Soil and Hydrologic Cycle

Rain water wetting the topsoil

Infiltration

water moving through a B horizon toward an aquifer

percolation

a flooded street

(surface) runoff or discharge

an area of land drained by a single system of streams

watershed

water emitted to the atmosphere from wet surfaces

evaporation

The expression, P - ET - D estimates the ________ a watershed.

discharge volume from

A valley with shallow soils overlaying impermeable bedrock is drained by a single river. It receives 680 mm of precipitation per year, approximately half as snow and half as rain.

From measurements of the river's depth, width, and velocity, it is determined that approximately 450 mm of water is discharged each year. 

How much water [mm] is lost from the valley to the atmosphere by evapotranspiration?

230

Cutting down trees to build housing units results in [ Select ] ["more"/"less"/ "the same amount of"] river discharge and surface erosion because less water is returned to the atmosphere by [ Select ] ["percolation"/ "evaporation"/ "photosynthesis"/"transpiration"] .

more; transpiration