on one side, wide on the other). Finally note the vegetation growing or stuck in the cracks, and the un-level bridge support – at bottom of center oval in row of three.

This image taken on 5/26/2021 and cropped from image below.
I-45 Southbound Feeder Road at Cypress Creek

For now, the bridge seems to be holding. But I’m not sure I would want to be the first one to drive over this after the next big flood.

During Harvey, residents say, this bridge went completely underwater. It appears that the force of the water lifted and twisted the bridge panels as much as 6 to 10 inches. However, TxDoT, the responsible authority in this case, has not yet fixed the issue.

Repairs Delayed

According to resident Frank Adamek, TxDoT originally said it would fix the bridge in 2020. Now, says Adamek, TxDoT says they hope to bid the job by the end of 2021 and start construction in March of 2022.

The bridge has other issues, too. Adamek says, the supports under the main lanes are 110 feet across. That allows trees swept downstream in floodwaters to pass through. However, the supports under the southbound feeder road are only 26 feet apart. Adamek says that they have caught trees and backed water up toward homes in the area.

Extreme events, such as Harvey, tend to reveal problems we didn’t even realize existed. Once you see them, though, they’re hard to forget. I, for one, intend to stay off that feeder road.

Posted by Bob Rehak on 6/2/2021

1373 Days since Hurricane Harvey