Soil Water

Soil Water

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                                                                            
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                                                    
                        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. _
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