In an unlined irrigation canal system, water loss through seepage is by far the largest problem you’ll face—and it’s also the biggest source of water loss. Every gallon counts in places like California where water use is tightly regulated. With that, most all soils will allow some water to seep away from the canal—and that is especially true of the loose and sandy soils commonly found in this region. Canals can lose up to 50% of their water supply due to seepage alone, not counting evaporation or other issues. This can in turn lead to high costs for growers who have to pay more for extra water resources to keep their crops going.
Seepage can also lead to damage in the surrounding soils, and it can undermine the stability of nearby soil by keeping the area overly saturated. This can lead to landslides, which are an already common phenomenon in California. In most cases, these landslides will result in blocked canals that end up starving plants for water. Another potential issue with seepage is that it can lead to root rot in nearby crops by keeping the soil too moist. This is why it’s smart to line irrigation canals with flexible geomembranes—because it gives you the most control over where the water is going while reducing maintenance concerns.
