What is an Arroyo?

Article Details
  • Written By: Mary McMahon
  • Edited By: Bronwyn Harris
  • Last Modified Date: 14 October 2019
  • Copyright Protected:
    Conjecture Corporation
  • Print this Article
Free Widgets for your Site/Blog
Scientists use the term "boring billion" to describe when evolution stalled and life on Earth was basically slime.  more...

November 12 ,  1927 :  Joseph Stalin became the leader of the Soviet Union.  more...

An arroyo is a dry riverbed which tends to fill with water in the rainy season. The term “arroyo” is Spanish in origin; such geographical features are known as wadis in Africa and the Middle East. Arroyos can potentially be very dangerous, as they are prone to flash-flooding and erosion. As a result, it is a good idea to learn to identify arroyos so that you are not inadvertently caught in one during inclement weather.

A characteristic arroyo takes the form of a deep cut in the desert. An arroyo may also feature scattered rocks and logs, testament to a previous period of flooding. In some cases, green shrubs and small trees line an arroyo, indicating that there is a source of underground water which these plants exploit. In populated areas, signs may designate an arroyo, to alert people to the potential danger.

In periods of rain, an arroyo acts like a channel, funneling all of the water into one place. As a result, the arroyo rapidly fills with water, which appears in such a high volume that it cannot percolate through the soil to dissipate. As a result, the water rises, and ultimately turns into a river which can create a flash flood, rapidly tearing through the arroyo and wrenching up trees and rocks. People and animals who are caught in the arroyo during the flood will be swept away.


In some regions, an arroyo will support a small, shallow stream or river during the wet season. This can be irritating in municipal areas, as the water can provide a breeding ground for mosquitoes and algae before it evaporates entirely in the late spring or summer. In regions where mosquitoes transmit diseases like malaria and West Nile virus, some cities treat these temporary accumulations of water to ensure that they remain inhospitable to insects.

One of the major concerns with arroyos for people like farmers is that their banks can become quickly eroded. A small channel in a field can turn into a gaping chasm during a period of heavy rain, as the flash flood eats away at the banks of the temporary river, undermining them and causing them to collapse. The flood also typically carries away lightweight usable topsoil, leaving useless sand and rocks behind. The decision to cut channels into fields for the purpose of transporting water should be undertaken with care to ensure that these channels do not cause problems later.


You might also Like


Discuss this Article

Post 4

The large field a few miles from my house has three arroyos running through it with just a small amount of water during most of the year. A highway runs across the field, so the arroyos are spanned by bridges.

When we have massive amounts of rain, these small streams become sources of worry. Once they fill up to the level of the bridge, which has happened several times, local schools close, along with several businesses.

At times, the arroyos cannot contain all the water. When this happens, that big field becomes one large lake. It’s pretty scary to have to drive through there then.

Post 3

An arroyo beside my childhood home rarely filled with water, but when it did, it raged with fury. I remember wishing that the arroyo would get just enough water in it for wading, but this never seemed to happen.

Once the spring rains came, they stuck around for awhile, filling the arroyo to its brim. I was tempted to jump in and swim, or at least grab a float and raft downstream, but my parents had warned me of how quickly someone could die in rapidly moving water.

I saw some neighborhood kids speeding down it in a rowboat once. I’m sure their parents didn’t know about this, but it looked like so much fun. However, if they had hit a big rock, they could have been thrown into the water to drown.

Post 2

My neighbor and his son died while camping in an arroyo. The weather man was forecasting rain, but it hadn’t rained in months, and no one really believed it would.

The two of them decided to camp in this little valley, because the temperature was a few degrees cooler down there. It wasn’t cleverly disguised, either; you could tell it was once a riverbed.

They were asleep when the rain started. They are both heavy sleepers, and I imagine that they didn’t wake up until they were floating downstream. By this time, the current was too strong for them to resist, and they drowned.

Post 1

The pasture beside my house has a channel that always floods during storms. The man who owns the land constructed it in such a way that it won’t widen and lose its banks, though.

The channel does help with small rains, but during flash floods, the water quickly rises to flood all the low-lying land around it. A big section of the pasture could be termed an arroyo, because the same part always floods.

In the spring, the evaporating rains leave a green algae stain behind in the arroyo. The ground there stays mushy until the hot summer drought comes along and cracks the earth.

Post your comments

Post Anonymously


forgot password?