There is something intriguing about rivers. These ribbons of water that snake through mountains and plains, tumbling headlong into the sea. If they have a purpose, it is only to act as a drain.Yet they do so much along the way. Given time they carve canyons. Too much rain in the highlands and the river swells and floods the lowlands. They generate enough energy to power cities. The are arteries of ecosystems. They are the heart of civilization.
Where would we be without rivers? Look at the world today. Every major city is on a river. New York? The Hudson. London? The Thames. Paris? The Seine.Cairo? The Nile. The Cradle of Civilization was the meeting place of two rivers, the Tigris and the Euphrates. Large populations rely on a river. Not only are they a source of fresh drinking water and fish for food, they are a vast transportation network. This is important for two reasons, one is trade. Using the power of the river you can easily send and receive your goods. One of the features that turned London into the powerhouse it is today is that the Thames experiences two tides a day. The waters of the sea rush inland, making it easy for ships to reach the city. Then the same waters rush back out again, carrying those same ships out for/with fresh supplies. All done quickly and efficiently, with the effect of nearly doubling trade capacity. Just as important as trade is communication. Before there was the internet, or phones, or other telecommunication systems, rivers were the communication network of choice. With rivers, rulers could more effectively command a larger area. The land and people could be brought to order. These factors together would help free people from constant farming and walking. With free time people could devote more of themselves to developing art and science.
Today, we use dams to hold back the river. This allows for even larger cities than a free flowing river. You have stored more water for drinking. You generate electricity to power it's businesses. You prevent flooding of the lowlands, thus producing more land that it is safe to build upon.
It took a long time, it seems, for cities to realize that they often poisoned their own waters. Because the river acts as a drain, people treat it as a sewer. The first toilets and sinks would drain into rivers, where the waters would take the waste away to be forgotten about. But a city can produce more waste than a river can disgorge. It's still a lesson many cities are learning today.
The river's basin is the area of land that the river acts as a drain for. Whenever there is precipitation, some of that water is absorbed by the earth into underground aquifers and some is consumed by plants and animals. The rest rolls along the surface, rain drop by rain drop collecting into larger and larger bodies. Glaciers and snow melt to swell rivers in the summer. Springs in the clefts of mountains release underground streams. These and other tributaries gather together into the river body that seeks it's path to the sea.
So, the map I am creating is one of viewing where the water goes. If a rain drop falls in such-and-such location and is not absorbed by the earth, plants, or animals. If it joins a stream that joins a river. Will that river be the Columbia or one of it's tributaries?
Next time I shall talk a little about the Columbia and the reasons I chose this river.
Happy hunting,
Brett
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