Two Inches of Rain Should Never Have Caused This

Today, we got two inches of rain between 1:30 and 3:20. That’s according to the closest official gage at US59 and the West Fork. See the graph below. Ben’s Branch came out of its banks almost immediately and nearly flooded St. Martha’s Catholic School and Kids in Action again.

Today’s Rainfall in 10-minute Increments

The closest gage at the West Fork and US59 registered a total of 2.08 inches for the event. In ten-minute increments, it looked like this. Source:

The Result

St. Martha’s School after two inches of rain in a two hour period. This is what the parking lot of the school looked like 1.5 hours after the rain ended. The floodwaters came from Ben’s Branch which was at a virtual standstill in this area. Water under the Woodland Hills Bridge just south of Northpark Drive barely moved.

St. Martha’s has not yet finished repairs from Imelda. No floodwater actually got in the school today, but it came dangerously close for a rain that was not unusual for this area. The school is at least two feet above the hundred year flood plain and this was a one-year rain at best (see table below).

Across the creek, Heather Jensen at Kids In Action wrote, “We’re currently rebuilding Kids In Action for the second time since May. Can’t stomach a third.” Many people would agree with that!

Expect a Rainfall This Intense at Least Annually

The latest NOAA Atlas-14 rainfall chart for this area shows that we can expect a two-inch rain in two hours at least once a year. If you measure the 10-minute peak, it also works out to a one-year event. Which we’ve had several of this year.

I have lived in Kingwood for 35 years and used to own commercial property near St. Martha’s for twenty years. I have never seen Ben’s Branch do this on a rain like we had today.

During those 35 years, not much has changed along the creek. With few exceptions, the bridges, homes and businesses along this portion of Ben’s Branch have been there the entire time.

New Upstream Development is Major Change

However, new upstream development could be adding to the peaks. The City of Houston confirmed after Imelda that the western tail of Woodridge Village empties into the City storm drains. See two images below.

Photo taken 9/25/2019, looking east. North is left; south is right. The area labeled Woodridge Village in the middle of the shot drains into Ben’s Branch which is out of frame to the right (south).

The storm drains, which also empty Sherwood, in turn empty into Ben’s Branch. See image below.

Looking north along Woodland Hills Drive toward Kingwood Park High School, Sherwood Trails and Woodridge Village. The City says this drain helps empty Woodridge Village.

The shot above is looking north, parallel to Woodland Hills Drive. Below, you can see the reverse angle, looking south. The shot was taken from the second floor of Kids in Action on the north side of the creek. Notice how water from that drain is shooting across the creek, creating more turbulence than the flood itself.

Photo by Heather Jensen of Kids In Action just north of St. Martha’s.

Below St. Martha’s, A Different World

Compare the width of the Ben’s Branch channel in the photos above to the width in the photos below, where the stream goes through a natural area.

Upstream from St. Martha’s, Ben’s Branch is a wide channel. Downstream, shown here, it turns into a narrow, twisting, turning creek. Photo from 9/25/2019, courtesy of St. Martha’s.
Photo from 9/25/2019. Courtesy of St. Martha’s, showing trees encroaching on Ben’s Branch.
In the foreground, you can clearly see evidence of erosion from Imelda. This shot was taken on 9/25/2019. Note the fallen tree in the background. Such blockages create “beaver dams” during heavy rains when other debris catches on them. Photo courtesy of St. Martha’s.

Such obstructions, turns, tangles and narrow beds slow the velocity of the water, causing it to back up. No doubt, these factors play a role in the repetitive flooding, as does upstream development.

Political and Legal Obstructions Complicate Matters

Maintenance responsibilities for this portion of Ben’s Branch are in flux. That may be the kindest way to say it. Nothing has really changed since Harvey.

The Bear Branch Trail Association owns the property according to this deed and the Harris County Appraisal District.

However, from reading the deed, you can see that Friendswood still exercises deed restrictions on the property, especially those applying to drainage. When it comes to saying yea or nay to major changes that affect the character of the greenbelt on either side of Ben’s Branch, Friendswood appears to be in control to this day.

Major Friendswood deed restrictions include:

  • Friendswood reserves for itself multiple easements for drainage. (sec. 3)
  • BBTA must keep the area “healthful” (sec. 8)
  • BBTA may not remove any trees except those that are dead or dying (sec. 8)
  • BBTA may not transfer the land (with a few exceptions that don’t apply to this discussion) (sec. 9)
  • The deed restrictions do not have an expiration date like those for many HOAs.

What Next for Ben’s Branch

Last year, the City reportedly agreed with Harris County Flood Control to assume responsibility for all underground drainage in the county would assume responsibility for all above ground drainage. Since then, the two have been trying to sort out responsibilities.

Harris County Flood Control has sought an easement at least since January from Friendswood and Bear Branch Trail Association. Reportedly, they want to remove some trees, and widen and straighten the channel. However, according to a frustrated Houston City Council Member Dave Martin, no agreement has been reached.

Meanwhile the school for more than 500 children almost flooded for the third time in six months. It’s hard to imagine Kingwood without its largest parochial school or one of its most popular day care/after school facilities. It’s time for

Harris County Flood Control should be concluding a major study of all Kingwood drainage soon…including Ben’s Branch. Let’s hope that helps wake Friendswood up to some new realities.

Posted by Bob Rehak on 10/29/2019

792 Days since Hurricane Harvey and 40 since Imelda