New National Landslide Map

Benjamin B. Mirus, Gina M. Belair, Nathan J. Wood, Jeanne Jones, Sabrina N. Martinez, Parsimonious High-Resolution Landslide Susceptibility Modeling at Continental Scales, First published: 11 September 2024. Parsimonious High‐Resolution Landslide Susceptibility Modeling at Continental Scales - Mirus - 2024 - AGU Advances - Wiley Online Library 

The below is executed from the above cited article and the USGS press release.

Landslides when rock, debris, and soil move downhill at rates that ranging from inches per year to tens of miles per hour are a significant threat. Some move faster than a person can run, some can happen with no notice or can take place over a period of days, weeks, or longer.  Landslides occur in any area composed of very weak or fractured materials resting on a steep slope. This can happen in every state of the union. Reducing loss of life and minimizing community disruptions from future landslides requires an understanding of landslide potential and related direct and indirect effects. 

Now the U.S. Geological Survey has released a new nationwide landslide susceptibility map that finds nearly 44% of the U.S. could potentially experience landslides. The new assessment provides a highly detailed, county-by-county picture of where these damaging, disruptive and potentially deadly geologic hazards are more likely as well as areas where landslide hazards are negligible.

The new map will support risk-reduction and land-use planning efforts by showing where potentially unstable areas are so planners and engineers can better prioritize and mitigate future landslide hazards.“This new national landslide susceptibility map addresses an important but difficult question: which areas across the entire U.S. are prone to landslides?” said Ben Mirus, USGS research geologist. “We are excited that it is now publicly available to help everyone be more prepared – to be a more hazard-ready nation.”

As you can see below the fractured rock slopes of Virginia are susceptible to landslides.

In the past two decades, there have been several efforts to combine landslide-occurrence data with geospatial technology to develop more accurate and precise landslide-susceptibility maps. The USGS and collaborators proposed a prototype landslide-susceptibility map to inform potential landslide insurance policies (Godt et al., 2012). Their map was based on the empirical analysis of approximately 16,000 landslides from five inventories across as many different states to calibrate a landslide threshold for topographic slope and relief.

This  detailed landslide map was only developed for a few areas of the U.S. where the landslide risks were considered high, but now using all data available and better computer modeling tools this map expands the assessment to include many other hazardous areas around the country where there was a limited understanding of landslide potential.

Ben Mirus and the current research team used an inventory of nearly 1 million previous landslides, high-resolution national elevation data from the USGS 3D Elevation Program, and advanced computing to build their comprehensive landslide susceptibility model. The resulting map of the contiguous U.S., Alaska, Hawaii, and Puerto Rico zeroes in on landslide locations by using much higher resolution data than existing continental and global landslide maps.

The primary goal of the research team was to develop a high-resolution model based on empirical evidence that consistently delineates areas with any potential for landsliding across the entire country, while at the same time not over-representing hazardous areas. The secondary goal was to explore ways to express relative differences in landslide susceptibility, instead of simply noting “some” or “negligible” as has been done in previous studies (e.g., Godt et al., 2012). The topographic data used, as well as the expanded inventory of landslide data, represent an order-of-magnitude improvement over existing susceptibility maps with coverage over most of the United States. However, the variety of landslide type and geologic conditions under which slopes may fail simply cannot be accounted for by topography alone. This is an area where more work needs to be done.

The new landslide map shows higher susceptibility areas across the most mountainous regions of the United States, including the Appalachian Mountains, Rocky Mountains, Pacific Coast Ranges, and Cascade Range. The map also highlights the extensive mountainous terrain throughout Alaska, as well as the higher susceptibility characterized across Puerto Rico (Hughes & Schulz, 2020) and the Hawaiian Islands (Baum, 2018).

RiverRenew Project Nears Completion

AlexRenew, the project to solve combined sewer overflows in Alexandria, is reaching out to the public to hear their concerns as the project moves into it’s last stages. The final components include: Pile Driving at the Pendelton Street site and months of concrete pours at the Royal Street site. This will finish the liner of the 130-foot-deep drop shaft connecting the site's diversion facility to the Waterfront Tunnel bringing the project to completion.

The area of Alexandria around Old Town has a Combined Sewer System which is a piped sewer system where there is one pipe that carries both sanitary sewage and stormwater to the local wastewater treatment plant, AlexRenew. This was how sewer systems were often built in the days when sanitation was simply moving sewage out of the city to the rivers and streams. Back then one piping system was cheaper and adequate for the job. Today when sewage is treated by wastewater treatment plants that is no longer adequate. 

When it rains, water that falls in the streets, enters the storm water drains and is combined with the sanitary wastewater entering the sewers from homes and businesses. The combined flow of the sewage and rain can overwhelm the wastewater treatment plant. So, to protect the sewage system as a whole, the combined sewage and rainfall has been released into the local creeks from one of the “Combined Sewer Overflows” which are release locations permitted and monitored by the regulators. Though it’s monitored it increases nutrient and bacterial contamination to the streams and rivers.

To solve this problem in 2017 the state passed legislation to eliminate these overflows by 2025, creating a challenge for the city, but partially based on the experience of Washington DC in addressing their combined sewer problem, AlexRenew was confident that they could meet this challenge. Alexandria and AlexRenew submitted a long term control plan to the Virginia Department of Environmental Quality (VDEQ) that was approved in 2018. Alexandria transferred ownership of the outfalls and the interceptor lines (the sewer mains transporting to the raw sewage to the treatment plant) to AlexRenew. The approved and almost compled plan, called RiverRenew, includes building a tunnel system with:

• Storage tunnels 
• Conveyance tunnels 
• Diversion facilities (diversion chambers and drop shafts) 
• Dewatering pumping stations

and upgrading the AlexRenew waste water treatment plant by:

• Adding a wet weather pumping station and
• Increase treatment peak capacity for the wastewater treatment plant from 108 to 116 million gallons a day 

 RiverRenew  will prevent millions of gallons of sewage mixed with rainwater from contaminating the Alexandria rivers and streams. This will limit the amount of bacteria, trash, and other pollutants flowing into Hooffs Run, Hunting Creek, and the Potomac River and achieve cleaner, healthier waterways for Alexandria. At completion of RiverRenew it is expected that only a few overflows will occur each year down from the current average of 70. Instead sewage and rainwater that flow through the city’s combined sewer system will pass through a diversion facility and then .make their way to AlexRenew via the Waterfront Tunnel. 

Each individual part of the diversion facility was carefully engineered to control and transfer these flows as efficiently as possible. However, there have been and will continue to be disruptions as the work is completed. AlexRenew continues to reach out to the public and hear their concerns. You can attend one of two listening sessions next week.

RiverRenew Community Listening Session: Pendleton Street

September 16, 2024 at 5:30 PM — 7:00 PM501 N. Union Street –

RiverRenew Community Listening Session: Pendleton Street

September 16, 2024 at 5:30 PM — 7:00 PM

Water Pledge

The corporate giants that behind the data center explosion in Northern Virginia have  pledged (from Alphabet, Meta, Amazon and Microsoft) to be water positive- to replenish the freshwater volume that they consume by 2030, and help restore and improve the quality of water and health of ecosystems in the communities where they operate. Alphabet and Microsoft have pledged to replenish 120% of the fresh water they consume.

Water is our most valuable resource and how we manage its use or allow its abuse may determine the fate of our country and mankind. On earth all the water that ever was or will be is here right now and has been here for over 4 billion years. There is no mechanism on earth for making or destroying water.

 More than 97% of the Earth’s water lies within the oceans. The remaining 2.8% is the "freshwater" within the land masses. The land masses water contains all the freshwater on the planet- 77% in icecaps and glaciers and the remaining freshwater is stored primarily in the subsurface as groundwater with a tiny fraction of a percent of water flows as rivers or is stored in lakes which are renewed by rainfall (or snow). Rain drops fall to earth and will evaporate, infiltrate into the soil, recharge groundwater or flow along the ground to a stream and ultimately flow into rivers and to the ocean-moving, always moving.

Mankind has interrupted the flow of streams and rivers to the oceans by diverting water for irrigation, withdrawing drinking water and building reservoirs. We have also interrupted the recharge of groundwater by changing land use, covering it with buildings, driveways, roads, walkways and other impervious surfaces which change the hydrology of the site reducing groundwater recharge in the surrounding area. 

The Gravity Recovery and Climate Experiment (GRACE) satellite mission from the National Aeronautics Space Administration (NASA) has been collecting data for more than two decades. The GRACE satellites measure monthly changes in total earth water storage by using measured gravity anomalies. In the first decade scientists found that more than one third of Earth's 37 largest groundwater basins are using up their groundwater faster than it is being replaced. Additional data has only confirmed the finding. 

Throughout history surface water served as the principal freshwater supply used by mankind. However, in recent decades as mankind’s demand for water has surpassed surface supplies and our ability to access groundwater has increased with technology, groundwater has become essential. Fresh surface water can no longer support the needs of 8 billion people. Accessing groundwater allowed populations to increase and provide reliable water as surface water has become less reliable and predictable as weather patterns change and regions experience extended droughts. The GRACE mission tells us we are using up the groundwater and we face a future with not enough water for our needs.

The United Nations projects that 68% of the projected 9 billion people that will be the earth’s population will live in urban areas by 2050. The water supply to the rapidly growing cities has become unstable because of changing rain patterns, increased impermeable surfaces and increased population and demand for water. The available supply of fresh water is limited to that naturally renewed by the hydrologic cycle or artificially replenished by the activities of mankind. Though it can still exceed water demands during unusually wet periods, during droughts it falls far below demand.

The Metropolitan Washington Council of Governments projects that  population in our region will reach nearly 6.8 million people by 2050 an increase of  1.1 million people. While our available water resources will not increase. Though only recently noticed by our communities, data centers use lots of water. Not at the magnitude of power use, but nonetheless they are estimated to use about 0.5 gallons of water for each kilowatt-hour consumed. Unfortunately, power usage and water usage at specific sites are guarded as trade secrets so I cannot project the power usage and water use as Northern Virginia's data center are fully built out.

We do know that Google reported in their last annual report that in 2022 their data centers used 5.2 billion gallons of water, which is a 20% increase from the previous year. In addition, it was reported that on average, a Google data center uses 450,000 gallons of water per day. (About as much as 6,400 people- which would be fine if there were one or even 10 data centers, but there are hundreds in Northern Virginia alone and more being built every day.

In cool and moderate climate regions, adiabatic cooling can be used for cooling the data servers, resulting in reduced energy and water consumption. During cooler months, outside air is directly drawn into the data center without using any water and during warmer months, the warm air is drawn through water-moistened pads. As the water in the pads evaporates, the air is chilled and pushed into the server halls. In warmer climates like Northern Virginia and other data center hubs in the United State water cooled system are used.

In a water-cooled system, water-cooled chillers and cooling towers located on top of the data center roofs produce chilled water, which is delivered to computer room air conditioners for cooling the entire building. These systems include the cooling towers, chillers, pumps, piping, heat exchangers / condensers, and air conditioner units in the computer rooms. Additionally, data centers need water for their humidification systems (to avoid static discharges) and facility maintenance. Water-based cooling using evaporative cooling systems are more common in Virginia, particularly for large data centers simply because it is more efficient and effective.

Traditionally, sustainability goals by the data center industry have focused on energy, but that trend is shifting. Changing climate and population growth are only exacerbating an existing problem. Large portions of the earth are experiencing water stress. Corporate water management efforts are shifting focus toward water replenishment and watershed health. Most data center companies typically target water replenishment as their water sustainability goal. The typical pledge is to replenish 120% of the freshwater volume that it consumes by 2030 and help restore and improve the quality of water and health of ecosystems in the communities where they operate.

Where exactly are the data center companies going to get this excess water, they plan to return more of than they use to communities? Obviously, they would have to take it from another watershed or somewhere else. Water is a zero-sum game here. No one is adding water to the watershed, but the data center companies only count fresh water. 

Loudoun County built a reclaimed water system to supply data centers more cheaply with water. The data centers loudly proclaim that they are using wastewater, not freshwater.  However, there are two problems with that. The expansion of data centers required more than that system could provide. The water from the Broad Run Wastewater Treatment plant was inadequate to serve all data centers and still provide adequate flow. The second problem is the discharge from Broad Run Wastewater treatment plant is upstream of the river intakes for Fairfax Water, WSSC, and the Washington Aqueduct. The Washington Metropolitan Area was previously drinking that reclaimed wastewater.

According to Loudoun County, Data center water use will have grown to an average 4 million gallons a day of potable water and 4 million gallons a day of reclaimed water by the end of this year- since in northern Virginia we indirectly drink the reclaimed water from UOSA and returned treated wastewater upstream to the Potomac, that is enough water to supply 100,000 people. The water demand, like the number of data centers, are growing very rapidly. Unfortunately, the water supply for the region is not growing. 

The Occoquan Reservoir, a locally essential portion of our water supply, is fed by the Occoquan River which receives up to 40 million gallons a day of the treated wastewater discharge of the Upper Occoquan Sewage Authority treatment plant, UOSA.  A significant portion of the flow (especially during dry periods) into the reservoir is recycled sewage. This has been true for decades because the region, though water rich, does not have enough water.

This treated wastewater is from areas supplied by the Potomac River (down river from the Broad Run release) or lake Manassas, so you do not end up with constantly recycling and concentrating the same impurities into the drinking water supply. These impurities include elevated salt levels and traces of  PFAS that have been found in the Occoquan Reservoir. The wastewater that originates from the Occoquan Reservoir served areas is treated at the HL Mooney Plant in Woodbridge and discharged into Neabsco Creek, a tributary of the Potomac River at Occoquan Bay.

Data center operators are making commitments to replenish water in the watersheds impacted by their operations. The projects they point to as examples range widely in scope from ecosystem protection and restoration to water rights reallocation. None of those kinds of projects would bring more water to the Washington Metropolitan Area, yet we have the lion share of data centers and now they are expanding to build in areas served by groundwater. They are destroying the groundwater recharge as they cover more and more of the ground with data centers, roads, driveways etc.

Climate change is only exacerbating an existing problem, we are growing and expanding our water demand beyond our available water resources. We need to manage our water resources to ensure that they are sustainable.

Salamanders

Some of the content below is excerpted from the articles cited below and USGS and Penn State news releases.

As I’ve mentioned, my house sits on a bit over 10 acres, about three of them lawn and ornamental gardens which turned into baby deer and doe pasture this summer. The remaining seven acres is woodland, and much of the woodland is part of the “resource protected area,” RPA of the Chesapeake Bay. 

For a number of years, I have been engaged in a project to restore the woodland and cut back the invasive species. The invasive vines especially the autumn olive and Japanese honeysuckle were choking out the natural renewal process. As we’ve cut back the invasive species inside the woods, we’ve been creating a woodland path to walk  down the hill towards the creek. Now the path ends at a constantly muddy area where there is a seep above Chestnut Lick creating vernal pools in the spring. The area is drier during the summer in the past two years when we have had droughts. Still the soil remains moist.

A seep is the low-pressure twin of spring and occurs where groundwater discharges to the surface. In my case the groundwater emerges where the hill cuts down to the creek. Usually, seeps are merely wet , but groundwater discharge flows at many seeps even through the driest summer months. I was walking in the woods with an eight-year-old and trying to see if the August rains had restored the seep when I saw a red backed salamander. I had not seen a salamander since I was a kid and the eight-year-old and I were both excited.

Salamanders (Amphibia: Caudata) are ancient vertebrates. The red-backed salamanders is  a native of the northeastern United States especially in moist forest leaf litter, headwater streams, riparian ecotones, swamps, and seasonally inundated pools. Pretty much my back yard.

Now a new study cited below (with the longest list of authors I have ever seen) highlights the ecological niche of red-backed salamanders in the northeastern United States. The article found that the salamander’s population densities and biomass across the region was much higher than expected, with the greatest abundance in Appalachia.

The study authors estimated an average of 5,300 salamanders in every patch of forest the size of a football field (1.32 acres) in the Northeast. Even though each salamander is only3 inches long, the  number of red-backed salamanders means that they also have some of the highest biomass estimated for animals other than insects in the Northeast, similar to or greater than the biomass of the white-tailed deer. Wow.

“Salamanders serve a vital function in forest ecosystems,” explained David Miller, professor of wildlife ecology at Penn State and one of the co-authors of the study. “They are at the top of the food chain on the forest floor, where everything is breaking down into the soil that sustains this entire network of life. In fact, salamanders are so important to this life cycle that we can use them as a barometer for forest health.”

Just as I was thinking that seeing a salamander was a positive sign of the forest health, they gave me something new to worry over. A lethal invasive fungal disease.  Batrachochytrium salamandrivorans, or Bsal for short, is a fungal disease closely related to the chytrid fungus that is already devastating amphibian populations around the world. It was first found in the Netherlands in 2013 and, since then, has decimated the salamander populations in central Europe and continues to spread across Europe.

Bsal hasn’t been detected in the U.S. yet, so scientists and wildlife managers are preparing for its arrival with the North American Bsal Task Force. Another study completed this week tested proactive measures to see if they are effective. The Bsal Task Force needed evidence that proactive management would be more effective than waiting to respond until the disease is detected in the wild. So, Grant co-authored another recent paper that tested a series of proactive and reactive management actions to forecast the impact on salamander populations over time.

The study, “Proactive management outperforms reactive actions for wildlife disease control,” used computer modeling to confirm what seems intuitively obvious: namely, initiating management of wild populations before Bsal arrives is, in fact, more successful at keeping salamanders from disappearing than waiting until after Bsal is detected or not doing anything at all.

 “If we do nothing to manage Bsal, the model forecasted that the disease would be catastrophic to North American salamander species,” said Molly Bletz, assistant professor of disease ecology at Penn State and lead author of the second study. “This study gives strong quantitative support to proactive management actions." Basically, if we want salamanders to be around in the future, doing something besides wringing your hands.

 In addition, in 2016, the US Fish and Wildlife Service issued a rule that prohibits the importation or interstate transport of 201species of salamander and samples derived from them unless a permit is issued. It's a start. 

Grant Evan H. Campbell, Fleming Jillian, Bastiaans Elizabeth, Brand Adrianne B., Brooks Jacey L., Devlin Catherine, Epp Kristen, Evans Matt, Fisher-Reid M. Caitlin, Gratwicke Brian, Grayson Kristine L., Haydt Natalie T., Hernández-Pacheco Raisa, Hocking Daniel J., Hyde Amanda, Losito Michael, MacKnight Maisie G., Matlaga Tanya J. H.,  Mead Louise, Muñoz David, Peterman William, Puza Veronica, Shafer Charles, Sterrett Sean C. Sutherland Chris, Thompson Lily M., Warwick Alexa R., Wright Alexander D., Yurewicz Kerry and Miller David A. W. 2024Range-wide salamander densities reveal a key component of terrestrial vertebrate biomass in eastern North American forestsBiol. Lett.2020240033 Range-wide salamander densities reveal a key component of terrestrial vertebrate biomass in eastern North American forests | Biology Letters (royalsocietypublishing.org)

Davic, Robert D.; Welsh Jr., Hartwell H. 2004. On the ecological role of salamanders. Annu. Rev. Ecol. Syst., Vol. 35: 405-434

Salamanders are surprisingly abundant in Northeastern forests, study finds | Penn State University (psu.edu)

Molly C. Bletz, Evan H. Campbell Grant, Graziella DiRenzo; Quantitative support for the benefits of proactive management for wildlife disease control; First published: 26 August 2024. The Society for Conservation Biology (wiley.com)

4.4 Billion Lack Safe Drinking Water

Greenwood, E. E. Lauber, Thomas, van den Hoogen, Johan,  Donmez, Ayca, Bain, Robert E. S.,  Johnston, Richard, Crowther, Thomas W.,  Julian, Timothy R.  Mapping safe drinking water use in low- and middle-income countries;  Science 385, 784–790 (2024).

 A recent study (cited above) found that more than 4.4 billion people in low- and middle-income countries lack access to safely managed drinking water.

According to the authors more than half the world’s population lacks safe drinking water and fecal contamination affects almost half the population of low and middle income countries. (The analysis excludes the richer nations which probably also have some portion of their populations without clean and safe drinking water.)  The findings either show that previous global estimates for lack of safe drinking water availability at 2.2 billion  have greatly underestimated the problem, or their model for prediction overstates it.

The availability of safe drinking water is far from universal, but exactly how it varies geographically and why this occurs is not well understood. Greenwood et al. combined Earth Observation data, geospatial modeling, and household survey data and linear regression modeling to estimate that only one in three people in low- and middle-income countries have access to safely managed drinking water. 

Using four criteria for safe drinking water: they must be improved, consistently available, accessible where a person lives and free from contamination. The authors used environmental data combined with survey responses about the 4 criteria from 64,723 households across 27 low- and middle-income countries between 2016 and 2020. If a household failed to meet any of the four criteria, it was categorized as not having safe drinking water. 

The authors trained a machine-learning algorithm using survey data and global geospatial data. “The resulting model was best at predicting drinking water accessibility on premises (R² = 0.48, MAE = 0.18) and fecal contamination (R² = 0.44, MAE = 0.16) followed by an improved drinking water source (R² = 0.25, MAE = 0.11). Model performance was worse when predicting populations with drinking water availability (R² = 0.01, MAE = 0.09) based on leave-one-country-out cross-validation R².” (Greenwood et al 2024) The low  R squared (R²) could reflect limited associations between predictors and a household member’s subjective assessment of experiencing water insufficiency which is influenced by their practices of water storage or use of multiple water sources when in need  to estimate that 4.4 billion people lack access to safe drinking water, of which half are accessing sources tainted with the pathogenic bacteria Escherichia coli.

 R-squared ( R²) is a statistical measure that indicates how well a model's independent variables explain the variation in a dependent variable. It's also known as the coefficient of determination. An R squared of 1.0 means that the model perfectly predicts the data. The closer the R squared is to 1.0 the better the fit. Not so much here. There are anomalies in the calculation that could generate a low R squared and still have the model be predictive. This data sample is incredibly small to build this type of model. Variations in water availability and quality change over time and location and population density. The predictive validity of the model is brought into question. 

The United Nations, General Assembly in its 64th session: 2009-2010 adopted a resolution that Safe Drinking Water and Sanitation was a Human Right. The WHO/UNICEF Joint Monitoring Program for Water Supply ,Sanitation and Hygiene (JMP) has reported country, regional and global estimates of progress on drinking water, sanitation and hygiene (WASH) since1990. The JMP uses a mathematical extrapolation of available data to create their estimates.

The 2017 report was the first this was followed by progress in 2019, 2021 and 2023. The 2023 update estimated (using country provided data) that in 2022, 27% of the global population (2.2 billion people) lacked “safely managed drinking water”– meaning water at home, available, and safe. 43% of the global population (3.5 billion people) lacked “safely managed sanitation” – meaning access to a toilet or latrine that leads to treatment or safe disposal of excreta. 25% of the global population (2.0 billion people) did not have access at home to a handwashing facility with soap and water.

Greenwood et al estimated that 88% of all people living in LMICs use an improved drinking water source. Their results emphasize that access to an improved drinking water source does not always provide safe drinking water as almost half of the LMIC populations (48%) were estimated to be exposed to fecal contamination in their primary drinking water source. Their predictions show that more than half of the populations of Oceania, sub–Saharan Africa, southeastern Asia, and Latin America and the Caribbean may be exposed to  drinking water contaminated with E. coli.

Lack of accessibility of drinking water on premises was the second most common subcomponent limiting safe drinking water coverage, with an estimated 36% of the overall LMIC population not having water on premises. This is especially true in sub–Saharan Africa where Greenwood et al estimated that over 650 million people lack drinking water services on premises. However, the bottom line is that Greenwood et al used  limited data and AI to create an model  with limited correlation to estimate the number of people on earth without access to safe drinking water. The WHO/UNICEF Joint Monitoring Program using limited data and estimating techniques found that number of people without access to safe drinking water to be half of the Greenwood estimate. It’s probably billions and it is humanity’s big challenge, just using an AI trained model, Earth Observation data, and geospatial modeling does not necessarily make the estimate better.

Read Tim Smedley’s book “The Last Drop” for a feel of what this means in people’s lives.