Anadromous fish are freshwater fish that migrate to sea then return to spawn in freshwater.In California, anadromous fish include coho salmon, Chinook salmon and steelhead.Whether a field is adequately drained, or saturated with water, the water still has to be removed.The disposal of this often-contaminated water continues to be a challenge in California, with the environmental effects of selenium and other drainage-related elements changing the course of drainage planning.The dry climate that provides the almost year-round growing season also can require heavily irrigated soils.But such irrigation can degrade the local water quality.An acre foot of water is a common way to measure water volume and use.
These natural basins that sit below the surface are found underneath 40 percent of California’s land area. Some are formed in the space between porous materials such as sand, gravel, silt or clay and are known as alluvial aquifers or unconfined aquifers.
Alluvium is found around deltas and rivers, frequently making soils very fertile.
Alternatively, “colluvium” refers to the accumulation at the base of hills, brought there from runoff (as opposed to a water body).
In ancient times, farmers let fields stay fallow hoping rain would flush out salt.
Today, salt and other contaminants continue to cause agricultural drainage problems, particularly in California.