Set II Soil Water Gravitational potential is determined by the height of the points above the reference level. Capillary or matric potential must be measured and, therefore, is provided. Total potential energy is simply the sum of the component potentials. Water flows from higher energy to lower energy. The Gradient is determined by the _______ between the two points divided by the _____ between the points. Multiplying the gradient by the hydraulic conductivity yields the total flow. 1. Soil water potentials:       100 cm               75 cm      50 cm      25 cm      0 cm                reference Note the soil diagram above. Point A is at 75 cm; point B is at 25 cm above the reference. The capillary potential energy at point A is -100 cm. The capillary potential energy at point B is -200 cm.    What is the total potential energy at point A? ______    What is the total potential energy at point B? ________    Will water flow between the points? _____ ___________________________    If so, in what direction? ____ _________    What is the gradient between the two points? ____ _______    If K = 10 cm/hr, determine the flow, Q between the points. __ __ 2. Soil Water potential:      400 cm               300 cm      200 cm                     Reference      100 cm             Note the soil diagram above. Point A is at 300 cm; point B is at 100 cm. The capillary potential energy at point A is -400 cm. The capillary potential energy at point B is -300 cm.    Note the reference level on the Figure    What is the gravitational potential energy at point B? _____________         What is the height of point A above the reference level? _________    What is the gravitational potential energy at point A? ___________    What is the total potential energy at point A? ___ ____    What is the total potential energy at point B? ______________    Will water flow between the points? _____ _______________________    If so, in what direction? _____ _____    What is the gradient between the two points? _ ____    If K = 5 cm/hr, determine the flow, Q between the points. 3. Soil Water potential:      400 cm          A B                     Reference      300 cm      200 cm                          100 cm                                               10 cm  20 cm Note the soil diagram above. Points A and B are at 300 cm. The capillary potential energy at point A is -200 cm The capillary potential energy at point B is -100 cm. Note the reference level for gravitational Potential. Will water flow between the points? ________ If so, in what direction? __ What is the difference in total potential energy between the points? _ What is the gradient between the two points?____ If K = 10 cm/hr, determine the flow, Q between the points. _