Stage and DischargeFlood StageDischarge (Q)HydrographShort-term HydrographOverland FlowHigh InfiltrationFarmingAnnual HydrographMore Overland Flow = Low Base-flowEphemeral Flow – no base-flowNorthern Hemisphere Tropical Wet and DryNorthern Hemisphere MediterraneanMountainous EnvironmentsGEO 155 1st Edition Lecture 19Last Lecture HydrologyOutline of Current LectureI. Hydrology and Hydrographsa. Stage and Dischargeb. Short-term Hydrographc. Annual Hydrographd. SlidesCurrent LectureStage and DischargeFlood Stage - How high is the water?- Shows different amounts of waterDischarge (Q)- Measured in feet cubed per seconds- Volume of water in a channel at a certain timeThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Hydrograph- The graph of a given amount of water in a river at a given time- Q vs. TShort-term HydrographOverland Flow- Short base-flow - High flood peak (large flooding)- Short lag (time between rainstorm and flood- Short duration- “rapid hydrologic response” to rain storm o High peak means water moved quickly across the landscape and got to the stream channel quickly and all at once Steep topography Sparse vegetation Intense precipitation Frozen ground Shallow/fine soil- Typical of urban settingsHigh Infiltration- High base-flow- Low flood peak- Long lag- Long duration- “Slow hydrologic response”o More water at ground water allows for a higher water table contributing to higher base-flow Deep soil Dense vegetation Gentle topography Etc.- Typical of ruralFarming- Pre-development – before settlers came, there was more infiltration- Post-development – settlers began using straight row plowing creating more overland flow- In between the two peaks, contour plowing made overland flow harderAnnual Hydrograph- How discharge changes over the course of a yearMore Overland Flow = Low Base-flowEphemeral Flow – no base-flow- Not enough water table in the desert to reach the stream channelsNorthern Hemisphere Tropical Wet and DryNorthern Hemisphere Mediterranean- Peak flooding in winterMountainous Environments- Mountainous environments have one peak flooding during the snow melt of
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