Assessment of erosion hazard with the USLE and GIS: A case study of the Upper Ewaso Ng'iro North basin of Kenya
Identifieur interne : 000D88 ( Istex/Corpus ); précédent : 000D87; suivant : 000D89Assessment of erosion hazard with the USLE and GIS: A case study of the Upper Ewaso Ng'iro North basin of Kenya
Auteurs : Bancy M. Mati ; Royston Pc Morgan ; Francis N. Gichuki ; John N. Quinton ; Tim R. Brewer ; Hans P. LinigerSource :
- International Journal of Applied Earth Observations and Geoinformation [ 0303-2434 ] ; 2000.
Abstract
The Universal Soil Loss Equation (USLE) was used to predict soil erosion hazard in the Upper Ewaso Ng'iro North basin of Kenya using data from erosion plots and reconnaissance surveys. The R-factor (rainfall erosivity) was determined by extrapolation from the rainfall amount-erosivity relationship, using data from autographic records. The K-factor (soil erodibility) was determined using data obtained by laboratory analysis of soil samples collected from 83 test sites in the basin. The LS-factors (slope length and steepness) were determined from a digital elevation model (DEM) of the basin, while the C-factor (crop and management) was determined from vegetation cover data, obtained from SPOT imagery and field surveys. The P-factor (conservation practice) was estimated from maps of soil conservation, obtained from the Ministry of Agriculture. A raster-based Geographic Information System (GIS) was used to interactively calculate soil loss and map erosion hazard. The results obtained were comparable to measured soil loss values from erosion plots. About 36 percent of the Upper Ewaso Ng'iro basin was predicted to have high risk of erosion, most of this land being in the overgrazed rangelands. Land use and management were the major factors associated with soil erosion, and — to a lesser extent — the topography. Due to the reconnaissance scale of this study there were limitations in determining reliable LS, C and P factors for the USLE. In addition, there is a need for research to determine appropriate P-factors for local soil conservation practices, such as trash lines, fanya-juu terraces and stone lines.
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DOI: 10.1016/S0303-2434(00)85002-3
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BOX 30197, Nairobi, Kenya</mods:affiliation></affiliation></author><author><name sortKey="Quinton, John N" sort="Quinton, John N" uniqKey="Quinton J" first="John N" last="Quinton">John N. Quinton</name><affiliation><mods:affiliation>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</mods:affiliation></affiliation></author><author><name sortKey="Brewer, Tim R" sort="Brewer, Tim R" uniqKey="Brewer T" first="Tim R" last="Brewer">Tim R. Brewer</name><affiliation><mods:affiliation>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</mods:affiliation></affiliation></author><author><name sortKey="Liniger, Hans P" sort="Liniger, Hans P" uniqKey="Liniger H" first="Hans P" last="Liniger">Hans P. 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Mati</name><affiliation><mods:affiliation>Jomo Kenyatta University of Agriculture and Technology, P.O. BOX 62000, Nairobi, Kenya</mods:affiliation></affiliation></author><author><name sortKey="Morgan, Royston Pc" sort="Morgan, Royston Pc" uniqKey="Morgan R" first="Royston Pc" last="Morgan">Royston Pc Morgan</name><affiliation><mods:affiliation>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</mods:affiliation></affiliation></author><author><name sortKey="Gichuki, Francis N" sort="Gichuki, Francis N" uniqKey="Gichuki F" first="Francis N" last="Gichuki">Francis N. Gichuki</name><affiliation><mods:affiliation>University of Nairobi, P.O. BOX 30197, Nairobi, Kenya</mods:affiliation></affiliation></author><author><name sortKey="Quinton, John N" sort="Quinton, John N" uniqKey="Quinton J" first="John N" last="Quinton">John N. Quinton</name><affiliation><mods:affiliation>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</mods:affiliation></affiliation></author><author><name sortKey="Brewer, Tim R" sort="Brewer, Tim R" uniqKey="Brewer T" first="Tim R" last="Brewer">Tim R. Brewer</name><affiliation><mods:affiliation>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</mods:affiliation></affiliation></author><author><name sortKey="Liniger, Hans P" sort="Liniger, Hans P" uniqKey="Liniger H" first="Hans P" last="Liniger">Hans P. Liniger</name><affiliation><mods:affiliation>Centre for Development and Environment University of Bern, Hallerstrass 12, CH-3012 Berne, Switzerland</mods:affiliation></affiliation></author></analytic><monogr></monogr><series><title level="j">International Journal of Applied Earth Observations and Geoinformation</title><title level="j" type="abbrev">JAG</title><idno type="ISSN">0303-2434</idno><imprint><publisher>ELSEVIER</publisher><date type="published" when="2000">2000</date><biblScope unit="volume">2</biblScope><biblScope unit="issue">2</biblScope><biblScope unit="page" from="78">78</biblScope><biblScope unit="page" to="86">86</biblScope></imprint><idno type="ISSN">0303-2434</idno></series><idno type="istex">BE01FEA83D7A9E94B0B273A2388DB94EADF2BD88</idno><idno type="DOI">10.1016/S0303-2434(00)85002-3</idno><idno type="PII">S0303-2434(00)85002-3</idno></biblStruct></sourceDesc><seriesStmt><idno type="ISSN">0303-2434</idno></seriesStmt></fileDesc><profileDesc><textClass></textClass><langUsage><language ident="en">en</language></langUsage></profileDesc></teiHeader><front><div type="abstract" xml:lang="en">The Universal Soil Loss Equation (USLE) was used to predict soil erosion hazard in the Upper Ewaso Ng'iro North basin of Kenya using data from erosion plots and reconnaissance surveys. The R-factor (rainfall erosivity) was determined by extrapolation from the rainfall amount-erosivity relationship, using data from autographic records. The K-factor (soil erodibility) was determined using data obtained by laboratory analysis of soil samples collected from 83 test sites in the basin. The LS-factors (slope length and steepness) were determined from a digital elevation model (DEM) of the basin, while the C-factor (crop and management) was determined from vegetation cover data, obtained from SPOT imagery and field surveys. The P-factor (conservation practice) was estimated from maps of soil conservation, obtained from the Ministry of Agriculture. A raster-based Geographic Information System (GIS) was used to interactively calculate soil loss and map erosion hazard. The results obtained were comparable to measured soil loss values from erosion plots. About 36 percent of the Upper Ewaso Ng'iro basin was predicted to have high risk of erosion, most of this land being in the overgrazed rangelands. Land use and management were the major factors associated with soil erosion, and — to a lesser extent — the topography. Due to the reconnaissance scale of this study there were limitations in determining reliable LS, C and P factors for the USLE. In addition, there is a need for research to determine appropriate P-factors for local soil conservation practices, such as trash lines, fanya-juu terraces and stone lines.</div></front></TEI><istex><corpusName>elsevier</corpusName><author><json:item><name>Bancy M Mati</name><affiliations><json:string>Jomo Kenyatta University of Agriculture and Technology, P.O. BOX 62000, Nairobi, Kenya</json:string></affiliations></json:item><json:item><name>Royston PC Morgan</name><affiliations><json:string>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</json:string></affiliations></json:item><json:item><name>Francis N Gichuki</name><affiliations><json:string>University of Nairobi, P.O. BOX 30197, Nairobi, Kenya</json:string></affiliations></json:item><json:item><name>John N Quinton</name><affiliations><json:string>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</json:string></affiliations></json:item><json:item><name>Tim R Brewer</name><affiliations><json:string>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</json:string></affiliations></json:item><json:item><name>Hans P Liniger</name><affiliations><json:string>Centre for Development and Environment University of Bern, Hallerstrass 12, CH-3012 Berne, Switzerland</json:string></affiliations></json:item></author><subject><json:item><lang><json:string>eng</json:string></lang><value>soil erosion hazard assessment</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>USLE</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>GIS</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>Kenya</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>Upper Ewaso Ng'iro basin</value></json:item></subject><language><json:string>eng</json:string></language><originalGenre><json:string>Full-length article</json:string></originalGenre><abstract>The Universal Soil Loss Equation (USLE) was used to predict soil erosion hazard in the Upper Ewaso Ng'iro North basin of Kenya using data from erosion plots and reconnaissance surveys. The R-factor (rainfall erosivity) was determined by extrapolation from the rainfall amount-erosivity relationship, using data from autographic records. The K-factor (soil erodibility) was determined using data obtained by laboratory analysis of soil samples collected from 83 test sites in the basin. The LS-factors (slope length and steepness) were determined from a digital elevation model (DEM) of the basin, while the C-factor (crop and management) was determined from vegetation cover data, obtained from SPOT imagery and field surveys. The P-factor (conservation practice) was estimated from maps of soil conservation, obtained from the Ministry of Agriculture. A raster-based Geographic Information System (GIS) was used to interactively calculate soil loss and map erosion hazard. The results obtained were comparable to measured soil loss values from erosion plots. About 36 percent of the Upper Ewaso Ng'iro basin was predicted to have high risk of erosion, most of this land being in the overgrazed rangelands. Land use and management were the major factors associated with soil erosion, and — to a lesser extent — the topography. Due to the reconnaissance scale of this study there were limitations in determining reliable LS, C and P factors for the USLE. In addition, there is a need for research to determine appropriate P-factors for local soil conservation practices, such as trash lines, fanya-juu terraces and stone lines.</abstract><qualityIndicators><score>7.988</score><pdfVersion>1.2</pdfVersion><pdfPageSize>594 x 846 pts</pdfPageSize><refBibsNative>true</refBibsNative><keywordCount>5</keywordCount><abstractCharCount>1626</abstractCharCount><pdfWordCount>5656</pdfWordCount><pdfCharCount>37380</pdfCharCount><pdfPageCount>9</pdfPageCount><abstractWordCount>249</abstractWordCount></qualityIndicators><title>Assessment of erosion hazard with the USLE and GIS: A case study of the Upper Ewaso Ng'iro North basin of Kenya</title><pii><json:string>S0303-2434(00)85002-3</json:string></pii><genre><json:string>research-article</json:string></genre><serie><language><json:string>unknown</json:string></language><title>Version 7.1 for UNIX and Windows NT</title></serie><host><volume>2</volume><pii><json:string>S0303-2434(00)X0005-0</json:string></pii><pages><last>86</last><first>78</first></pages><issn><json:string>0303-2434</json:string></issn><issue>2</issue><genre><json:string>journal</json:string></genre><language><json:string>unknown</json:string></language><title>International Journal of Applied Earth Observations and Geoinformation</title><publicationDate>2000</publicationDate></host><categories><wos><json:string>science</json:string><json:string>remote sensing</json:string></wos><scienceMetrix></scienceMetrix></categories><publicationDate>2000</publicationDate><copyrightDate>2000</copyrightDate><doi><json:string>10.1016/S0303-2434(00)85002-3</json:string></doi><id>BE01FEA83D7A9E94B0B273A2388DB94EADF2BD88</id><score>0.044070948</score><fulltext><json:item><extension>pdf</extension><original>true</original><mimetype>application/pdf</mimetype><uri>https://api.istex.fr/document/BE01FEA83D7A9E94B0B273A2388DB94EADF2BD88/fulltext/pdf</uri></json:item><json:item><extension>zip</extension><original>false</original><mimetype>application/zip</mimetype><uri>https://api.istex.fr/document/BE01FEA83D7A9E94B0B273A2388DB94EADF2BD88/fulltext/zip</uri></json:item><istex:fulltextTEI uri="https://api.istex.fr/document/BE01FEA83D7A9E94B0B273A2388DB94EADF2BD88/fulltext/tei"><teiHeader><fileDesc><titleStmt><title level="a">Assessment of erosion hazard with the USLE and GIS: A case study of the Upper Ewaso Ng'iro North basin of Kenya</title></titleStmt><publicationStmt><authority>ISTEX</authority><publisher>ELSEVIER</publisher><availability><p>ELSEVIER</p></availability><date>2000</date></publicationStmt><sourceDesc><biblStruct type="inbook"><analytic><title level="a">Assessment of erosion hazard with the USLE and GIS: A case study of the Upper Ewaso Ng'iro North basin of Kenya</title><author xml:id="author-1"><persName><forename type="first">Bancy M</forename><surname>Mati</surname></persName><affiliation>Jomo Kenyatta University of Agriculture and Technology, P.O. BOX 62000, Nairobi, Kenya</affiliation></author><author xml:id="author-2"><persName><forename type="first">Royston PC</forename><surname>Morgan</surname></persName><affiliation>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</affiliation></author><author xml:id="author-3"><persName><forename type="first">Francis N</forename><surname>Gichuki</surname></persName><affiliation>University of Nairobi, P.O. BOX 30197, Nairobi, Kenya</affiliation></author><author xml:id="author-4"><persName><forename type="first">John N</forename><surname>Quinton</surname></persName><affiliation>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</affiliation></author><author xml:id="author-5"><persName><forename type="first">Tim R</forename><surname>Brewer</surname></persName><affiliation>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</affiliation></author><author xml:id="author-6"><persName><forename type="first">Hans P</forename><surname>Liniger</surname></persName><affiliation>Centre for Development and Environment University of Bern, Hallerstrass 12, CH-3012 Berne, Switzerland</affiliation></author></analytic><monogr><title level="j">International Journal of Applied Earth Observations and Geoinformation</title><title level="j" type="abbrev">JAG</title><idno type="pISSN">0303-2434</idno><idno type="PII">S0303-2434(00)X0005-0</idno><imprint><publisher>ELSEVIER</publisher><date type="published" when="2000"></date><biblScope unit="volume">2</biblScope><biblScope unit="issue">2</biblScope><biblScope unit="page" from="78">78</biblScope><biblScope unit="page" to="86">86</biblScope></imprint></monogr><idno type="istex">BE01FEA83D7A9E94B0B273A2388DB94EADF2BD88</idno><idno type="DOI">10.1016/S0303-2434(00)85002-3</idno><idno type="PII">S0303-2434(00)85002-3</idno></biblStruct></sourceDesc></fileDesc><profileDesc><creation><date>2000</date></creation><langUsage><language ident="en">en</language></langUsage><abstract xml:lang="en"><p>The Universal Soil Loss Equation (USLE) was used to predict soil erosion hazard in the Upper Ewaso Ng'iro North basin of Kenya using data from erosion plots and reconnaissance surveys. The R-factor (rainfall erosivity) was determined by extrapolation from the rainfall amount-erosivity relationship, using data from autographic records. The K-factor (soil erodibility) was determined using data obtained by laboratory analysis of soil samples collected from 83 test sites in the basin. The LS-factors (slope length and steepness) were determined from a digital elevation model (DEM) of the basin, while the C-factor (crop and management) was determined from vegetation cover data, obtained from SPOT imagery and field surveys. The P-factor (conservation practice) was estimated from maps of soil conservation, obtained from the Ministry of Agriculture. A raster-based Geographic Information System (GIS) was used to interactively calculate soil loss and map erosion hazard. The results obtained were comparable to measured soil loss values from erosion plots. About 36 percent of the Upper Ewaso Ng'iro basin was predicted to have high risk of erosion, most of this land being in the overgrazed rangelands. Land use and management were the major factors associated with soil erosion, and — to a lesser extent — the topography. Due to the reconnaissance scale of this study there were limitations in determining reliable LS, C and P factors for the USLE. In addition, there is a need for research to determine appropriate P-factors for local soil conservation practices, such as trash lines, fanya-juu terraces and stone lines.</p></abstract><abstract xml:lang="fr"><p>Résumé: L'équation universelle de perte de sol (USLE) a été utilisée pour prédire le risque d'érosion du sol dans le bassin Ewaso Ng'iro Supérieur au Kenya, en utilisant des données de tracés d'érosion et des levés de reconnaissance. Le facteur R (érosivité de la pluie) a été déterminé par extrapolation à partir de la relation quantité de pluie — érosivité, en utilisant des données d'enregistrements autographiques. Le facteur K (érodibilité du sol) a été déterminé en utilisant des données obtenues à partir d'analyses d'échantillons de sols prélevés sur 83 sites tests dans le bassin. Les facteurs LS (longueur des pentes et raideur) ont été déterminés à partir d'un modèle numérique du terrain (MNT) du bassin, alors que le facteur C (récolte et gestion) a été déterminé à partir des données de couverture végétale, obtenues à partir d'images SPOT et de levés terrain. Le facteur P (pratique de conservation) a été estimé à partir de cartes de conservation des sols, obtenues du Ministère de l'Agriculture. Un système d'information géographique (SIG) raster a été utilisé pour calculer interactivement le risque de perte de sol et des cartes d'érosion. Les résultats obtenus ont été comparables aux valeurs de perte de sol mesurées à partir de tracés d'érosion. A peu près 36 pour-cent du bassin Ewaso Ng'iro Supérieur a été considéré comme présentant un risque élevé d'érosion, la plupart des terres étant dans des pâturages surexploités. L'utilisation et la gestion ont été les principaux facteurs associés avec l'érosion du sol, et, à un degré moindre, la topographie. Du fait de l'échelle de la reconnaissance de cette étude il y a eu des limitations dans la détermination fiable des facteurs LS, C, et P pour l'équation universelle de perte de sol (USLE). En plus, il est nécessaire de faire des recherches pour déterminer des facteurs P appropriés pour des pratiques de conservation de sol local, telle que lignes vagues, des terrasses fanya-juu et des lignes de pierres.</p></abstract><abstract xml:lang="es"><p>Resumen: Se implementó la ecuación universal de pérdida de suelo (Universal Soil Loss Equation, USLE) para predecir el riesgo de erosión de suelos en la cuenca del Alto Ewaso Ng'iro North de Kenya, a partir de datos de parcelas de erosión y levantamientos de reconocimiento. Se determinó el factor R (erosividad de la Iluvia) por extrapolación a partir de la relación entre cantidad de Iluvia y erosividad, en base a datos de registro automático. Se determinó el factor K (erodabilidad del suelo) en base a datos obtenidos por análisis de laboratorio de muestras de suelo tomadas en 83 sitios de ensayo en la cuenca. Se determinaron los factores L y S (longitud e inclinación de la pendiente) a partir de un modelo digital de elevación de la cuenca, mientras que el factor C (cultivos y manejo de las tierras) fué determinado en base a datos de la cobertura vegetal, obtenidos a partir de imágenes SPOT y levantamientos de campo. Se estimó el factor P (prácticas de conservación) a partir de mapas de conservación de suelos obtenidos del Ministerio de Agricultura. Se usó un Sistema de Información Geográfica (SIG) basado en celdas, para calcular la pérdida de suelo y mapear el riesgo de erosión en forma interactiva. Los resultados obtenidos fueron similares a los valores de pérdida de suelo medidos en parcelas de erosión. Aproximadamente 36% de la cuenca del Alto Ewaso Ng'iro tiene alto riesgo de erosión; estas tierras se encuentran mayormente bajo pastos naturales sobrepastoreados. Los principales factores asociados con la erosión de suelos fueron el uso y el manejo de las tierras y, en un grado menor, la topografía. La escala de reconocimiento de este estudio causó limitaciones para determinar valores confiables de los factores L, S, C y P para la ecuación de USLE. Adicionalmente, se requiere más investigación para determinar valores del factor P apropiados para las prácticas locales de conservación de suelos, tales como líneas de desechos orgánicos, terrazas del tipo fanya-juu y líneas de piedras.</p></abstract><textClass><keywords scheme="keyword"><list><head>Keywords</head><item><term>soil erosion hazard assessment</term></item><item><term>USLE</term></item><item><term>GIS</term></item><item><term>Kenya</term></item><item><term>Upper Ewaso Ng'iro basin</term></item></list></keywords></textClass></profileDesc><revisionDesc><change when="2000">Published</change></revisionDesc></teiHeader></istex:fulltextTEI><json:item><extension>txt</extension><original>false</original><mimetype>text/plain</mimetype><uri>https://api.istex.fr/document/BE01FEA83D7A9E94B0B273A2388DB94EADF2BD88/fulltext/txt</uri></json:item></fulltext><metadata><istex:metadataXml wicri:clean="Elsevier, elements deleted: tail"><istex:xmlDeclaration>version="1.0" encoding="utf-8"</istex:xmlDeclaration><istex:docType PUBLIC="-//ES//DTD journal article DTD version 4.5.2//EN//XML" URI="art452.dtd" name="istex:docType"></istex:docType><istex:document><converted-article version="4.5.2" docsubtype="fla"><item-info><jid>JAG</jid><aid>00850023</aid><ce:pii>S0303-2434(00)85002-3</ce:pii><ce:doi>10.1016/S0303-2434(00)85002-3</ce:doi><ce:copyright type="unknown" year="2000"></ce:copyright></item-info><head><ce:title>Assessment of erosion hazard with the USLE and GIS: A case study of the Upper Ewaso Ng'iro North basin of Kenya</ce:title><ce:author-group><ce:author><ce:given-name>Bancy M</ce:given-name><ce:surname>Mati</ce:surname><ce:cross-ref refid="AFF1"><ce:sup>a</ce:sup></ce:cross-ref></ce:author><ce:author><ce:given-name>Royston PC</ce:given-name><ce:surname>Morgan</ce:surname><ce:cross-ref refid="AFF2"><ce:sup>b</ce:sup></ce:cross-ref></ce:author><ce:author><ce:given-name>Francis N</ce:given-name><ce:surname>Gichuki</ce:surname><ce:cross-ref refid="AFF3"><ce:sup>c</ce:sup></ce:cross-ref></ce:author><ce:author><ce:given-name>John N</ce:given-name><ce:surname>Quinton</ce:surname><ce:cross-ref refid="AFF2"><ce:sup>b</ce:sup></ce:cross-ref></ce:author><ce:author><ce:given-name>Tim R</ce:given-name><ce:surname>Brewer</ce:surname><ce:cross-ref refid="AFF2"><ce:sup>b</ce:sup></ce:cross-ref></ce:author><ce:author><ce:given-name>Hans P</ce:given-name><ce:surname>Liniger</ce:surname><ce:cross-ref refid="AFF4"><ce:sup>d</ce:sup></ce:cross-ref></ce:author><ce:affiliation id="AFF1"><ce:label>a</ce:label><ce:textfn>Jomo Kenyatta University of Agriculture and Technology, P.O. BOX 62000, Nairobi, Kenya</ce:textfn></ce:affiliation><ce:affiliation id="AFF2"><ce:label>b</ce:label><ce:textfn>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</ce:textfn></ce:affiliation><ce:affiliation id="AFF3"><ce:label>c</ce:label><ce:textfn>University of Nairobi, P.O. BOX 30197, Nairobi, Kenya</ce:textfn></ce:affiliation><ce:affiliation id="AFF4"><ce:label>d</ce:label><ce:textfn>Centre for Development and Environment University of Bern, Hallerstrass 12, CH-3012 Berne, Switzerland</ce:textfn></ce:affiliation></ce:author-group><ce:abstract><ce:section-title>Abstract</ce:section-title><ce:abstract-sec><ce:simple-para>The Universal Soil Loss Equation (USLE) was used to predict soil erosion hazard in the Upper Ewaso Ng'iro North basin of Kenya using data from erosion plots and reconnaissance surveys. The R-factor (rainfall erosivity) was determined by extrapolation from the rainfall amount-erosivity relationship, using data from autographic records. The K-factor (soil erodibility) was determined using data obtained by laboratory analysis of soil samples collected from 83 test sites in the basin. The LS-factors (slope length and steepness) were determined from a digital elevation model (DEM) of the basin, while the C-factor (crop and management) was determined from vegetation cover data, obtained from SPOT imagery and field surveys. The P-factor (conservation practice) was estimated from maps of soil conservation, obtained from the Ministry of Agriculture. A raster-based Geographic Information System (GIS) was used to interactively calculate soil loss and map erosion hazard. The results obtained were comparable to measured soil loss values from erosion plots. About 36 percent of the Upper Ewaso Ng'iro basin was predicted to have high risk of erosion, most of this land being in the overgrazed rangelands. Land use and management were the major factors associated with soil erosion, and — to a lesser extent — the topography. Due to the reconnaissance scale of this study there were limitations in determining reliable LS, C and P factors for the USLE. In addition, there is a need for research to determine appropriate P-factors for local soil conservation practices, such as trash lines, fanya-juu terraces and stone lines.</ce:simple-para></ce:abstract-sec></ce:abstract><ce:abstract xml:lang="fr"><ce:section-title>Résumé</ce:section-title><ce:abstract-sec><ce:simple-para>L'équation universelle de perte de sol (USLE) a été utilisée pour prédire le risque d'érosion du sol dans le bassin Ewaso Ng'iro Supérieur au Kenya, en utilisant des données de tracés d'érosion et des levés de reconnaissance. Le facteur R (érosivité de la pluie) a été déterminé par extrapolation à partir de la relation quantité de pluie — érosivité, en utilisant des données d'enregistrements autographiques. Le facteur K (érodibilité du sol) a été déterminé en utilisant des données obtenues à partir d'analyses d'échantillons de sols prélevés sur 83 sites tests dans le bassin. Les facteurs LS (longueur des pentes et raideur) ont été déterminés à partir d'un modèle numérique du terrain (MNT) du bassin, alors que le facteur C (récolte et gestion) a été déterminé à partir des données de couverture végétale, obtenues à partir d'images SPOT et de levés terrain. Le facteur P (pratique de conservation) a été estimé à partir de cartes de conservation des sols, obtenues du Ministère de l'Agriculture. Un système d'information géographique (SIG) raster a été utilisé pour calculer interactivement le risque de perte de sol et des cartes d'érosion. Les résultats obtenus ont été comparables aux valeurs de perte de sol mesurées à partir de tracés d'érosion. A peu près 36 pour-cent du bassin Ewaso Ng'iro Supérieur a été considéré comme présentant un risque élevé d'érosion, la plupart des terres étant dans des pâturages surexploités. L'utilisation et la gestion ont été les principaux facteurs associés avec l'érosion du sol, et, à un degré moindre, la topographie. Du fait de l'échelle de la reconnaissance de cette étude il y a eu des limitations dans la détermination fiable des facteurs LS, C, et P pour l'équation universelle de perte de sol (USLE). En plus, il est nécessaire de faire des recherches pour déterminer des facteurs P appropriés pour des pratiques de conservation de sol local, telle que lignes vagues, des terrasses <ce:italic>fanya-juu</ce:italic> et des lignes de pierres.</ce:simple-para></ce:abstract-sec></ce:abstract><ce:abstract xml:lang="es"><ce:section-title>Resumen</ce:section-title><ce:abstract-sec><ce:simple-para>Se implementó la ecuación universal de pérdida de suelo (Universal Soil Loss Equation, USLE) para predecir el riesgo de erosión de suelos en la cuenca del Alto Ewaso Ng'iro North de Kenya, a partir de datos de parcelas de erosión y levantamientos de reconocimiento. Se determinó el factor R (erosividad de la Iluvia) por extrapolación a partir de la relación entre cantidad de Iluvia y erosividad, en base a datos de registro automático. Se determinó el factor K (erodabilidad del suelo) en base a datos obtenidos por análisis de laboratorio de muestras de suelo tomadas en 83 sitios de ensayo en la cuenca. Se determinaron los factores L y S (longitud e inclinación de la pendiente) a partir de un modelo digital de elevación de la cuenca, mientras que el factor C (cultivos y manejo de las tierras) fué determinado en base a datos de la cobertura vegetal, obtenidos a partir de imágenes SPOT y levantamientos de campo. Se estimó el factor P (prácticas de conservación) a partir de mapas de conservación de suelos obtenidos del Ministerio de Agricultura. Se usó un Sistema de Información Geográfica (SIG) basado en celdas, para calcular la pérdida de suelo y mapear el riesgo de erosión en forma interactiva. Los resultados obtenidos fueron similares a los valores de pérdida de suelo medidos en parcelas de erosión. Aproximadamente 36% de la cuenca del Alto Ewaso Ng'iro tiene alto riesgo de erosión; estas tierras se encuentran mayormente bajo pastos naturales sobrepastoreados. Los principales factores asociados con la erosión de suelos fueron el uso y el manejo de las tierras y, en un grado menor, la topografía. La escala de reconocimiento de este estudio causó limitaciones para determinar valores confiables de los factores L, S, C y P para la ecuación de USLE. Adicionalmente, se requiere más investigación para determinar valores del factor P apropiados para las prácticas locales de conservación de suelos, tales como líneas de desechos orgánicos, terrazas del tipo <ce:italic>fanya-juu</ce:italic> y líneas de piedras.</ce:simple-para></ce:abstract-sec></ce:abstract><ce:keywords><ce:section-title>Keywords</ce:section-title><ce:keyword><ce:text>soil erosion hazard assessment</ce:text></ce:keyword><ce:keyword><ce:text>USLE</ce:text></ce:keyword><ce:keyword><ce:text>GIS</ce:text></ce:keyword><ce:keyword><ce:text>Kenya</ce:text></ce:keyword><ce:keyword><ce:text>Upper Ewaso Ng'iro basin</ce:text></ce:keyword></ce:keywords></head></converted-article></istex:document></istex:metadataXml><mods version="3.6"><titleInfo><title>Assessment of erosion hazard with the USLE and GIS: A case study of the Upper Ewaso Ng'iro North basin of Kenya</title></titleInfo><titleInfo type="alternative" contentType="CDATA"><title>Assessment of erosion hazard with the USLE and GIS: A case study of the Upper Ewaso Ng'iro North basin of Kenya</title></titleInfo><name type="personal"><namePart type="given">Bancy M</namePart><namePart type="family">Mati</namePart><affiliation>Jomo Kenyatta University of Agriculture and Technology, P.O. BOX 62000, Nairobi, Kenya</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Royston PC</namePart><namePart type="family">Morgan</namePart><affiliation>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Francis N</namePart><namePart type="family">Gichuki</namePart><affiliation>University of Nairobi, P.O. BOX 30197, Nairobi, Kenya</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">John N</namePart><namePart type="family">Quinton</namePart><affiliation>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Tim R</namePart><namePart type="family">Brewer</namePart><affiliation>Cranfield University, Silsoe, Bedfordshire, MK45 4DT, England, UK</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Hans P</namePart><namePart type="family">Liniger</namePart><affiliation>Centre for Development and Environment University of Bern, Hallerstrass 12, CH-3012 Berne, Switzerland</affiliation><role><roleTerm type="text">author</roleTerm></role></name><typeOfResource>text</typeOfResource><genre type="research-article" displayLabel="Full-length article"></genre><originInfo><publisher>ELSEVIER</publisher><dateIssued encoding="w3cdtf">2000</dateIssued><copyrightDate encoding="w3cdtf">2000</copyrightDate></originInfo><language><languageTerm type="code" authority="iso639-2b">eng</languageTerm><languageTerm type="code" authority="rfc3066">en</languageTerm></language><physicalDescription><internetMediaType>text/html</internetMediaType></physicalDescription><abstract lang="en">The Universal Soil Loss Equation (USLE) was used to predict soil erosion hazard in the Upper Ewaso Ng'iro North basin of Kenya using data from erosion plots and reconnaissance surveys. The R-factor (rainfall erosivity) was determined by extrapolation from the rainfall amount-erosivity relationship, using data from autographic records. The K-factor (soil erodibility) was determined using data obtained by laboratory analysis of soil samples collected from 83 test sites in the basin. The LS-factors (slope length and steepness) were determined from a digital elevation model (DEM) of the basin, while the C-factor (crop and management) was determined from vegetation cover data, obtained from SPOT imagery and field surveys. The P-factor (conservation practice) was estimated from maps of soil conservation, obtained from the Ministry of Agriculture. A raster-based Geographic Information System (GIS) was used to interactively calculate soil loss and map erosion hazard. The results obtained were comparable to measured soil loss values from erosion plots. About 36 percent of the Upper Ewaso Ng'iro basin was predicted to have high risk of erosion, most of this land being in the overgrazed rangelands. Land use and management were the major factors associated with soil erosion, and — to a lesser extent — the topography. Due to the reconnaissance scale of this study there were limitations in determining reliable LS, C and P factors for the USLE. In addition, there is a need for research to determine appropriate P-factors for local soil conservation practices, such as trash lines, fanya-juu terraces and stone lines.</abstract><abstract lang="fr">Résumé: L'équation universelle de perte de sol (USLE) a été utilisée pour prédire le risque d'érosion du sol dans le bassin Ewaso Ng'iro Supérieur au Kenya, en utilisant des données de tracés d'érosion et des levés de reconnaissance. Le facteur R (érosivité de la pluie) a été déterminé par extrapolation à partir de la relation quantité de pluie — érosivité, en utilisant des données d'enregistrements autographiques. Le facteur K (érodibilité du sol) a été déterminé en utilisant des données obtenues à partir d'analyses d'échantillons de sols prélevés sur 83 sites tests dans le bassin. Les facteurs LS (longueur des pentes et raideur) ont été déterminés à partir d'un modèle numérique du terrain (MNT) du bassin, alors que le facteur C (récolte et gestion) a été déterminé à partir des données de couverture végétale, obtenues à partir d'images SPOT et de levés terrain. Le facteur P (pratique de conservation) a été estimé à partir de cartes de conservation des sols, obtenues du Ministère de l'Agriculture. Un système d'information géographique (SIG) raster a été utilisé pour calculer interactivement le risque de perte de sol et des cartes d'érosion. Les résultats obtenus ont été comparables aux valeurs de perte de sol mesurées à partir de tracés d'érosion. A peu près 36 pour-cent du bassin Ewaso Ng'iro Supérieur a été considéré comme présentant un risque élevé d'érosion, la plupart des terres étant dans des pâturages surexploités. L'utilisation et la gestion ont été les principaux facteurs associés avec l'érosion du sol, et, à un degré moindre, la topographie. Du fait de l'échelle de la reconnaissance de cette étude il y a eu des limitations dans la détermination fiable des facteurs LS, C, et P pour l'équation universelle de perte de sol (USLE). En plus, il est nécessaire de faire des recherches pour déterminer des facteurs P appropriés pour des pratiques de conservation de sol local, telle que lignes vagues, des terrasses fanya-juu et des lignes de pierres.</abstract><abstract lang="es">Resumen: Se implementó la ecuación universal de pérdida de suelo (Universal Soil Loss Equation, USLE) para predecir el riesgo de erosión de suelos en la cuenca del Alto Ewaso Ng'iro North de Kenya, a partir de datos de parcelas de erosión y levantamientos de reconocimiento. Se determinó el factor R (erosividad de la Iluvia) por extrapolación a partir de la relación entre cantidad de Iluvia y erosividad, en base a datos de registro automático. Se determinó el factor K (erodabilidad del suelo) en base a datos obtenidos por análisis de laboratorio de muestras de suelo tomadas en 83 sitios de ensayo en la cuenca. Se determinaron los factores L y S (longitud e inclinación de la pendiente) a partir de un modelo digital de elevación de la cuenca, mientras que el factor C (cultivos y manejo de las tierras) fué determinado en base a datos de la cobertura vegetal, obtenidos a partir de imágenes SPOT y levantamientos de campo. Se estimó el factor P (prácticas de conservación) a partir de mapas de conservación de suelos obtenidos del Ministerio de Agricultura. Se usó un Sistema de Información Geográfica (SIG) basado en celdas, para calcular la pérdida de suelo y mapear el riesgo de erosión en forma interactiva. Los resultados obtenidos fueron similares a los valores de pérdida de suelo medidos en parcelas de erosión. Aproximadamente 36% de la cuenca del Alto Ewaso Ng'iro tiene alto riesgo de erosión; estas tierras se encuentran mayormente bajo pastos naturales sobrepastoreados. Los principales factores asociados con la erosión de suelos fueron el uso y el manejo de las tierras y, en un grado menor, la topografía. La escala de reconocimiento de este estudio causó limitaciones para determinar valores confiables de los factores L, S, C y P para la ecuación de USLE. Adicionalmente, se requiere más investigación para determinar valores del factor P apropiados para las prácticas locales de conservación de suelos, tales como líneas de desechos orgánicos, terrazas del tipo fanya-juu y líneas de piedras.</abstract><subject><genre>Keywords</genre><topic>soil erosion hazard assessment</topic><topic>USLE</topic><topic>GIS</topic><topic>Kenya</topic><topic>Upper Ewaso Ng'iro basin</topic></subject><relatedItem type="host"><titleInfo><title>International Journal of Applied Earth Observations and Geoinformation</title></titleInfo><titleInfo type="abbreviated"><title>JAG</title></titleInfo><genre type="journal">journal</genre><originInfo><dateIssued encoding="w3cdtf">2000</dateIssued></originInfo><identifier type="ISSN">0303-2434</identifier><identifier type="PII">S0303-2434(00)X0005-0</identifier><part><date>2000</date><detail type="volume"><number>2</number><caption>vol.</caption></detail><detail type="issue"><number>2</number><caption>no.</caption></detail><extent unit="issue pages"><start>69</start><end>149</end></extent><extent unit="pages"><start>78</start><end>86</end></extent></part></relatedItem><identifier type="istex">BE01FEA83D7A9E94B0B273A2388DB94EADF2BD88</identifier><identifier type="DOI">10.1016/S0303-2434(00)85002-3</identifier><identifier type="PII">S0303-2434(00)85002-3</identifier><recordInfo><recordContentSource>ELSEVIER</recordContentSource></recordInfo></mods></metadata></istex></record>Pour manipuler ce document sous Unix (Dilib)
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