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start:hype_model_description:hype_np_soil [2019/05/09 08:18]
cpers [Crop cover and ground cover]
start:hype_model_description:hype_np_soil [2019/12/19 16:49]
cpers [Soil erosion]
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 <m> MobilisedSR = {{(sflow*365)^{sreroexp}} * (1-common_{groundcover}) * {1/​{0.5*soilcoh}} * sin(slope/​100)} / 365 </m> <m> MobilisedSR = {{(sflow*365)^{sreroexp}} * (1-common_{groundcover}) * {1/​{0.5*soilcoh}} * sin(slope/​100)} / 365 </m>
  
-All mobilized ​particles is not removed from the field, because sometimes the transport capacity of the particle-bearing water (//eflow//) will not suffice for the task. A //​transportfactor//​ will reduce the particle amount:+All mobilised ​particles is not removed from the field, because sometimes the transport capacity of the particle-bearing water (//eflow//) will not suffice for the task. A //​transportfactor//​ will reduce the particle amount:
    
 <m> transportfactor = MIN(1.0,​(eflow {/} 4)^{1.3}) </m> <m> transportfactor = MIN(1.0,​(eflow {/} 4)^{1.3}) </m>
    
-Eroded ​sediment (kg/km2) is calculated as:+Mobilised ​sediment (kg/km2) is calculated as:
  
-<​m> ​erodedSed ​= 1000 * (MobilisedRain + MobilisedSR) * transportfactor </m>+<​m> ​mobilSed ​= 1000 * (MobilisedRain + MobilisedSR) * transportfactor </m>
   ​   ​
-The alternative erosion model calculates ​eroded ​sediment (//erodedSed// (kg/km2)) based on precipitation ​(//prec//) and a number of model parameters and subbasin input data.+The alternative erosion model calculates ​mobilised ​sediment (//mobilSed// (kg/km2)) based on rainfall ​(//rain//) and a number of model parameters and subbasin input data.
  
-<​m> ​erodedSed ​= 1000. * ({slope / 5})^{erodslope} * erodluse * erodsoil * {EI/​erodindex} * prec^{erodexp} </m>+<​m> ​mobilSed ​= 1000. * ({slope / 5})^{erodslope} * erodluse * erodsoil * {EI/​erodindex} * rain^{erodexp} </m>
  
 The parameters //​erodslope//,​ //erodexp// and //​erodindex//​ are general. The parameters //​erodluse//​ and //​erodsoil//​ are land-use and soil type dependent. Subbasin input is needed on //slope//, the subbasins average slope, and an erosion index, //EI//. The parameters //​erodslope//,​ //erodexp// and //​erodindex//​ are general. The parameters //​erodluse//​ and //​erodsoil//​ are land-use and soil type dependent. Subbasin input is needed on //slope//, the subbasins average slope, and an erosion index, //EI//.
Line 159: Line 159:
  
  
-Eventually the eroded ​PP (kg/km2) is calculated as:+Eventually the mobilised ​PP (kg/km2) is calculated as:
  
-<​m> ​erodedP ​= 0.000001 * erodedSed ​* {{PartP + HumusP}/ {thickness * bulkdensity}} * enrichment </m>+<​m> ​mobilP ​= 0.000001 * mobilSed ​* {{PartP + HumusP}/ {thickness * bulkdensity}} * enrichment </m>
  
-The calculated ​eroded sediment (//​erodedSed//​) and eroded ​phosphorus (//erodedP//) are now available to add to the suspended sediment (SS) or particulate phosphorus (PP) of surface runoff.+The calculated ​mobilised ​phosphorus (//mobilP//) is now available to add to the particulate phosphorus (PP) of surface runoff.
    
-A portion of SS and PP in surface runoff (//sflow//) is filtered out (for example by buffer zones). Filtering (//​srfilt//​) is determined by land use dependent parameters (//​bufferfilt,​ innerfilt, otherfilt//​),​ percentage of agricultural land close to a watercourse (//alfa//), and proportion of agricultural land near the rivers which have a protective buffer zone (//​bufferpart//​).+A portion of PP in surface runoff (//sflow//) is filtered out (for example by buffer zones). Filtering (//​srfilt//​) is determined by land use dependent parameters (//​bufferfilt,​ innerfilt, otherfilt//​),​ percentage of agricultural land close to a watercourse (//alfa//), and proportion of agricultural land near the rivers which have a protective buffer zone (//​bufferpart//​).
  
 <m> srfilt = otherfilt + alfa * (1. + bufferpart * (bufferfilt - 1.)) + innerfilt * (1. - alfa) </m> <m> srfilt = otherfilt + alfa * (1. + bufferpart * (bufferfilt - 1.)) + innerfilt * (1. - alfa) </m>
  
-Similarly, part of the SS and PP which is transported by macropore flow (//mflow//) is filtered away between the soil surface and drainage pipes. The parameter that determines this effect (//​macrofilt//​) is soil dependent. The SS or PP transported (//transp//) by surface runoff and macropore flow is collected in a temporary storage pool (//​relpool//​ (kg/km2)) together with SS and PP in tile runoff (//​tilep//​).+Similarly, part of the PP which is transported by macropore flow (//mflow//) is filtered away between the soil surface and drainage pipes. The parameter that determines this effect (//​macrofilt//​) is soil dependent. The PP transported (//erodedP//) by surface runoff and macropore flow is collected in a temporary storage pool (//​relpool//​ (kg/km2)) together with PP in tile runoff (//​tilep//​).
  
-<​m> ​transp ​= (srfilt*sflow+macrofilt*mflow)*erodedSed/​eflow </m> or +<​m> ​erodedP ​= (srfilt*sflow+macrofilt*mflow)*mobilP/eflow </m>
-<m> transp = (srfilt*sflow+macrofilt*mflow)*erodedP/eflow </m>+
  
 <m> eflow=sflow+mflow </m> <m> eflow=sflow+mflow </m>
  
-<m> relpool = relpool + transp ​+ tilep </m> \\+<m> relpool = relpool + erodedP ​+ tilep </m> \\
  
-From the temporary pool sediment and phosphorus is released (//​release//​ (kg/km2)) and then transported to the local river depending on the size of the total runoff (//runoff// (mm)). The parameters //​pprelmax//​ and //​pprelexp//​ are general.+From the temporary pool phosphorus is released (//​release//​ (kg/km2)) and then transported to the local river depending on the size of the total runoff (//runoff// (mm)). The parameters //​pprelmax//​ and //​pprelexp//​ are general.
  
 <m> release = MIN(relpool,​ relpool *(runoff {/} pprelmax)^{pprelexp}) </m> <m> release = MIN(relpool,​ relpool *(runoff {/} pprelmax)^{pprelexp}) </m>
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 ==== Crop cover and ground cover ==== ==== Crop cover and ground cover ====
  
-Erosion can be mitigated by protective vegetation or vegetation residues that are in contact with the ground. Crop cover and ground cover erosion ​reduction are used for particulate phosphorus (PP) and the default sediment transport model (SS). The reduction is given by the fraction of coverwith full cover (1halting the erosion completely. Harvested crops have seasonally varying ground and crop cover, while permanent vegetation (e.g. forest) has constant values for these parameters. The input data needed for calculations (//ccmax1, ccmax2, gcmax1, gcmax2//) are given in [[start:​hype_file_reference:​cropdata.txt|CropData.txt]]. Parameters //ccmax1// and //gcmax1// describe the maximum crop and ground cover during spring-summer growing season, parameters //ccmax2// and //gcmax2// are corresponding maxima for winter crop's growth. These maximum ratios are reached at //maxday1// and //​maxday2//,​ which are defined as halfway between planting and harvest, and halfway between autumn planting and midwinter (1 January or 30 June depending on autumn planting date), respectively. ​ From sowing the coverage fractions increase linearly up to their maximum values. After these dates maximum coverage is maintained to the next ploughing, harvest, or until the growing season starts again in the spring (for winter crops) (Figure 4). During the period between harvesting and ploughing, crop cover is equal to ground cover (//​gcmax1//​). At ploughing, ground and crop cover are reduced to zero. Parameters //bd1// and //bd4// describe the dates of spring and autumn ploughing. In the case of spring sowing, when no winter crop is crowing, either one of the ploughing parameters can be set for ploughing date.+Erosion can be mitigated by protective vegetation or vegetation residues that are in contact with the ground. Crop cover and ground cover reduce ​erosion ​by rain and surface runoff ​for particulate phosphorus (PP) and the default sediment transport model (SS). Each crop covers a fraction of the groundthus for simultanous crops (1st and 2nd croptheir respective crop/ground cover is combined to a common crop/ground cover 
 + 
 +Harvested crops have seasonally varying ground and crop cover, while permanent vegetation (e.g. forest) has constant values for these parameters. The input data needed for calculations (//ccmax1, ccmax2, gcmax1, gcmax2//) are given in [[start:​hype_file_reference:​cropdata.txt|CropData.txt]]. Parameters //ccmax1// and //gcmax1// describe the maximum crop and ground cover during spring-summer growing season, parameters //ccmax2// and //gcmax2// are corresponding maxima for winter crop's growth. These maximum ratios are reached at //maxday1// and //​maxday2//,​ which are defined as halfway between planting and harvest, and halfway between autumn planting and midwinter (1 January or 30 June depending on autumn planting date), respectively. ​ From sowing the coverage fractions increase linearly up to their maximum values. After these dates maximum coverage is maintained to the next ploughing, harvest, or until the growing season starts again in the spring (for winter crops) (Figure 4). During the period between harvesting and ploughing, crop cover is equal to ground cover (//​gcmax1//​). At ploughing, ground and crop cover are reduced to zero. Parameters //bd1// and //bd4// describe the dates of spring and autumn ploughing. In the case of spring sowing, when no winter crop is crowing, either one of the ploughing parameters can be set for ploughing date.
  
 {{ :​start:​hype_model_description:​groundcover_cropcover.png?​400 |}} {{ :​start:​hype_model_description:​groundcover_cropcover.png?​400 |}}
start/hype_model_description/hype_np_soil.txt · Last modified: 2024/02/20 17:21 by cpers