1,067. Labor Permitted on Chol Hamoed
Shvisas Yom Tov 7:1
Even though chol hamoed is not referred to as Shabbos, it is referred to as a “holy gathering” and the Chagigah offering was brought in the Temple on chol hamoed. Accordingly, we are not permitted to perform acts of labor on chol hamoed so it will not be seen as a regular, secular weekday. One who performs a proscribed act of labor on chol hamoed is given lashes for acting rebelliously because the prohibition against labor on chol hamoed is of rabbinic origin. Not all types of work prohibited on yom tov are prohibited on chol hamoed because the idea is to distinguish chol hamoed from weekdays. Therefore, some forms of labor are permitted on chol hamoed while others are prohibited.
Shvisas Yom Tov 7:2
The following types of labor are permitted: Any act of labor may be performed if failure to do so would result in a great loss, so long as performing the labor does not require strenuous activity. For example, one may irrigate a parched parcel of land on chol hamoed but not land that is well-irrigated. The reason the former is permitted is because if the parched land is not irrigated, the trees on it will be ruined. When one irrigates a plot of land, he may not draw water from a pool or from rain water because this is strenuous. Rather, one irrigates from a spring, whether it be one that already existed or one that must be newly opened for this purpose. One may extend this spring for the purpose of irrigation. The same principles apply in all similar scenarios.