La cuenca del río Nazas es la principal fuente de agua de la Región Hidrológica 36 ( R H 3 6 ) ; ... more La cuenca del río Nazas es la principal fuente de agua de la Región Hidrológica 36 ( R H 3 6 ) ; su escurrimiento proviene esencialmente de la parte alta que recibe de 500 a 5'00 mm anuales de precipitaciones pluviales y posee fuertes coeficientes de escurrimiento (10 a 20 por ciento). Estas aguas superficiales representan$ para las Areas semiAridas de la cuenca, un potencial interesante en la agricultura, ya que pueden ser utilizadas como complemento de la lluvia o irrigación total de los cultivos.
The Hydrological Region 36 (HR 36), with a surface area of 92,000 km2, is one of the three Mexica... more The Hydrological Region 36 (HR 36), with a surface area of 92,000 km2, is one of the three Mexican hydrological endorheic regions. North of the tropic of Cancer, at a latitude of 23° to 27° north, the HR 36 stretches from the Western part of the Sierra Madre, which is more than 3,130 meter high, to the lagoons of Mayran and Viesca. These lagoons are the outlets of the Rios Nazas and Aguanaval on the high plateau of North-Mexico (Altiplano) at an altitude of 1,100 m. The analysis of the annual rainfall with a sample of 123 pluviometric stations made it possible to distinguish three areas in the HR 36: a sub-humid area on the western part of the Sierra Madre, a semiarid area on the piedmont of the Sierra and an arid area on the high plateau. Thirteen units of the FAO/Unesco soil classification are present in the HR 36, but only three units occupy 70% of this region: the litosols, the xerosols and the feozems. The vegetation counts four main groups but the xerophile matorral, a dense e...
Le but du projet étant la détermination des ressources en eau de ruissellement, l'imagerie sa... more Le but du projet étant la détermination des ressources en eau de ruissellement, l'imagerie satellitaire sert à la définition de zones supposées homogènes vis-à-vis du ruissellement; sur ces zones sont ensuite installés des bassins-versants et parcelles de mesure du ruissellement dont les résultats peuvent être extrapolés grâce aux zones définies par télédétection. D'autre part, l'évolution de la couverture végétale sur plus de 20 ans (depuis le lancement de premiers Landsat MSS) est mise en parallèle avec les données hydrométriques existantes du réseau mexicain, afin de connaître l'impact du surpâturage et du déboisement sur les écoulements.
The objective is to assess the suitability of commonly used high-resolution satellite rainfall pr... more The objective is to assess the suitability of commonly used high-resolution satellite rainfall products (CMORPH, TMPA 3B42RT, TMPA 3B42 and PERSIANN) as input to the semi-distributed hydrological model SWAT for daily streamflow simulation in two watersheds (Koga at 299 km 2 and Gilgel Abay at 1656 km 2 ) of the Ethiopian highlands. First, the model is calibrated for each watershed with respect to each rainfall product input for the period 2003-2004. Then daily streamflow simulations for the validation period 2006-2007 are made from SWAT using rainfall input from each source and corresponding model parameters; comparison of the simulations to the observed streamflow at the outlet of each watershed forms the basis for the conclusions of this study. Results reveal that the utility of satellite rainfall products as input to SWAT for daily streamflow simulation strongly depends on the product type. The 3B42RT and CMORPH simulations show consistent and modest skills in their simulations but underestimate the large flood peaks, while the 3B42 and PERSIANN simulations have inconsistent performance with poor or no skills. Not only are the microwave-based algorithms (3B42RT, CMORPH) better than the infrared-based algorithm (PERSIANN), but the infrared-based algorithm PERSIANN also has poor or no skills for streamflow simulations. The satellite-only product (3B42RT) performs much better than the satellite-gauge product (3B42), indicating that the algorithm used to incorporate rain gauge information with the goal of improving the accuracy of the satellite rainfall products is actually making the products worse, pointing to problems in the algorithm. The effect of watershed area on the suitability of satellite rainfall products for streamflow simulation also depends on the rainfall product. Increasing the watershed area from 299 km 2 to 1656 km 2 improves the simulations
Apres une phase de depeuplement rapide, les alpes du sud connaissent un amoindrissement des pheno... more Apres une phase de depeuplement rapide, les alpes du sud connaissent un amoindrissement des phenomenes lies a l'erosion lineaire, du en particulier a la progresion importante de la couverture forestiere. Cette erosion demeure forte dans les secteurs deja erodes (badlands des "terres noires" du jurassque): l'epaisseur de la tranche erodee y est de l'ordre de 0,5 a 1 cm. Par an, avec une opposition marquee liee a l'exposition. On note une recrudescence des phenomenes de solifluxion, lies proballement en partie au defaut d'entretien de l'ancien systeme hydraultique (drainage; irrigation) et des terrasses de cultures. Les evenements paroxysmaux ont, tant pour l'erosion lineaire que pour la solifluxion, une importance primordiale: dans le premier cas, c'est l'intensite des precipitations qui a le plus d'importance; dans le deuxieme. C'est la quantite d'eau tombee et infiltree qui joue le plus grand role.
La cuenca del río Nazas es la principal fuente de agua de la Región Hidrológica 36 ( R H 3 6 ) ; ... more La cuenca del río Nazas es la principal fuente de agua de la Región Hidrológica 36 ( R H 3 6 ) ; su escurrimiento proviene esencialmente de la parte alta que recibe de 500 a 5'00 mm anuales de precipitaciones pluviales y posee fuertes coeficientes de escurrimiento (10 a 20 por ciento). Estas aguas superficiales representan$ para las Areas semiAridas de la cuenca, un potencial interesante en la agricultura, ya que pueden ser utilizadas como complemento de la lluvia o irrigación total de los cultivos.
The Hydrological Region 36 (HR 36), with a surface area of 92,000 km2, is one of the three Mexica... more The Hydrological Region 36 (HR 36), with a surface area of 92,000 km2, is one of the three Mexican hydrological endorheic regions. North of the tropic of Cancer, at a latitude of 23° to 27° north, the HR 36 stretches from the Western part of the Sierra Madre, which is more than 3,130 meter high, to the lagoons of Mayran and Viesca. These lagoons are the outlets of the Rios Nazas and Aguanaval on the high plateau of North-Mexico (Altiplano) at an altitude of 1,100 m. The analysis of the annual rainfall with a sample of 123 pluviometric stations made it possible to distinguish three areas in the HR 36: a sub-humid area on the western part of the Sierra Madre, a semiarid area on the piedmont of the Sierra and an arid area on the high plateau. Thirteen units of the FAO/Unesco soil classification are present in the HR 36, but only three units occupy 70% of this region: the litosols, the xerosols and the feozems. The vegetation counts four main groups but the xerophile matorral, a dense e...
Le but du projet étant la détermination des ressources en eau de ruissellement, l'imagerie sa... more Le but du projet étant la détermination des ressources en eau de ruissellement, l'imagerie satellitaire sert à la définition de zones supposées homogènes vis-à-vis du ruissellement; sur ces zones sont ensuite installés des bassins-versants et parcelles de mesure du ruissellement dont les résultats peuvent être extrapolés grâce aux zones définies par télédétection. D'autre part, l'évolution de la couverture végétale sur plus de 20 ans (depuis le lancement de premiers Landsat MSS) est mise en parallèle avec les données hydrométriques existantes du réseau mexicain, afin de connaître l'impact du surpâturage et du déboisement sur les écoulements.
The objective is to assess the suitability of commonly used high-resolution satellite rainfall pr... more The objective is to assess the suitability of commonly used high-resolution satellite rainfall products (CMORPH, TMPA 3B42RT, TMPA 3B42 and PERSIANN) as input to the semi-distributed hydrological model SWAT for daily streamflow simulation in two watersheds (Koga at 299 km 2 and Gilgel Abay at 1656 km 2 ) of the Ethiopian highlands. First, the model is calibrated for each watershed with respect to each rainfall product input for the period 2003-2004. Then daily streamflow simulations for the validation period 2006-2007 are made from SWAT using rainfall input from each source and corresponding model parameters; comparison of the simulations to the observed streamflow at the outlet of each watershed forms the basis for the conclusions of this study. Results reveal that the utility of satellite rainfall products as input to SWAT for daily streamflow simulation strongly depends on the product type. The 3B42RT and CMORPH simulations show consistent and modest skills in their simulations but underestimate the large flood peaks, while the 3B42 and PERSIANN simulations have inconsistent performance with poor or no skills. Not only are the microwave-based algorithms (3B42RT, CMORPH) better than the infrared-based algorithm (PERSIANN), but the infrared-based algorithm PERSIANN also has poor or no skills for streamflow simulations. The satellite-only product (3B42RT) performs much better than the satellite-gauge product (3B42), indicating that the algorithm used to incorporate rain gauge information with the goal of improving the accuracy of the satellite rainfall products is actually making the products worse, pointing to problems in the algorithm. The effect of watershed area on the suitability of satellite rainfall products for streamflow simulation also depends on the rainfall product. Increasing the watershed area from 299 km 2 to 1656 km 2 improves the simulations
Apres une phase de depeuplement rapide, les alpes du sud connaissent un amoindrissement des pheno... more Apres une phase de depeuplement rapide, les alpes du sud connaissent un amoindrissement des phenomenes lies a l'erosion lineaire, du en particulier a la progresion importante de la couverture forestiere. Cette erosion demeure forte dans les secteurs deja erodes (badlands des "terres noires" du jurassque): l'epaisseur de la tranche erodee y est de l'ordre de 0,5 a 1 cm. Par an, avec une opposition marquee liee a l'exposition. On note une recrudescence des phenomenes de solifluxion, lies proballement en partie au defaut d'entretien de l'ancien systeme hydraultique (drainage; irrigation) et des terrasses de cultures. Les evenements paroxysmaux ont, tant pour l'erosion lineaire que pour la solifluxion, une importance primordiale: dans le premier cas, c'est l'intensite des precipitations qui a le plus d'importance; dans le deuxieme. C'est la quantite d'eau tombee et infiltree qui joue le plus grand role.
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