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icraf-indonesia / drained_peat_canal_block

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Write description about the state before and after the computation #4

Open dindiarto opened 6 months ago

dindiarto commented 6 months ago

  1. Describe what DEM, canal water level, D, and elevation-phi are!

  2. What are the units for each map, and how should we interpret them in relation to the water level across the study area? image image

  3. Describe what the cross-section plot is! How does the cross-section plot tell us about the peat water level at a certain time and section of the study area? image

dindiarto commented 5 months ago

@fazamahezs please draft the answers to the questions above, feel free to provide the anwers by adding a comment below

fazamahezs commented 5 months ago

<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">

1. Describe what DEM, canal water level, D, and elevation-phi are!

a. DEM

First, the model resulted DEM map as it become one of the input for simulation. This parameter matter because in model, DEM will represent as the elevation of peat surface. DEM also used as topology information for canal network to compute how canal water level would be affected by building a block in any pixel of the canal raster, DEM is necessary to know the direction of water flow to determine which adjacent pixels are upstream (and therefore potentially affected by the block).

 

b. Canal water level

The canal water level represents the water level within the canal network of the study area. Initially, before the installation of any canal blocks, this parameter is assumed to have a uniform initial value across the network. However, after the installation of canal blocks, the canal water level (CWL) may change due to alterations in water flow and drainage patterns. This updated information regarding CWL is crucial for the peat hydrological model, which simulates the water table depth (WTD) and its dynamics within the peatland ecosystem.

c. D

D is defined as transmissivity of water through the peat layer. The hydraulic gradient is calculated as the difference between the water table depth `phi` and the elevation `ele`. This gradient indicates the slope or direction of water flow within the peat layer. Higher transmissivity values indicate areas where water can flow more easily through the peat layer, while lower values indicate areas with more resistance to water flow.

 

d. Elevation-phi

`elevation-phi` represents the difference between the elevation `ele` and the water table depth `phi`. This parameter is resulted from calculation in a raster where each pixel value represents the vertical distance between the elevation of the terrain and the corresponding water table depth. Areas with positive values in `elevation-phi` represent regions where dry peat volume can potentially accumulate. This is because the space above the water table in these areas can be filled with air, allowing for the preservation of organic matter and the formation of peat.

 

The difference between before and after computation results lies in the transformation of initial conditions and input parameters into updated values that reflect the model's calculations. Initially, the data represents the starting state of the system, such as initial water levels. After computation, these initial conditions are processed by the model to simulate changes in transmissivity, canal water levels, and the distribution of dry peat volume. The after computation results also reflect simulated changes, such as the placement of canal blocking. Overall, the before computation data establishes a baseline, while the after computation results provide insights into the dynamic behavior of the system in response to various intervention and input on environmental conditions.

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2. What are the units for each map, and how should we interpret them in relation to the water level across the study area?

No | Parameter | Unit | Interpretation -- | -- | -- | -- 1 | DEM | meter (elevation above sea level) | It helps identify lower areas where water may accumulate or flow and influence water table depth. 2 | Canal Water Level | meter | It provides insights into how water is distributed within the canal network and how changes in canal water levels may impact nearby areas (canal blocking placement). 3 | D (Transmissivity) | m2/day | Areas with higher values in D have higher water flow rates, potentially leading to changes in water table depth. 4 | Elevation – Phi (Water Table Depth) | meter (difference between peat surface and water table depth) | Positive values indicate areas where dry peat volume may accumulate, while negative values suggest areas where water may pond or accumulate above the surface.

 

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3. Describe what the cross-section plot is! How does the cross-section plot tell us about the peat water level at a certain time and section of the study area?

The cross-section plot provides a visual representation of the water table depth variation along a specific transect or line at a particular time within the study area. The horizontal axis of the plot represents the distance along the transect, while the vertical axis represent the elevation of the water table depth with blue lines and the peat surface with a brown line. Each line on the plot corresponds to a specific day simulated, showcasing the temporal dynamics of water table depth over time.

fazamahezs commented 5 months ago

sorry for the very late comment mas, should we add this explanation to readme?