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Lightweight expanded clay aggregate (LECA) or expanded clay (exclay) is a lightweight aggregate made by heating clay to around 1,200 °C (2,190 °F) in a rotary kiln. The heating process causes gases trapped in the clay to expand, forming thousands of small bubbles and giving the material a porous structure.
Soil sieve nests with dry soil aggregates after removal from a laboratory drying oven. Soil aggregate stability is a measure of the ability of soil aggregates—soil particles that bind together—to resist breaking apart when exposed to external forces such as water erosion and wind erosion, shrinking and swelling processes, and tillage.
An artesian well is a well that brings groundwater to the surface without pumping because it is under pressure within a body of rock or sediment known as an aquifer. [1] When trapped water in an aquifer is surrounded by layers of impermeable rock or clay, which apply positive pressure to the water, it is known as an artesian aquifer. [1]
Approximately 85% of water used in California by farmers and residents today is from groundwater, with 6 million Californians relying solely on this resource. [2] The Central Valley is a big user of groundwater for agricultural purposes which supplies a large portion of food for not only California, but for the rest of the United States as well. [3]
Groundwater recharge is an important process for sustainable groundwater management, since the volume-rate abstracted from an aquifer in the long term should be less than or equal to the volume-rate that is recharged. Recharge can help move excess salts that accumulate in the root zone to deeper soil layers, or into the groundwater system.
The National Ground Water Association (NGWA), headquartered in Westerville, Ohio, is a membership-based nonprofit organization. Founded in 1948, the organization is composed of United States and international groundwater professionals in four membership divisions: water well contractors, scientists and engineers, manufacturers, and suppliers.
Graphic on Groundwater Flow. Groundwater-Dependent Ecosystems (or GDEs) are ecosystems that rely upon groundwater for their continued existence. Groundwater is water that has seeped down beneath Earth's surface and has come to reside within the pore spaces in soil and fractures in rock, this process can create water tables and aquifers, which are large storehouses for groundwater.
A run-to-waste hydroponics system, referred to as "The Bengal System" after the region in eastern India where it was invented (circa 1946) This method can be set up in various configurations. In its simplest form, a nutrient-and-water solution is manually applied one or more times per day to a container of inert growing media, such as rockwool ...