I got curious, could we make "underground irrigation" to reduce evaporation of water?<p>I mean, water underground is usually contained on a certain level (or levels), e.g. if there's a clay soil layer, then almost always there's water above it, because clay is hardly permeable by water.<p>We could make an artificial clay layer (or plastic or whatever that's hard for water to get through), at a depth of a few feet or meters. That way, water would evaporate way less than with open surface irrigation/watering.