Document Type

Capstone Project

Degree Name

Bachelor of Science (B.S.)


Science & Environmental Policy


he Chualar Creek watershed has recently experienced flooding and erosion problems. Projected changes in the climate and atmospheric CO₂ may alter the hydrologic balance, thus exacerbating the problem. This project modeled the effects of double CO₂ in the atmosphere, 3⁰C increase in mean global temperature, and 20% increase in precipitation for the Central Coast region. In this study the Biogeochemical (BGC) ecosystem model was used to simulate the effects of increased atmospheric carbon dioxide (CO₂) levels and global climatic change on the Chualar Creek watershed. The BGC model was developed for the Pacific Northwest to model the chemical, biological and hydrological cycles of a forest ecosystem. This specifically has to do with the uptake, storage and release of water, carbon, and nutrients in an ecosystem (Waring and Running, 1998). The Chualar Creek watershed demonstrates a warm dry Mediterranean climate with Evapotranspiration approaching zero in the late summer and early fall. The BGC ecosystem model shows a direct relationship between soil moisture and runoff, with different levels of soil saturation and wilting points for each land classification. With the simulated climate change, the model predicts Runoff in the Chualar watershed will increase by 25%. The watershed as a whole experiences a net increase in Npp (Net primary productivity). This change in climate condition could exacerbate current flood and erosion problems.


Capstone Project (B.S.) Earth Systems Science & Policy Institute

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