What is Saga wetness index?

What is Saga wetness index?

The ‘SAGA Wetness Index’ is, as the name says, similar to the ‘Topographic Wetness Index’ (TWI), but it is based on a modified catchment area calculation (‘Modified Catchment Area’), which does not think of the flow as very thin film.

What two terms define the topographic wetness index?

The topographic wetness index (TWI) was developed by Beven and Kirkby (1979) within the runoff model TOP- MODEL. It is defined as ln(a/tanβ) where a is the local upslope area draining through a certain point per unit con- tour length and tanβ is the local slope.

What is TWI in gis?

Topographic Wetness Index (TWI) that quantifies topographic controls of basic hydrological. processes (Schillaci et al., 2015). TWI is derived through interactions of fine-scale landform. coupled to the up-gradient contributing land surface area according to the following relationship. (Beven et al., 1979):

Is there a scale for wetness?

The TWI has been used to study spatial scale effects on hydrological processes. The topographic wetness index (TWI) was developed by Beven and Kirkby within the runoff model TOPMODEL. The topographic wetness index is unitless.

What is Stream Power Index?

The Stream Power Index (SPI) is a measure of the erosive power of flowing water. SPI is calculated based upon slope and contributing area. SPI approximates locations where gullies might be more likely to form on the land- scape.

What is a topographic position?

The Topographic Position Index (TPI) compares the elevation of each cell in a DEM to the mean elevation of a specified neighborhood around that cell (Fig. At a fine scale of 100m, the topographic position would be a flat plain.

What factors lead to a wet area when using the topographic wetness index?

Topographic wetness index (TWI) describes how likely an area is to be wet based on its specific catchment area and local slope as described in Eq. (2), where As is the specific catchment area and slope is the slope of the grid cells in degrees (Beven and Kirkby 1979).

What is compound topographic index?

The topographic wetness index (TWI), also known as the compound topographic index (CTI), is a steady state wetness index. It is commonly used to quantify topographic control on hydrological processes.

How do you calculate stream power?

Stream power is calculated as: ρgQs where ρ is density of water (1000 kg/m3), g is acceleration due to gravity (9.8 m/s2), Q is discharge (m3/s) and S is channel slope.

What is sediment transport index?

The sediment transport index characterises the process of erosion and deposition. Unlike the length-slope factor in the Universal Soil Loss Equation (USLE) it is applicable to three-dimensional surfaces (Burrough et al. As is the upstream area and β is the slope at a given cell.

How to calculate the topographic wetness index TWI?

However, in the equation TWI = ln (As/tan (a)), As is the up-slope contributing area per unit contour width or also termed as specific contributing area and is expressed in units of m^2/m or m. In this case, the pixel size (or resolution) can be considered as a proxy for the contour width and the specific contributing area can be computed as:

What are the capabilities of taudem in hydrology?

TauDEM provides the following capability: Development of hydrologically conditioned (pit removed) DEMs using the flooding approach Calculates contributing area using single and multiple flow direction methods

How are digital elevation models used in terrain analysis?

TauDEM ( T errain A nalysis U sing D igital E levation M odels) is a suite of Digital Elevation Model (DEM) tools for the extraction and analysis of hydrologic information from topography as represented by a DEM. TauDEM provides the following capability: Development of hydrologically conditioned (pit removed) DEMs using the flooding approach

Is there a pre compiled version of taudem?

The ArcGIS toolbox GUI makes system calls to the command line executables to allow users to access the tools as standard ArcGIS toolbox tools. Pre-compiled versions of TauDEM are available in both 32-bit and 64-bit versions.