1,080. More About Irrigation on Chol HaMoed
Shvisas Yom Tov 8:2
If half a row of crops is on low ground and the other half is on high ground, one may not draw water from the lower to irrigate the higher because doing so is very strenuous. One is permitted to draw water to irrigate vegetables so that they will be fit to eat on chol hamoed but not merely to improve their quality.
Shvisas Yom Tov 8:3
One may not dig a pit at the root of a grapevine to collect water. If such pits were already dug but they have become damaged, they may be repaired on chol hamoed. Similarly, one may repair a damaged irrigation ditch on chol hamoed. For example, if the ditch is only one handbreadth deep (about 3”), one is permitted to dig until it is six handbreadths deep; if it’s two handbreadths deep, one may dig until it is seven. One may make water flow from tree to tree as long as it doesn’t irrigate the whole field. If the field was already watered, then it is permitted to irrigate the whole field. One may sprinkle water on a field on chol hamoed. All of these things are permitted because they’re not very strenuous.