Estimation of direct runoff, peak discharge or hydrographs is often necessary in small to medium-sized ungauged basins. Different models are used in practice for these purposes, depending on the type of problem, the available data and the prevailing runoff mechanisms in the study basin. This paper discusses the applicability of the curve number procedure developed by the US Soil Conservation Service (SCS) to estimate direct runoff in basins characterized by small to gentle undulating slopes mainly covered with natural grasslands. Rainfall and runoff data measured in the Canada de Los Chanchos basin in Uruguay is used to fit the curve numbers and to analyse the antecedent soil moisture condition proposed by the SCS.

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Most research on hydrology in developed countries does not emphasize problems that are often encountered by hydrologists in developing countries, problems such as the scarcity and poor quality of data. In developing countries the available data base is often a major constraint and a limiting factor in any hydrological study. This paper analyses the consistency of a network of nonrecording raingauges based on the annual rainfall recorded by six representative stations in the Tacuarembô River basin in Uruguay. The identification of possible errors not revealed in the printed records was accomplished by application of the factor correspondence analysis method and verified with success by the classical double-mass analysis. This ability to identify suspicious data with very modest requirements for data management implies that the methodology based on factor correspondence analysis could find wide application. Analyse multivariée en hydrologie: l'analyse de correspondance appliquée à des données de précipitations annuelles Résumé La plupart des travaux de recherche en hydrologie menés dans les pays développés ne s'intéressent pas beaucoup aux problèmes que rencontrent habituellement les hydrologues des pays en voie de développement, comme la rareté ou la médiocre qualité des données. Dans ce pays les données de base disponibles sont souvent un facteur de contrainte et de limitation majeur dans toute étude hydrologique. Cet article analyse la cohérence d'un réseau de pluviomètres: nous avons considéré les précipitations annuelles enregistrées en six stations représentatives du bassin de la rivière Tacuarembô en Uruguay. L'identification d'erreurs possibles non découvertes dans les enregistrements imprimés a été réalisée par l'analyse de correspondance, puis vérifiée avec succès en appliquant la méthode classique de l'analyse de doubles cumuls. Cette capacité à identifier des données douteuses, avec des exigences très modestes en ce qui concerne le traitement des donnés, signifie que la méthodologie pourrait trouver un vaste champ d'application.

The pre-sprouted sugarcane plantlets (PSP) system aims the production of healthy and vigorous plants in reduced time, reducing the number of stalks needed for planting. Irrigation is used in all PSP system stages and water management plays an important role. Stage 1 acclimation follows the budding stage and lasts for approximately 21 days. At this stage the plantlets are grown within an agricultural greenhouse to improve initial development. The objectives of this trial were: to identify the irrigation management which results in highest plantlet growth; to evaluate if responses to irrigation management depends on the cultivar; to evaluate water consumption and water use efficiency at early stage under PSP system; and to assess the water management effect on substrate water matrix potential and stomatal conductance in the cultivar IACSP95-5000. The experimental design was a split-plot randomized block design with four replications. Treatments applied in the plots were different irrigation depths based on daily reference evapotranspiration (ETo): 96, 80, 64 and 48%, estimated by Penman-Monteith method. In the subplots, there were sugarcane cultivars IAC91-1099, IACSP95-5000 and IACSP97-4039. Irrigation management based on 80% ETo resulted in higher growth, dry mass accumulation and greater leaf area. Water use efficiency was not influenced by irrigation management. IAC91-1099 presented higher overall growth, leaf area and dry mass accumulation. Water consumption was cultivar-dependent in irrigation managements using 80 and 96% of ETo. Water use efficiency was higher in IAC91-1099 and lower in IACSP95-5000. Lower substrate water matrix potential reduced leaves stomatal conductance, impairing IACSP95-5000 plantlet growth.