1. Drainage basins
Discussion: What factors determine the volume of water flowing in a stream?
1. Hydrograph: graph of variations in discharge over time
2. Hydrograph shape
rising limb: affected by Hortonian and saturated zone overland flow
falling (recession limb): affected by subsurface storm flow
lag time
peak discharge
afffected by drainage basin characteristics, hydrologic processes operating within the basin, & storm characteristics & history
1. Importance
applied purposes
geomorphological purposes
2. Data Sets
annual maximum series: single highest flood event for each year of record
partial duration series: all events greater than some arbitrary base magnitude
3. Statistics
recurrence interval or return period: average interval of time within which a given flow will be equaled or exceeded
mean annual flood: average of either the annual maximum series or the partial duration series; often denoted as the 2.33 year flood
dominant discharge: discharge that determines the characteristics and dimensions of a channel; generally accepted as bankfull discharge
humid vs arid climates
4. Paleoflood hydrology
use the historical statistical record to estimate the magnitude of the maximum probable flood in a drainage basin; can only extend to about 1.5 times the historical record
techniques that rely on sedimentary & botanical record; can extend record back 1000s of years
|
©
K.A. Lemke (klemke@uwsp.edu)
Last modified August 25, 2005 |
