Lecture 1
How much water enters a stream can be calculated with: precipitation - evaporation.
Soil layer with coarse material → aquifer (gaat er makkelijk doorheen)
Soil layer with fine material → aquitard (confining bed, gaat er lastig doorheen)
Mean Residence Time: (layer thickness * porosity (waar lucht in de deeltjes in de bodem zit)) /
groundwater recharge
Groundwater recharge = discharge
Layer thickness (L) * area (L2) → volume (L3) (groundwater recharge (mm/y) * catchment area (km2) →
discharge (m3/s))
Continuous measurement water level + relation between water level and discharge → continuous
estimate discharge
Discharge + 1.7 * width * water level1.5
Discharge = area * velocity (stroomsnelheid)
,Lecture 2, 1.1-1.4
Video 1.1: Catchment characteristics
A catchment/watershed/basin is the area from which rainwater flows to a certain river.
Topographic divide: the divide by surface water.
Groundwater divide: the divide by groundwater.
A river flow through three cores/zones:
- The upper core/production zone: Where the first channels are formed, and sand and other
sediments enter the river.
- The middle core/transportation zone: Water and sediments are flowing downstream.
- The lower core/deposition zone: The water comes closer to the sea, and so the water is more
slowly. More sediments settle down. This results in that some channels are blocked and new ones
are formed.
The elevation difference and the types of soil in the ground determine where the river will flow. In
lowland areas is the slope of the groundwater table more important than the slope of the land surface.
Steep slopes on elevation maps indicate where water will flow and how wet it is. For instance, if the
surface drops quickly then water will pass it quickly. A large draining area and a local slope increase the
change of wet conditions.
Topographic wetness index (λ) = draining area / local slope
A digital elevation model allows you to study a river in a relatively easy way.
With a digital elevation model (DEM), you can easily create a topographic index, as you can
read/calculate the slopes and surface. This only gives an indication, as no other factors are taken into
account.
Drainage density indicates how much water there is per surface area.
- Dd = Ltot / A
o Dd = drainage density (m-1)
o Ltot = total length of all channels (m)
o A = catchment area (m2)
- B = 1 / Dd
o B = (effective) width of catchment (m)
o Dd = drainage density (m-1)
,Video 1.2: Channels
If you want to know how many channels there are in an area you can use the drainage density.
Drainage density = total channel length / catchment area
Channels will form a network. The most common and efficient network is the dendritic one. However,
because of the soil and/or rocks the network can also be formed as a trellis one. A trellis channel
network patterns occur when there are geologic folds in the ground.
, When there are steep slopes the water flows downhill very fast and doesn’t have the time to flow in
another channel. This is a parallel pattern unless this happens on a cone-shaped mountain like a volcano.
Then you have a radio pattern.
How much water enters a stream can be calculated with: precipitation - evaporation.
Soil layer with coarse material → aquifer (gaat er makkelijk doorheen)
Soil layer with fine material → aquitard (confining bed, gaat er lastig doorheen)
Mean Residence Time: (layer thickness * porosity (waar lucht in de deeltjes in de bodem zit)) /
groundwater recharge
Groundwater recharge = discharge
Layer thickness (L) * area (L2) → volume (L3) (groundwater recharge (mm/y) * catchment area (km2) →
discharge (m3/s))
Continuous measurement water level + relation between water level and discharge → continuous
estimate discharge
Discharge + 1.7 * width * water level1.5
Discharge = area * velocity (stroomsnelheid)
,Lecture 2, 1.1-1.4
Video 1.1: Catchment characteristics
A catchment/watershed/basin is the area from which rainwater flows to a certain river.
Topographic divide: the divide by surface water.
Groundwater divide: the divide by groundwater.
A river flow through three cores/zones:
- The upper core/production zone: Where the first channels are formed, and sand and other
sediments enter the river.
- The middle core/transportation zone: Water and sediments are flowing downstream.
- The lower core/deposition zone: The water comes closer to the sea, and so the water is more
slowly. More sediments settle down. This results in that some channels are blocked and new ones
are formed.
The elevation difference and the types of soil in the ground determine where the river will flow. In
lowland areas is the slope of the groundwater table more important than the slope of the land surface.
Steep slopes on elevation maps indicate where water will flow and how wet it is. For instance, if the
surface drops quickly then water will pass it quickly. A large draining area and a local slope increase the
change of wet conditions.
Topographic wetness index (λ) = draining area / local slope
A digital elevation model allows you to study a river in a relatively easy way.
With a digital elevation model (DEM), you can easily create a topographic index, as you can
read/calculate the slopes and surface. This only gives an indication, as no other factors are taken into
account.
Drainage density indicates how much water there is per surface area.
- Dd = Ltot / A
o Dd = drainage density (m-1)
o Ltot = total length of all channels (m)
o A = catchment area (m2)
- B = 1 / Dd
o B = (effective) width of catchment (m)
o Dd = drainage density (m-1)
,Video 1.2: Channels
If you want to know how many channels there are in an area you can use the drainage density.
Drainage density = total channel length / catchment area
Channels will form a network. The most common and efficient network is the dendritic one. However,
because of the soil and/or rocks the network can also be formed as a trellis one. A trellis channel
network patterns occur when there are geologic folds in the ground.
, When there are steep slopes the water flows downhill very fast and doesn’t have the time to flow in
another channel. This is a parallel pattern unless this happens on a cone-shaped mountain like a volcano.
Then you have a radio pattern.
