start:hype_tutorials:floodplain_tutorial
Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision Next revision | Previous revision | ||
|
start:hype_tutorials:floodplain_tutorial [2018/06/11 08:24] cpers |
start:hype_tutorials:floodplain_tutorial [2024/02/05 12:45] (current) cpers |
||
|---|---|---|---|
| Line 8: | Line 8: | ||
| - area related data; area fractions between floodplain, water bodies and subbasins (including ''fpfol'', ''fpfmr'') | - area related data; area fractions between floodplain, water bodies and subbasins (including ''fpfol'', ''fpfmr'') | ||
| - elevation thresholds; thresholds between water body and flood plain and between water body and downstream lake/river (''floll'', ''flolp'', ''flmmr'', ''flmrp'', ''fymol'', ''fymmr'') | - elevation thresholds; thresholds between water body and flood plain and between water body and downstream lake/river (''floll'', ''flolp'', ''flmmr'', ''flmrp'', ''fymol'', ''fymmr'') | ||
| - | - recession coefficients; coefficients to regulate the flow between water body and floodplain (''rclfp'', ''rclpl'', ''rclfp'', ''rclpr''). | + | - recession coefficients; coefficients to regulate the flow between water body and floodplain (''rclfp'', ''rcfpl'', ''rcrfp'', ''rcfpr''). |
| These input data can be estimated in different ways. The suggestion here is to define those that can be observed/derived relatively easy from data (area and elevation threshold) and manually calibrate the others (recession coefficients). A method to do that is described below: | These input data can be estimated in different ways. The suggestion here is to define those that can be observed/derived relatively easy from data (area and elevation threshold) and manually calibrate the others (recession coefficients). A method to do that is described below: | ||
| Line 20: | Line 20: | ||
| |Figure 1: Example of determining fraction of floodplain area (''fpfmr'' and ''fpfol''). A represents the whole subbasin area, the subscripts lake and mr, outlet lake and main river, respectively.| | |Figure 1: Example of determining fraction of floodplain area (''fpfmr'' and ''fpfol''). A represents the whole subbasin area, the subscripts lake and mr, outlet lake and main river, respectively.| | ||
| - | * Introduce the area changes in [[start:hype_file_reference:geodata.txt|GeoData.txt]]. A new distribution of the slc-classes' area fractions is needed, reducing the non-water classes area in favor of the water areas. Remember that the new olake area (A3 in the example in Fig 1) is composed of the original outlet lake area (<m> A3_lake </m>) plus the area flooded by the olake (<m> {A3}_{flood lake} </m>); same for the new main river area. The area of the subbasin that is not flooded can be distributed between the non-water classes present in the subbasin before the changes using the same distribution as before or it can be distributed among a subset of these classes. Remember that the sum of all classes' area fractions in a subbasin needs to be one. | + | * Introduce the area changes in [[start:hype_file_reference:geodata.txt|GeoData.txt]]. A new distribution of the slc-classes' area fractions is needed, reducing the non-water classes area in favor of the water areas. Remember that the new olake area (A3 in the example in Fig 1) is composed of the original outlet lake area (<m>A3_lake</m>) plus the area flooded by the olake (<m>{A3}_{flood lake}</m>); same for the new main river area. The area of the subbasin that is not flooded can be distributed between the non-water classes present in the subbasin before the changes using the same distribution as before or it can be distributed among a subset of these classes. Remember that the sum of all classes' area fractions in a subbasin needs to be one. |
| **Elevation thresholds** | **Elevation thresholds** | ||
| Line 39: | Line 39: | ||
| * If no elevation information is available, both the threshold for flow from water body to floodplain (''flmrr'' and ''floll'') and the threshold for flow from floodplain to water body (''flmrp'' and ''flolp'') can be set to zero as a starting value. | * If no elevation information is available, both the threshold for flow from water body to floodplain (''flmrr'' and ''floll'') and the threshold for flow from floodplain to water body (''flmrp'' and ''flolp'') can be set to zero as a starting value. | ||
| - | * For ''modeloption floodmodel 3'', two extra input data are needed (''hrefr'' and ''hrefl''). These are the floodplain threshold in an absolute reference system. For these the values **x2** can be used. | + | * For ''modeloption floodmodel 3'', two extra input data are needed (''hrefr'' and ''hrefl''). These are the floodplain threshold in an absolute reference system. For these the value **x2** can be used. |
| **Recession coefficients** | **Recession coefficients** | ||
| - | * The water levels of the river/lake and floodplain will try to reach equilibrium. The speed of equalization is determined by recession coefficients that say how far to equilibrium the water level will reach on one time step. There are separate recession coefficients for flow to and from the floodplain and for main river and outlet lake, in total 4 possible parameters (''rcrfp'', ''rcfpr'', ''rclfp'', ''rcfpl''). The recession coefficients must be between zero and one. A recession coefficient of one gives a fast response. These coefficients usually need to be calibrated. | + | * The water levels of the river/lake and floodplain will try to reach equilibrium. The speed of equalization is determined by recession coefficients that say how far to equilibrium the water level will reach on one time step. There are separate recession coefficients for flow to and from the floodplain and for main river and outlet lake, in total four parameters (''rcrfp'', ''rcfpr'', ''rclfp'', ''rcfpl''). The recession coefficients must be between zero and one. A recession coefficient of one gives a fast response. These coefficients usually need to be calibrated. |
| **Model parameters** | **Model parameters** | ||
| Line 50: | Line 50: | ||
| * The parameter used to calculate the dead volume in the main watercourse, ''deadm'', should not be changed after/if it has been used to determine the thresholds. The parameter, if larger than zero, lets the river hold a water volume after the flow from the river has stopped. This can be important if you simulate substances. It can also delay the start of flow after a dry (zero-flow) period by being filled up with inflowing water replacing evaporated water during the dry period. | * The parameter used to calculate the dead volume in the main watercourse, ''deadm'', should not be changed after/if it has been used to determine the thresholds. The parameter, if larger than zero, lets the river hold a water volume after the flow from the river has stopped. This can be important if you simulate substances. It can also delay the start of flow after a dry (zero-flow) period by being filled up with inflowing water replacing evaporated water during the dry period. | ||
| - | * Lake, river and floodplains evaporates according to the value of the evaporation parameters (''cevp'', ''ttmp'', land use dependent) for the land use defined for these classes. | + | * Lake, river and floodplains evaporates according to the value of the evaporation parameters (''cevp'', ''ttmp'', both land use dependent) for the land use defined for these classes. |
| - | * Surface runoff recession coefficient (''srrcs'', land use dependent) should be set to 1 for lake and river classes with floodplains. All standing water of teh dry part of the floodplain will then be added to the flooded water. | + | * Surface runoff recession coefficient (''srrcs'', land use dependent) should be set to 1 for lake and river classes with floodplains. Then no water will be left standing on the dry part of the floodplain, but will be added to the flooded water. |
| + | * There is a possibility to (temporary) replace the some of the data in [[start:hype_file_reference:flooddata.txt|FloodData.txt]] with model parameters (in [[start:hype_file_reference:par.txt|par.txt]]). This possibility can be used to (automatically) calibrate the elevation thresholds and recession coefficients. The parameters are general parameters, and thus only one floodplain can be in the set-up or all floodplains in the set-up will have the same parameter values during calibration. The use of this calibration parameters are set with a parameter ''optonoff'', and the parameters are called ''opt1'', .., ''opt8''. Different values for optonoff will replace different sets of floodplain data. You can replace none (optonoff=0) or all of them (optonoff=1), but alternatively replace only thresholds (optonoff=2), only recessioncoefficients (optonoff=3) or only maximum extent of floodplain (optonoff=4). | ||
| + | |||
| + | | ''opt1'' | replacing ''floll'' | | ||
| + | | ''opt2'' | replacing ''flolp'' | | ||
| + | | ''opt3'' | replacing ''flmrr'' | | ||
| + | | ''opt4'' | replacing ''flmrp'' | | ||
| + | | ''opt5'' | replacing ''rclfp'' and ''rcrfp'' | | ||
| + | | ''opt6'' | replacing ''fymol'' | | ||
| + | | ''opt7'' | replacing ''fymmr'' | | ||
| + | | ''opt8'' | replacing ''rcfpl'' and ''rcfpr'' | | ||
| + | |||
| + | The parameters are described in [[start:hype_file_reference:par.txt|par.txt]]. | ||
start/hype_tutorials/floodplain_tutorial.1528698298.txt.gz · Last modified: 2023/11/16 14:28 (external edit)
Except where otherwise noted, content on this wiki is licensed under the following license: CC Attribution-Share Alike 4.0 International
