If your site is swampy, then the minimum width of the trench thirty centimeters can be increased to fifty centimeters, with one meter high.
The slope is an integral part of the drainage system and very important. If you do it not qualitatively or not at all, then water will accumulate into the trench. According to the construction standards, one centimeter should be one meter of trenches. Now let’s calculate, with the length of the trench a hundred meters, which happens quite often, then based on the minimum value of seventy centimeters, the slope will be one meter seventy centimeters. Which is quite upholstered for any private trader. In order to save, it is enough to observe another ratio of one meter half a centimeter slope. With proper non -hasty work, the water will perfectly leave with such a bias. With this, you will be quite significantly saved on loose material and earthwork.