ENVIRSC 2B03 Lecture Notes - Lecture 5: Hydraulic Head

• School: McMaster University
• Department: Environmental Science
• Course: ENVIRSC 2B03
• Professor: Sherry Smith

Document Summary

Pressure gradients and gravity work together to create a hydraulic gradient that dictates the motion of water. Water is under tension by differences in pressure between air and water. Plot of soil moisture content near the root. Root takes water in, like a pipeline, reducing water content by the root. Reduced water content = lower pressure, more negative. Pressure in the soil is negative, closer to atmospheric = higher pressure, less negative. Minisci will retreat back into the smaller pores. Halo around the roots allows water to enter the roots by creating a pressure gradient. Ability to conduct water depends on how wet the soil is. Water characteristic curve defines how much water is held at different pressures. Pressure is getting higher and higher as more water is added. Infiltration is slower than it would be because of capillary barrier effect. Coarse layer over fine layer: infiltrate coarse layer quickly, and then slows when it hits the fine layer.