Yodha Ela in Sri Lanka.

https://en.wikipedia.org/wiki/Yodha_Ela

The giant stream that follows in the footsteps of a pregnant woman
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The original 17-mile watershed was 6 inches per mile
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Konuppattuman Selpiya, the Ten Commandments on Water

The Old Giant Canal is not really a canal but it is about 54 miles in length from Kala Wewa to Tissa Wewa. The history of the Giant Canal, a unique creation that embodies the splendour of local waffles and irrigation, dates back nearly five thousand years. When his father, King Dhatusena, asked his son Dhatusena to show his fortune, he said: "I will come with me to show my earnings for the country and the nation." Legends along the banks of the canal are still popular today. That sensory history is rolling along the giant canal.

Kala Oya which originated in Kalawewa has been referred to as the Mahavamsa in the Mahavamsa. By the first century, Kalawewa and Cataluva were not tanks but lakes. Pliny, a traveller of the era of Ptolemy's map of Lanka, tells of a lake called the Megisba of the Taprobane (Sri Lanka). It was this lake that later became Kalawewa and the cat lake.

According to folklore, it was used by a pregnant lion to reveal the path leading to the giant canal created by King Dhatusena, about 54 miles from Kalawewa to Tissa Wewa. It is said that the canal was built along the Elchchiya front. This is a very important legend. Cervical weights often do not go up and down steep slopes. She will travel roughly along the contour lines. That is, this folk theory implies that the Giant Canal is roughly located along the contour lines. In his first statement, Mr Brohier said that the first 17 inches of the bass was 6 inches in length, and we should get a sense of how accurately the "canal" was constructed along the contour lines.

Otherwise, this does not mean the creation of a canal with such a slight inclination. The Giant Canal is actually a long tank. It does not make for a rapid flow of water from one place to another. It is designed to create a link between water over a large area. It has a large water capacity. This long tank is made along the contour line. It has a wall (mainly) on the lower side. On the upper side is a natural slope with an upward slope. The stream collects water through the land and its tanks and distributes it to the tanks below the dam. There is also a sluice to spill more water over the wall.

Water flows along the Giant Canal. That is, when a certain amount of water is added to an area, the water pressure in the area increases with increasing pressure and the water spreads to other areas. Thus the water of the Giant Canal can be traversed. One of the most important aspects of our past reservoir systems is that there is no need to move water from one area or another to another. This is because there is water retention everywhere. That is because there are tanks. Tanks and water are used by humans for their work. The tank receives water throughout the year. That water does not deserve the lake. All that is needed is to get water from the tank throughout the year. It does not have to be received from the tank itself. It is not correct to take the water of Kalawewa to the Tissa Wewa in Anuradhapura. As mentioned earlier, all these water bodies between Kala Wewa and Tissa Wewa link together. This creates a water table that distributes water from high to low. The flow of water through this tank is not important.

In fact, this is how groundwater behaves. They are also moving very slowly. That is to say, from high to low. Let us make wells and use this water in place. The water from our wells does not attract groundwater. But because of the volume (volume) of the well, the well does not dry up. Instead, its water volume is only temporarily reduced. The groundwater will slowly return to the well and the well will return to normal. The tank works to some extent in the water system on the surface of the earth.

In our tradition, water source and water usage are clearly inseparable. It is indeed a futile task to take water from somewhere in the Giant Canal water system and find out where its source is. But today

The Jaya Ganga which replaces the old Giant Canal is the main source of water for the river. There are no other small tanks in the vicinity of this system. Therefore, today the Jaya Ganga is a modern type of stream. The water is released to the Kala Wewa with control at various points. Accordingly, water should be supplied to the farms. This is similar to getting water to homes from pipes. However, the water from the Giant Canal is available to the village and the water of the tank can be used for gemming. There is no need for water control in Kalawewa.

If water source and water usage are not clearly distinguished in our tradition, then we need to look carefully at how water taxes were levied at some point. This tax is a certain amount of water