Consider the internal water balances that control the overall water balance of a
ID: 297837 • Letter: C
Question
Consider the internal water balances that control the overall water balance of a watershed or a hillslope.
a. Based on the hillslope hydrology concept we built in class, define the inputs and outputs of the water balance for the soil water storage compartment. In other words, define the inputs and outputs that are likely to drive the changes in stored water () in the unsaturated zone of a hillslope. For each input and output, be sure to specify from where input water originates and to where output water goes. Hint, I am expecting 1 input and 3 outputs here, and be careful not to skip any steps when designating water sources for inputs or destinations for outputs.
b. The movement of water in the soil water storage component of the watershed is often described using Darcy’s law for unsaturated conditions (). Briefly describe 1 of the 3 critical considerations (as discussed in class) necessary to apply Darcy’s law in unsaturated conditions.
Explanation / Answer
a) The soil ground water inputs can be rain water percolation and ground water inflow and even anthropogenic inputs(rare though)
The ground water outputs can be ground water outflow,antropogenic outflow .
2) The considerations for Darcy's law are:-
¹. The Darcy's law is valid only if the soil is completely saturated with water.
².The flow of the groundwater is laminar.
³.The flow is continuous.
The temperatures is close to 27°C at the site of testing.
5.The law is valid for sediment diameters less than 0.5mm, above which the flow deviates from being laminar.
6.The law also does not hold true for extremely fine grained soils like clayey soil,where the flow is inexistent.