Hydrologic Cycle

The movement of water has a vast impact, not only on living creatures that require it but also on the landscape itself. The landscape, in turn, has a profound effect on the movement of water. This is true all across the world. However, when it comes to living beings such as us the pressing interest is in the relationship between landscape features and water movement locally. This paper will explain in summary the basic processes of the hydrologic cycle, relate those processes to California in particular, and finally give a brief overview of how glaciers form landscapes. This should show not only the interplay between land and water, but also give an impression of how that interplay concerns human beings who live in the region, using California as an object example.

The movement of water through the atmosphere and landscape takes place via a number of regularly repeating events, the whole of which makes up the hydrologic cycle. The hydrologic cycle can more simply be thought of as the water cycle. According to the online version of the Encyclopædia Britannica (2013), the major components of the water cycle are “evaporation, transpiration, condensation, precipitation, and runoff” (p. 1). A quick explanation of each follows. Evaporation is when water is transformed into vapor due to heat and rises into the atmosphere. Transpiration is the exhalation of water vapor by plants. Condensation is the re-transformation of vapor water into liquid water when it is cooled. Condensation in the atmosphere creates precipitation in the form of rain, snow, sleet, etc. Finally, runoff is when precipitation collects on the surface of the earth flows to lower points of the landscape before being absorbed deeper into the soil or pooling. The formation of the landscape and the presence of bodies of water affect the particulars of these occurrences. Each region’s topography interacts with the water cycle to create a distinct character of climate and water availability.

In the case of California in particular, the proximity to the ocean provides an enormous resource to feed the water cycle. Warm temperatures and the plentiful seawater allow for large quantities of water to evaporate, and it should be expected that this would eventually condense and precipitate upon the Californian landscape. Of course, climate affects the actual temperatures at any given time, both at the sea level and in the upper atmosphere, so there is variation. Landscape, in turn, determines the amount of groundwater available, as Flint et. al. (2013) explains in the case of Central Valley soils soaking up precipitation and withholding it for potential use during drier weather (Introduction section, para. 5). Harder landforms, such as exposed rock, do not absorb precipitation, creating runoff that can sometimes lead to flash floods. Of course, the relative warmth of Californian climate assures that the water cycle continuously moves between vaporous and liquid water, but in other regions, solid water is also part of the cycle and can have a tremendous impact on the geography.

Glacial ice is known to move, albeit sluggishly from our perspective, and it is to some extent that movement that impacts the land beneath it. It is difficult to perceive what a mass of ice is doing to the soil and stone underneath while it still lies atop it, but the effects can be seen in landscapes that remain in regions where ice from glacial environments have long departed. The National Snow & Ice Data Center (2013) writes that “The ice erodes the land surface and carries the broken rocks and soil debris far from their original places” (para. 1). The results are unique: glaciers can form moraines, arêtes, cirques, mountain horns, and kettle lakes (para. 3, 5) Moraines are deposits of dirt left behind by melting glaciers, where arêtes, cirques, and horns are all landforms that occur when glaciers erode their way up an existing mountain. Other landscapes are possible, but the essential aspect is that the weight of glacial ice carves and disturbs the geography as the cold-temperature water cycle causes the glacier to creep along, fractionally melting and reforming with slightly altered dimensions.

The above paragraphs not only explain the water cycle itself, also called the hydrologic cycle, but it also gives an extremely brief summation of how liquid and solid water are affected by the landscape, and also how they affect the landscape in return. All of these effects are mediated by the water cycle itself, but the landscape against which this cycle occurs is vitally important to humans and other beings who live there. In the case of California, the possibility for flash floods endangers human life, while areas of softer soil preserve water for those same humans to drink from even when the weather is otherwise arid. If the landscape were otherwise the situation would be remarkably different for the human population. Likewise, the movement of water does gradually alter the geography, and one can predict that those changes will themselves change how humans live there and how the water cycle itself changes.

References

Flint, A. L., Flint, L. E., Boynton, R., &Thorne, J. H. (2013). Fine-Scale Hydrologic Modeling for Regional Landscape Applications: the California Basin Characterization Model Development and Performance. Ecological Processes, 2(25). doi:10.1186/2192-1709-2-25

Hydrologic Cycle. (2013). In Encyclopædia Britannica online. Retrieved from  http://www.britannica.com/EBchecked/topic/278858/hydrologic-cycle

National Snow & Ice Data Center. (2013). How Do Glaciers Affect Land? Retrieved from  http://nsidc.org/cryosphere/glaciers/questions/land.html