Summer Block One Project

For this project I jumped in ambitiously and I wanted to model how runoff changes due to the distribution of vegetation. In order to do that, I wanted the soil, rainfall, and hill steepness(grade) to be constant and change the amount vegetation. The runoff would have been measured by grams of displaced soil. I quickly realized that would be too complicated to make. That was too much to consider and research initially so I settled to first make my model on how the absorption rate of water is affected by the soil infiltration rate and hardwood tree consumption. I later worked up to adding the other components.

System Model

For the Vensim Modle, I factored in tree absorption and ground infiltration but gave them a range to reflect the different types of soil and trees. I chose not to include hill grade and instead included evaporation. Evaporation was affected by surface area, a value I included to be inversely related to the amount of trees, and temperature, which increased tree absorption and evaporation rates. The graph it produces shows the volume of water left on the y-axis and the time that passes on the x-axis. When the y is at zero all the water is gone and the graph flat-lines.

Agent Model

For the Agent Cubes Modle, I used the world to represent a rainy day in durham North Carolina. Durham has a clay-loam soil, 65 percent tree cover, and most of the trees are hardwood . When it rains, it will come up to 3.5 in on average. I used those values to plot a 10m by 10m area to for the controlled environment. The rain has a small chance of disappearing every time step to reflect the gallons lost every hour.