No Swimming Sign warning customers indicates permanence of water.

“No Swimming” in Dry-Bottom Pond!

The stormwater-detention basin at the Laurel Springs RV Resort is supposed to have, according to the construction permit plans, a dry bottom. However, the basin almost always retains water, despite the fact that it should empty within 48 hours of a 100-year rain. A 100-year rain is 17.3 inches in the Lake Houston Area.

The pond retains so much water for so long – after even minor rains – that the resort has posted “No Swimming” signs.

As a tribute to the presence of water, the pond has even attracted nesting ducks, which can be an aviation hazard so close to Bush Intercontinental Airport.

Reason for Dry-Bottom Requirement

The Resort falls within a defined radius of Houston Bush Intercontinental Airport and the City wants to discourage birds from nesting there, especially large birds that can damage aircraft. Hence the requirement on the permit plans. (See more below.)

A retired airline pilot, who lives nearby and knows the dangers of bird strikes all too well, sent me the two photos below. The first shows seven ducklings in the Resort pond. The next shows a “No Swimming” sign next to the walking trail around the pond.

Seven ducklings enjoying the waters of the Laurel Springs RV Resort. No adults seen at this time.
Sign warning customers not to swim indicates permanence of water.

Construction Permit Plans Note Restriction

Because of this pond’s location near IAH, the FAA and City of Houston stipulate that the stormwater detention basin should have a dry bottom within 48 hours after a “design storm.” The requirement helps discourage birds, especially geese and other large waterfowl, from taking up residence close to the airport. That’s an important consideration, especially during the migration season, which we are in right now. 

screen capture from detention and drainage permit plans
Reference to “design storm” means a 100-year event. In this location, that means 17.3 inches of rain in 24 hours.

Wet-bottom ponds attract ducks and geese that create a hazard for aircraft taking off, landing or circling. This requirement is clearly marked on the Resort’s detention and mitigation plan approved by the City of Houston on 12/2/2020.

A retired airline captain who lives near the RV resort keeps calling this to my attention.

I first posted about this in May of last year and was told that the Resort hadn’t hooked up electricity to its pumps yet. Six months later, the pumps still weren’t working.

Now, a full year later, we have a brood of ducklings in the pond and a no-swimming sign that shouldn’t be necessary if the drainage worked properly.

No Rain in Past 48 Hours, Little Rain in Past Week

It hasn’t rained in the last 48 hours, according to the official gage at US59 gage about a half mile from the basin.

And in the last week, we have received only .72 inches of rain. That occurred in two events more than 24 hours apart.

That’s about one sixth of a 1-year rain according to Atlas-14 standards below. It’s also less than one twenty-fourth of a 100-year rain stipulated by the FAA.

atlas 14 rainfall probabilities
Atlas-14 Rainfall standards used as the basis for designing detention basins.

Here’s what the pond looked like today – five days after after the last rain – which could have been pumped out within hours.

Laurel Springs RV Resort Detention basin should be dry but obviously isn’t.

Two Bird Strikes Force United Flights Down at IAH Last Week

CNN reported last week that two bird strikes within 20 minutes of each other forced United flights to return to Intercontinental. CNN said that this year alone the FAA has already reported about 2,000 bird strikes, and 85% involved commercial airliners. Most bird strikes are waterfowl, although admittedly larger than the ducklings above.

Something to think about next time you fly.

Posted by Bob Rehak on 5/3/2023 based on pictures from a reader

2073 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.