Water management and environmental protection is vulnerable to extreme low flows during streamflow droughts. During the last decades, in most rivers of Central Europe summer runoff and low flows have decreased. Discharge projections agree that future decrease in runoff is likely for catchments in Brandenburg, Germany. Depending on the first-order controls on low flows, different adaption measures are expected to be appropriate. Small catchments were analyzed because they are expected to be more vulnerable to a changing climate than larger rivers. They are mainly headwater catchments with smaller ground water storage. Local characteristics are more important at this scale and can increase vulnerability. This thesis mutually evaluates potential adaption measures to sustain minimum runoff in small catchments of Brandenburg, Germany, and similarities of these catchments regarding low flows. The following guiding questions are addressed: (i) Which first-order controls on low flows and related time scales exist? (ii) Which are the differences between small catchments regarding low flow vulnerability? (iii) Which adaption measures to sustain minimum runoff in small catchments of Brandenburg are appropriate considering regional low flow patterns? Potential adaption measures to sustain minimum runoff during periods of low flows can be classified into three categories: (i) increase of groundwater recharge and subsequent baseflow by land use change, land management and artificial ground water recharge, (ii) increase of water storage with regulated outflow by reservoirs, lakes and wetland water management and (iii) regional low flow patterns have to be considered during planning of measures with multiple purposes (urban water management, waste water recycling and inter-basin water transfer). The question remained whether water management of areas with shallow groundwater tables can efficiently sustain minimum runoff. Exemplary, water management scenarios of a ditch irrigated area were evaluated using the model Hydrus-2D. Increasing antecedent water levels and stopping ditch irrigation during periods of low flows increased fluxes from the pasture to the stream, but storage was depleted faster during the summer months due to higher evapotranspiration. Fluxes from this approx. 1 km long pasture with an area of approx. 13 ha ranged from 0.3 to 0.7 ls depending on scenario. This demonstrates that numerous of such small decentralized measures are necessary to sustain minimum runoff in meso-scale catchments. Differences in the low flow risk of catchments and meteorological low flow predictors were analyzed. A principal component analysis was applied on daily discharge of 37 catchments between 1991 and 2006. Flows decreased more in Southeast Brandenburg according to meteorological forcing. Low flow risk was highest in a region east of Berlin because of intersection of a more continental climate and the specific geohydrology. In these catchments, flows decreased faster during summer and the low flow period was prolonged. A non-linear support vector machine regression was applied to iteratively select meteorological predictors for annual 30-day minimum runoff in 16 catchments between 1965 and 2006. The potential evapotranspiration sum of the previous 48 months was the most important predictor (r²=0.28). The potential evapotranspiration of the previous 3 months and the precipitation of the previous 3 months and last year increased model performance (r²=0.49, including all four predictors). Model performance was higher for catchments with low yield and more damped runoff. In catchments with high low flow risk, explanatory power of long term potential evapotranspiration was high. Catchments with a high low flow risk as well as catchments with a considerable decrease in flows in southeast Brandenburg have the highest demand for adaption. Measures increasing groundwater recharge are to be preferred. Catchments with high low flow risk showed relatively deep and decreasing groundwater heads allowing increased groundwater recharge at recharge areas with higher altitude away from the streams. Low flows are expected to stay low or decrease even further because long term potential evapotranspiration was the most important low flow predictor and is projected to increase during climate change. Differences in low flow risk and runoff dynamics between catchments have to be considered for management and planning of measures which do not only have the task to sustain minimum runoff. / Sowohl Gewässermanagement als auch die Gewässerökologie können durch extreme Niedrigwasserereignisse stark betroffen sein. In den letzten Jahrzehnten haben sowohl der Abfluss während der Sommermonate als auch die Niedrigwasserabflüsse in den meisten Flüssen Zentraleuropas abgenommen. Projektionen des zukünftigen Abflusses lassen einen weiteren Rückgang der Abflüsse aus Einzugsgebieten Brandenburgs erwarten. Anpassungsmaßnahmen zur Stützung von Niedrigwasserabflüssen müssen den hydrologischen Prozessen gerecht werden. In dieser Arbeit werden Kopfeinzugsgebiete mit kleineren Grundwasserspeichern betrachtet, weil sie anfälliger gegenüber dem Klimawandel erscheinen als größere. Lokale Gegebenheiten können darüber hinaus ihre Vulnerabilität erhöhen. In dieser Arbeit werden Ergebnisse über die ähnlichkeit von kleinen Einzugsgebieten verwendet, um geeignete Anpassungsmaßnahmen zur Stützung von Niedrigwasserabflüssen herauszuarbeiten. Folgende Leitfragen werden bearbeitet: (i) Was sind die maßgeblichen Prozesse und Zeitskalen, die zu Niedrigwasserabflüssen führen? (ii) Wie unterscheiden sich die Einzugsgebiete bezüglich ihrer Vulnerabilität? (iii) Was sind geeignete Anpassungsmaßnahmen unter Berücksichtigung der vorherrschenden Prozesse und ihrer räumlichen Muster? Mögliche Anpassungsmaßnahmen können in drei Kategorien unterteilt werden: (i) Landnutzungsänderungen, änderungen der Feldbewirtschaftung und künstliche Grundwasseranreicherung führen zur Erhöhung der Grundwasserneubildung und somit des Basisabflusses. (ii) Talsperren, Seen, Teiche und ein entsprechendes Wassermanagement in Feuchtgebieten eignen sich zur Wasserspeicherung und regulierten Wasserabgabe. (iii) Maßnahmen bei deren Planung Wissen über Niedrigwasserabflüsse einfließen muss, aber die Stützung von Niedrigwasserabflüssen nicht die einzige Aufgabe ist (Siedlungswassermanagement, Abwassermanagement und Wasserüberleitungen zwischen Einzugsgebieten). Darüber hinaus wurde die Effektivität ufernaher Grundwasseranreicherung durch bestehende Bewässerungsgräben explizit an einem Standort unter Verwendung des Models Hydrus-2D quantifiziert. Hohe Wasserstände in den Gräben und das Unterbrechen der Wassereinleitung führten zu einer Niedrigwasseraufhöhung. Im Sommer wurde der Wasserspeicher wegen der Verdunstung schneller verbraucht. Je nach Szenario betrug die Niedrigwasseraufhöhung, die von der ca. 1 km langen und 13 ha großen Fläche ausging, zwischen 0.3 und 0.7 l/s. Eine Vielzahl solcher dezentraler Maßnahmen wären für eine deutliche Stützung der Niedrigwasserabflüsse in mesoskaligen Einzugsgebieten notwendig. Das Niedrigwasserrisiko sowie meteorologische Niedrigwasserprädiktoren wurden vergleichend analysiert. Der tägliche Abfluss aus 37 Einzugsgebieten zwischen 1991 und 2006 wurde mittels einer Hauptkomponentenanalyse ausgewertet. Der Abfluss in Südost Brandenburg ging klimabedingt stärker zurück. Das Niedrigwasserrisiko war in der Region östlich Berlins als Folge des kontinentaleren Klimas und der lokalen geohydrologischen Verhältnisse am größten. Diese Einzugsgebiete zeigten einen relativ schnellen Abflussrückgang während der Sommermonate und eine längere Niedrigwasserperiode. Darüber hinaus wurde eine nichtlineare Support Vektor Machine Regression zur iterativen Bestimmung der meteorologischen Prädiktoren für den jährlichen Niedrigwasserabfluss im 30-Tage Mittel in 16 Einzugsgebieten zwischen 1965 und 2006 durchgeführt. Die potentielle Verdunstungshöhe der vorhergegangenen 48 Monate war der wichtigste Prädiktor (r²=0.28). Die potentielle Verdunstungshöhe der vorhergegangenen 3 Monate sowie die Niederschlagshöhe der vorhergegangenen 3 Monate und des letzten Jahres verbesserten die Modellgüte zusätzlich (r²=0.49, für alle vier Prädiktoren). Die Modellgüte war höher in Einzugsgebieten mit geringer Abflussspende und gedämpftem Abflussverhalten. In Einzugsgebieten mit hohem Niedrigwasserrisiko war die potentielle Langzeitverdunstung wichtiger, um Niedrigwasserabflüsse zu erklären. In Einzugsgebieten mit hohem Niedrigwasserrisiko östlich von Berlin und deutlichem Abflussrückgang im Südosten Brandenburgs besteht der höchste Anpassungsbedarf. Maßnahmen zur Erhöhung der Grundwasserneubildung sollten bevorzugt werden. Einzugsgebiete mit hohem Niedrigwasserrisiko haben verhältnismäßig tiefe Grundwasserstände, was eine Erhöhung der Grundwasserneubildung in den höher gelegenen Neubildungsgebieten möglich und sinnvoll macht. Es ist davon auszugehen, dass Niedrigwasserabflüsse weiterhin niedrig bleiben oder sogar weiter fallen werden, da die potentielle Langzeitverdunstung der wichtigste Prädiktor war und Klimamodelle einen weiteren Anstieg dieser projizieren. Des Weiteren sind die Ergebnisse dieser Arbeit wichtig für die integrierte Planung von Maßnahmen, die nicht ausschließlich die Stützung von Niedrigwasserabflüssen zur Aufgabe haben.

In many of the rural areas of South Africa local communities rely on wetland resources for daily living. For a symbiotic relationship to exist between these communities and the wetlands, the wetlands must be utilised in a manner sustainable to both parties. To prevent exploitation thereof, a comprehensive understanding of the processes and functions of wetlands, of the values and needs of rural community members, and of the interactions between these entities is essential. This study focuses on research at three scales; the plot scale (10m\ the microcatchment scale (lkm2 ), represented by the Craigiebum wetland and microcatchment, and the catchment area upstream of the gauging weir X3H008, all of which exist in the Sand River catchment in the Mpumalanga and Limpopo Provinces of South Africa. Relationships between the geomorphological properties of the Craigiebum microcatchment, the wetland management practices of the local communities, and the hydrological properties of the microcatchment have been investigated. Various hydrological models, but in the main the ACRU model, have been adopted as tools to facilitate this research. Possible scenarios of changes in land use, rainfall and soil texture were performed at the plot scale and at the scale of the microcatchment, and changes in wetland extent were simulated and analysed at the scale of the catchment. Results of the modelling exercises simulating the effects of differences in soil texture higWight the positive effects of retention of fine particles within a wetland in a sandy environment. These results also depict greater rates of hydraulic conductivity, erosion and desiccation within coarse-textured soils than fmer textured soils. Low levels of fertility can also be attributed to the lack of fine particles present in the soils of the Craigiebum microcatchment wetland. Results of the modelling exercises that investigate the likely hydrological effects of a variety of land uses within the Craigiebum microcatchment verify accepted hydrological theory, as they highlight that more impervious areas produce more stormflow and lose more water to evaporation, and that the natural vegetation of the area contributes to streamflow regulation more than other land uses do. The exercises performed at the scale of the Sand River catchment do not provide conclusive evidence of the effects of changes in wetland extent, as the hydrological effects that other land uses in the area have appear to override the effects of the simulated wetland areas. Analysis of the sociological data captured highlights the great extent to which the local community depends on the Craigieburn wetland resources for a variety of livelihood strategies. Furthermore it illustrates the degree to which a reduction in wetland health negatively impacts upon the community. Viewed in conjunction, the hydrological, biophysical and sociological results highlight the degree to which changes in one aspect of the environment affect other aspects thereof, thereby highlighting the degree to which these aspects of the Craigieburn microcatchment are inextricably linked. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

Wetlands are now recognized as being an integral component of the physical landscape. Geomorphology has recently been recognised by wetland scientists as being of fundamental importance in wetland genesis, maintenance and evolution, thereby providing the context for informed, effective wetland management and conservation. At present there exists a paucity of geomorphological wetland research in South Africa. A hydro-geomorphic approach was adopted to attain an understanding of wetland genesis, distribution and functioning of a range of different palustrine wetland systems in the upper Mooi-River Catchment of KwaZulu-Natal. The physical, chemical and landscape-morphological characteristics of wetland soils were investigated to interpret the processes operating within those wetland systems. Both field and laboratory work suggest that wetland creation and maintenance in the upper Mooi River catchment may be attributed primarily to climatic factors, landscape position, landform and geological characteristics. These factors were found to cumulatively control the hydrological characteristics of wetlands, which impart an important influence on internal wetland conditions. While soil properties do not appear to be a primary factor in the establishment of these wetlands, they are nevertheless found to be important in the regulation of the hydrological dynamics of wetland systems. The close interdependence between wetlands and the surrounding landscape and the hydrological cycle is evident in the wetland systems investigated. Geomorphic processes within wetlands such as overbank flooding, overland flow, sedimentation, piping, leaching, soil swelling, shrinkage and cracking and channel incision and dynamics were found to be important variables in determining the nature and internal characteristics of wetland systems. In several of the systems investigated, all of the above mentioned processes were operative, while in other systems, a number of these processes were either insignificant or absent. Canonical Variate Analysis indicated that while commonalities exist between the palustrine wetland systems investigated in this study, significant differences were found between different groups. This supports the argument that a subclassification of the palustrine system into five different palustrine wetland types is warranted. While the scope of the present research did not allow for an extensive investigation of suitable methods of rehabilitation, the study suggests that an understanding of geomorphic process and wetland dynamics will be beneficial to wetland management and conservation as a whole. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

Im Fokus der Untersuchungen steht das hydrologische Einzugsgebiet der oberen Wilzsch im Westerzgebirge. Veränderte Stoffausträge des bewaldeten und zum Teil vermoorten hydrologischen Einzugsgebietes führen zu erhöhten Stoffkonzentrationen im Hauptzufluss der Trinkwassertalsperre Weiterswiese (Carlsfeld). Seitens der Trinkwasseraufbereitung stellen insbesondere die gestiegenen Gehalte an gelösten organischen Kohlenstoffen (DOC) Mehraufwendungen dar. Im Zuge der Wiedervernässung der Moorflächen kommt es zu relevanten bodenchemischen Veränderungen, die im Abfluss messbar sind. Eine räumliche Betrachtung der Teileinzugsgebiete des hydrologischen Einzugsgebietes der oberen Wilzsch ermöglicht, das Abflussgebiet in verschiedene Herkunftsräume zu gliedern. Dieser raumbezogene Ansatz leistet einen wesentlichen Beitrag in der Herkunftsanalytik von Wässern, deren Fließwege durch Standorte unterschiedlicher Nutzung geprägt sind. Die Arbeit bedient sich hydrochemischen Analysen sowie multitraceranalytischen Verfahren. Die Analyse der stabilen Umweltisotope ²H und 18O am Wasser, 13C am DIC und DOC, 34S und 18O am Sulfat sowie 15N und 18O am Nitrat hilft bei der Identifizierung von Stoffquellen und Transformationsprozessen. Die Arbeit verfolgt das Ziel, den Beitrag der verschiedenen Stoffsysteme am gesamten Stoffaustrag des Vorfluters aufzuzeigen sowie die atmosphärische Grundlast an den Messstandorten nachzuweisen. Dazu wurden von Mai 2009 bis August 2010 fünf Beprobungskampagnen angelegt. Das Messdesign erstreckte sich auf 19 Standorte in ausgewählten Teileinzugsgebieten, die maßgeblichen Einfluss auf die Vorflut haben. Parallel dazu erfolgte die Untersuchung des Niederschlags an der Station Talsperre Weiterswiese. Erfasst wurden die Inhalte von Wässern verschiedener Moorgebiete, Moorwasserpegel unterschiedlich degradierter Moorbereiche, Gräben und Bodendrainagen im Fichtenforst, der Vorfluter Wilzsch und Kranizsch und des Grundwassers im Fichtenforst. Es kann festgehalten werden, dass je nach Lage bzw. Entfernung der Ursprungsgebiete der Anteil des DOC - Exports unterschiedlich stark ist. So sind die DOC - Austräge saisonal sehr verschieden. Im Ergebnis ist der hydrochemische Beitrag - im Besonderen DOC - der unterschiedlichen Stoffsysteme des hydrologischen Einzugsgebietes letztlich am finalen Pegel der Wilzsch messbar. Die vom Basisabfluss gesteuerten silikatischen Standorte im Fichtenforst leisten einen wesentlichen Anteil zum hydrochemischen Milieu der Vorfluter. Die im Untersuchungsgebiet eingeleiteten Renaturierungsmaßnahmen beeinflussen die Trinkwasserqualität in der Talsperre Carlsfeld nicht. Eine Abgrenzung der atmosphärischen Grundlast ist ebenfalls möglich, atmogen eingetragene Stoffe können an den Standorten ausgewiesen werden.

[Truncated abstract]This thesis investigates aspects of urban stormwater modeling and uses a small urban catchment (NE38) located in the suburb of Nedlands in Perth, Western Australia to do so. The MUSIC (Model for Urban Stormwater Improvement Conceptualisation) model was used to calibrate catchment NE38 using measured stormwater flows and rainfall data from within the catchment. MUSIC is a conceptual model designed to model stormwater flows within urban environments and uses a rainfall-runoff model adapted to generate results at six minute time steps. Various catchment scenarios, including the use of porous asphalt as an alternative road surface, were applied to the calibrated model to identify effective working stormwater disposal systems that differ from the current system. Calibrating catchment NE38 using the MUSIC model was attempted and this involved matching modeled stormwater flows to stormwater flows measured at the catchment drainage point. This was achieved by measuring runoff contributing areas (roads) together with rainfall data measured from within the catchment and altering the seepage constant parameter for all roadside infiltration sumps. ... The MUSIC model generated future scenario outcomes for alternative stormwater disposal systems that displayed similar or improved levels of performance with respect to the current system. The following scenarios listed in increasing order of effectiveness outline future stormwater disposal systems that may be considered in future urban design. 1. 35% porous asphalt application with no sumps in 2036 2. 35% porous asphalt application with no sumps in 2064 3. 68% porous asphalt application with no sumps in 2036 4. 68% porous asphalt application with no sumps in 2064. Future scenarios using the current stormwater disposal system (with roadside infiltration sumps) with porous asphalt were also run. These scenarios reduced stormwater runoff and contaminant loading on the catchment drainage point however the inclusion of a roadside infiltration sump system may not appeal to urban designers due to the costs involved with this scenario. Climate change will affect the design of future stormwater disposal systems and thus, the design of these systems must consider a rainfall reducing future. Based on the findings of this thesis, current stormwater runoff volumes entering catchment drainage points can be reduced together with contaminant loads in urban environments that incorporate porous asphalt with a stormwater disposal design system that is exclusive of roadside infiltration sumps.

[Truncated abstract] Runoff generation behaviour and flooding in a lake dominated catchment are nonlinear, threshold-driven processes that result from the interactions between climate and various catchment characteristics. A complicating feature of the rainfall to runoff transformation, which may have implications for the flood frequency, is that the various surface and subsurface flow pathways are dynamic, heterogeneous and highly nonlinear, consisting of distinct thresholds. To understand the impact of threshold nonlinearities on the rainfall-runoff transformation in such catchments, a systematic examination was carried out to investigate runoff generation behaviour of the catchment itself, the overflow behaviour of a lake in combination with the catchment draining into it, as well as the lake organisation within a lake chain network. Three storage based thresholds were considered: the catchment field capacity storage governing catchment subsurface stormflow, total storage capacity governing catchment surface runoff, and lake storage capacity governing lake-overflow. ... Through these investigations, this thesis has provided valuable insights into the process controls of lake-overflow events and the associated flood frequency behaviour in lake dominated catchments. In particular, the relative roles of climate, soil depth, the soil?s drainage capacity, as well as the relative geometry of the lake vis a vis the contributing catchment, in the determination of the dynamic characteristics of lake-overflow events and associated flood frequency behaviour have been highlighted. In addition, the importance of lake organization, as expressed in terms of the average ratio of catchment area to lake area and the spatial variability of this ratio from upstream to downstream, and their impact upon connectivity and flood frequency have also been explored. The outcomes of this study highlight the importance of thresholds governing flood frequency, and provide insights into the complex interactions between rainfall variability and the various threshold nonlinearities in the rainfall-runoff process, which are shown to have a significant impact on the resulting flood frequency curves. The improved understanding of these process controls will be useful in assisting the 1 management of the catchment-lake system in the study region, and in regions elsewhere. In particular, the outcome of this study can provide guidance towards the adoption of various management strategies for lake chain systems by illustrating the effects of potential flow interruption and retardation as ways to assist in flood prevention and mitigation, whether it is aimed at decreasing the frequency of occurrence of lake overflows, or merely decreasing the flow magnitude for a given return period.

It is proven that the ongoing refinement of the quality of rainfall data hand in hand with time and space variability of the rainfall has immense effect on the management of watercourses, flood control and hydrologic modelling. The aim of this thesis is to do an analysis of selected precipitation events in the Kopaninský stream research basin for more accurate information on rainfall-runoff processes. The aim of the analysis of individual precipitation events is to evaluate differences in total precipitation and volume measurements recorded in the basin and radar estimated precipitation. The output is detailed data series of spatial and temporal distribution of major precipitation events in the GIS used as input to hydrologic models. The issues of atmospheric precipitatio and meteorological radars are discussed in the literature review, which explains selected basic concepts and principles of these topics.

This thesis focuses on the issue of water tanks especially in the aspect of their functions, maintenance, reconstruction, development and revitalization of tanks. It also deals with the application of reservoirs in agricultural landscape. This thesis contains a description and evaluation of the history and development of tanks in the selected location of South Bohemia, which is the catchment Mladějovický stream. Within the selected and interested area contains a estimate of the economic severity of reconstruction tanks.

ALBUQUERQUE, Cícero Lima. Avaliação das tecnologias sociais como alternativa de convivência com o Semiárido Cearense: O Projeto de Cisternas . 2012. 104f. – Dissertação (Mestrado) – Universidade Federal do Ceará, Programa de Pós Graduação em Avaliação de Políticas Públicas, Fortaleza (CE), 2012. / Submitted by Gustavo Daher (gdaherufc@hotmail.com) on 2017-05-05T17:19:07Z No. of bitstreams: 1 2012_dis_clalbuquerque.pdf: 1332863 bytes, checksum: b58a5597319ac0333a642773e6cadf25 (MD5) / Approved for entry into archive by Márcia Araújo (marcia_m_bezerra@yahoo.com.br) on 2017-05-08T11:05:12Z (GMT) No. of bitstreams: 1 2012_dis_clalbuquerque.pdf: 1332863 bytes, checksum: b58a5597319ac0333a642773e6cadf25 (MD5) / Made available in DSpace on 2017-05-08T11:05:12Z (GMT). No. of bitstreams: 1 2012_dis_clalbuquerque.pdf: 1332863 bytes, checksum: b58a5597319ac0333a642773e6cadf25 (MD5) Previous issue date: 2012 / This study assesses the project selected in Proclamation 02/2008 of the BNB / ETENE - New Social Technologies (ST) Living with the Semi-Arid.These technologies are intended to promote better coexistence with the semiarid, with the increase of farming systems, income generation and community participation. Technology should be used as an example to reapply in the Brazilian semiarid. We opted for an ex post evaluation, which is held throughout the execution or after completion of the project. Through qualitative and quantitative methodologies, we seek to verify the implementation of TS cistern in three communities of the cities of Santana and Acaraú Morrinhos, Ceará. The field was developed with the use of questionnaires with representatives of the families, and interviews with the coordinator and community leaders. We observed the dependency of families on the help of government and civil society, low educational levels of most parents, the small amount of land used for cultivation and production of traditional beans, maize and cassava. We present the characterization of Brazilian Semiarid (SAB), the biome, the coexistence of man with that environment, the technologies adapted to their reality, as well as key programs developed by civil society. Farmers traditionally hold their crops during the winter, receiving little or no technical assistance from municipal and state agencies. The social technology implemented by the project requires more time for use to generate satisfactory income families. Water is a precious asset for these communities, however, it is essential that the availability of infrastructure such as better roads, schools and health posts to local development and improved coexistence with the semiarid. / Esta pesquisa faz uma avaliação do projeto selecionado no Edital 02/2008 do BNB/ETENE – Novas Tecnologias Sociais (TS) de Convivência com o Semiárido. Essas tecnologias têm como objetivo promover uma melhor convivência com o semiárido, com o aumento das explorações agropecuárias, a geração de renda e a participação comunitária. A tecnologia deveria ser utilizada como exemplo de reaplicabilidade no semiárido brasileiro. Optamos por uma avaliação ex post, que é realizada ao longo da execução ou após a conclusão do projeto. Através de metodologias qualitativas e quantitativas, procuramos verificar a implantação da TS cisterna calçadão em três comunidades dos municípios de Santana do Acaraú e Morrinhos, no Ceará. A pesquisa de campo foi desenvolvida com a aplicação de questionários com os representantes das famílias, e entrevistas com a coordenadora e os líderes comunitários. Observamos a dependência das famílias quanto à ajuda do Governo e da sociedade civil organizada, a baixa escolaridade da maioria dos pais, a pouca quantidade de terra utilizada para a produção e o cultivo tradicional do feijão, do milho e da mandioca. Apresentamos a caracterização do Semiárido Brasileiro (SAB), o bioma, a convivência do homem com esse ambiente, as tecnologias adaptadas à sua realidade, bem como os principais programas desenvolvidos pela sociedade civil. Os agricultores, tradicionalmente, realizam seus plantios durante o inverno, recebendo pouca ou nenhuma assistência técnica dos órgãos municipal e estadual. A tecnologia social implementada pelo projeto requer maior tempo de utilização para a satisfatória geração de renda às famílias. A água é um bem precioso para essas comunidades, entretanto, verificou-se que é fundamental a disponibilidade de infraestrutura, como melhores estradas, escolas e postos de saúde para o desenvolvimento local e a melhor convivência com o semiárido.

Pour améliorer la prévision des crues dans les bassins versants torrentiels, les hydrologues doivent connaître les conditions initiales de l'état hydrique des sols précédant les événements pluvieux. La cartographie de l'humidité des sols, dont les variations sont principalement influencées par la topographie, la couverture végétale et l'hétérogénéité des propriétés des sols, constitue alors un outil précieux pour étudier les processus de formation des écoulements. Ce travail aborde la problématique de la spatialisation des variations spatio-temporelles de l'état hydrique des sols en utilisant la modélisation géostatistique et hydrologique appliquées au bassin versant expérimental marneux du Laval (0.86 km², ORE Draix-Bléone, France). Le suivi in situ des épisodes pluvieux de mai 2015 à novembre 2016 a permis de mettre en évidence une relation significative entre la teneur en eau des sols, la topographie et l'occupation de surface dans les badlands. Il a également permis de mieux appréhender la dynamique spatio-temporelle des variations de teneur en eau des versants à l'échelle saisonnière et événementielle, et de confirmer la majeure contribution aux écoulements de crue des horizons superficiels dénudés. Enfin, la modélisation hydrologique associée au traçage chimique et isotopique des eaux du bassin a apporté une amélioration de la compréhension de l'organisation spatiale de la réponse hydrologique du bassin à l'échelle événementielle. / Hydrologists need to know soil moisture antecedent conditions before rainfall events to improve floodforecasting in torrential catchments. Soil moisture mapping, whose variations are mainly influenced bytopography, vegetation cover, and heterogeneity of soil properties, is therefore a valuable tool to studyhydrological processes. This work adresses the issue of the spatio-temporal variations of soil water statusspatialization using geostatistical and hydrological modeling applied to the Laval marly experimental catchment(0.86 km², ORE Draix-Bléone, France). In situ monitoring of rainfall events from May 2015 to November 2016revealed a significant relationship between soil water content, topography and land cover in the badlands. Italso led to better assess soil water content spatio-temporal dynamics at the hillslope scale and the seasonaland event time scales. It confirmed the major contribution of bare areas to stream flows. Eventually, thehydrological modeling associated to the chemical and isotopic water tracing made it possible to better understand the spatial organization of the catchment hydrological response at the event scale.