Reprinted with minor edits from an article posted by the Texas Water Development Board (TWDB) on 9/11/2023 – Flooding is the most common and deadly disaster in the state. It has plagued Texans for generations, costing billions in property damage—and worse, loss of lives. So, flood mitigation is at the top of the list when it comes to addressing the most challenging water issues across the 269,000 square miles of Texas.
2018 NOAA Study Revealed Rainfall Assumptions Inadequate
The National Oceanic and Atmospheric Administration published a study in 2018 revealing that rainfall values in some parts of Texas previously classified as 100-year events are now categorized as much more frequent 25-year events.
Varied topography and proximity to the Gulf of Mexico have always played a significant role in the state’s flood events. So has the population in Texas; it surpassed 30 million last year. according to estimates from the U.S. Census Bureau.
Recent exponential growth, coupled with the already complex landscape, necessitates more forward-thinking flood planning and coordination. For instance…
We need to consider how natural features in new developments and infrastructure projects can work to our benefit to reduce flood risks.
TWDB
Participate in Online Survey
To help address flood issues across the state, TWDB is conducting an online survey now through September 29. Purpose: to collect input on the use of nature-based solutions to mitigate flood risk. Responses will help develop a guidance manual for communities seeking to implement these projects.
Nature-based solutions are broad, ranging from detention and retention ponds to preservation of natural features, such as floodplains and wetlands, or may even include roadside ditches with nature-based components. Sometimes, projects designed to improve water quality or intended to provide other environmental benefits can also work to mitigate flooding.
“The work that we’re doing is from a lens of flood mitigation. But really, there are likely greater benefits for water quality, environmental enhancement, and even for public recreation and enjoyment,” said Saul Nuccitelli, the TWDB’s Director of Flood Science and Community Assistance. “We’re looking to try to integrate and connect those project benefits and encourage folks who are doing flood work to seek out ways to incorporate nature-based components into their projects.”
Examples of Nature-Based Solutions
Nature-based solutions often include community benefits:
Nature-based solutions can often provide benefits to the community while serving as flood-mitigation strategies. The Humble-Kingwood area has numerous examples of flood-mitigation solutions that improve quality of life. For example, the 100+ mile Kingwood trail network, East End Park, Creekwood Nature Preserve, River Grove Park, and the Spring Creek Nature Trail are hugely popular community amenities that reduce flood risk.
188-acre East End Park attracts more than 100,000 visitors per year. It contains 5 miles of trails weaving through meadows, forests and wetlands that reduce flood risk while enhancing quality of life for people and animals.
Goal of Survey: ID Sustainable Building Blocks for Growth
The TWDB’s survey will capture examples of projects and programs using nature-based solutions with flood mitigation benefits. TWDB wants to learn about solutions in the varying ecoregions across Texas.
The goal of the guidance manual is to make practical case studies of projects, incentive program concepts, and regulatory templates available to community officials, decision-makers, and other practitioners. Many are interested in nature-based solutions as value-added alternatives to traditional flood infrastructure.
“If you find ways to incorporate nature-based solutions, it doesn’t mean people need to stay out of it all the time,” said Nuccitelli. “For example, you may have an area that’s wetland mitigation or wetland banking, so you may want to minimize how much traffic goes through it or what goes on there, but to the extent that you can include recreational activities associated with a project, urban economic benefit and utilizing nature can be somewhat synergistic.”
Reducing Runoff up to 5X
According to the Environmental Protection Agency, when 10 to 20 percent of a watershed is covered by impervious surfaces like roads or parking lots, runoff doubles. If impervious surfaces cover 100 percent of a watershed, the runoff is five times that of a forested area, which significantly increases the potential for flooding.
Incorporating nature-based solutions into a new project could potentially help manage runoff from future growth. For example, identifying and preserving healthy stands of trees or wetlands to utilize those existing natural features as amenities, such as a pocket park or an area of trees next to homes.
Data Will Ultimately Help Build/Fund Community Resources
By developing a guidance manual, the TWDB aims to
1) Share data and information about the benefits of nature-based solutions that could then empower communities to adopt them
2) Provide tools, research, case studies, incentive program concepts, and example ordinances—anything that a community may use as a resource if it’s interested in pursuing these solutions
3) Share details about funding opportunities and grant applications for these types of projects.
“That would be a big success if communities could take what we’re developing within the guidance manual to further encourage or enhance nature-based solutions,” said Nuccitelli.
Once the survey responses are compiled and the guidance manual is developed, the TWDB plans to release the draft in the summer of 2024 for public input.
For More Information
To learn more about nature-based solutions for flood mitigation in Texas, visit the TWDB website. To take the survey, click here. It takes about 15 minutes, but is a very thought-provoking.
See more TWDB articles about flood mitigation posted in Flood.
Posted by Bob Rehak on 9/13/2023 based on a TWDB article
2206 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2023/09/EEP-Poster-Small-scaled-e1694619352344.jpg?fit=1100%2C1646&ssl=116461100adminadmin2023-09-13 10:38:222023-09-13 11:31:52TWDB Wants Your Input on Nature-Based Flood-Mitigation Solutions
4PM Tuesday 9/12/2023 – A Libyan flood in Derna (also spelled Darnah) killed thousands and authorities say more than 10,000 are missing.
At this hour, exact numbers are hard to come by as large areas are still cut off from rescue workers and reporters. But to put those estimates in perspective, Harvey killed 36 in Harris County.
The Cause: Months of Rain Fall in Day
Torrential rains from Mediterranean storm Daniel burst two dams, wiped out four bridges and flooded large areas of Derna. The flash floods swept homes, bodies and vehicles into the sea while knocking out communications in large parts of the area.
Daniel dumped months of rain in one day on a large swath of northern Libya.
Libya is normally one of the driest countries in the world. The Sahara dominates most of the country’s climate. But the Mediterranean also influences rainfall along the northern coast.
In Al Bayda, about 50 miles west, Libya’s National Meteorological Centre said that 16 inches of rain fell between 10 Sep 8am and 11 Sep 8am, a new rainfall record.
Weather Spark shows that average precipitation in Derna during September amounts to less than an inch. And even in the wettest years, Derna receives at most 4 inches per month.
Average September Rainfall in Darnah equals .2 inches, Courtesy of Weather Spark.
Weather Spark also indicates that Derna receives rainfall on less than one day in an average September.
Terrain Funneled Floodwater Toward City
Derna lies along the coast of the Mediterranean Sea, at the end of a long, narrow, natural valley, called a wadi, which is dry for much of the year.
As the city was inundated by Daniel, which made landfall in Libya on Sunday night, the wadi funneled rushing water into the center of the city. Riverbanks swelled, bridges were washed out and two dams farther up the wadi burst, adding their waters to the deluge.
Tropical-like storms rarely happen in the Mediterranean, but they do happen occasionally. And when they do, meteorologists call them “Medicanes,” short for Mediterranean hurricanes.
Google “flood Derna Libya” to find hundreds of links and the latest news. Stories are being updated almost hourly.
Parallels With Harvey
Perusing many of those stories revealed several parallels with Hurricane Harvey which struck the Houston area in 2017.
Rainfall Records
Both areas encountered record rainfalls. Harvey dumped far more rain than Daniel. But then Daniel’s rainfall fell over a much drier area where infrastructure was designed to handle smaller amounts. Still, both were records, and both overwhelmed local infrastructure with unexpectedly high volumes.
Dam Concerns
Both Houston and Derna lay downstream from dams. During Harvey, the SJRA cited fear of failure of the Lake Conroe Dam as the reason for its massive release. In Derna, the dams just failed.
Lack of Warning
During Harvey, downstream residents received no warning that Lake Conroe would open its massive floodgates. Many stepped out of bed in the middle of the night to find themselves in knee deep water. CNN reported that there was no warning that the Derna dams could fail and no order to evacuate. Many who tried to evacuate found themselves cut off by collapsed bridges, washed out roads, and rising water, just as in Houston.
Lack of Maintenance
Aljazeera indicated that lack of maintenance may have played a role in the Derna disaster. The dams that failed hadn’t been maintained for years, even though severe erosion had been reported in scientific journals for more than a decade. Likewise, deferred maintenance played a role in flooding the Lake Houston Area during Harvey. During the drought in 2011, the water level in Lake Houston fell so low that the City of Houston could have removed sediment with dump trucks instead of dredges. But Mayor Anise Parker refused to do so. The accumulated sediment later wound up blocking the San Jacinto West Fork and contributing to the flooding of thousands of homes in the Humble/Kingwood area.
Enforcement of Building Codes
In Libya, political turmoil since 2011 reportedly distracted government from the mundane task of enforcing building codes. As a consequence, many hastily constructed buildings went up without adequate safeguards or supervision, and were swept away during the flood. Sound familiar?
Learning from Disasters
We should learn from the past and others’ mistakes. I wonder how many other communities have been surprised by:
Record rainfalls
Dam failures or unexpectedly high dam releases
Warning systems that failed and left people with no time or way to evacuate
Impacts of deferred maintenance
Lax enforcement of building codes
I hope the world learns the lessons of the Derna disaster so that we can compare them to other floods and get smarter about mitigation measures that make a difference.
Posted by Bob Rehak on 9/12/2023
2205 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2023/09/20230912-Screenshot-2023-09-12-at-1.49.20-PM.jpg?fit=1100%2C699&ssl=16991100adminadmin2023-09-12 16:08:042023-09-12 20:37:21Worse than Harvey, Libyan Flood Kills Thousands
We have two tropical systems in the Atlantic this morning – Hurricane Lee and Tropical Storm Margo which is projected to intensify into a hurricane by tomorrow.
I love looking at the satellite imagery of earth on the National Hurricane Center website. It lets you verify all the complex descriptions of weather developments. And this morning when I went to look at the satellite imagery of the full Atlantic, I was startled by what appeared to be a pair of eyeballs staring back at me, perfectly centered in the sunrise.
And the cloud formations below them loosely resembled a nose and a frown.
Frankly, it looked a bit spooky to me. A cosmic coincidence? But one that triggered thoughts of Halloween a little more than a month away.
Please share with your kids and grandkids. This could be an interesting way to teach them to keep their eyes on the weather.
TWDB Wants Your Input on Nature-Based Flood-Mitigation Solutions
Reprinted with minor edits from an article posted by the Texas Water Development Board (TWDB) on 9/11/2023 – Flooding is the most common and deadly disaster in the state. It has plagued Texans for generations, costing billions in property damage—and worse, loss of lives. So, flood mitigation is at the top of the list when it comes to addressing the most challenging water issues across the 269,000 square miles of Texas.
2018 NOAA Study Revealed Rainfall Assumptions Inadequate
The National Oceanic and Atmospheric Administration published a study in 2018 revealing that rainfall values in some parts of Texas previously classified as 100-year events are now categorized as much more frequent 25-year events.
Varied topography and proximity to the Gulf of Mexico have always played a significant role in the state’s flood events. So has the population in Texas; it surpassed 30 million last year. according to estimates from the U.S. Census Bureau.
Recent exponential growth, coupled with the already complex landscape, necessitates more forward-thinking flood planning and coordination. For instance…
Participate in Online Survey
To help address flood issues across the state, TWDB is conducting an online survey now through September 29. Purpose: to collect input on the use of nature-based solutions to mitigate flood risk. Responses will help develop a guidance manual for communities seeking to implement these projects.
Nature-based solutions are broad, ranging from detention and retention ponds to preservation of natural features, such as floodplains and wetlands, or may even include roadside ditches with nature-based components. Sometimes, projects designed to improve water quality or intended to provide other environmental benefits can also work to mitigate flooding.
“The work that we’re doing is from a lens of flood mitigation. But really, there are likely greater benefits for water quality, environmental enhancement, and even for public recreation and enjoyment,” said Saul Nuccitelli, the TWDB’s Director of Flood Science and Community Assistance. “We’re looking to try to integrate and connect those project benefits and encourage folks who are doing flood work to seek out ways to incorporate nature-based components into their projects.”
Examples of Nature-Based Solutions
Nature-based solutions often include community benefits:
Nature-based solutions can often provide benefits to the community while serving as flood-mitigation strategies. The Humble-Kingwood area has numerous examples of flood-mitigation solutions that improve quality of life. For example, the 100+ mile Kingwood trail network, East End Park, Creekwood Nature Preserve, River Grove Park, and the Spring Creek Nature Trail are hugely popular community amenities that reduce flood risk.
Goal of Survey: ID Sustainable Building Blocks for Growth
The TWDB’s survey will capture examples of projects and programs using nature-based solutions with flood mitigation benefits. TWDB wants to learn about solutions in the varying ecoregions across Texas.
The goal of the guidance manual is to make practical case studies of projects, incentive program concepts, and regulatory templates available to community officials, decision-makers, and other practitioners. Many are interested in nature-based solutions as value-added alternatives to traditional flood infrastructure.
“If you find ways to incorporate nature-based solutions, it doesn’t mean people need to stay out of it all the time,” said Nuccitelli. “For example, you may have an area that’s wetland mitigation or wetland banking, so you may want to minimize how much traffic goes through it or what goes on there, but to the extent that you can include recreational activities associated with a project, urban economic benefit and utilizing nature can be somewhat synergistic.”
Reducing Runoff up to 5X
According to the Environmental Protection Agency, when 10 to 20 percent of a watershed is covered by impervious surfaces like roads or parking lots, runoff doubles. If impervious surfaces cover 100 percent of a watershed, the runoff is five times that of a forested area, which significantly increases the potential for flooding.
Incorporating nature-based solutions into a new project could potentially help manage runoff from future growth. For example, identifying and preserving healthy stands of trees or wetlands to utilize those existing natural features as amenities, such as a pocket park or an area of trees next to homes.
Data Will Ultimately Help Build/Fund Community Resources
By developing a guidance manual, the TWDB aims to
1) Share data and information about the benefits of nature-based solutions that could then empower communities to adopt them
2) Provide tools, research, case studies, incentive program concepts, and example ordinances—anything that a community may use as a resource if it’s interested in pursuing these solutions
3) Share details about funding opportunities and grant applications for these types of projects.
“That would be a big success if communities could take what we’re developing within the guidance manual to further encourage or enhance nature-based solutions,” said Nuccitelli.
Once the survey responses are compiled and the guidance manual is developed, the TWDB plans to release the draft in the summer of 2024 for public input.
For More Information
To learn more about nature-based solutions for flood mitigation in Texas, visit the TWDB website. To take the survey, click here. It takes about 15 minutes, but is a very thought-provoking.
See more TWDB articles about flood mitigation posted in Flood.
Posted by Bob Rehak on 9/13/2023 based on a TWDB article
2206 Days since Hurricane Harvey
Worse than Harvey, Libyan Flood Kills Thousands
4PM Tuesday 9/12/2023 – A Libyan flood in Derna (also spelled Darnah) killed thousands and authorities say more than 10,000 are missing.
At this hour, exact numbers are hard to come by as large areas are still cut off from rescue workers and reporters. But to put those estimates in perspective, Harvey killed 36 in Harris County.
The Cause: Months of Rain Fall in Day
Torrential rains from Mediterranean storm Daniel burst two dams, wiped out four bridges and flooded large areas of Derna. The flash floods swept homes, bodies and vehicles into the sea while knocking out communications in large parts of the area.
Libya is normally one of the driest countries in the world. The Sahara dominates most of the country’s climate. But the Mediterranean also influences rainfall along the northern coast.
Wikipedia says the annual rainfall in Derna is around 11 inches. But CNN reported that in Derna, eight months worth of rain fell in one day.
In Al Bayda, about 50 miles west, Libya’s National Meteorological Centre said that 16 inches of rain fell between 10 Sep 8am and 11 Sep 8am, a new rainfall record.
Weather Spark shows that average precipitation in Derna during September amounts to less than an inch. And even in the wettest years, Derna receives at most 4 inches per month.
Weather Spark also indicates that Derna receives rainfall on less than one day in an average September.
Terrain Funneled Floodwater Toward City
Derna lies along the coast of the Mediterranean Sea, at the end of a long, narrow, natural valley, called a wadi, which is dry for much of the year.
As the city was inundated by Daniel, which made landfall in Libya on Sunday night, the wadi funneled rushing water into the center of the city. Riverbanks swelled, bridges were washed out and two dams farther up the wadi burst, adding their waters to the deluge.
Tropical-like storms rarely happen in the Mediterranean, but they do happen occasionally. And when they do, meteorologists call them “Medicanes,” short for Mediterranean hurricanes.
World and Social Media Focus on Flood
YouTube is awash in videos from the Derna flood.
NBC reported that a quarter of the city of 125,000 people was destroyed.
This CBS story shows pictures of the incredible destruction. This flood didn’t invade homes slowly, but leave them standing. It pummeled homes and whole neighborhoods.
Google “flood Derna Libya” to find hundreds of links and the latest news. Stories are being updated almost hourly.
Parallels With Harvey
Perusing many of those stories revealed several parallels with Hurricane Harvey which struck the Houston area in 2017.
Rainfall Records
Both areas encountered record rainfalls. Harvey dumped far more rain than Daniel. But then Daniel’s rainfall fell over a much drier area where infrastructure was designed to handle smaller amounts. Still, both were records, and both overwhelmed local infrastructure with unexpectedly high volumes.
Dam Concerns
Both Houston and Derna lay downstream from dams. During Harvey, the SJRA cited fear of failure of the Lake Conroe Dam as the reason for its massive release. In Derna, the dams just failed.
Lack of Warning
During Harvey, downstream residents received no warning that Lake Conroe would open its massive floodgates. Many stepped out of bed in the middle of the night to find themselves in knee deep water. CNN reported that there was no warning that the Derna dams could fail and no order to evacuate. Many who tried to evacuate found themselves cut off by collapsed bridges, washed out roads, and rising water, just as in Houston.
Lack of Maintenance
Aljazeera indicated that lack of maintenance may have played a role in the Derna disaster. The dams that failed hadn’t been maintained for years, even though severe erosion had been reported in scientific journals for more than a decade. Likewise, deferred maintenance played a role in flooding the Lake Houston Area during Harvey. During the drought in 2011, the water level in Lake Houston fell so low that the City of Houston could have removed sediment with dump trucks instead of dredges. But Mayor Anise Parker refused to do so. The accumulated sediment later wound up blocking the San Jacinto West Fork and contributing to the flooding of thousands of homes in the Humble/Kingwood area.
Enforcement of Building Codes
In Libya, political turmoil since 2011 reportedly distracted government from the mundane task of enforcing building codes. As a consequence, many hastily constructed buildings went up without adequate safeguards or supervision, and were swept away during the flood. Sound familiar?
Learning from Disasters
We should learn from the past and others’ mistakes. I wonder how many other communities have been surprised by:
I hope the world learns the lessons of the Derna disaster so that we can compare them to other floods and get smarter about mitigation measures that make a difference.
Posted by Bob Rehak on 9/12/2023
2205 Days since Hurricane Harvey
Earth Grows Eyeballs
We have two tropical systems in the Atlantic this morning – Hurricane Lee and Tropical Storm Margo which is projected to intensify into a hurricane by tomorrow.
I love looking at the satellite imagery of earth on the National Hurricane Center website. It lets you verify all the complex descriptions of weather developments. And this morning when I went to look at the satellite imagery of the full Atlantic, I was startled by what appeared to be a pair of eyeballs staring back at me, perfectly centered in the sunrise.
And the cloud formations below them loosely resembled a nose and a frown.
Frankly, it looked a bit spooky to me. A cosmic coincidence? But one that triggered thoughts of Halloween a little more than a month away.
Please share with your kids and grandkids. This could be an interesting way to teach them to keep their eyes on the weather.
Posted by Bob Rehak on 9/11/2023
2204 Days since Hurricane Harvey