Water companies are continually adopting catchment management as a way of improving the quality of raw water prior to treatment. The catchments from which raw water is abstracted are often heterogeneous which regularly presents multiple pollutant issues and variability in the spatial distribution of pollutant-contributing areas. For catchment management to be effective, it is crucial that water companies select and target appropriate interventions at multi-pollutant high risk areas. Within this thesis a conceptual framework is developed to disaggregate and compare multiple pollutant risks in drinking water catchments to aid water companies in this decision making process. A review of pollutant processes highlights links between pollutants often mitigated using catchment management and therefore confirms the feasibility for a multi- pollutant framework. Criteria were developed with water industry catchment management professionals to determine framework requirements. No current framework or model fully meets these criteria.

>Magister Scientiae - MSc / The objective of this study was to determine the hydrosalinity fluxes associated with overland and subsurface (vadose zone) flow for different soils and land uses. For this purpose, the following data were collected during 2005 and 2006 in a typical small scale catchment located near the town of Riebeeck-Wes: weather data, hydrological and water quality measurements, soil water contents and chemistry, and vegetation growth. The area is characterized by a Mediterranean climate receiving winter rainfall of approximately 300 mm a catchment is conservative, with Na + and Cl- being the dominant ions.

Wetlands are an important part of the landscape as hydrogeomorphological ecosystems. Over the centuries their importance has not received relevant attention; instead they have been treated as wastelands impeding development for maximum economic benefits. Research evidence from different parts of the world has influenced the change of such negative perceptions to an extent that the issue of wetlands' rehabilitation/restoration, conservation and management is firmly on the global agenda and local agendas of various countries, as evidenced by the adoption of the Ramsar Convention in 1971, and the Working for Water and Working for Wetlands programmes of the South African government. The aim of this research was to investigate the hydrological and geomorphological functions of a headwater wetland located in the Featherstone Kloof Catchment near Grahamstown, South Africa. The research was based on the hypotheses that wetlands store sediments, attenuate floods, store water and prolong downstream flows. A literature survey was conducted to gauge the state of knowledge about wetlands, particularly their hydrogeomorphology. An attempt was made to locate the study area within the broad historical and spatial context using a number of methods, including the radiocarbon dating of wetland sediments, the review of relevant literature and the analysis of historical hydroclimatic data. The results revealed that the wetland has existed for approximately 2000 years - as the oldest radiocarbon date obtained was 1850±50 BP. An analysis of more than a century (+120 years) long Grahamstown rainfall series indicated a steady fluctuation of rainfall around the mean, with regular decada1 cycles of wet and dry spells. Years with more rain below average were more common than those with higher rainfall, and storms events were quite common in the III area over the period. The distribution of seasons in the area over a calendar year period was demonstrated through the use of evaporation data. An intensive monitoring of hydrological and geomorphological variables was carried out using a combination of methods. The topography of the instrumented site was determined using a Total Station from reference benchmarks. Hydrological measurements included a nest of forty-eight piezometers for water table monitoring, and streamflow gauges at the upstream and downstream limits of the study site. Soil stratigraphic analysis was carried out through field techniques and laboratory measurements. A survey of wetland sediments was carried out after the main floods events. Data generated were used to analyse relationships between various variables and their role on the functioning of the wetland. The water balance of the wetland was quantified. The results indicated that the wetland was able to perform the cited hydrogeomorphological functions to some extent. For example, one of the key findings of this research is that the wetland was important in sustaining base flows under normal circumstances. However, the wetland did little to attenuate large floods. The results also revealed some important questions that require further research, including the role played by extreme flood events in altering wetland characteristics, the contribution of each water balance component in the hydrological functioning of wetlands, and importance of quantifying sediment budgets of headwater wetlands. The study demonstrated the complex nature of the wetland hydro geomorphology and that certain questions about wetlands require direct field monitoring to be better understood. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

No abstract. See Front page / Dissertation (MSc (Microbiology))--University of Pretoria, 2007. / Microbiology and Plant Pathology / unrestricted

Philosophiae Doctor - PhD / Groundwater is an important of water resources and plays a significant role in the water supply in most parts of the world. It is also an important ecological environment factor, and its variations often affect natural balance of the ecosystem. China is one of the few countries in the world where Karst is intensively developed Karst water is heavily utilized as water supply source. Shanxi is such a province with largest Karst distribution in places in North China, where 19 large Karst springs and their catchment are identified to provide an important source of the water supply and ecosystem functioning in Shanxi

PhD (Environmental Sciences) / Department of Hydrology and Water Resources / Luvuvhu River Catchment (LRC) exhibits diverse land use and land cover patterns that are influenced by seasonality and socio-cultural practices of the local communities. From 1950, the catchment has been undergoing land cover changes caused by expanding villages, new urban centres and clearing forest land for agriculture. Conversion of natural landscape for agricultural and urban purposes degraded the catchment by negatively affecting the hydrologic processes. This study was therefore conducted to evaluate the impact of land cover and land use change on the hydrology and water resources of LRC. Geographical Information Systems (GIS) and remote sensing techniques were applied to evaluate the impact of the changes on the catchment. Remotely sensed imagery was used as the primary sources of data for classification and detection of changes. Digital Elevation Models (DEMs) were used for hydrologic and geomorphic modeling in combination with information from remotely sensed imagery. Field data sets for soil and meteorology were obtained from selected sampling segments, based on the area frame sampling. The method of direct expansion was used to quantify land use classes. Flood frequency was analysed using probability distribution methods at recurrence intervals of 2, 5, 10, 20, 25, 50, 100, and 200 years. The FAO CROPWAT software based on Penman-Montheith equation was used to assess the impact of land cover changes on evapotranspiration regimes. To study the hydrological response of land cover change in the catchment, the Soil Conservation Services-Curve Number (SCS-CN) method was first used independently to simulate surface runoff and investigate the impact of land use change on runoff under historical land cover regimes. The Soil and Water Assessment Tool (SWAT) model was then applied in the Tshakhuma-Levubu subcatchment to assess the impact of land management practices on the soil and water bodies in the catchment. The results indicated that changes were having negative impacts on the hydrology of the catchment. The impact of land use and land cover change on hydrology of LRC was manifested in stream flow, surface runoff, suspended sediment and flood frequency and magnitudes. There was significant land cover and land use change from forestland, woodland and open grassland to medium size farms, subsistence agriculture and built-up land. These developments were concentrated on hillsides and hilltops in the catchment and they were of concern as they were ix impacting on the hydrological processes. Throughout the 2000’s, land use change revealed a decrease in natural forest from 32.15% to 20.67%, giving rise to agriculture which rose to 38.57% in 2010. Runoff was observed to be highly variable during the month of February with maximum runoff records of 1.63 m3 and 3.84 m3 upstream and downstream, respectively. Flood frequency results showed that an increase in the peak discharges was to be expected, especially for the discharge range corresponding to smaller and medium flood magnitudes. The use of imagery and DEMs within GIS was found to efficiently represent ground surface and allow automated extraction of features, thus bringing advantages in terms of processing efficiency, cost effectiveness, and accuracy assessments. This technique could therefore be adopted to improve land use planning, water management, and rapid identification of slopes and elevations in consideration for their functional and structural requirements. Analysis showed that the SWAT model was suitable for predicting the location and extent of pollution in the catchment. It assumed sheet and rill erosion as the dominant erosion type contributing to siltation and water pollution in rivers. The study recommends close monitoring and sustained enforcement of the rural land use regulations to prevent the conversion of land to urban land use. / NRF

Philosophiae Doctor - PhD / The risk of increasing global pollution dictates the need to understand environmental processes and develop innovative ways to monitor pollution levels and address associated problems. In order to address this need, this study used a selection of plants leaves (Commelina benghalesis, Paspalum urvillei, Persicaria lapathifolia and Salix babylonica) as biomonitors to assess the state of the environment, more specifically the concentration of certain heavy metal pollutants (Cu, Zn, Fe, Ni, Pb and Cd) of river water and soils in the Eerste River catchment, Western Cape, South Africa.

Dissolved Organic Carbon accounts for many different functions in the boreal forest ecosystem. It is the main vehicle for organic carbon transport from the litterfall to the forest soil profile and together with water drainage it can be transported to streams. In boreal forests, the DOC transport have gain attention because of recently documented rise in concentration. Several models have been proposed, first to gain understanding in the main cauces of this increase in concentration, and then to simulate the transport of DOC in the landscape. An exploratory work was made to identify the extent of physical control and hydrological pathways for DOC discharge and the long-term biological control over DOC production, transport in the soil profile and discharge in 2 different situations. A 22-year dataset from the Krycklan Catchment site was used. Meteorological data was used as driving variables to calibrate DOC concentration and runoff in a small catchment (Site C7). The CoupModel was set up to represent the described vegetation and documented soil characterization and then calibrated to fit the measured variables. A stepwise calibration process was preferred to promote the understanding of the different components of the landscape in the organic carbon cycle. Results point to soil heat and water transfer processes as the most relevant group to explain both water runnof and DOC discharge, with increasing relevance in the deeper layers, explaining up to 97% of short-term variability in DOC discharge for the 27-35 cm layer. Soil organic carbon pools showed to have relevance in organic carbon stock balance along the soil profile. Conclusions state that, In concordance with other authors, there is a hydrological primary control over DOC discharge, but that soil organics and especially vegetation perform a relevant role in long-term balance of the organic carbon cycle. Further studies with this model could include time-series of atmospheric deposition of Sulphur and nitrogen and running the model in cascade.

Philosophiae Doctor - PhD / Enhancing our understanding of wetland properties and the ecosystem services provided by wetlands within a dynamic landscape, is fundamental to ensuring appropriate management strategies for enhanced biodiversity and ecosystem benefits. With increased anthropogenic activities and the impacts of climatic variability, a better understanding of the factors influencing the water balance dynamics of wetlands can provide insight into how wetlands respond to change. The main aim of the research was to improve the understanding of the spatial and temporal availability of water and storage of a depression wetland in a semi-arid climate, and to relate these to ecosystem functions. As ecosystems are intricately connected to society, a secondary aim of the research was to gain insight to how wetland ecosystems, within a changing climate and landscape, provide benefits to society, and add value to human-wellbeing. Soetendalsvlei, a shallow freshwater depression, and one of the few coastal freshwater lakes of South Africa, was the focus of the research.

>Magister Scientiae - MSc / Somerset West and Strand in the Western Cape, South Africa, were developed on the Lourens River floodplain. This hardened the catchment and reduced the capacity of the river to transport and store floodwaters. The result was recurrent flooding of residential and industrial areas and a fear that this could lead to loss of human life. In response to these concerns, the City of Cape Town implemented flood alleviation measures with a ‘soft’ engineering approach that incorporated geomorphological and ecological principles into their design. This was one of the first engineer/ecologist collaborations in South Africa, which attempted to make better decisions for the river ecosystem within the constraints imposed on it by urban development; and in so doing to create a self-sustaining river that requires little ongoing manipulation. The aim of this dissertation was to assess the extent to which ecological considerations were incorporated into the flood alleviation works on the Lourens River and whether this improved physical habitat and the diversity of riverine biota. Physical habitat was mapped from 1:50 000 topographic maps and aerial imagery in a GIS, and cross-sectional profiles, diversity of hydraulic biotopes and subtsrate composition were surveyed in the field.