Coordinates will take you to the Forestier Underground Gardens California Historical Site 916.
There is no physical container to find at GZ in order to log this Earth Cache as a find you must message me the answers to the following 4 question:
1. What type of environment is hardpan likely to form in?
2. What specific soil types likely lead to the formation of hardpan in the Fresno area?
3. Where and how deep can hardpan be found in Fresno's soil table?
4. Either enter the gardens or peer through the gate and estimate how deep the hardpan was excavated to create the stairs leading to the entrance of the Underground Gardens.
In soil science, agriculture and gardening, hardpan or soil pan is a dense layer of soil, usually found below the uppermost topsoil layer. In Fresno hardpan can typically be found 1-6 feet below the top soil level. There are different types of hardpan, all sharing the general characteristic of being a distinct soil layer that is largely impervious to water. Some hardpans are formed by deposits in the soil that fuse and bind the soil particles. These deposits can range from dissolved silica to matrices formed from iron oxides and calcium carbonate. Others are man-made, such as hardpan formed by compaction from repeated plowing, particularly with moldboard plows, or by heavy traffic or pollution.
Soil structure strongly affects its tendency to form a hard pan. One such common soil condition related to hardpan is soil pH. Acidic soils are most often affected due to the propensity of certain mineral salts, most notably iron and calcium, to form hard complexes with soil particles under acid conditions.
Another major determinant is the soil particle size. Clay particles are some of the smallest particles commonly found in soils. Due to their structure the spaces between individual clay particles is small and already restricts the passage of water, reducing infiltration and hence drainage. Soils with a high clay content like those that are in Fresno, are also easily compacted and affected by man-made discharges. Clay particles have a strong negative electrostatic charge and will readily bond to positively charged ions dissolved in the soil-water matrix. Common salts such as sodium ions contained in wastewater can fulfil this role and lead to a localized hardpan in some soil types. This is a common cause of septic system failure due to the prevention of proper drainage in field.
Hardpan is a common feature of arid or semiarid environments throughout the world. In the United States, hardpan is a familiar deposit in many parts of the Southwest, especially in Arizona, California, Nevada, New Mexico, and Texas. There, hardpan is associated with problems such as poor soil drainage, difficult soil conditions for plant growth, and excavation problems at construction sites.
Additional Information on The Forestier Underground Gardens:
Baldassare Forestiere, a Sicilian immigrant, came to America in 1901 to pursue his dreams of becoming a citrus farmer. In Fresno, California, Forestiere crafted a subterranean complex of patios, grottoes and garden courts, all featuring arches and stonework using the local hardpan sedimentary rock. He became a self-taught artist, and patterned his underground world after the ancient catacombs he admired as a boy, near his home town of Filari, Sicily. No plans were put on paper; each room and passageway was created in Forestiere's mind as he worked. With simple farm tools - a pick, a shovel and a wheelbarrow - the young immigrant dug, chipped and carved the unforgiving hardpan for 40 years, all in his spare time! By the time he was 44 years old, he had excavated and planted over 10 acres.
In addition to his unique building methods, the humble immigrant was also able to plant multiple varieties of fruit-bearing trees and vines, up to 20 feet underground! Orange, lemon and grapefruit trees were planted throughout his underground gardens - many varieties growing together on the same tree! Forestiere also grew more unusual varieties like kumquat, loquat, jujube, carob, quince and dates as well as wine and table grapes. Fruit could easily be plucked from the surface of the gardens, by simply bending down. He truly created an oasis in a modern-day desert of pavement!
The Forestiere Underground Gardens were designated a CALIFORNIA REGISTERED HISTORICAL LANDMARK in 1979. It is also listed on the National Register of Historic Sites.