start:hype_model_description:hype_np_soil
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start:hype_model_description:hype_np_soil [2018/11/13 16:07] cpers [Soil erosion] |
start:hype_model_description:hype_np_soil [2018/12/14 13:12] cpers [Soil erosion] |
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| 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//. | ||
| - | A selective process is affecting the soil erosion of phosphorus. Smaller and lighter particles are eroded easier than larger ones. The tiny particles contain more P per unit weight than the average particle of the soil. Therefore an enrichment factor (//enrichment//) is used. | + | A selective process is affecting the soil erosion of phosphorus. Smaller and lighter particles are eroded easier than larger ones. The tiny particles contain more P per unit weight than the average particle of the soil. Therefore an enrichment factor (//enrichment//) is used. The enrichment factor is calculated from three parameters (//ppenrmax, ppenrstab, ppenrflow//), one of which is soil type dependent (//ppenrmax//), and the particle bearing flow. Typical values of the parameters, here called max, stab and flowstab, are given in the example in Figure 2. |
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| <m> erodedP = 0.000001 * erodedSed * {{PartP + HumusP}/ {thickness * bulkdensity}} * enrichment </m> | <m> erodedP = 0.000001 * erodedSed * {{PartP + HumusP}/ {thickness * bulkdensity}} * enrichment </m> | ||
| - | | + | |
| - | A certain proportion 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//). | + | 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. |
| + | |||
| + | 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//). | ||
| <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 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 (//transPP//) by surface runoff and macropore flow is collected in a temporary storage pool (//PPrelpool// (kg/km2)) together with PP in tile runoff (//tilePP//). | + | 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//). |
| - | <m> transPP = (srfilt*sflow+macrofilt*mflow)*erodedP/eflow </m> | + | <m> transp = (srfilt*sflow+macrofilt*mflow)*erodedSed/eflow </m> or |
| + | <m> transp = (srfilt*sflow+macrofilt*mflow)*erodedP/eflow </m> | ||
| <m> eflow=sflow+mflow </m> | <m> eflow=sflow+mflow </m> | ||
| - | <m> PPrelpool = PPrelpool + transPP + tilePP </m> \\ | + | <m> relpool = relpool + transp + tilep </m> \\ |
| - | From the temporary pool phosphorus is released (//PPrel// (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 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. |
| - | <m> PPrel = MIN(PPrelpool, PPrelpool *(runoff {/} pprelmax)^{pprelexp}) </m> | + | <m> release = MIN(relpool, relpool *(runoff {/} pprelmax)^{pprelexp}) </m> |
| ==== Crop cover and ground cover ==== | ==== Crop cover and ground cover ==== | ||
start/hype_model_description/hype_np_soil.txt · Last modified: 2024/04/16 09:10 by cpers
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