The problem: Changes affect both water quality downstream and land development upstream. That’s why the rules change so often. Competing interests! Public health and safety vs. economic expansion.
The Cuyahoga River caught fire a total of 13 times dating back to 1868. It is still rated one of the most polluted rivers in America by almost every group that compiles lists. Photo: Cleveland State University Library.
The photographers took about 81,000 images, more than 20,000 of which were archived. At least 15,000 have been digitized by the National Archives. They form a time capsule showing the way things were.
Warning: These images are disturbing…for people on both sides of the political net.
Why the Changes This Time?
The AP article by Jim Salter and Michael Phillis says, “The Trump-era rule, finalized in 2020, was long sought by builders, oil and gas developers, farmers and others who complained about federal overreach that they said stretched into gullies, creeks and ravines on farmland and other private property.”
However, the writers continued, “…the Trump rule allowed businesses to dump pollutants into unprotected waterways and fill in some wetlands, threatening public water supplies downstream and harming wildlife and habitat.”
They quoted Kelly Moser, Senior Attorney for the Southern Environmental Law Center’s Clean Water Defense Initiative. She said, “Today, the Biden administration restored needed clean water protections so that our nation’s waters are guarded against pollution for fishing, swimming, and as sources of drinking water.”
At Issue: Definition of “Waters of the U.S.”
Meanwhile, courts at various levels are still pondering the definition of “Waters of the U.S.” At issue: How far up in the branching structure of a river may the government enforce regulations? As far as it’s navigable? One level up from that? Two? Three? Infinitely? And do the rules apply to desert areas the same way they do to subtropical areas like SE Texas?
The Biden administration decision is a setback for various industries. It broadens which wetlands, streams and rivers can be regulated under the Clean Water Act.
But given the impacts to public health and the immense economic interests at stake, this won’t be the last time we see the rules change. An army of lobbyists is likely mobilizing right now.
Local Impact
Several developments in the Lake Houston Area contained wetlands affected regulation changes. Consider, for instance, the case of Woodridge Village. The Army Corps ruled that it contained wetlands, but that the wetlands didn’t fall under their jurisdiction because of rules in effect at the time. So there was no violation of the Clean Water Act. Hundreds of homes in Elm Grove and North Kingwood Forest flooded, partially as a result of the environmental destruction.
Confluence of Spring Creek and West Fork by 59 Bridge. TCEQ found that Liberty Mines discharged 56 million gallons of white waste water into the West Fork.Repeated and multiple breaches atTriple PG mine discharged sediment-laden water directly into Caney Creek. This one lasted for months.
Searching on the word “breach” in ReduceFlooding.com pulls up 116 stories, many of which show multiple breaches.
But mining isn’t the only upstream issue at stake. So is sediment pollution from new development.
Drainage ditch in Artavia.March 2020 in West Fork watershedEroding ditch in Colony Ridge (East Fork Watershed) due to lack of backslope interceptor systems and grass.
Making Private Expenses a Public Cost
The EPA lists sediment as the most common pollutant in rivers, streams, lakes and reservoirs. It has contributed to flooding thousands of homes in the Lake Houston Area.
West Fork mouth bar almost totally blocked the river where it meets Lake Houston.East Fork Mouth Bar grew 4000 feet in two years between Harvey and Imelda.
Both mouth bars above have since been dredged at great public expense, but abuses continue. I just wish we could all find a way to live together. This should not be a case of health and safety vs. economic development. We need all three for communities to prosper.
Posted by Bob Rehak on 1/2/23
1952 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/11/RJR_4154-e1775771233982.jpg?fit=1100%2C733&ssl=17331100adminadmin2023-01-02 11:04:302023-01-02 11:49:14Biden Changes Trump’s Changes to Water Regulations
On November 21, 2022, the U.S. Government filed a 70-page motion for a summary judgment in the Addicks-Barker Downstream Cases. In 2020, Judge Loren A. Smith dismissed the downstream cases, ruling that the plaintiffs had no right to sue the government for “taking” their property in what he called a 2,000-year storm. However, in June 2022, a federal appeals court reversed Judge Loren’s decision, re-opening the case. The appeals court ruled on a number of procedural issues and remanded the case back to Loren’s court for further consideration.
Both appellants and the government had urged the appeals court to order a summary judgment. But the appeals court declined. It noted that “due to the fact-intensive nature of takings cases, summary judgment should not be granted precipitously.”
In summary, the government contends that the Addicks and Barker dams:
Historically prevented far more damage ($16.5 billion through 2016) than the release of water during Harvey caused
Reduced plaintiff’s level of flooding by up to 7-8 feet
Did not “cause” – in a legal sense – the plaintiffs’ flooding
Further, the government contends that plaintiffs’ claims are based on a single, extraordinary, catastrophic event and any action undertaken by the Corps during the event does not constitute a “taking” under the Fifth Amendment.
Dams Modified in Response to Downstream Development
The original design from the 1930s included a downstream channel with a capacity of approximately 18,000 cubic feet per second (CFS), and 4 ungated and 1 gated outlets on each dam. They permitted a combined, uncontrolled discharge of floodwater into Buffalo Bayou of approximately 15,700 cfs.
In 1948, the Corps constructed gates on two additional conduits on each dam so that three of the five conduits were gated. This design reduced the combined uncontrolled discharge into Buffalo Bayou to approximately 7,900 cfs, which was considered at that time to be the capacity of that channel.
“However, increasing urban development along Buffalo Bayou in the 1940s and 1950s created a potential flood threat from uncontrolled releases at that level,” says the motion.
The Corps then added gates to additional conduits in the early 1960s to provide more protection to developing downstream areas. With all conduits gated, “[t]he total of all releases, plus local runoff downstream of the dams, would start at 4,000 cfs and be gradually increased to 6,000 cfs except under emergency conditions.”
Later, the motion states, “Continued residential development along Buffalo Bayou downstream of the reservoirs resulted in channel encroachment and by late 1970, water flows in excess of 3,000 cfs in the unimproved channel below the dams would begin to threaten the first floor elevations of some residences, and release rates of 2,500 to 2,800 cfs would produce nuisance type flooding of flower beds, trees and lawns in some areas along Buffalo Bayou and its tributaries.”
Causation Argument
Plaintiffs claimed that the opening of the dams’ gates during Harvey caused their flooding. But the government argues that the plaintiffs must demonstrate what would have happened if the government had not acted at all. In other words, the government argues that “causation” must be “based on the entirety of government actions.” See Page 26. That includes construction of the dams! And without them, the government says on Page 42, “properties along Buffalo Bayou would have experienced much greater flooding.”
“Plaintiffs have not alleged—let alone identified any evidence to prove—that their properties experienced more flooding than they would have experienced if the Corps had never constructed the Project, their claims fail,” the government argues.
Doctrine of Relative Benefits
The government also invokes a legal principle called the “relative benefits doctrine.” Under the relative benefits doctrine, “[e]ven if a causal relationship exists between the Government’s action and plaintiff’s damage . . . no liability attaches if the Government’s conduct bestowed more benefit than detriment on plaintiff’s property.”
The motion then alleges that the benefits to downstream properties far outweigh the Harvey-related damages. A 2016 study the government quotes alleges the dams reduced/avoided damages to downstream properties by $16.5 billion. That total is updated annually and based on a with/without the dams comparison.
Comparison of Peak Inflows/Outflows
The government motion cites the following statistics of the two reservoirs during Harvey:
Addicks peak inflow: 70,000 cfs
Addicks peak release: 6,500 cfs or 9.3% of the peak inflow.
Barker peak inflow: 77,000 cfs,
Barker peak outflow: 4,821 cfs or 6.3% of the peak inflow.
Peak flow rates downstream along Buffalo Bayou ranged from 13,800 cfs to 36,400 cfs. The government alleges that at those levels, plaintiffs properties would flooded regardless of discharge from the dams. The government also alleges that without the dams, flooding in Piney Point would have been 7 to 8 feet higher.
The Corps calculated after Harvey that the dams prevented 30,000 structures from flooding.
In this section of the motion, government lawyers point out that plaintiffs’ properties would have flooded in previous floods such as Tax Day and Memorial Day had it not been for the dams.
What Constitutes a Taking?
In conclusion, the government argues that the flooding during Harvey did not constitute a “taking” under the Fifth Amendment.
It was not intended.
It resulted from an extreme hurricane with unprecedented rainfall.
The government’s role in any flooding of downstream properties was secondary to the severe rainfall.
The dams were designed and built decades before the plaintiffs’ properties.
Releases during Harvey were designed to protect the integrity of the dam.
Flooding of plaintiffs’ property is not frequent enough to rise to the level of a taking.
The failure of government to take certain actions alleged by plaintiffs would constitute a tort a most, not a taking.
A tort is a failure to take action that results in damage to someone.
I will let you know how the plaintiffs’ lawyers respond later this month.
Posted by Bob Rehak on 1/1/2023
1951 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/05/20210520-RJR_6640.jpg?fit=1200%2C725&ssl=17251200adminadmin2023-01-01 14:12:402023-01-01 14:22:49Government Again Moves for Summary Judgment In Addicks-Barker Downstream Cases
Data provided by the National Weather Service (NWS) shows that precipitation appears to be increasing with temperature in Houston and Harris County. A reader recently asked whether there was a correlation. The hypothesis: in this climate, if temperature increases, then so will evaporation and rainfall. Eighty to 130 years worth of data at different locations show both variables trending up. But most scientists would consider the coefficient of correlation weak to non-existent.
Behind the Theory
The theory is plausible from several perspectives.
Warm air holds more moisture than cool air. Warm air also rises. As it cools at higher altitudes, precipitation forms. Think “afternoon thunderstorms on hot summer days.”
Precipitation also forms when warm and cool fronts collide.
It often forms when warm moisture-laden air streams in from the Gulf.
Hurricanes form in the hottest parts of the year.
Distribution of hurricanes by month during the last 100 years.
But the question concerned correlation, not causation.
Other outside factors could reduce precipitation, such as droughts triggered by changes in Pacific Ocean currents. Those who remember the drought from 2011 to 2014 may also remember how hot it was.
But looking at 80 to 130 years of data highlights long-term climate trends. That “evens out” the influence of individual events.
Qualifiers
NWS plotted all available historical data for precipitation and temperature on line graphs and then superimposed trend lines. The graphs show official data from two sources: Houston-Hobby Airport and the “City of Houston.”
I put City of Houston in quotes because the the official City-of-Houston data is currently collected at Bush Intercontinental Airport. But the location has bounced around. So the “City” isn’t one location, but many:
Cotton Station (July 1881 – September 1909)
Stewart Building at Preston and Fannin (September 1909 – February 1926)
Shell Building at Texas and Fannin (March 1926 – August 1938)
Federal Building at Franklin and Fannin (August 1938 – May 1969)
Intercontinental Airport (June 1969 – Present)
We have less data for Houston-Hobby because Hobby Airport didn’t exist until 1927. That’s when someone turned a 600-acre pasture into a landing field. The City of Houston purchased the field in 1937 and expanded it.
With those qualifiers, see the charts below. Both temperature and rainfall vary from year to year. But rainfall shows extreme variance. Regardless, in all four graphs the trend lines slowly increase.
Houston-Hobby Airport
Mean temps at Hobby increased from 69 to 73 degrees – a 4 degree increase between 1931 and 2022.During roughly the same time period, precipitation increased approximately 9 inches from about 48 to 57 inches.Also notice the extreme range – from less than 30 to more than 80 inches.
City of Houston Data
The City of Houston data covers a wider time period. Within that, the location varied as noted above. The big jump was from downtown to Bush Intercontinental Airport in 1969. Generally speaking, as you go farther north from the coast, precipitation decreases. But the difference is less than an inch. Atlas 14 shows that a 100-year, 24-hour storm is 17.6 inches at Hobby, 17 inches downtown, and 16.9 inches at Intercontinental.
City data indicates mean temp has increased roughly 4 degrees in last 120 years.During roughly the same years, precipitation increased about 5-6 inches. Here, the range was even more extreme. From less than 20 inches to 80 – a 4X difference.
So the change in where the City collects official data actually worked against the hypothesis. And it shows.
Summary of Trend Differences
Summarizing the key differences:
As the temp trend line increased 4 degrees at Hobby, precipitation increased 9 inches.
As temp increased 4 degrees at various City locations, precipitation increased 6 inches.
Low Coefficient of Correlation
Jimmy Fowler of the National Weather Service’s Houston/Galveston office calculated the coefficients of correlation between the two series of data at each location.
For Hobby, the coefficient of correlation is only .03. The City’s is slightly higher at .11.
Jimmy Fowler, Meteorologist, National Weather Service
For those who didn’t study statistics in college, the coefficient of correlation tells you how much one variable changes in response to another.
A perfect positive correlation is 1.0. Example: population growth and food consumption.
A perfect negative correlation is -1. Example: hours worked and free time.
In both cases, one unit of change in the first variable accounts for an equal unit of change in the second. But most correlations fall between the two extremes with different degrees of strength.
The chart below indicates how scientists would characterize correlation coefficients of .03 and .11. Both are considered “very weak” or having “no association.”
So, if the trends are all up, why is the co-efficient of correlation so low? Part of the answer has to do with those R2 (R squared) values you see at the bottom of the charts. They show the data doesn’t conform to the trend lines very well. Temperature fits moderately well. But precipitation shows extreme variance.
A perfect fit (1.0) would show all the data points on the line. As a rule of thumb, 0.8 (80%) or higher is considered a good fit. But the R2 values in these trend lines range from 0.03 to 0.5.
Conclusion
You can read into this data whatever you want depending on your point of view. Climate change advocates might see proof in the consistent slope of the trend lines that warming temperatures and more precipitation are related. A deeper dig into the data reveals the correlation is weak at best and possibly non-existent. Other factors may be at play and influencing the data.
To demonstrate causation, you need to show a directional relationship with no alternative explanations. But with weather, you have a multitude of alternative explanations.
Remember that weather is global and that we looked only at Houston in this instance.
However, a friend who traded weather-related derivatives before retirement tracked hundreds of temperature sites. He found they all trended warmer over time. But he believed the variance resulted primarily from changes in surrounding ground cover, i.e., replacement of natural ground cover with concrete – also known as the urban heat island effect.
He also tracked variance to changes in measurement locations (as with Houston).
Finally, remember that some of the hottest and coldest places on earth get very little precipitation. The Sahara and the North and South Poles are all considered deserts based of the amount of precipitation they get.
Net: I find the similarities in the graphs interesting enough to keep digging. As my friend suggested, it would be interesting to find the coefficient of correlation between population growth and temperature change. I won’t leap to any generalizations at this point.
Posted by Bob Rehak on 12/30/2022with thanks to Jeff Lindner, Harris County Meteorologist and Jimmy Fowler of the National Weather Service.
1949 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/12/Hobby-Rainfall.png?fit=3144%2C2282&ssl=122823144adminadmin2022-12-30 17:24:042022-12-31 12:50:38Is Precipitation Increasing with Temperature?
Biden Changes Trump’s Changes to Water Regulations
The Associated Press reported on December 30, 2021, that the Biden administration had reversed Trump-era changes to water regulations, which themselves were changes to Obama regulations and other previous administrations. This is getting to be like a tennis match. “Advantage Downstream.”
The EPA regulations have changed numerous times over the years. Enforcement changes, too.
The problem: Changes affect both water quality downstream and land development upstream. That’s why the rules change so often. Competing interests! Public health and safety vs. economic expansion.
Rivers Before the EPA and Clean Water Act
About two thirds of Americans alive today had not yet been born when Cleveland’s Cuyahoga River caught fire in 1969. So they have no memory of the event that helped give birth to the Environmental Protection Agency (EPA) in 1970.
Shortly after its founding, the EPA dispatched photographers all around the country to document environmental abuses.
The photographers took about 81,000 images, more than 20,000 of which were archived. At least 15,000 have been digitized by the National Archives. They form a time capsule showing the way things were.
Warning: These images are disturbing…for people on both sides of the political net.
Why the Changes This Time?
The AP article by Jim Salter and Michael Phillis says, “The Trump-era rule, finalized in 2020, was long sought by builders, oil and gas developers, farmers and others who complained about federal overreach that they said stretched into gullies, creeks and ravines on farmland and other private property.”
However, the writers continued, “…the Trump rule allowed businesses to dump pollutants into unprotected waterways and fill in some wetlands, threatening public water supplies downstream and harming wildlife and habitat.”
They quoted Kelly Moser, Senior Attorney for the Southern Environmental Law Center’s Clean Water Defense Initiative. She said, “Today, the Biden administration restored needed clean water protections so that our nation’s waters are guarded against pollution for fishing, swimming, and as sources of drinking water.”
At Issue: Definition of “Waters of the U.S.”
Meanwhile, courts at various levels are still pondering the definition of “Waters of the U.S.” At issue: How far up in the branching structure of a river may the government enforce regulations? As far as it’s navigable? One level up from that? Two? Three? Infinitely? And do the rules apply to desert areas the same way they do to subtropical areas like SE Texas?
The Biden administration decision is a setback for various industries. It broadens which wetlands, streams and rivers can be regulated under the Clean Water Act.
But given the impacts to public health and the immense economic interests at stake, this won’t be the last time we see the rules change. An army of lobbyists is likely mobilizing right now.
Local Impact
Several developments in the Lake Houston Area contained wetlands affected regulation changes. Consider, for instance, the case of Woodridge Village. The Army Corps ruled that it contained wetlands, but that the wetlands didn’t fall under their jurisdiction because of rules in effect at the time. So there was no violation of the Clean Water Act. Hundreds of homes in Elm Grove and North Kingwood Forest flooded, partially as a result of the environmental destruction.
In this area, sediment pollution is one of our most serious concerns. We’ve seen repeated and almost constant releases into the West Fork from 20-square miles of sand mines immediately upstream from us.
Searching on the word “breach” in ReduceFlooding.com pulls up 116 stories, many of which show multiple breaches.
But mining isn’t the only upstream issue at stake. So is sediment pollution from new development.
Making Private Expenses a Public Cost
The EPA lists sediment as the most common pollutant in rivers, streams, lakes and reservoirs. It has contributed to flooding thousands of homes in the Lake Houston Area.
Both mouth bars above have since been dredged at great public expense, but abuses continue. I just wish we could all find a way to live together. This should not be a case of health and safety vs. economic development. We need all three for communities to prosper.
Posted by Bob Rehak on 1/2/23
1952 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.
Government Again Moves for Summary Judgment In Addicks-Barker Downstream Cases
On November 21, 2022, the U.S. Government filed a 70-page motion for a summary judgment in the Addicks-Barker Downstream Cases. In 2020, Judge Loren A. Smith dismissed the downstream cases, ruling that the plaintiffs had no right to sue the government for “taking” their property in what he called a 2,000-year storm. However, in June 2022, a federal appeals court reversed Judge Loren’s decision, re-opening the case. The appeals court ruled on a number of procedural issues and remanded the case back to Loren’s court for further consideration.
Both appellants and the government had urged the appeals court to order a summary judgment. But the appeals court declined. It noted that “due to the fact-intensive nature of takings cases, summary judgment should not be granted precipitously.”
Now three years later, the parties are again asking for summary judgement. The government has already filed its motion and the plaintiffs have until January 10, 2023, to respond with their own cross-motion.
Government Claims
In summary, the government contends that the Addicks and Barker dams:
Further, the government contends that plaintiffs’ claims are based on a single, extraordinary, catastrophic event and any action undertaken by the Corps during the event does not constitute a “taking” under the Fifth Amendment.
Dams Modified in Response to Downstream Development
The government brief contains an illuminating historical discussion (starting on Page 23) of how the Army Corps modified the release capacity of the dams over the years in response to downstream development. Both dams release water through concrete box culverts, some of which have been gated to help the Corps reduce discharges.
The original design from the 1930s included a downstream channel with a capacity of approximately 18,000 cubic feet per second (CFS), and 4 ungated and 1 gated outlets on each dam. They permitted a combined, uncontrolled discharge of floodwater into Buffalo Bayou of approximately 15,700 cfs.
In 1948, the Corps constructed gates on two additional conduits on each dam so that three of the five conduits were gated. This design reduced the combined uncontrolled discharge into Buffalo Bayou to approximately 7,900 cfs, which was considered at that time to be the capacity of that channel.
“However, increasing urban development along Buffalo Bayou in the 1940s and 1950s created a potential flood threat from uncontrolled releases at that level,” says the motion.
The Corps then added gates to additional conduits in the early 1960s to provide more protection to developing downstream areas. With all conduits gated, “[t]he total of all releases, plus local runoff downstream of the dams, would start at 4,000 cfs and be gradually increased to 6,000 cfs except under emergency conditions.”
Later, the motion states, “Continued residential development along Buffalo Bayou downstream of the reservoirs resulted in channel encroachment and by late 1970, water flows in excess of 3,000 cfs in the unimproved channel below the dams would begin to threaten the first floor elevations of some residences, and release rates of 2,500 to 2,800 cfs would produce nuisance type flooding of flower beds, trees and lawns in some areas along Buffalo Bayou and its tributaries.”
Causation Argument
Plaintiffs claimed that the opening of the dams’ gates during Harvey caused their flooding. But the government argues that the plaintiffs must demonstrate what would have happened if the government had not acted at all. In other words, the government argues that “causation” must be “based on the entirety of government actions.” See Page 26. That includes construction of the dams! And without them, the government says on Page 42, “properties along Buffalo Bayou would have experienced much greater flooding.”
“Plaintiffs have not alleged—let alone identified any evidence to prove—that their properties experienced more flooding than they would have experienced if the Corps had never constructed the Project, their claims fail,” the government argues.
Doctrine of Relative Benefits
The government also invokes a legal principle called the “relative benefits doctrine.” Under the relative benefits doctrine, “[e]ven if a causal relationship exists between the Government’s action and plaintiff’s damage . . . no liability attaches if the Government’s conduct bestowed more benefit than detriment on plaintiff’s property.”
The motion then alleges that the benefits to downstream properties far outweigh the Harvey-related damages. A 2016 study the government quotes alleges the dams reduced/avoided damages to downstream properties by $16.5 billion. That total is updated annually and based on a with/without the dams comparison.
Comparison of Peak Inflows/Outflows
The government motion cites the following statistics of the two reservoirs during Harvey:
Peak flow rates downstream along Buffalo Bayou ranged from 13,800 cfs to 36,400 cfs. The government alleges that at those levels, plaintiffs properties would flooded regardless of discharge from the dams. The government also alleges that without the dams, flooding in Piney Point would have been 7 to 8 feet higher.
In this section of the motion, government lawyers point out that plaintiffs’ properties would have flooded in previous floods such as Tax Day and Memorial Day had it not been for the dams.
What Constitutes a Taking?
In conclusion, the government argues that the flooding during Harvey did not constitute a “taking” under the Fifth Amendment.
A tort is a failure to take action that results in damage to someone.
To see the exact text of the full 70-page motion, click here.
I will let you know how the plaintiffs’ lawyers respond later this month.
Posted by Bob Rehak on 1/1/2023
1951 Days since Hurricane Harvey
Is Precipitation Increasing with Temperature?
Data provided by the National Weather Service (NWS) shows that precipitation appears to be increasing with temperature in Houston and Harris County. A reader recently asked whether there was a correlation. The hypothesis: in this climate, if temperature increases, then so will evaporation and rainfall. Eighty to 130 years worth of data at different locations show both variables trending up. But most scientists would consider the coefficient of correlation weak to non-existent.
Behind the Theory
The theory is plausible from several perspectives.
But the question concerned correlation, not causation.
Other outside factors could reduce precipitation, such as droughts triggered by changes in Pacific Ocean currents. Those who remember the drought from 2011 to 2014 may also remember how hot it was.
But looking at 80 to 130 years of data highlights long-term climate trends. That “evens out” the influence of individual events.
Qualifiers
NWS plotted all available historical data for precipitation and temperature on line graphs and then superimposed trend lines. The graphs show official data from two sources: Houston-Hobby Airport and the “City of Houston.”
I put City of Houston in quotes because the the official City-of-Houston data is currently collected at Bush Intercontinental Airport. But the location has bounced around. So the “City” isn’t one location, but many:
We have less data for Houston-Hobby because Hobby Airport didn’t exist until 1927. That’s when someone turned a 600-acre pasture into a landing field. The City of Houston purchased the field in 1937 and expanded it.
With those qualifiers, see the charts below. Both temperature and rainfall vary from year to year. But rainfall shows extreme variance. Regardless, in all four graphs the trend lines slowly increase.
Houston-Hobby Airport
City of Houston Data
The City of Houston data covers a wider time period. Within that, the location varied as noted above. The big jump was from downtown to Bush Intercontinental Airport in 1969. Generally speaking, as you go farther north from the coast, precipitation decreases. But the difference is less than an inch. Atlas 14 shows that a 100-year, 24-hour storm is 17.6 inches at Hobby, 17 inches downtown, and 16.9 inches at Intercontinental.
So the change in where the City collects official data actually worked against the hypothesis. And it shows.
Summary of Trend Differences
Summarizing the key differences:
Low Coefficient of Correlation
Jimmy Fowler of the National Weather Service’s Houston/Galveston office calculated the coefficients of correlation between the two series of data at each location.
For those who didn’t study statistics in college, the coefficient of correlation tells you how much one variable changes in response to another.
In both cases, one unit of change in the first variable accounts for an equal unit of change in the second. But most correlations fall between the two extremes with different degrees of strength.
The chart below indicates how scientists would characterize correlation coefficients of .03 and .11. Both are considered “very weak” or having “no association.”
Fit of Trend Lines to Data
So, if the trends are all up, why is the co-efficient of correlation so low? Part of the answer has to do with those R2 (R squared) values you see at the bottom of the charts. They show the data doesn’t conform to the trend lines very well. Temperature fits moderately well. But precipitation shows extreme variance.
A perfect fit (1.0) would show all the data points on the line. As a rule of thumb, 0.8 (80%) or higher is considered a good fit. But the R2 values in these trend lines range from 0.03 to 0.5.
Conclusion
You can read into this data whatever you want depending on your point of view. Climate change advocates might see proof in the consistent slope of the trend lines that warming temperatures and more precipitation are related. A deeper dig into the data reveals the correlation is weak at best and possibly non-existent. Other factors may be at play and influencing the data.
To demonstrate causation, you need to show a directional relationship with no alternative explanations. But with weather, you have a multitude of alternative explanations.
Remember that weather is global and that we looked only at Houston in this instance.
However, a friend who traded weather-related derivatives before retirement tracked hundreds of temperature sites. He found they all trended warmer over time. But he believed the variance resulted primarily from changes in surrounding ground cover, i.e., replacement of natural ground cover with concrete – also known as the urban heat island effect.
He also tracked variance to changes in measurement locations (as with Houston).
Finally, remember that some of the hottest and coldest places on earth get very little precipitation. The Sahara and the North and South Poles are all considered deserts based of the amount of precipitation they get.
Net: I find the similarities in the graphs interesting enough to keep digging. As my friend suggested, it would be interesting to find the coefficient of correlation between population growth and temperature change. I won’t leap to any generalizations at this point.
Posted by Bob Rehak on 12/30/2022 with thanks to Jeff Lindner, Harris County Meteorologist and Jimmy Fowler of the National Weather Service.
1949 Days since Hurricane Harvey