Exercise 1: Watershed Delineation Flashcards
define
watershed delineation
creation of a boundary that represents the contributing/catchment area for a particular pour point or outlet
components of drainage basin
- watershed (basin, catchment, contributing area)
- watershed boundaries (drainage divides)
- pour points (outlets)
2 types of drainage divides
- topographic divide
- geologic divide
2 types of drainage divides
uses topography to bound watersheds with ridges
topographic divide
true or false
topographic watershed divides correspond to the line that is effectively delimiting the groundwater
true
but it does not always correspond to that line
2 types of drainage divides
also known as the phreatic divide or groundwater divide
geologic divide
watershed boundary
these barriers are caused by watershed boundaries that modified by artificial flow
artificial barriers
why delineate?
- to determine the extent or influence of hydrologic flows
- to define boundaries of the AOI
- to divide the AOI into sub-areas (segmentation)
- for watershed characterization and hydrologic modelling
methods of delineation
- automated DEM-based delineation
- manual topographic map delineation
methods of delineation
outputs that can be produced using automated DEM-based delineation
- digital surface model
- digital terrain model
methods of delineation
advantages of automated DEM-based delineation
- more accurate
- reproducible outputs
- requires GIS software and a DEM
- used flow direction to delineate boundaries
methods of delineation
manual topographic map delineation in comparison with automated DEM-based delineation
- tedious, less accurate
- requires other supporting data
- requires practice and familiarity
- assumes water flow is perpendicular to contour lines
these are circles of high elevation
peaks
portions of contour that curve towards the peak
valleys
portions of contour that curve away from the peak
ridges
