10 Water-Cycle

Before we start our topic how the climate change impacts the water cycle of Puget Sound, let me explain the entire process of the water cycle . The heat from the sun turn the water in the ocean, river, and lake into the invisible gas, called water vapor. This process is called evaporation. After the evaporation, water vapor get high in the sky, and the temperature around them will be cooler, cause the higher the elevation be, the colder the temperature will be. The cold temperature changes the water vapor into cloud, which is formed by the gaseous and liquid water, and then drop rain or snow back to earth, and forms underground water, which will become the main resource of the river and lake. That the whole process of the water cycle.

Back to our topic, what the climate change impacts the water of Puget Sound. The first thing we need to know is what climate change happened. Recent years, the rate of plant coverage becomes lower than it used to be. There are a lot of reasons cause the rate of plant coverage becomes lower, for example the deforest deforestation, large-scale agricultural projects, change of the temperature, pollution made by human, and so on. But the most important and primary reason is the development of the city. Especially over the last half century, expansion of the major metropolitan areas, such as the Everett-Seattle-Tacoma corridor of western Washington, has resulted in conversion of substantial portions of the landscape from forest to urban and suburban uses. (Cou) City development turns the forest into commercial zone, living area, highway and so on. For example, there are more skyscrapers in Seattle and the total building area has increased a lot than one century ago. The main problem is people use water-proof material to help develop their cities, like the using of pitch to build road. That causes rain from the sky can’t get into the underground. In other word, the main resource of the river and lake may not exist anymore.

But where will those water be, instead of forming river and lake? Following model testing, the overall effects of urbanization were investigated, showing that urbanization increased both seasonal and annual stream-flows substantially (Julie). The example here shows those water will skip the process of water cycle and get into the river and lake directly, which lead to the overall stream-flows increased. Sometimes the increased stream-flows may not be a good thing, although it seems like there are more water in the river and lake so that people have more water resource to use instead of being arid and barren. Increased steam-flows may be a challenge for the water cycle system, cause the total steam-flows for a water cycle system can controled is constant. If more water is in this system, it may happen flood and soil erosion, which will caused tons of loss for agriculture and economy, even the life of human.

Cuo, L., D.P. Lettenmaier, B.V. Mattheussen,  P. Storck, and M. Wiley

“Effects of a century of land cover and climate change on the hydrology of the Puget Sound basin”

http://www.prism.washington.edu/story/Water+Cycle+of+Puget+Sound

Julie A. Vano1 , Nathalie Voisin1 , Lan Cuo1,2, Alan F. Hamlet1,2, Marketa McGuire Elsner2 , Richard N. Palmer3 , Austin Polebitski1 , and Dennis P. Lettenmaier1,2

“Climate Change Impacts on Water Management in the Puget Sound Region, Washington, USA”

https://digital.lib.washington.edu/researchworks/bitstream/handle/1773/34594/4.pdf?sequence=1