III. Water budget
The hydrology of a particular wetland can characterized by an equation that includes all the various inputs and outputs.
A. Equation
DV/Dt = Pn + Si + Gi - ET - S0 - G0 ± T
where
DV/Dt = change in volume per unit time
Pn = net precipitation
Si = surface inflow
Gi = groundwater inflow
ET = evapotranspiration
S0 = surface outflow
G0 = groundwater outflow
T = tidal inflow/outflow
B. Relative importance of each term varies among wetland types
Complete the following table:
|
Wetland type |
Major input(s) |
Major output(s) |
|
Coastal (salt/freshwater/mangrove) |
|
|
|
Inland: freshwater marshes |
|
|
|
Inland: riparian/bottomland swamps |
|
|
All the terms in a water budget will affect what kinds of plants occur in a wetland, by way of the hydroperiod and/or the chemistry of the water. (Sometimes the physical energy of water moving through a wetland is high enough that it can limit what kinds of plants grow there.)