The Town of Charming: Hydrology and Soil

The San Joaquin Valley exists in a dry and arid region. This climate plays a large part in the formation of Charming's hydrology and soil.

Hydrology can be defined as the study of the movement of the Earth’s water in relation to the land or soil. This study tells us a lot about the soil of an area, but first one must have a simple understanding of the important factors in hydrology. Among the most important parts of hydrology, groundwater sits close to the top of the list. The name “groundwater” comes from the fact that the water resides below the surface, in an area of the ground known as the zone of saturation. (Source: Casey Allen Lecture Notes)

The blue section of this diagram is the Zone of Saturation where groundwater sits.
Here, rather than air and water filling in the porous spaces of the ground, water
saturates the area. Source: Casey Allen Lecture Notes

Most natural wells tap into this phenomenon. However, by pumping this ground water out of these aquifers for drinking water or for growing crops, compaction occurs where the water no longer supports the spaces between sediment. This process, known as subsidence, appears in a dramatic case in the San Joaquin Valley south of Charming. (Source: Casey Allen Lecture Notes)

The San Joaquin Valley has experienced so much groundwater subsidence since 1925 that by 1977 the elevation of the land had decreased by roughly 9 meters (or about 30 feet)! This is the result of groundwater subsidence: the compaction of the ground after the removal of groundwater. Credit: (Casey Allen Lecture Notes)

The hydrology and climate of an area define its soil. Based on the climate and hydrology of the San Joaquin Valley, one can safely assume that Charming has an Alfisol soil type. Alfisol soil types generally thrive in warm, wet/dry climates with some amount of noticeable humidity (Source: Online Text)

As seen in this map, the area of Charming appears to be
mostly Alfisol soil. (Credit: Casey Allen Lecture Notes)

All soil types contain horizontal layers called "horizons". These horizons are identified based on their different physical, chemical, and organic compositions (Casey Allen Lecture Notes). San Joaquin soil contains high levels of minerals and nutrients making it ideal for growing crops. This may explain the extreme case of subsidence mentioned above. The process of calcification creates alfisol soil. Calcification causes excess calcium carbonate to leach down from the B horizon and, over a long period of time, create a K horizon.