Drought and its companion disasters of extreme heat and wildfire have been in the news a lot lately. More than 99% of the nine-state Western Region of the U.S. was experiencing some level of drought on July 27, 2021, according to the U.S. Drought Monitor, and 65% of that region was in “extreme” or “exceptional” drought.

An April 2020 article in the journal Science suggested that our current, multi-year drought in the Western States may be the most severe in 1,200 years. Lake Mead, the nation’s largest reservoir, is at its lowest level since Hoover Dam was built and the reservoir created in 1931; the current surface elevation (August 3, 2021) is 1,068 feet above sea level and expected to keep dropping through late-fall.

Lake Oroville, California’s second-largest reservoir, was at 25% of capacity on August 3, 2021, and operators of the hydropower facility at the Edward Hyatt Powerplant at the reservoir warn that the water level could drop below the level at which power can be generated in August or September—for the first time ever. Reservoirs throughout California are at near-record-low levels.

The extreme drought we’re witnessing is exacerbated by record temperatures throughout the West. Temperature records were set this summer in many areas of the Pacific Northwest, including Portland and Seattle. In parts of British Columbia, Canada, peak temperature records were broken by double digits, and the province recorded the highest temperatures ever measured in Canada.

Where there is drought and extreme heat there are also wildfires. Following a series of years with record wildfire in the West, this year is projected to be as bad or worse. According to an August 3, 2021 report from the National Interagency Fire Center, wildfires in a dozen Western states have already burned over 3.2 million acres.

Other cascading impacts of drought

We typically consider only the direct impacts of drought, extreme heat, and wildfire: dropping reservoir levels; record temperatures; and forests aflame. But there are other, cascading impacts that we will increasingly have to deal with.

Power generation

When droughts are severe enough, power generation is affected. With hydropower, that impact is pretty straightforward. There isn’t as much water flowing through the turbines at our hydropower reservoirs, and dropping water levels reduce the head (power production potential) at those facilities. If the water levels drop low enough power generation ceases altogether.

The Hoover Dam on Lake Mead had to be reconfigured in recent years to allow power generation at the lower water levels that are expected in the coming years. While the Hoover Dam originally produced about 2,000 megawatts (MW) of power, production has been downgraded to about 1,500 MW, and if the water level were to drop another 172 feet, power generation would no longer be possible.

But power production is also affected by extreme drought in most thermo-electric plants. These are power plants that use natural gas, coal, nuclear power, or another heat source to create high-pressure steam, which drives turbines to generate power. Thermo-electric plants require cooling systems to condense that steam back into water. Some of these plants—especially those in the Southwest and California—recirculate the cooling water, use ocean water for cooling, or use other technologies to minimize or avoid water consumption, but throughout most of the U.S. thermo-electric plants use once-through, fresh-water cooling, and if water levels drop in the cooling-water source, or when the temperature of that cooling water gets too high, power generation can be reduced or even cease.

For these power plants, during extreme droughts, power generation can be significantly reduced. To make matters even worse, these times of constrained power generation are typically when cooling loads are the highest, due to electricity consumption for air conditioning.

Increased flooding threat

Ironically, during very dry periods, the risk of flooding can increase. Extreme drying of the ground can alter the soil in ways that reduce water infiltration and increase runoff. Droughts can also kill vegetation that normally enhances infiltration.

On top of this, data over the past fifty years has shown an increase in extreme precipitation events with climate change. Even if an area is getting less total precipitation due to drought, that precipitation is often falling in larger dollops, leading to increased stormwater runoff and downstream flooding.

Increased landslides and debris flows

Dry, hot conditions destabilize soils in a number of ways. Either wildfires or excessive heat can kill vegetation, which normally plays a critical role in holding soils in place on slopes. Without that vegetation, soils are less stable and landslides, or debris flows, can occur. We regularly see this in hilly California communities following wildfires.

In early January 2018 the community of Montecito, California experienced devastating landslides that claimed the lives of 23 people and destroyed or damaged hundreds of homes. The landslides occurred when a half-inch of rain fell in a five-minute period at 3:30 am in Santa Barbara County, including on an area that had been heavily damaged by the Thomas Fire a month earlier. The resulting debris flow was up to 15 feet deep and flowed at speeds up to 20 miles per hour, carrying boulders and trees into the thickly developed valley.

Reduced food production

With less water and higher temperatures, agricultural production drops. Some farmers in California have been abandoning almond orchards and selling their water rights to other producers and urban areas. As droughts get more severe this will become more common.

Severe drought in 2012 affected 80% of agricultural land in the U.S., causing two-thirds of counties to be declared disaster areas and resulting in $14.5 billion in loss payments by the Federal Crop Insurance Program, according to the National Integrated Drought Information System.

California has 26.4 million acres of land in agriculture, and roughly 40% of that is irrigated, with allocations determined by the state. During severe droughts, allocations to agriculture are reduced to be able to provide more water to urban areas. With these reductions, farmers are reducing their planted acres and, in some cases, changing their crop plans—for example replacing relatively low-value, high-water-demand crops like alfalfa with smaller areas of higher-value crops.

In 2018 the Public Policy Institute of California reported than alfalfa production (for livestock feed) uses 18% of the California’s agricultural water and produce just 4% of the state’s agricultural revenue, while tree crops and vines (almonds, fruit trees, grapes) use 34% of the state’s agricultural water but account for 45% of the revenue. Shortages of water are resulting in changes in how agricultural land is being planted.

In addition to the impact of drought on crop production, excessive heat also has a very significant impact. A 2017 Research Article in the Proceedings of the National Academy of Sciences, “Temperature Increase Reduces Global Yields of Major Crops in Four Independent Estimates,” reported that each one decree Celsius of temperature increase, reduces average crop yields as follows: wheat 6.0%; rice 3.2%; corn 7.4%; and soybeans 3.1%. Worldwide, these four crops account for two-thirds of human caloric intake.

Impacts on air quality and health

When I walked out of my Dummerston, Vermont home one day a couple weeks ago, the sky was thick with smoke. The smoke was so thick and the smell so strong I thought there was a structure fire in the village below our house. But it was region-wide—smoke from wildfires in the far western Canada and the Pacific Northwest. This resulted in the worst summertime air quality our state has seen in years and advisories to stay indoors.

The American West has been dealing with these advisories for years, and the poor air quality in the West has fueled demand for improved air filtration and air purifiers (including plenty of scams for systems that don’t deliver what they promise). Oregon reported a 10% increase in hospitalizations in September 2020, likely due to air quality impacts from wildfires, the New York Times reported that month, and studies show such long-term health impacts as reduced birth weight for babies and impaired lung function in adults.

The more direct health impact is extreme heat, which is blamed for hundreds of deaths in the Pacific Northwest and western Canada this summer. The late-June heat wave was described by officials in Oregon as a “mass casualty” event. We didn’t hear much about it, because another mass-casualty event, the condominium collapse in Florida, happened at the same time.

An article in the May 2020 issue of Science Advances, “The Emergency of Heat and Humidity Too Severe for Humans to Tolerate,” describes the compounding impact of high humidity to the health risks from extreme heat. At a wet-bult temperature above 95°F (35°F) the human body is unable to cool itself. A few parts of the world already experience wet-bulb temperatures above 95°F, and with climate change more regions are expected to exceed that threshold.

Threats to development and prosperity

When I lived in Santa Fe in the late-1970s, I remember a small article in the local newspaper about a study showing that within a few decades water shortages could limit continued growth of the burgeoning city. The article sparked barely a ripple of concern. The city’s population—then about 50,000—is now over 70,000 and projected to reach 125,000. We keep kicking the can down the road, but there are signs that in some parts of the West, the impact of water shortages on real estate are starting to be felt.

Friends of mine from the Santa Fe area, concerned that water limitations would cause their property value to drop, picked up stakes and moved to New Hampshire. Throughout the West such actions may become more common in the coming years.

A July 20, 2021 article in the New York Times , “A Drought So Dire That a Utah Town Pulled the Plug on Growth,” describes how the fresh-water spring that had long served the town of Oakley, Utah ran dry for the first time in 2021. The town of 1,750, an hour east of Salt Lake City, that had been experiencing rapid growth during the COVID pandemic, imposed a moratorium on building—one of the first in the nation.

So what should we do about these interrelated crises of drought, wildfire, and extreme heat?

Unfortunately, there aren’t easy answers to this question. There will continue to be denial and inaction by many. But there are some important ways in which we can slow the impacts and prepare for the challenges ahead.

1. Get serious about addressing climate change.

This is, arguably, the most important priority. Scientists tell us that there may still be time to head off the worst impacts of a changing climate—impacts that could make today’s impacts seem trivial. Society needs to redouble efforts to phase out fossil fuels, fluorocarbons, and other greenhouse gases, while capping abandoned methane wells and working to sequester carbon in soil, forests, and sustainable agriculture.

We need to develop new ways to remove carbon from the atmosphere and permanently sequester that carbon—such as new formulations of concrete that could transform this building material from being one of the largest sources of carbon emissions into a carbon sink.

2. Dramatically reduce water consumption

Institute state-of-the-art water conservation practices to dramatically reduce water use in buildings, in our landscapes around buildings, in agriculture, in power generation, and in industrial processes. There is a lot of low-hanging fruit—such as funding buy-back programs for older, water-wasting toilets and showerheads; replacement of thirsty turfgrass with native prairie plantings; drip irrigation practices in agriculture and avoidance of the most water-intensive, irrigation-dependent crops in arid regions; and elimination of once-through, fresh-water cooling for thermo-electric power plants.

Fortunately, there are some opportunities through which multiple benefits can be achieved. We can replace coal-fired, thermo-electric power plants with solar-electric and wind farms, which require virtually no water. Newer, water-efficient toilets perform better than their older relatives. Replacement of turfgrass with native ecosystems, along with saving water, can enhance biodiversity. Adding a large cistern for rainwater storage can be used both for landscape irrigation and for fire suppression.

3. Make resilience a priority

Institute a wide range of resilience measures in designing and constructing structures and landscape features in our built environment. We need to examine where we build, how we build, and how to protect existing buildings and infrastructure.

In areas prone to wildfires, we need to manage the landscapes appropriately, while using fire-resistant building practices: ember-excluding soffit and ridge vents, tempered insulated-glass windows, fiber-cement siding, avoidance of decks, etc.

Where flooding is a risk, we should try to avoid building in the 500-year flood zone, elevate structures to minimize risk, move mechanical and electrical equipment out of basements, specify building materials able to get wet and dry out without damage, etc.

To enhance safety during heat waves, and especially in the event of power outages, we should incorporate passive survivability features that I’ve often written about on the RDI website. These strategies include cooling-load avoidance measures, design for natural ventilation, very high levels of energy performance, etc.

Resilient design is a growth industry that will require the smartest minds as we progress through this century. It will be extremely difficult; it will be very expensive; it will be disruptive…. But we don’t have any choice.

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Along with founding the Resilient Design Institute in 2012, Alex is founder of BuildingGreen, Inc. To keep up with his latest articles and musings, you can sign up for his Twitter feed. To receive e-mail notices of new blogs, sign up at the top of the page.