A kunstgraben is a type of channel that is made by humans to help move water from one place to another. Imagine playing with a hose in your backyard to water your plants, but instead of a hose, people dug a big ditch in the ground. This ditch is the kunstgraben.
In the olden days, before we had special machines to pump water around, people would use kunstgrabens to bring water to their farms or houses. They would dig a long channel or ditch in the ground that would start at a high point - like a mountain - and then slope down, so the water would flow along it.
Sometimes, they would dig tunnels or build walls to keep the water from leaving the channel. It was important to keep the water flowing because sometimes, the kunstgraben would travel for many miles to get to where it was needed.
People would use the kunstgraben to water their crops, wash their clothes or even provide drinking water for their animals and themselves. So, in short, a kunstgraben is like a big ditch that people dug to help move water from one place to another.