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There’s Hurricanes in Florida and Texas Had Rain

Posted on September 19, 2017 by Bill Leave a comment

Colorado Desert

I am a child of the desert, and the guy sitting next to me in the coffee shop is from Saudi Arabia. Those of us from dry country usually don’t understand why people would choose to live in wet, low country with hurricanes. Yes, there is the ocean, but we can always go to Lake Powell or Lake McCounaughy. We do have a few tornados and hailstorms, and one of the canyons floods every 15 years or so.

On the gulf or Florida coast they get a hurricane at roughly the same intervals, but the damage is widespread and many more people are affected. For some reason, most of the people in the world live close to a seacoast. Yes, trade is easier and things tend to grow there (not like our Great American Desert).

Too low, too many people, too wet. And yes, the oceans are headed inland. It will be even wetter. It is somewhat harder to make a living here in mid-continent and the seasons can be more harsh, but grand catastrophes are rarer. I must confess a warm ocean is good for visits, but I did not like the mid-Atlantic, but maybe it was because I was on a troopship.

Another problem with seacoasts is many of them have a tendency to shake. The tectonic plates collide on the coasts, thus mountains and earthquakes. I prefer the ground under me to hold still. When we visited Carol’s daughter in Menlo Park CA, I was a bit nervous being halfway between the San Andreas and Hayward faults in a flood plain. The real irony is that the U.S. Geological Survey regional office is there.

Japan Earthquake and Tsunami

Here in Denver, there were big earthquakes once when the Rockies were rising, but it has been a while. We had a flurry of small ones when they were pumping hazardous waste down a drill hole at the Rocky Mountain Arsenal. When they stopped pumping, the earthquakes stopped. That lesson was ignored in the Oklahoma oil fields where they pump fracking water back down drill holes instead of treating it. Most of the state is shaking.

“Do it cheaply, don’t bother with doing what is right.” It seems to be standard procedure in the extractive industries such as oil and gas and mining. The solution is regulation, but the oil business owns the government in Oklahoma and Texas. They are close to owning the U. S. Government.

I seem to have drifted into a rant. Weren’t we discussing living on the coast? The coasts stand to reason from a short term economic standpoint. The rivers are there, shipping is cheap, it is fairly flat, and the climate tends to be moderated by the ocean. Except when it is not. Hurricanes, nor’easters, increasingly wetter monsoons, and sea level rise is scary.

Tidal Flood in Florida

How would you like having sea water pouring out of the storm drains in your street at high tide? What about having your crops inundated by incessant rain? Do you want the roof ripped off your house and be without power for many days? Then there are tsunamis. Take a look at the Japan tsunami on YouTube. If none of this stuff bothers you, live on the coast.

Posted in Climate Change, Desert, Earthquakes, Environment, Floods, Hurricanes, Politics, Stories, Weather

Water

Posted on February 8, 2017 by Bill Leave a comment

Colorado River Basin

I spent thirty years in the water business. I was one of the troops, not a manager or staff person. I did, however, do what I could to keep up with developments in the water and wastewater business. With the Clean Water Act and the Environmental Protection Agency, rivers no longer catch fire, and our fresh water. Supply is in much better shape than, say, the 1950’s.

I worked at the Greeley, Colorado wastewater plant for three years. The water we sent to the river met EPA standards until the Cache La Poudre flooded and washed out the pipe carrying water from one side of the river to the other for final treatment. Lots of raw sewage went into the river for about a week until an emergency pipeline was laid on the highway bridge next to the plant.

An old adage in the wastewater business goes, “The solution to pollution is dilution”. That saying is mostly obsolete, but during that flood there was plenty of water for dilution. We had to wear hip waders to get around the north side of the plant, flooded with almost three feet of water.

The Denver Water System

Here is a big part of the water story in the American West. There is either too much water or not enough. Here on the Colorado Front Range a water crisis is slowly developing. The available water is starting to run out. Half of Denver Water’s water supply comes under the Continental Divide from the Colorado River. There is little more water available from the river for the Denver Metro population except from spring runoff, when there is more water than can be stored. Most years.

Other years, the snowpack is down, spring runoff is low, reservoirs drop, and worry starts. Water supply fluctuates, but demand only increases. Oh, wait, during a big drought recently, the Denver Water Board shifted its priority from dam building and water diversion to conservation. It worked, and continues to work, not just with Denver. Another water source is also coming into use.

Water law says if you use water from your nearby stream, you must return what you didn’t use to the stream. Water users downstream get lots of their water from return flows from irrigation or wastewater plant outflows. Water law also states that water you divert from another basin does not have to be returned. You can use it to extinction. So what once went downstream is being captured in new reservoirs downstream made from old gravel pits and used for water exchanges, where downstream users trade their upstream water rights for return flow water from Denver. The potato and corn fields don’t seem to mind.

The other thing happening is taking that foreign water, treating it, and pumping it upstream for reuse. At this point it is mostly for irrigation of parks, golf courses, and the like, but it is also being treated to drinking water standards. Yes, you might be drinking water that once was sewage. Not to worry, think about Omaha, St. Louis, Memphis, and New Orleans. What are they drinking?

Eventually this will all end. The water will run out. At some point, tap fees for new housing or industry will soar and development will go elsewhere. The growth cannot continue indefinitely. The same thing will occur in the entire Colorado River Basin. Despite every effort to conserve or store more water, it is going to run out. The new growth will then go to Cincinnati and Birmingham, all those wet places back East.. They have lots of water.

Posted in Stories, Water, Water Treatment, Water Treatment Plants

Politicians, Geologists, Engineers, and Water

Posted on January 3, 2017 by Bill One comment

Mosul Dam

This story relies on a report by Dexter Filkins in the New Yorker magazine. Mr. Filkins, a Pulitzer Prize winner, is one of the best writers covering the Middle East.

The Fertile Crescent, where civilization developed, exists because the Tigris and Euphrates rivers flow from mountains in Lebanon and Turkey to the Red Sea. The terrain along and between the rivers is relatively flat making agriculture feasible. The rivers flood every spring, bringing water and new sediment to the region. Those conditions support a significant population, but annual fluctuations have always created problems for the people living there. During drought years, crops fail and famines ensue. Wet years bring flooding which displaces people and affects farming.

These conditions prevail in every arid region dependent on irrigation for farming. The Nile, the Fertile Crescent, and the Colorado river are prime examples. In all three regions, the political system has chosen to attempt to regulate the annual fluctuations in the river. The solution? Dam the river, store water for dry years and catch excessive runoff in wet years.

Glen Canyon Dam and Hoover Dam on the Colorado, Aswan High dam on the Nile, and the Mosul dam on the Tigris are the attempts at a solution. So, they decide on a dam upstream of the people, hire geologists to recommend a good location, and hire engineers to design and build the thing.

This worked, to a degree, on the Colorado and the Nile. Not so well on the Tigris. The geology above Mosul with its 2.5 million people is a jumble of sedimentary rocks formed in conditions similar to today. That means flat coastal areas are intermittently flooded by the sea or nearby rivers. The water evaporates, leaving the minerals dissolved in the water. That means salt, gypsum, limestone, and a mixture of soluble minerals and mud called marl.

The layers are deposited in flat layers, but Middle East geology is like Middle East politics, a big jumble with forces pushing from several directions. Above Mosul, it is quite a jumble, but sinkholes have always formed as water dissolves the soluble minerals, leaving voids that collapse. It is called Karst topography. Florida is a prime example, a limestone peninsula in a wet climate surrounded by water. It rains, the water sinks in, dissolves the limestone, and goes to the sea. Florida is dissolving, the rock resembling a sponge.

The rock above Mosul has both limestone and gypsum. Gypsum is a sulfate mineral that is called plaster if pretty dry, wallboard if more hydrated, goo if very wet, and then dissolves. The geologists said “No, no dam, it will fail”. The politicians then talked to the engineers who said “it isn’t good to build here, but we can make it work”.

Now, engineers make their money by designing and building stuff, whether asphalt, steel, concrete, earth, or software. They seldom say “no, we can’t do that”. They would be breaking their rice bowl. So they proposed grouting the rock below and under the dam with concrete to keep reservoir water from dissolving all that gypsum, which is much more soluble than limestone. They built a grout curtain under the Dam site, but it wasn’t perfect. There were gaps. They built the dam, and the increased pressure from the water in the reservoir started dissolving the gypsum at a higher rate.

Sinkholes developed below the dam before it was built. They put a big long room made of concrete called a gallery at the base of earthfill dam. Where their tests show a void is developing, they drill a hole in the floor of the gallery. Water shoots out, confirming there is a big hole down there. They then use big pumps to pump grout into the hole until it stops, hoping the void is filled. They then move to the next place.

This has been going on since the dam was built in the 1980’s. All that concrete pumped below the dam has not stopped the leakage, it just moves the leaks to another weak spot. They will never be able to pump enough grout. An Italian firm is there now, and they are a bit hopeful they can control the leaks. The confounding variable is the political situation. ISIS controlled the dam for a while, and grouting mostly halted, but void creation did not. The battle lines of the war today are within earshot of the dam. The Iraqi government is unstable, despite support from shifting coalitions. The grouting program is at risk. Maybe that doesn’t matter. The dam will fail, we just don’t know when.

Sixty feet of water will inundate Mosul. Refugee camps with 1.2 million people will be affected. In two days parts of Baghdad would be under sixteen feet of water. Downstream, an even wider area would be flooded with at least six inches of water. As geologists always say, “It’s not a matter of if, but when.” Death toll estimates range from 500,000 to 1.5 million souls. The Iraqi economy will be destroyed. Moral, listen to the geologists.

Posted in Engineers, Floods, Geology, Iraq, Mosul Dam, Politics, Stories

Climate Change

Posted on November 30, 2016 by Bill One comment

Florida Flooding

Here it is, the last day of November, and we still have some tomatoes from our garden. We had the hard freeze a couple of weeks ago, but we brought quite a few in before it froze. This fall has been the fall of pasta sauce and tomato soup. Traditionally the first freeze is in September or early October. Not this year. Now, just because we have one warm fall doesn’t necessarily mean global warming, it is a matter of relatively long term trends. That is happening, folks.

Worldwide, it is about one degree Celsius and climbing. The culprit is carbon. We need carbon, our bodies are mostly water, but carbon hangs everything together. Florida, for example, is mostly calcium carbonate, limestone. The limestone formed even the peninsula was underwater with a climate encouraging the growth of untold billions of tiny organisms with calcium carbonate shells. They die, and if whales don’t eat them, their shells sink to the sea floor. Well, even if they do get eaten, the whale turds are calcareous.

Porous Limestone

Millions of years and sea level change, and Florida emerges. The cycle doesn’t end there. It rains on Florida, and the slightly acidic rain starts dissolving the limestone, sending the carbonates back to the sea. Enough of the limestone has dissolved to make the peninsula a honeycomb. Sinkholes, underground rivers, high tides bringing ocean water inland and flooding streets in Broward county. The southern part of the state is headed back underwater. The really big deal is that sea level is rising.

I have given an example of the carbonate cycle, which is going on worldwide. The other cycle going on is the water cycle. Our planet is delicately balanced in temperature around the freezing point of water. The water evaporates, and if it is cool enough, some of it falls as snow and accumulates, mostly in the polar regions. At times the ice forming from all that snow has made it as far as Central Park in New York, that is a lot of water tied up on land. Sea level drops, and Florida emerges.

Currently, the cycle is going the opposite direction. The ice is melting, and the process seems to be accelerating. Why? Carbon. Here in Denver, I see huge coal trains hauling coal south to be burned to run air conditioners in Texas. The coal, carbon, is ripped from the ground where it has lain for millions of years, mostly dead plant life converted into coal. It is burned, sending carbon into the atmosphere. I drove here to the coffee shop burning gasoline, which comes from oil made deep underground from what once were living organisms. The carbon goes into the air, the climate changes due to human activity. We are in a new epoch, the Anthropocene.

Elemental carbon is fairly rare. Diamonds, graphite. Carbon likes to combine with other stuff to make, well, us and other living things. That carbon gets sequestered in the earth, reducing the amount of carbon available to make new stuff. There is a cyclical balance, dependent on worldwide temperature and, lately, us. We burn carbon based fuels and the carbon dioxide goes into the atmosphere.

The sun shines, warming everything up. A lot of that heat gets radiated back into space, maintaining a balance favorable to life. When that radiant heat meets a CO2 molecule, it warms the molecule. More carbon, more heat in the atmosphere. That’s greenhouse gas doing its thing. The global climate warms up, making some regions wetter, some more dry. We have gotten used to having a relatively stable climate, and we adapt to it in many ways.

When the rain and snow fall changes, our adaptations stop working so well. This is especially important in coastal regions, because all that polar ice starts melting and sea level rises. Most of the population lives near the coast. With the coasts moving inland, the people and all their stuff will have to move as well. Battery Park at the southern tip of Manhattan gets flooded in big storms. The subway tunnels flood, and people have trouble getting around. The time is coming when they will be living in central New Jersey. The horror.

There are lots of people denying all this, saying it is just the normal weather cycle. That is true, but it is a new normal, and is changing. What to do? Stop putting so much carbon into the air and start putting it back into the earth. That means big change in the way we do things, and those getting rich on the status quo don’t want their businesses upset. Oil and coal, mostly, but they drive all of our economy. So, they say it isn’t so, and let’s burn, burn, burn.

What goes around comes around. It is just a matter of time.

Posted in Climate Change, Coal, Environment, Floods, Geology, Oil and Gas Policy, Weather

Weather

Posted on April 10, 2016 by Bill Leave a comment

Climate Change

2013 Flood

There is currently a lot of controversy about climate change and whether humankind has a role in the warming trend. While I think it is true that pouring huge amounts of sequestered carbon is the culprit, I don’t think it matters much for us here in Colorado and much of the west.

We live in a land of extremes except for the rainy Pacific Northwest, but, they have their earthquakes and volcanos. Here in Colorado, we dwell in a land of extremes. The west is dry, it snows in the mountains, the Front Range is kind of a mix, and it is pretty dry in the east. That varies from year to year. It varies a lot.

In the late nineteenth century it was a wet cycle in the eastern prairie, and the railroads made millions enticing settlers to buy their land and get rich farming. The population in eastern Colorado peaked then and has been declining ever since. The mountain ski areas have lots of snow some years and almost no snow other years. The western desert country looks dry and desolate most of the time, but I have seen it bloom in a stunning variety of color.

Then there are the floods, blizzards, and tornados, often followed by drought. The one thing we can count on is change. There are long term trends. Most archeologists think one reason the ancestral Pueblo Indians left southwestern Colorado was a prolonged drought cycle. Anyone who tries to raise dry land beans in that country can tell you not much has changed.

2013 Flood

Here along the base of the mountains we have the extremes as well. There was the drought of 2002, and the floods of 2013. The mountains create an unusual weather pattern that stalls along the mountain front, bringing more moisture than the land can handle. That is when lots of the mountains wash out into the flat country. It has been going on for more than sixty million years. The gravel in the Platte River in Nebraska is Rocky Mountain gravel. Some of the Louisiana mud is Long’s peak mud.

Some climate models say climate change is going to dry Colorado out, other models say it will be wetter. My money is on more extreme weather. Longer, more violent wet periods and long droughts. Look for more frequent floods, not the thirty or forty year cycle we have had since the first European-American settlers and miners arrived. Think about the tornados and hailstorms recently.

I like the extremes. We have our regular four seasons here but the winters are milder than in Iowa. It can get hot but there are few days over one hundred degrees, but not like southeastern Utah. I think that may change, hotter in the summer. I don’t think the winters will be colder. I can remember forty below in Boulder when I was flunking out of CU. Twenty below seems to be more the cold winter norm now. What I do not like is the hailstorms. I don’t think the insurance companies like them much either. Homeowners insurance costs keep rising. That hail is hard on the garden as well. We had only one tomato plant survive last year.

One of the big impacts of climate change will be on water supplies. The amount of precipitation may not change, but if it is warmer, the snowpacks will not last as long in the spring. That means more spring floods and a shorter runoff period, which will impact water storage. That could be bad news for the populated Front Range. People keep coming, but there will not be more water, and a lot of the big spring runoff will go out of the state. That will be good for the Sandhill Cranes in Nebraska, but bad for Parker and Highlands ranch.

I spent a long time in the water business, and it always disturbed me watching all that high quality drinking water being used to attempt to replicate Surrey or Connecticut foliage in the Great American Desert. All that bluegrass will have to go. The urban forest will have more drought-hardy trees. Denver Water’s customers have done a good job of conserving since the big drought of 2002, but the bluegrass model of landscaping continues. In Denver, daily water consumption is about 110 million gallons per day in winter. I the hot part of summer, it’s over 400 million gallons per day, most of it run out onto the ground.

At our house, we have significantly reduced the size of our lawn, but we still have a lot of crabgrass. It should be buffalo grass and blue grama, both native drought-resistant grasses. They don’t stay green all summer, so we are stalling and paying the water bill. Marijuana legalization is bringing lots of people to Colorado, and the economy is booming. Those people use water, and lots of water is used growing the stuff. One of the unintended consequences of legalizing pot is increased water consumption.

Myself, I am not too concerned about climate change for myself. After all I am 73 years old and don’t live on the coast. Long term change is a reality, but as John Maynard Keynes said, “In the long range we are all dead”.

Posted in Colorado, Earthquakes, Environment, Floods, Hailstorm, Money, Rain, Spring Flowers, Stories, Volcanos, Water Treatment, Weather, Winter

Our Little Planet

Posted on May 29, 2015 by Bill One comment

Mt. St. Helens showing a Lahar, a mud and ash flow that ran 50 miles downstream during the eruption.

Stephen Hawking says we need to have to develop means to get off the planet when the Big One, whatever it is, is about to strike. That is not terribly realistic, relocating several billion people to a place light-years away. In other words, life on earth is toast. Someday.In the meantime, life goes on. It is spooky how we are fouling the planet. We humans may create the need to get off this little ball without the means to do so. In other words, life on earth is toast. Sometime, maybe sooner.So, let’s deal with what we have while we can. There are things we can do, but the means to act are part of a political process. As long as politics is motivated by greed at the level it is currently, we are likely toast. Maybe sooner.

The cliff that collapsed into a massive mudslide is seen covered with felled trees in Oso, Washington March 31, 2014. Recovery teams struggling through thick mud up to their armpits and heavy downpours at the site of the devastating landslide in Washington state are facing yet another challenge – an unseen and potentially dangerous stew of toxic contaminants. REUTERS/Rick Wilking (UNITED STATES – Tags: DISASTER ENVIRONMENT) – RTR3JE4A

As individuals, we must do what we can, and get along with our lives. We can help, and maybe stave off the inevitable to some degree. We can respond to natural events. Floods, earthquakes, tornados, landslides, hurricanes, those things we can react to and help. We must do more than sit in the Lazy-Boy looking at the screen eating Doritos. We can give money away, stir things up in meetings, vote, and give some time.

Well, we can do things until Yellowstone blows. It is surprising how resilient humans are. Ice ages, cataclysms, droughts, they may kill some and move others around, but the species has struggled on through it all. We haven’t been around very long, however, and haven’t had to deal with any Really Big Ones in the blink of time we have been around.

The Yellowstone Caldera

The Park Service says the Yellowstone super-volcano is pretty safe, that most eruptions are limited lava flows. But, someday, it will be like the last big one that created a caldera almost as large as the park. The Snake River Plain in Idaho with all those lava flows is the track of the Yellowstone hot spot as the North American Plate traveled west. The plate moves at about the rate your fingernails grow. As it moves, it erupts. It just takes a while.

Hurricanes, tornadoes, floods, drought, all interest me, but I am most interested in geologic cataclysm. One of my favorite potential geologic disasters is climate-related. Years ago I read an article proposing that sea level rise could lead to the Gulf Stream moving over the continental shelf and invading the Arctic Ocean. Europe would cool off with the loss of that warm water and the Arctic Ocean would thaw. With all that open water in the north, evaporation would increase, snowfall would increase in the Arctic, precipitating a new ice age.

I haven’t seen much on that hypothesis lately. Researchers seem to be concentrating on the rapid melting going on without Gulf Stream migrations, although the Gulf Stream does seem to be weakening. There are just so many variables to consider.

Ash From a Yellowstone Eruption

With respect to the Yellowstone super volcano exploding and killing most life in North America, there is only one variable: when. A couple of years ago I was on a ramble in Wyoming. Fort Laramie was my destination, but on the way I looked for the Oregon-California trail wagon ruts along the Platte outside Guernsey. The ruts are dramatic, going up from the river bottom to some higher ground. They are axle-deep in some tan colored rock that looks like sandstone at first glance. It is volcanic tuff from the last time Yellowstone blew. The layer is four or five feet deep about 200 miles from Yellowstone. That is a lot of stuff blown into the atmosphere. All that material along with the CO2 and SO2 would kill most everything for many hundreds of miles.

The most recent volcanic eruption in Colorado was about 4500 years ago at Dotsero. The entire San Juan mountain range is volcanic. Huerfano Butte near Walsenberg is a volcanic neck. There are eroded lava flows on Trail Ridge Road in Rocky Mountain National Park. There are lots of hot springs in Colorado. Where is all that heat coming from? Will the Glenwood Hot Springs Pool erupt? Will Steamboat Springs’ boiler explode?

Landslides. There is even one not far from Fruita on I-70. Debeque canyon on the Colorado River is famous landslide country. That landslide that killed three men outside Collbran last year is the same geologically. Green Mountain in Lakewood has a landslide that destroyed several houses. The Vail/Eagle River valley is good landslide country. All it takes is a lot of moisture in spring. The canyons incising the front range are landslide prone. All that rock will eventually find its way to Louisiana as mud.

The upside of all that landslide country is that it gives geologists and earthmoving contractors work.

There is a radioactive isotope of radon gas that is common in some of our Colorado rocks that houses are built on. Basements become carcinogenic. There is an anthropomorphic cause of radioactive basements as well. In Grand Junction, uranium mill tailings were used as backfill around basements is some subdivisions. More work for geologists, and a Superfund site.

Debris is strewn over an area affected by an earthquake and tsunami in Miyako, Iwate Prefecture, March 14, 2011. REUTERS/Aly Song (JAPAN – Tags: DISASTER ENVIRONMENT)

Earthquakes. Again two causes, natural and human-caused. All those earthquakes in Texas and Oklahoma caused by injecting fracking water back underground have a Colorado history. Rocky Mountain Arsenal outside Denver was used to manufacture poison gas for military use and later poison gas for agriculture. They pumped a lot of the toxic wastewater down wells and set off earthquakes. They stopped that. The oil companies are not stopping. Yet.

Colorado is earthquake country. Making mountains, shoving rock around to make room for more rock shakes things up. The Flatirons outside Boulder used to be flat. North and South Table mountains are capped with basalt from lava flows. These processes are still going on in lots of places.

The Rio Grande Rift is a Rift Valley stretching from Southern New Mexico to north of Leadville. The earth is pulling apart. Look at the San Luis valley, that is a lot of pulling. It is still going on, but slowly in human terms. There will be earthquakes. The biggest quake-causing fault near Denver is the Golden Fault, formed when the Rockies were uplifted. That uplift has happened about three times. The mountains come up, get eroded down, come up again, get eroded again. Will it happen again? There seems to be some weakness in the crust around here.

What the Meteor Looked Like Impacting off Yucutan

There are asteroids out there that have orbits that coincide with the earth’s orbit. It has happened before, could again. I saw Charlie Rose interviewing Neil DeGrasse Tyson, and he mentioned the possibility. We have the technology to deal with the the threat, but it will take a lot of money and cooperation. Will it happen before we need it? Will it be too late when the danger is imminent? Ask a Republican. I hope you sleep well tonight.

Posted in Colorado History, Colorado Mountains, Earthquakes, Extinction, Floods, Geology, Landslides, Mt. St. Helens, Stories, Volcanos, Yellowstone Volcano

Colorado’s Front Range Floods

Posted on May 7, 2014 by Bill One comment

2013 Flood

Those of us who live along the eastern base of the Rocky Mountains enjoy a unique set of circumstances; a fine climate, mountain views, a mountain playground, and rivers that provide much of our water needs. There are millions of people living in an urban area that runs from Pueblo to Fort Collins.

Most of the time, the physical setting and the climate combine to make the Front Range a fine place to live. There is risk, however. Most of the time we don’t have quite enough water for every need. The people are along the Front Range, and the water is on the western slope. On occasion, we have way too much water. We are subject to drought, our own waste of the water we have, and the floods that come out of the mountain canyons.

To understand these problems requires a look at two histories, the Rocky Mountain history for the last 75 million years and human history from 1859. Around 75 million years ago the Rockies began to form. As they grew, they also wore down. The debris from the mountains spread from their base to as far as Nebraska.

The streams were bigger then. Drive east to Bijou Creek and see the valley that obviously was not formed by the current flow in the creek. The wind blew. It still does, leaving eolian sand deposits. Sand Creek, draining the area east through Stapleton and into Aurora is appropriately named. You can identify the sand hills – they are grazing land, not good for farming. That sand and dirt comes from as far as Utah and coats our cars.

Today, the Rockies are not eroding as fast as they did during the ice ages, but they are still coming down. Back in the Precambrian when I took geology, the assumption was that erosion was a steady, gradual process. Taking the long view, that is so, but on a human time scale, erosion is punctuated by periodic floods. Some of the floods are from spring runoff from wet winters. The catastrophic floods pound out of the canyons when storms park themselves over an area and it rains. And rains. Sometimes it rains more in a few hours than it does in several normal years. Sometimes the rain is where the people are, just east of the mountains.

Large amounts of moist monsoonal air from the Gulf of Mexico move north along the Rockies and encounter a cold front coming from the west. Sometimes the rains are short in a fairly small area. At other times, as in 2013, the rain comes down over a large area, and it rains for days. To humans, these storms seem like unusual events, but they have been happening for millions of years. Along with normal erosion, they have filled the Denver Basin with 13,000 feet of debris. That is a lot of rocks and mud.

1864 Cherry Creek Flood

One of the first recorded monsoonal floods was in 1864, not long after Denver was settled. Cheyenne and Arapaho Indians told the settlers seeking fortune not to build where Cherry Creek and the South Platte meet. The town builders built there anyway. It was a logical town site. Trails met, grass, trees, and water were available, and the gold-rich mountains just a short distance away. Much of the new town went downstream.

The town was rebuilt in the same place. Floods came again. Denver flooded in 1876, 1885, 1894, 1912, 1921, 1933, and 1965. Pueblo flooded in 1921, the Big Thompson in 1976, Manitou Springs and Colorado Springs in 2013, and much of the Front Range from Denver to Fort Collins in 2013. The link is from the Atlantic Monthly, with dramatic images from the 2013 flooding.

Most vulnerable are towns at the base of the mountains: Manitou Springs, Palmer Lake, Morrison, Golden, Boulder, Lyons, Loveland, and Fort Collins. Towns along the South Platte, St. Vrain, Cache La Poudre, and Big Thompson rivers are at special risk.

Jamestown 2014

Will people stop building there? Rebuilding is underway in every area flooded in 2013. While researching this piece I traveled to Boulder, Jamestown, Lyons, and the farmland along the St Vrain. I saw travel trailers parked nest to damaged homes with building permits on the flood-damaged houses.

Some actions do prevent floods. Denver has Cherry Creek, Bear Creek, and Chatfield dams. They are flood control dams designed to capture floodwaters. Let’s hope they are big enough.

The photo above has a lot of rock in the foreground. The rocks range in size from sand and silt to head size. They were exposed by the 2013 flood, but were deposited by a previous flood that had enough force to carry that debris and dump it there. upstream, there are narrow gulches with the lower ends scoured down to bedrock. That debris went further downstream.

The Rocky Mountains are on the way to the Mississippi river delta in Louisiana. It will take many millions of years, but they will wear down and become Mississippi mud. Floods will hasten the process.

Posted in Colorado History, Environment, Floods