If you’ve been reading my posts you’ve seen the words “water towers” numerous times. Are you still wondering though,

exactly what is he talking about?

That is a fair question. I’ve made a career out of studying water towers. You perhaps have never even heard these two words until you stumbled upon my webpage.

So…let’s explore, in all their glory, the WATER TOWERS of Wyoming!

High elevation lands are incredible weather system barriers…

The high elevation lands scattered in various locations across the State of Wyoming (Map 1) serve as huge barriers to weather systems. This is because these lands reach to great heights, forcing air masses to do all kinds of crazy gyrations in order to get over and around them. As the air masses work up, over, and around these barriers, moisture is squeezed out of the atmosphere as rain or snow.

We’ll watch a video in a bit that explains how this physical process works. First though, let’s look at where high elevation lands, or mountains and plateaus, occur in Wyoming.

Wyoming’s weather barriers…

The majority of Wyoming’s high elevation lands are north-south trending mountain ranges or broad plateaus. Elevations in these high lands typically range between 7,000 to 13,000 feet above sea level. To put just how high that is in perspective, the Empire State Building in New York City, which is at sea level, is only 1,250 feet tall. And you thought the Empire State Building was tall! Wrong…

Map 1. The mountains of Wyoming. Wyoming’s highest peak (Gannett – 13,084-foot high) is in the Wind River Range. These mountains have the greatest concentration of glaciers in the lower 48 States. Yellowstone National Park in northwest Wyoming is a high elevation plateau. The Uinta Mountains in northeastern Utah are a de facto Wyoming water tower because the north slope of this east-west trending mountain range drains into Wyoming. 

The greatest contiguous area of high elevation lands are in northwestern Wyoming (Map 2). There are other high elevation individual mountain ranges in the south central, central west, north central, northeast, and southeast areas of the state. 

Map 2. Digital elevation map of Wyoming. Areas in white and blue color are highest in elevation and receive the most annual precipitation, and thus are Wyoming’s water towers. The areas in darker red may be water towers depending upon precipitation any given year. This is because, as a general rule, areas that receive over 19 inches of annual precipitation can contribute to streamflow. Areas that receive less than 19 inches of precipitation typically do not contribute to streamflow. Vegetation and solar radiation transpire and evaporate the precipitation back to the atmosphere.

How do these weather system barriers affect precipitation?

As air masses move across Wyoming they encounter the high elevation mountain ranges and plateaus (Maps 1 and 2). The air masses are forced to rise to get over the mountains. As the air rises it cools and water vapor condenses to form clouds. That condensation can then become rain or snow (Video 1). While the video is about the Sierra Nevada mountains in California, the process is the same in Wyoming.

Video 1. Air masses that circulate the Earth collide with mountain ranges, producing rain or snow.

Much of the precipitation in Wyoming’s high elevation areas falls as snow. Beginning in October, snow depth increases through the winter and well into the spring. In essence, this snowpack is a large annual reservoir of frozen water spread across very large landscapes. The snowpack then slowly melts beginning in April. By mid-summer much of the snow is gone, but the melted snow continues draining through the soil and into groundwater. Discharge from groundwater then keeps streams flowing the rest of the year. As summer transitions to fall, the snowpack cycle then begins anew in October.

High elevation lands in Wyoming are huge natural reservoirs…

High elevation lands in Wyoming, because of their annual snowpack, are natural reservoirs. Annual precipitation varies from 25 to over 60 inches. Three-fourths of that annual precipitation, or 19 to over 45 inches, falls as snow. THAT IS A LOT OF SNOW. THAT IS A LOT OF TEMPORARILY STORED WATER.

To say this another way, the high elevation lands…DRUM ROLL PLEASE…are WATER TOWERS! 

Now how cool is that!!!

Water towers and the public lands debate…

When you look at Map 2 you can see that perhaps one-fourth of the State of Wyoming is high elevation land. The rest of the state is semi-arid to arid desert. Areas in the Bighorn Basin just east of where I live receive less than six inches of annual precipitation (Photograph 1). The Absaroka Range water tower just west of where I live receives over 60 inches of annual precipitation. (Photograph 2).

Photograph 1. Semi-arid to arid desert just east of where I live.

Photograph 2. Francs Fork and JoJo Mountain portion of the Absaroka Range water tower just west of where I live.

The water that flows from annual snowpacks in the high elevation towers of Wyoming is an ecosystem service. I believe, even though water is not “sexy” like grizzly bears or awesome scenery, that it is the most valuable ecosystem service public lands in Wyoming provide.

Wyoming is the headwaters for three major river basins in the United States. These headwaters, or water towers, are predominately public land. They are also mostly national forests and national parks for which YOU are part owner. It’s hard to dismiss the importance of YOUR public lands and the ecosystem services they provide.

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Cheers!

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