Water 1 Catchments Flashcards
What is a digital elevation model (DEM)?
A model that shows the elevation of each pixel.
What is GIS?
a Geographical Information System.
What is topology?
The pattern of channel networks
what is geomorphology?
the origin of landscape and channels.
what is the drainage density?
the abundance of channels - how many channels there are in an area.
what is the equation for drainage density?
The length of all channels/ area
Ltot/ A
when do you get high drainage density?
areas with low soil conductivity and agricultural zones.
what does the dendritic pattern look like?
a tree
on what type of soil can you find a dendritic channel network?
homogeneous geological formation, either soil or rock. The river network has many tributaries.
What does a radial pattern look like?
When all the streams flow away from a central point.
Where can you find a radial channel pattern?
on mountains or volcanoes.
What does the trellis pattern look like?
Most complicated - a straight fiver flowing down with channel networks between parallel resistant ridges.
Where can you find the trellis pattern?
areas with folds in the earth crust.
What does the parallel channel network pattern look like?
lots of parallel rivers flowing straight down.
where do you find the parallel river network?
on steep slopes, where water flows down the fast. Often on harder rock.
what is the headwater?
the upstream part of a catchment.
how does the headwater behave differently from the main part of the river?
it often runs dry and overflows. The chemistry is determined by only natural conditions.
what is the source?
a point upstream in the river where it starts.
What is order numbering?
when you give orders to parts of the river - you start at the sources and work your way towards the outlet.
What are the most common losses of water in a system?
evapotranspiration (ET) or effective precipitation.
what is effective precipitation?
the precipitation that is no tintercepted or used for evapotranspiration but instead flows through a river.
what are the three most important fluxes in a catchment?
discharge, precipitation, evapotranspiraiton.
what are the forms of precipitation?
rain, snow, hail, fog, dew.
what are the two types of precipitaiton?
stratiform (or frontal)
convective