The canals in Japan are very beautiful.  Although they were originally created for productive purposes, they are no longer used in this way.  The canals in Japan run from the top of mountains through the cities into many different channels.  They connect to major rivers and ultimately lead into the ocean.  Here is a photo I took while in Japan.  

Canals In JapanCredit: Jeff Pack

 This was taken with my camera phone.  That's how beautiful these canals are!  You can see how breathtaking the view is as it runs through the city.  

Many years ago these canals were used for various purposes.  The water from the canals would be channeled to run through the rice fields.  The rice fields in Japan need to be saturated with water and since turning on a garden hose was not an option two hundred years ago, they used these manmade irrigation systems.  Other purposes include drinking water and laundry.  

While in Japan I have seen people use the canals to cool off the hot ground.  The summers in Japan are very hot.  Residents have long sticks that look like a broomstick handle.  At the end of the handle is a pot, as you would use for cooking.  They use the long stick to scoop water out of the canal and they pour it onto the surface of the ground around where they live.  The cold water from the mountains helps to cool off the ground and makes the area around the home less hot.  It basically reduces urban heat.  

Unfortunately the canals are no longer clean enough for drinking water.  However, there are definitely a lot of fish in these canals.  I have seen both small and very large fish as well.  Even though these canals are shallow many fish like to live there.  The reason is that it is safer for them, less people go fishing in the canals compared to the rivers, and the fish can stay in one place eating all the food they want as the food comes to them from upstream.  I have seen these fish staying in one place eating and eating until they get their fill.  

If you ever go to Japan, make sure to check out the canals.  They are everywhere, both in small cities and in large ones as well.  One time I rode my bike, following the canals as far as I could and eventually reached a rice field up in the mountains that had tons of water flowing out of it.  It was very interesting to see.  Now a days most rice fields use water hoses because they offer more control over the irrigation of the crops, but the nearby canals are still beautiful to see.  I definitely recommend renting a bike and riding along the canals.  I followed a canal that joined a river and after many miles lead me to the ocean.  It was a spectacular view.  

I hope that one day you will be able to experience firsthand how beautiful the canals in Japan are.