Tag Archive for: Descartes Labs

Growth of Impervious Cover Across Political Boundaries, Watersheds Complicates Flooding

In December, the New York Times published a story about a company called Descartes Labs, which had trained computers to scan satellite images to detect changes in impervious cover. Descartes found that Texas had 9 of the top 20 counties in the US when ranked by the growth of impervious cover. So I contacted them to learn more.

A Better Understanding of the Planet

Descartes positions itself as a data refinery for satellite imagery. They process images from the major NASA and ESA satellite constellations at scale, creating a digital data twin of the entire planet that monitors the whole earth, in near real-time. Their mission: to better understand the planet.

The red dots in the map below show land that is newly covered in concrete or rooftops. It is a form of “heat map” that shows the hottest areas for growth. Studying this map, we can learn several things:

  • Stories about the demise of suburbs and exurbs after the real estate crash in 2008 proved short-lived. From the numerous rings around major metropolitan centers, you can see that growth outside of major metropolitan areas continues.
  • Texas appears to have the greatest increase in density of any state.
  • Far more growth happened in the East than the West.
Growth of impervious cover in continental US from 2008 to 2018. Copyright ©2020 Descartes Labs. Used with permission.

A Closer Look at Texas

This next map, also courtesy of Descartes, zooms in on Texas and surrounding states. The yellow dots simply correspond to the names of metropolitan centers.

Growth around Houston seems fairly uniform, though my eye does detect slightly more weight to the north, west and south than the east. This will likely change in the next decade with the extension of the Grand Parkway toward the east.

Growth of impervious cover in Texas and surrounding states from 2008 to 2018. ©2020 Descartes Labs. Used with permission.

Factors Contributing to Flooding

Several factors contribute to Houston’s reputation for flooding:

  • Rapid population growth and corresponding growth of impervious cover, as Descarte showed. The impervious cover causes floodwaters to concentrate/accumulate faster.
  • Loss of wetlands And flood plain storage
  • Flat, poorly drained landscape
  • Gulf moisture that regularly brings hurricanes, tropical storms and torrential rains
  • Fierce dedication to individual freedom, property rights, and local authority (Hey, this IS TEXAS after all.)
  • Political fragmentation
  • Widely varying flood control regulations
  • Upstream development that overwhelms the capacity of downstream drainage channels

In the last century, Houston has exploded from a sleepy city of less than 200,000 to a 9-county metropolitan statistical area with a population of about 7 million covering more than 9 thousand square miles.

Nine counties comprise the Houston metropolitan statistical area, home to 7 million people. Source: Greater Houston Partnership.

Now, superimpose watersheds over those counties and you can see how difficult the flood control situation becomes.

Watersheds of the Houston MSA. The Upper San Jacinto River Basin (above Lake Houston) contains 13 major watersheds. But, there are many smaller watersheds within each larger one. Source: San Jacinto River Authority.

Solutions Will Require Cooperation

Rivers and streams cross political boundaries throughout this region. So solutions to flooding problems are, by definition, regional. Yet development regulations and guidelines are anything but.

Most regulations pay lip service to “no adverse impact” on downstream neighbors. But in many areas, the regulations may be based on ancient maps and antiquated data. Moreover, they may have little to no oversight or enforcement.

Retain Your Rain

The region’s growth depends on its reputation for quality of life. If we are to continue growing, we must work together to solve flooding problems.

If every developer did one simple thing, we could eliminate most of our flooding problems. Just be responsible for the rain that falls on your property. Detain it long enough to avoid adding to flood peaks.

It’s that simple and that difficult. Especially considering that Texans don’t like having other people tell them what to do.

Posted by Bob Rehak, with thanks to Descartes Labs

863 Days since Hurricane Harvey and 112 since Imelda

When Measured by Growth of Impervious Cover, Texas Has 9 of Top 20 Counties in U.S.

According to a recent New York Times article, nine of the 20 counties in the U.S. that have experienced the most development the last decade are in Texas. Prominent among them is Harris County. The article does not cite population growth. Rather, it relies on computer analysis of satellite imagery that detects the growth of impervious cover.

Analysis of Satellite Imagery Shows Land Newly Paved or Topped With Buildings

The Times cites the work of Santa-Fe-based Descartes Labs, which positions itself as a data refinery. The company trained a computer model to automatically identify newly impervious surfaces — land that appears paved or topped with buildings — in satellite imagery. It then produced dozens of paired images that show the effects of development. It also produced a map that shows where that development took place.

This Descarte map clearly shows the pattern in Texas. Each of the major cities looks like a bullet hole in the map with development splashing out ward…a ring of concrete.

Return of Suburban and Exurban Growth

The data suggests that the growth of suburbs and exurbs has returned. There was a brief hiatus of suburban development after the housing bust in 2008, which saw people returning to the inner city. But that trend appears to be over, according to this analysis.

I’m not sure if this should be a source of pride, alarm or both.

Texas Grows While Other Areas Lose Population

Many Rust Belt cities are experiencing population shrinkage. That presents another set of problems altogether. The Times article shows how several northern cities, including Detroit, are clearing thousands of dilapidated and abandoned homes. In the process, they are restoring pervious (natural) cover.

As luck would have it, another article in The NY Times the next day talked about a slowdown in U.S. population growth. Population grew at its slowest pace in decades in 2019. A decline in the number of new immigrants, fewer births and the graying of America accounted for the decline, which the Census Bureau estimated.

Given slow population growth on the national level, local growth in Texas and Houston must come from migration. I’m not talking about foreign immigration. I’m talking about one area attracting residents and businesses from another.

Texas Has Seven of Fifteen Fastest Growing Cities in U.S.

In marketing, if the market itself is not growing, the only way for a company to grow is to steal share from its competitors. And that is exactly what Texas seems to be doing. Markets such as New York and California are losing population while Texas gained more than 14% in the last decade. From 2010 to 2018, Texas had the largest population growth in America: 3,555,731.

Texas also had 7 of the top 15 fastest growing cities in the country between 2017 and 2018.

So clearly, from a marketing point of view, Texas must be seen as a desirable place to live by many people. We’re doing many things right.

Can Texas Meet the Challenge of Rapid Growth?

But in my 45 year career in marketing and advertising, I have seen many instances where companies had record growth one year only to have record losses later. It comes down to how you manage growth.

Can you deliver what you promise and keep product quality up as you grow?

Many areas can. Many areas can’t.

County officials face a conundrum: growing rapidly while maintaining quality of life. You want to attract growth, but you don’t want to be overwhelmed by it.

Montgomery Vs. Fort Bend Counties: Strategic Differences

Some compete for growth by relaxing regulations. For instance, this video from the East Montgomery County Improvement District boasts, “We don’t have rules that confine us.” The no-hassle upfront, anything-goes, follow-your-dream approach tempts many, especially those coming from other areas with onerous regulations.

Meanwhile, other fast-growing counties, such as Fort Bend, are adopting new flood plain regulations, designed to protect the quality of life they are selling.

Tougher Fort Bend County Regulations Went Into Effect New Year’s Day.

As of 1/1/2020, Fort Bend County adopted new Atlas 14 rainfall statistics and updated their drainage criteria manual accordingly to protect new homes AND existing downstream developments. Fort Bend is the fastest growing county in the region.

There you have it. Two opposite ends of the spectrum.

It will be interesting to see the outcomes that these two development strategies produce ten years from now.

Posted by Bob Rehak on 1/2/2020

856 Days since Hurricane Harvey and 104 since Imelda