A carência, absoluta ou relativa, de água direcionou diversas ações no sentido de amenizar esse problema. A política nacional de recursos hídricos (Lei 9.433/97), com seus cinco instrumentos de gestão e planejamento, pode ser considerada o principal marco. Entre esses instrumentos, encontra-se o sistema de informações, que tem por finalidade coletar, armazenar e disponibilizar dados para uma gestão racional. É nesse âmbito e no sentido de contribuir para a evolução desses sistemas, que se apresenta essa tese de doutoramento. O tema principal trata da implementação de um sistema de suporte a decisões – SSD com base nos conceitos da programação orientada a objetos – POO, forma esta de programação que procura representar os sistemas por meio de classes de maneira a buscar a semelhança à realidade. Esse SSD, denominado de ARENA (análise de recursos naturais), é composto de um sistema de informações geográficas – SIG, dois simuladores (simulação do fluxo de águas subterrâneas e do ciclo hidrológico superficial), uma base de dados georeferenciada e módulos de acesso aos dados. A forma como os simuladores foram implementados, baseado em conceitos da POO e suas integrações às entidades geométricas do SIG, é apresentada como contribuição. No ARENA, o SIG não é apenas utilizado nas fases de pré e pós-processamento de dados para modelos, e sim no processo de simulação. Aplicações do ARENA a uma bacia hidrográfica (escoamento superficial) e a dois sistemas hipotéticos (escoamento subterrâneo) são apresentados ao final do trabalho. A maneira como esse SSD foi implementado induz ao desenvolvimento de simuladores adicionais sem realizar modificações nos pacotes já implementados neste trabalho, sendo facilitada a utilização dos pacotes que compõem esse SSD / The relative or complete lack of water has been directing various actions in order to solve this problem. The national water resources politic (Law 9.433/97) with its five instruments for water resources planning and management can be considered the main action. Among these instruments, it is found the information system that has as purpose to collect, store and turn it into available data to the rational management. In this scope and in order to give some contributions to the improvement of these systems, this Ph.D. thesis is presented. The main topic deals with the decision support system (DSS) implementation based on oriented object – OO, a kind of programming which tries to represent systems through classes very closely to the reality. This DSS, called ARENA (análise de recursos naturais, in Portuguese), is made up of a geographic information system (GIS), two models (a groundwater model and a distributed rainfall-runoff model), a georeferenced database and graphic user interfaces (GUI). The way the models were built, based on OO concepts and its integration to GIS geographic data, is presented as contribution. In the ARENA, the GIS is not only used in the pre and post processing steps, but also in the simulation. The ARENA applications were carried out for two examples, a watershed (surface water simulation) and a hypothetic system (groundwater simulation), both presented in the end of this study. The way this DSS was built induces to the development of other models without modifications in the existing packages, so that the development of new applications becomes easy because the use of existing packages that made this DSS up

Orientador: Jose Teixeira Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-03T23:55:35Z (GMT). No. of bitstreams: 1 Ferreira_Lucia_D.pdf: 1500242 bytes, checksum: f168afe0384add0cf44eeb8198bdd9c6 (MD5) Previous issue date: 2004 / Doutorado / Agua e Solo / Doutor em Engenharia Agrícola

Ph.D. / Wetlands play an integral role in the hydrological cycle and biodiversity. Despite this, wetlands have been neglected in terms of research and monitoring in South Africa. This lack of research has become even more insufficient when it comes to endorheic wetlands. Endorheic wetlands in South Africa are known as pans. Pans are isolated depressions that for through wind erosion are generally shallow and lack an integrated drainage. Water gain is depended on rainfall and surface runoff and water loss is largely due to evaporation. Pans can be either ephemeral in nature or can remain inundated for long periods of time. There are close to 5000 pans in the study area of the Mpumalanga province of South Africa. An estimated 40% of these pans are perennial in nature. The little information on the ecology of pans is all focussed on those systems that are ephemeral. The lack of knowledge is, however, not restricted to the ecology of perennial pans but also the management tools available for these ecosystems. Whereas a variety of methods are available to determine the quantity and quality of water needed to sustain riverine systems (and wetlands connected to rivers), there are no such methods for pans. Especially important is the lack in standardised methods to assess the ecological integrity of perennial pans. This is important as perennial pan ecosystems are increasingly under threat from an increase in coal mining and agricultural activities in Mpumalanga. Coal mining activities have increased in the study area due to both an increase in energy demands and the ease of mining coal deposits in the study area. The lack in standardised methods could be as a direct result of the lack in knowledge of the ecology of the perennial pans. The aim of this study was thus to develop standardised methods for assessing the ecological integrity of perennial pans in Mpumalanga by studying the ecology of the pans. The study thus uses a fundamental approach to reach certain applied goals. To achieve the aim, a total of nine pans were included in the study of which seven were surveyed seasonally for two years and two were sampled on a single occasion. Five of these pans were located in the Mpumalanga Lake District (MLD) and were in a relatively pristine condition. The other four pans were impacted either by agricultural activities, mining activities or both. During these surveys, various components of the ecosystem were studied. These components included the spatial and temporal variations in the abiotic components like the physico-chemical characteristics, habitat quality and quantity, and the sediment characteristics. It also included the spatial and temporal variations in the vegetation communities surrounding the pans and the aquatic invertebrate communities within the pans. The aquatic invertebrate communities were assessed based on a taxonomic approach (diversity) and functional approach (biological traits).

A distributed hydrological rainfall-runoff model has been developed using a GIS integrated with a dynamic programming module (PCRaster). The model has been developed within the framework of the EU-project TWINBAS at IVL Swedish Environmental Research Institute, and is intended for use in WATSHMAN – a tool for watershed management developed at IVL. The model simulates runoff from a catchment based on daily mean values of temperature and precipitation. The GIS input data consist of maps with soil type, land-use, lakes, rivers and a digital elevation model. The model is a hybrid between a conceptual and a physical model. The snow routine uses the degree-day method, the evapotranspiration routine uses the Blainey-Criddle equation, the infiltration routine is based on Green-Ampt, groundwater is modelled assuming a linear reservoir and the flow routing is done with the kinematic wave equation combined with Manning’s equation. The GIS and the hydrologic model are embedded in one another, allowing calculation of each parameter in each grid cell. The output from the model consists of raster maps for each time step for a pre-defined parameter, or a time series for a parameter at a specified grid cell. The flow network is generated from the digital elevation model and determines the water flow on the grid scale. The smallest possible grid size is thus obtained from the resolution of the digital elevation model. In this implementation the grid size was 50 m x 50 m. The raster structure of the model allows for easy use of data from climate models or remotely sensed data. The model was evaluated using the River Kölstaån catchment, a part (110 km2) of the Lake Mälaren catchment, which has its outflow in central Stockholm, Sweden. The integration of the GIS and the hydrologic model worked well, giving significant advantages with respect to taking lakes and land-use into account. The evaluation data consisted of observed run-off for the period 1981 to 1991. The result from the calibration period shows a great variation in Reff (Nash & Sutcliffe) between the years, the three best years having Reff-values of 0.70 – 0.80. The Reff-value for the entire calibration period was 0.55 and 0.48 for the validation period, where again there was great variation between different years. The volume error was 0.1 % for the calibration period and -21 % for the validation period. The evapotranspiration was overestimated during the validation period, which is probably a result of excess rain during the calibration period. The results are promising and the model has many advantages – especially the integrated GIS-system – compared to the present WATSHMAN model. It could be further developed by introducing a second groundwater storage and refining the evapotranspiration and infiltration routine. Given the promising results, the model should be evaluated in other larger and hillier areas and preferably against more distributed data. / En helt distribuerad GIS-baserad hydrologisk modell för modellering i avrinningsområden på lokal/regional skala har byggts upp i PCRaster. Arbetet utfördes på IVL Svenska Miljöinstitutet AB inom ramen för EU-projektet TWINBAS, som har som mål att identifiera kunskapsluckor inför implementeringen av EU:s ramdirektiv för vatten. Modellen är tänkt att användas i WATSHMAN (Watershed Management System), IVLs verktyg för vattenplanering i avrinningsområden där bland annat källfördelningsberäkningar och åtgärdsanalyser ingår. Den uppbyggda modellen är en hybrid mellan en fysikalisk och en konceptuell hydrologisk modell och predikterar vattenföring på pixelnivå i avrinningsområden. Simuleringen drivs av dygnsmedelvärden för temperatur och nederbörd och modellen tar hänsyn till markanvändning, jordart, topografi och sjöar. De modellekvationer som används är grad-dagsmetoden för snö, Blainey-Criddle för evapotranspiration, Green-Ampt för infiltration, linjärt magasin för grundvatten och Mannings ekvation för flödesrouting. Det geografiska informationssystemet och den hydrologiska modellen är helt integrerade, vilket gör att alla parametervärden beräknas för varje enskild pixel. Som utdata ger modellen en rasterkarta för varje tidssteg för en i förväg bestämd parameter, eller tidsserier över parametervärden i definierade punkter. Vattnet transporteras i ett utifrån höjdmodellen genererat flödesnätverk och vattnets flödesväg bestäms därmed på pixelnivå. Minsta möjliga pixelstorlek bestäms således utifrån höjdmodellens upplösning, och var vid denna tillämpning 50 m gånger 50 m. Modellens uppbyggnad med raster gör det enkelt att använda data från klimatmodeller eller fjärranalys. Avrinningsområdet för Kölstaån, ett biflöde till Köpingsån i Mälardalen, har använts för att utvärdera modellen. Integreringen av GIS och hydrologisk modell fungerade mycket väl och gav stora fördelar t ex vad gäller att ta hänsyn till sjöar och markanvändning. Modellen kalibrerades med data från åren 1981 till 1986 och det erhållna volymfelet var då 0,1 % och Reff-värdet (Nash & Sutcliffe) 0,55. Stora variationer erhölls dock mellan åren; för de tre bästa åren låg Reff-värdet mellan 0,70 och 0,80. Ett mycket kraftigt nederbördstillfälle samt regleringar i huvudfåran av vattendraget ligger troligtvis bakom de mindre väl beskrivna åren. Även under valideringsperioden (1987 till 1991) fungerade modellen väl, så när som på att avdunstningen överskattades på vårarna (antagligen beroende av det stora regnet under kalibreringen), och Reff-värde och volymfel hamnade på 0,48 respektive -21 %, även här med stora variationer mellan åren. Resultaten är lovande och modellen har många fördelar jämfört med den nuvarande WATSHMAN-modellen. Den skulle kunna förbättras ytterligare genom att dela upp grundvattnet i två magasin samt förfina evapotranspirations- och infiltrationsrutinerna. Den höjdmodellsbaserade modellen bör utvärderas även i andra mer kuperade områden samt mot mer distibuerade data.

D.Phil. / Land cover changes associated with growing human populations and expected changes in climatic conditions are likely to accelerate alterations in hydrological phenomena and processes on various scales. Subsequently, these changes could significantly influence the quantity and quality of water resources for both nature and human society. Documenting the distribution of land cover types within the Shire River catchment is the foundation for applications in this study of the hydrology of the Shire catchment. The aim of this study is to investigate the relationships between the measured land cover changes and hydrological regimes in the Shire River Catchment in Malawi. Maps depicting land cover dynamics for 1989 and 2002 were derived from multispectral and multi-temporal Landsat 5 (1989) and Landsat 7 ETM+ (2002) satellite remote sensing data for this catchment. Other spectral-independent data sets included the 90-m resolution Shuttle Radar Topographic Mission (SRTM) digital elevation model (DEM), Geographical Information System (GIS) layers of soils, geology and archived land cover. Core image-derived data sets such as individual Landsat bands, Normalized Difference Vegetation Index (NDVI), Principal Components Analysis and Tasseled Cap transformations were computed. From generated composite images, land cover classes were identified using a maximum likelihood algorithm. Eight land cover classes were mapped. A hierarchical multispectral shape classifier with an object conditional approach determined by the Food and Agriculture Organisation (FAO) Land Cover Classification System (LCCS) legend structure was used to map land cover variables. LCCS was used as a basis for classification to achieve legend harmonization within Africa and on a global scale. Flexibility of the hierarchical system allowed incorporation of digital elevation objects, soil and underlying geological features as well as other available geographical data sets. This approach improved classification accuracy and can be adopted to discriminate land cover features at several scales, which are internally relatively homogeneous.In addition to compatibility with the FAO/LCCS classification system, the derived land cover maps have provided recent and improved classification accuracy, and added thematic detail compared to the existing 1992 land cover maps. Fieldwork was conducted to validate the land cover classes identified during classification. Accuracy assessment was based on the correlation between ground reference samples collected during field exercise and the satellite image classification. The overall mapping accuracy was 87%, with individual classes being mapped at accuracies of above 77% for both user and producer accuracy. The combination of Landsat images, vector data and detailed ground truthing information was used successfully to classify land cover of the Shire River catchment for years 1989 and 2002.

Magister Scientiae - MSc / The research was driven by a need to increase the knowledge base concerning wetland ecological responses, as well as to identify and evaluate the factors driving the functioning of the Franschhoek Trust Wetland. An ecohydrological study was undertaken in which vegetation cover, depth to groundwater, water and soil chemistry were monitored at 14 sites along three transects for a 12 month period. The parameters used include temperature, pH, electrical conductivity (EC), sodium, potassium, magnesium, calcium, iron, chloride, bicarbonate, sulphate, total nitrogen, ammonia, nitrate, nitrite and phosphorus. T-tests and Principal Component Analysis (PCA) were used to analyze trends and to express the relationship between abiotic factors and vegetation. / South Africa

Countries around the world have been developing ecological policies to protect their water resources and minimise the impacts of development on their river systems. The concept of ‘minimum flows’ was initially established as a solution but it did not provide sufficient protection as all elements of a flow regime were found to be important for the protection of the river ecosystem. “Environmental flows” were developed to determine these flow regimes to maintain a river in some defined ecological condition. Rapid, initial estimates of the quantity component of environmental flows may be determined using the Desktop Reserve Model in South Africa. However, the Desktop Reserve Model is dependent upon the characteristics of the reference natural hydrology used. The advancements in hydraulic and ecological relationships from the past decade have prompted the development of a Revised Desktop Reserve Model (RDRM) that would incorporate these relationships. The research in this thesis presents the development of the hydraulic sub-model for the RDRM. The hydraulic sub-model was designed to produce a realistic representation of the hydraulic conditions using hydraulic parameters/characteristics from readily available information for any part of South Africa. Hydraulic data from past EWR studies were used to estimate the hydraulic parameters. These estimated hydraulic parameters were used to develop hydraulic estimation relationships and these relationships were developed based on a combination of regression and rule-based procedures. The estimation relationships were incorporated into the hydraulic sub-model of the integrated RDRM and assessments of the hydraulic outputs and EWR results were undertaken to assess the ‘applicability’ of the hydraulic sub-model. The hydraulic sub-model was assessed to be at a stage where it can satisfactorily be incorporated in the RDRM and that it is adequately robust in many situations. Recommendations for future work include the refinement of estimation of the channel forming discharge or the use of spatial imagery to check the maximum channel width estimation. It is also proposed that a future version of the hydraulic sub-model could include flow regime change impacts on channel geomorphology and sedimentology so that flow management scenarios can be more effectively assessed.

The availability of adequate information is one of the basic requirements of sound water resources development. Simple water resource development options that required less detailed studies have already been developed, such that development proposals today require more detailed and comprehensive studies. Among other factors, these studies generate information on the hydrological risk of implementing water resources projects. The modelling tools used to generate water resources information are usually complicated by the many variables involved, which are inter-linked and usually unpredictable. The National Water Act (Republic of South Africa, 1998) emphasises the need for integrated water resources management, social equity, and ecological sustainability, which have added new dimensions to water resources planning. Water catchment simulation models that account for all the dimensions of water resources planning and bring more information than ever before to the decision-maker have become the preferred tools. Whilst earlier water resources planning tools are still in common use, this study found that these earlier tools lagged behind developments in important aspects such as national legislation, water stakeholders’ working environment, and rapid changes in computer software and hardware. The appropriateness of water resources modelling tools in South Africa was investigated in the light of a changing water environment as well as the need to address specific factors that are unique to South Africa. The water resources factors investigated included hydro-climatic, water institutional frameworks and stakeholder needs, available expertise and technological aspects of the available water management and planning tools. On the basis of the outcome of the investigation of South Africa’s unique water environment, recommendations and guidance were developed with the aim of developing a preferred local water resources modelling approach. This study investigated and recommended the use of water resources system models which are based on up to date modelling and Information Technology (IT) developments, such as HYDRO25, for multi-criteria planning of integrated water resources. In this study, the development of object oriented programming (OOP) models with visual interfaces that fit in the popular Windows operating environment was distinguished as a key aspect of water resources modelling. This modelling route was selected because it generates tools that are more user-friendly, have visual clues that relate closely with the physical system, including easy GIS integration, can handle the higher computer memory volume demands of longer time series data, and could handle a greater number of parameters as well as the increasingly more complex management scenarios. In the OOP approach, modelling tools are easily integrated with the input processing and output analysis objects that are developed separately before integration into the main model framework. All the separate software objects can easily be utilised in other models when the need arises. The HYDRO25 model uses modular objects and a visual-based programming language that easily accommodates integration with other software objects based on the component object model system. This has made further upgrading and redevelopment of the model easy to handle. In this study, the HYDRO25 model was developed and used in the Doring River catchment as a case study which was aimed at providing first-hand information about model development and application in South Africa. In the HYDRO25 model, computer code was used systematically to handle the catchment hydrology, geographical information, climatic factors, water use, catchment development proposals, the requirement of water legislation, and other factors to provide information that is useful for decision-making. In the Doring River case study, proposed irrigation developments in the Koue Bokkeveld and Aspoort area of the Western Cape were assessed using the HYDRO25 model to determine the most viable development options from a hydrological perspective. The study showed that the full irrigation potential of the catchment cannot be utilised with the available surface water resources in the catchment. The model simulation results showed that a maximum of 700 hectares can be irrigated in the Koue Bokkeveld area without creating additional water storage. Analysis of the Aspoort irrigation scheme showed that the irrigation area should be limited to 1000 hectares, with the proposed 178 million m3 Aspoort Dam being developed to support irrigation water demand and, to a small extent, to contribute to other water uses in the catchment, such as ecological flows and domestic uses. / Thesis (PhD (Water Resources Management))--University of Pretoria, 2007. / Microbiology and Plant Pathology / unrestricted

Predicted future precipitation is downscaled and used to drive a hydrologic model to assess future erosion potential in a semi-alluvial clay-bed watercourse, Watts Creek. The 21 km2 watershed is predominantly urban, with overall impervious cover of 22%, and the remaining land use split between agricultural and forested areas. Continuous simulations for the open water year, excluding spring freshet (April 1st to October 31st) were performed using the SWMHYMO (Stormwater Management Hydrologic Model) lumped hydrologic modelling platform. A shear stress exceedance and stream power erosion routine was added to the platform to calculate erosion potential. To account for uncertainty in the collected data, nine different observed discharge data sets were used to calibrate the model, each leading to a distinct set of calibrated parameter values. The difference between the observed data sets lies in the choice of rating curves and the collection period. The 2041-2080 precipitation outputs of the fourth version of the Canadian Regional Climate Model (CanRCM4) ran under Representative Concentration Pathways (RCPs) 4.5 and 8.5 at the MacDonald Cartier International Airport were downscaled using quantile matching and then used as input to the hydrologic model. For each set of calibrated parameters, a cumulative effective work index (CWI) based on the reach-averaged shear stress was calculated for Watts Creek during the open water year using both the historic (1968 2007) and projected future (2041-2080) flows, using a bed material critical shear stress for entrainment of 3.7 Pa. Results suggest an increase of 75% (resp. 139%) under RCP4.5 (resp. RCP8.5) in CWI compared to historic conditions for the average measured bed strength. The work index increase is driven by an increased occurrence of above-threshold events, and more importantly by the increased frequency of large events. The predicted flow regime under climate change would significantly alter the erosion potential and stability of Watts Creek. A channel adjustment sensitivity analysis, which balances future erosion potential with historic potential, was implemented and indicated that the channel could widen in the future from the current bankfull width of 6.1 m to 8.2 m for RCP4.5 and 10.2 m for RCP8.5. Specific morphological behaviour should be investigated in more detail, particularly to assess if the governing erosion mechanism is seasonally dependent, perhaps incising during spring freshet and widening when the bed is vegetated in the summer.

La gestion par éclusées des aménagements hydroélectriques (plus de 150 en France) pour la production d'énergie de pointe engendre de brusques variations de débit sur les cours d'eau et est susceptible d’altérer la composition, l’abondance et la structure des populations de poissons et d’invertébrés, sur de longues distances. Les objectifs de cette thèse ont été (1) de développer une méthode de caractérisation des éclusées au sein des hydrogrammes, ainsi qu'un indicateur synthétique du niveau de perturbation hydrologique, et (2) de progresser dans la définition des mesures de mitigation des impacts des éclusées sur les poissons. A partir de l'analyse de 97 stations et 1575 années de données de débit, les gradients des variations naturelles de débit ont tout d’abord été caractérisés sur 8 gammes entre 5% et 4 fois le débit moyen interannuel (module). Des formules représentant les variations de débit « les plus rapides possibles naturellement » ont été construites en tenant compte du type de variation (hausse ou baisse), de la taille du cours d'eau (via le module) et de la gamme de débit sur laquelle se déroule la variation, pour ensuite discriminer les éclusées des événements naturels. A partir de l'analyse de 80 stations et 491 années de données de débit influencées par les éclusées, une méthode a été mise au point pour repérer au sein des hydrogrammes les éclusées dont les caractéristiques sont au-delà de ce qui peut se rencontrer en hydrologie naturelle, à partir de 3 critères : une amplitude minimale (≥ à 10% du module et ≥ à 20% du débit de base de l’éclusées), un gradient minimal (> au gradient naturel maximal) et une limite haute sur le débit maximum (pour éliminer les événements de crues). Une grande variabilité des régimes d'éclusées du fait de la diversité des aménagements hydroélectriques et des fluctuations des apports hydrologiques et de la demande énergétique, a été constatée et illustrée […]. / Hydropeaking management of hydroelectric facilities (more than 150 in France) generates sudden changes in flow on the river and can affect the composition, the abundance and the structure of fish and invertebrates populations over long distances. The objectives of this thesis were (1) to develop a method for characterizing hydropeaks within hydrograph and a synthetic indicator of hydrological disturbance, and (2) to progress in defining mitigation measures of hydropeaking impacts on fish. From the analysis of 97 stations and 1575 years of flow data, rate of change of natural flow variations have been characterized within 8 ranges between 5% and 4 times the mean inter-annual discharge. Formulas representing the "fastest variations possible naturally" and taking into account the type of change (increase or decrease), the size of the stream (via the mean inter-annual discharge) and the flow range over which the variation takes place have been constructed and then used to discriminate hydropeaks and natural events. From the analysis of 80 stations and 491 years of flow data affected by hydropeaks, a method was developed to identify, within the hydrograph, hydropeaks whose characteristics are beyond what can occur in natural hydrology, using 3 criteria: a minimum range (≥ 10% of the mean inter-annual discharge and ≥ 20% of the hydropeak base flow), a minimal rate of change (> to the maximum natural rate of change) and an upper limit on the maximum flow rate (to remove flood events). A large variation in hydropeaking regimes, due to the diversity of hydroelectric schemes and fluctuations in incoming flow and energy demand, was observed and illustrated […]