Thesis (MEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The processes of monitoring, modelling and managing the water quality of a catchmerit system including all its unique complexities and interrelationships requires an innovative tool or set of tools to help water managers with their decision making. Numerous methods and tools have been developed to analyse and model the real world. However, many of these tools require a fair degree of technical expertise and training to operate correctly and their output may have to be translated or converted to meaningful information for decision-making using a further set of analytical and graphical display tools. A more appropriate technique for management would be to combine all these functions into a single system. The objective of this research was to develop one such tool, an integrated water quality information system (WQIS). A review of the literature revealed that there has been extensive research and development of tools for the management of individual aspects of water resource distribution, augmentation and quality. However, these tools have rarely been integrated into a comprehensive information system offering decision support to a wide variety of river users and managers. Many of the literature sources also noted that a process of interactive development and integration (i.e. including the intended users in the decision of which components to include, the interface design and the graphical display and output) was vital to ensuring the information system becomes an integral part of the users routine work and decision-making. The WQIS was developed using the recommendations from numerous knowledgeable persons in response to questionnaires, interviews and a prototype demonstration. It includes the results of hydrodynamic river and reservoir simulations and the ability to perform operational river scenario testing. However, the development process is continual and always evolving based on the current or local requirements of water managers. These further developments and research needs are discussed in more detail in the conclusion. / AFRIKAANSE OPSOMMING: Die proses om die waterkwaliteit van 'n opvanggebied, met al die unieke kompleksiteite en onderlinge verhoudings van so 'n stelsel te monitor, modelleer en bestuur, vereis 'n innoverende instrument om waterbestuurders te ondersteun in hul besluitnemings. Talle instrumente en metodes vir die ontleding en modellering van die werklikheid is reeds ontwikkel. Die gebruik van hierdie instrumente vereis gewoonlik 'n redelike mate van tegniese kundigheid en opleiding. Dit mag verder nodig wees om die uitvoer van sulke instrumente te vertaal en/of om te skakel na betekenisvolle inligting vir besluitneming deur die gebruik van bykomende analitiese en grafiese vertoon instrumente. 'n Meer toepaslike bestuurstegniek sou wees om al die funksies in 'n enkele stelsel te kombineer. Die doel van hierdie navorsing was om een so 'n instrument, naamlik 'n geïntegreerde waterkwaliteit inligtingstelsel (WQIS), te ontwikkel. 'n Hersiening van bestaande literatuur het getoon dat daar omvattende navorsing en ontwikkeling van instrumente gedoen is vir die bestuur van individuele aspekte van waterbronverspreiding, waterbronaanvulling en waterkwaliteit. Integrasie van hierdie instrumente, in 'n uitgebreide stelsel wat besluitnemingsondersteuning aan 'n verskeidenheid riviergebruikers en bestuurders bied, kom egter selde voor. Verskeie literatuurbronne het ook aangedui dat 'n proses van interaktiewe ontwikkeling en integrasie (m.a.w. in agname van die voorgenome gebruikers se behoeftes in die kense van komponente, die gebruiker raakvlak ontwerp en grafiese vertoon instrumente en uitvoer) noodsaaklik is om te verseker dat die inigtingstelsel 'n integrale deel word van die gebruiker se daaglikse roetine en besluitnemingsproses. Die WQIS is ontwikkel deur gebruikmaking van die insette en aanbevelings van verskeie kenners in reaksie op vraelyste, onderhoude en 'n demonstrasie van 'n prototype. Dit sluit in die resultate van hidro-dinamiese rivier en dam simulasies en die vermoë om operasionele rivier scenario ontledings uit te voer. Die ontwikkeling is egter 'n deurlopende proses, gebaseer op huidige of plaaslike behoeftes van waterbestuurders. Hierdie verdere ontwikkelings- en navorsingsbehoeftes word meer breedvoerig in die gevolgtrekkings bespreek.

Thesis (MEng)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: The Berg River is one of the largest rivers in the winter rainfall area of the Western Cape and is one of the most important water supply sources of the area. The Riviersonderend-Berg system needs to be expanded in order to meet increasing water demands of the Greater Cape Town (GCT) region. The implementation of future schemes will remove additional fresh water from the Berg River main stem, which will give rise to increased nutrient levels and higher salinity in the water. A water quality information system (WQIS) has been proposed to benefit the management of water resources, the flow quantity and the quality of the water. A part of this WQIS will be a water-quality simulation model that characterizes the water quality situation and is able to predict water quality responses to future implementations, as well as simulate different scenarios that can be used for management purposes. The objective of this study is to represent the water quality situation of the Berg River in a simulation model by implementing, testing and verifying a water quality simulation model, and assembling a hydraulic and water quality database suitable to meet foregoing objectives. This study firstly examined the water quality variables of concern: pH, Total Dissolved Salts (TDS) and phosphates to develop an understanding of the water quality responses and causes of the main stem of the Berg River system. A thorough review of the available models has been undertaken in the light of certain selection criteria, before determining that DUFLOW would be an acceptable model for this study. The water quality variables that have been modelled are TDS, Phosphates as P04, Oxygen and Temperature. As no predefined module simulating temperature, TDS and COD was included; these algorithms, describing the processes of these water quality variables have been additionally coded. The coding was possible, as DUFLOW' s water quality module consists of an open structure. The predefined water quality module was simplified to only include the water quality process algorithms, for water quality variables where data was available. Unfortunately, phosphates were mainly simulated on advection, and the influence of all the additional processes could not be assessed. All data gathering and preparation for the model had to be completed before commencing the model configuration. This included information on cross-sections, historical flow records, bridges and weirs for the hydraulic component ofDUFLOW. For the water quality module, information on historical grab samples has been obtained and 'infilled' to provide daily time series. To simulate the water quality in a river as accurately as possible, the flow simulation needs to be accurate. Ungauged subcatchment runoff was added to the simulation model to improve the correspondence between the simulated and the measured flow. Calibration of the water quality part of DUFLOW was completed by adjusting the different parameters after a sensitivity analysis. The model was verified by using a different time period than for the configuration, to ensure that an independent data set has been used. After configuring, calibrating and verifying the model, the applicability of the model could be tested for different scenario runs. Three scenarios were chosen according to real situations: • a short term effluent spill, with and without water releases from an upstream source (either Skuifraam Dam or Voëlvlei Dam); • the impact on the flow and water quality situation of the river when an upstream dam is built; • a long term management control scenario, that analyses load or concentration releases into the river according to limitations upstream and downstream of the discharge location. The scenario analysis provides an opportunity to assess the applicability of DUFLOW to simulate real time management and operational issues in a river and to aid in management decisions. / AFRIKAANSE OPSOMMING: Die Bergrivier is een van die grootste riviere in die winterreënvalgebied van die Weskaap en is een van die mees belangrike waterverskaffingsbronne in die area. Die Riviersonderend-Bergrivier-stelsel moet uitgebrei word om aan die groeiende waterbehoefte van die groter Kaapse Metropolitaanse Area te voldoen. Die implementering van toekomstige skemas sal addisionele vars water uit die hoof-loop van die Bergrivier onttrek, wat tot hoër voedingstof-vlakke en soutgehalte in die water sal lei. 'n Waterkwaliteitsinformasiestelsel (WQIS) sal van nut wees om die vloei-omvang en waterkwaliteit van waterbronne te bestuur. 'n Deel van die WQIS sal 'n waterkwaliteit-simulasiemodel wees, wat die waterkwaliteitsituasie sal kan ontleed, waterkwaliteit-reaksies op toekomstige implementerings kan voorspel, asook verskeie scenarios vir bestuursdoeleindes kan simuleer. Hierdie studie behandel spesifiek die waterkwaliteitsveranderlikes pH, totale opgeloste soute, fosfate, temperatuur en suurstof om 'n begrip te ontwikkel van die waterkwaliteitsreaksies en oorsake van die hoofloop van die Bergriviersisteem. Die doelwit van hierdie studie is om die waterkwaliteitsituasie van die Bergrivier uit te beeld deur die implementering, toets en kalibrasie van 'n waterkwaliteit-simulasie model, asook die insameling van hidrouliese- en waterkwaliteitsdata om aan bogenoemde doelwitte te voldoen. 'n Reeks beskikbare modelle is deeglik ondersoek voordat besluit is dat die DUFLOW model 'n gepaste model vir hierdie spesifieke studie is. Die keuse was gebaseer op spesifieke vereistes wat as belangrik beskou is deur potensiële bestuursgeorienteerde gebruiksgroepe. Die waterkwaliteitsveranderlikes wat gemodelleer is, is totale opgeloste soute, fosfate as P04, suurstof en temperatuur. Omdat geen voorgegewe temperatuur-, TDS- en COD modules in die model ingesluit is nie, is die algoritmes wat die prosesse van hierdie waterkwaliteitsveranderlikes beskryf, addisioneel gekodeer. Die kodering is moontlik gemaak deur die oop struktuur van DUFLOW se waterkwaliteitsmodule. Die voorgegewe waterkwaliteitsmodule is vereenvoudig om alleenlik die waterkwaliteit proses-algoritmes in ag te neem wanneer data vir waterkwaliteitsveranderlikes beskikbaar was. Ongelukkig is die fosfate hoofsaaklik op beweging gesimuleer, en die invloed van alle addisionele prosesse kon nie getoets word nie. Alle data-insameling en -voorbereidings vir die model moes voltooi word, voordat begin kon word met die opstel van die simulasie-model. Dit het inligting oor dwarssnitte, historiese vloeirekords, brik en keerwalle vir die hidrouliese komponent van DUFLOW ingesluit. Vir die waterkwaliteitsmodule is inligting van historiese bemonstering verkry en ingevulom 'n daaglikse tydreeks te verkry. Om die water-kwaliteit van 'n rivier so akkuraat as moontlik te simuleer, moet die vloei-simulasie redelik akkuraat wees. Ongemete sub-opvanggebied afloop is bygetel om die korrelasie tussen die gesimuleerde en gemete vloei te verbeter. Kalibrasie van die waterkwaliteitmodule van DUFLOW is voltooi deur die verskillende parameters te verstel na 'n sensitiwiteits-analise. Die model is geverifieer deur 'n ander tydperiode as die vir die opstel te gebruik, om sodoende te verseker dat Inonafhanklike data stel gebruik word. Na die opstel, kalibrasie en verifiering van die model, kon dit toegepass word vir verskillende bestuursscenanos. Drie scenarios is na aanleiding van werklike situasies gekies: 'n korttermyn uitvloeisel storting-situasie met en sonder loslatings van 'n stroomop bron (Of Skuifraamdam Of Voëlvleidam), die impak op die vloei- en waterkwaliteitsituasie van die rivier sou 'n dam stroomop gebou word. 'n langtermyn bestuurs-scenario waarin die lading en konsentrasies, veroorsaak deur die loslatings vanuit die dam na die rivier, ontleed word na aanleiding van beperkings stroomop en -af van die loslatingsplek. Die analise van die scenarios verskaf 'n geleentheid om die toepaslikheid van DUFLOW te ondersoek om werklike operasionele aangeleenthede te simuleer en om sodoende bestuursbesluite te vergemaklik.