Section 4

• Define discharge, and explain how it is calculated.
Discharge: Water flow, Units: vol/time… cfs. Relates surface of water to discharge.
• Where do you find the highest/lowest velocities of water in a stream channel?
Highest Velocity in Stream Channel: Center of stream
Lowest Velocity in Stream Channel: Near banks/beds. Friction slows velocity
• Identify the following parts of a hydrograph: rising limb, recession limb, baseflow.
• What is the source of baseflow in a stream?
Groundwater discharge?
• Write a water balance equation. Where can water be stored in a watershed?
Water Balance: Any type of balance equation. Inputs – outputs = change in storage.
P – ET = Q (annual time scale)
P – ET – Q = Change in storage
Water can be Stored: Reservoir, snow, groundwater, lakes, ice, soil moisture.
• What is the difference between perennial, intermittent, and ephemeral streams?
Perennial: Flows year round (groundwater)
Intermittent: Flows occasionally
Ephemeral: Flows during/after storms (only)
• What factors favor HIGH erosion?
High Erosion: Vegetation loss, steep slopes, high intensity rainfall (overland flow), easily transported particles
• What factors favor LOW erosion?
Low Erosion: High vegetation, low rain intensity, gentle slopes…?
• What factors favor sediment transport? Sediment deposition?
Sediment Transport: Highest where there is a steep slope, easily transported sediments, high flow velocity.
Sediment Deposition: Favored with low slopes, low velocity, and hard to transport sediments.
• What can cause aggradation of a stream bed? Incision of a stream bed?
Aggradation of a Stream Bed: Increase in bed elevation, increased sediment load, decreased flow.
Incision of a Stream Bed: Decrease in bed elevation, decreased sediment, increased flow.