Lecture 2 - Hillslope Processes Flashcards
What is a hyetopgraph?
A hyetograph measures time overall rainfall. This is normally a bar graph
What is a hydrograph?
a hydrograph measures time over discharge. This is normally a line graph.
What are the four main pathways that precipitation flows?
1: Direct precipitation
2: Overland flow
3: Throughflow
4: Groundwater discharge
Define direct precipitation
Precipitation falls directly into open water
Define Overlandflow
Water that runs across the surface of the catchment
Define throughflow
Water that flows through the soil above the groundwater
What is the definition of groundwater discharge
drainage from water stored as groundwater
What are three important factors that affect the pathways?
1: Climate
2: Time
3: Catchment physical properties
Is storm runoff ‘new’ (event) or ‘old’ water?
New water that falls during a rainfall event is translated directly to the river
Also known as quickflow
How to read a hydrogrpah
Quick flow is the peak of the water event.
Slow flow is the tail of the hydrograph.
What are the 4 dominant hillslope transport processes?
1: Soil creep and solifluction
2: Mass movement (slides and debris flow)
3: Wash (rainsplash-flow and sheet-rill wash)
4: Transport in solution
What is rain splash erosion?
This is when the rain erodes the more permeable sediment, but cannot erode other sediment, this leaves tall pillars where rocks have protected sediment from rain splash erosion.
What is sheet wash erosion?
Sheet wash erosion is where the surface or topsoil is eroded.
Extreme cases; the topsoil is totally removed, exposing roots from plants
Rill erosion explained
An accumulation of concentrated channels occurs on slopes around 2-3º.
Has huge impact on farmland due to the channel depth
Gully erosion
A more exaggerated from of rill erosion, the size of the gully hs increased, allowing for mass movement to take place
