Water Balance + Recap (Week4) (copy)

Evaporation

water is converted to water vapor as it is heated by the sun

Transpiration

• water vapor is emitted to atmosphere from plant surfaces

• evotranspiration is combination of evaporation and transpiration

Condensation

water vapor condenses back into liquid after it rises and cools

Precipitation

discharge of water out of the atmosphere

Interception

precipitation is caught and held by trees and other vegetation

Infiltration

movement of water through soil surface into the soil

Surface Runoff

water that does not infiltrate but flows over the surface. aka overland flow

Percolation

precipitation that moves downwards, percolates or infiltrates through cracks until it reaches water table to become groundwater

Interflow

lateral movement of infiltrated water

Groundwater Flow

percolated water found in deep aquifer zone

Unit of Measurement

• Rainfall Depth or Volume

  • inches, cm

• Rainfall Rate

  • inches/hr, cm/hr

• Infiltration

  • in/hr, cm/hr

• Evaporation

  • in/hr, cm/hr

• Streamflow

  • cfs or m³/s

• Groundwater Flow

  • ft³/day or m³/day

Water Budget Equation

• accounting or allocation of water to each of the component of the hydrologic cycle

P - R - G - E - T = ΔS

ΔS - change un storage in a specified time period

P - precipitation

R - surface runoff

G - groundwater flow

E - evaporation

T - transpiration

Hydrologic Continuity Equation

I - Q = dS/dt

I - inflow in vol/time

O - outflow in vol/time

dS/dt - change in storage in vol/time

Watershed

• basin area

• determines the volume of runoff to be expected from a given rainfall event

• varies in size

Watershed Divide

• ridge line

• separates two adjacent watersheds

• area encompassed by the divide is watershed area

• runoff originates at higher elevations and moves toward lower elevation perpendicular to contour lines

Contour Lines

they are used to determine surface water flow direction, delineate watershed boundaries, and map groundwater flow paths.