The early efforts of Booth, Johnson, Rubidge, Catuneanu, de Wit, Chevallier, Stankiewicz, Weckmann and many other scientists in studying the Karoo Supergroup has led to comprehensive documentation of the geology on the main Karoo Basin with regards to understanding the age, sedimentology, sedimentary facies and depositional environments. In spite of these studies, the subsurface structure, variations in thickness of various formations in large parts of the basin, the location and orientation of subsurface dolerite intrusions, and the depth to magnetic and gravity sources remains poorly documented. A geological study with the aid of geophysical techniques, magnetic and gravity, was conducted in the southwestern part of the main Karoo Basin. The objectives of the study were to construct numerous models of the main basin that image the crust to a depth of 45 km, to determine thicknesses of various formations, to relate observed geophysical anomalies with geological bodies and lineaments, to estimate the depth of existing anomalous bodies, to determine densities and porosity of various formations, as well as to determine the mineralogy of various rocks in the Karoo Basin.

This thesis deals with a groundwater investigation conducted in the Van Rynevelds Pass Dam basin, north of Graaff-Reinet, in the Cape Province. The objective of the study was to assess the groundwater potential of the basin in terms of its development and exploitation as a municipal supply. In order to achieve this objective, fieldwork was carried out involving a hydrocensus, geological/geophysical mapping, drilling, aquifer testing and hydrochemical sampling. The fieldwork was conducted during the period January 1983 to February 1984. The investigation revealed that the most significant ground water occurrence in the study area is an alluvial/weathered bedrock aquifer (Graaff-Reinet aquifer ) . The volume of ground water stored in the Graaff-Reinet aquifer is in the order of 27 x 10⁶ m³, while its exploitation potential is conservatively estimated at 9 300 m³/day. However, the quality of this water is poor and should be blended with dam water or better quality groundwater. Two minor fractured aquifer units were also identified.

The investigation reported in the thesis concerns an area south and west of Graaff-Reinet, in the Cape Province. The research projec t identified the existence of four groundwater units. The aquifers predominantly occur in Beaufort Group sediments and the boundary of each unit is formed by dolerite intrusives or with topographical highs. The objective of the study was to quantitatively assess these units in terms of both quantity and quality for possible future development as a municipal supply for Graaff-Reinet. In order to achieve the objective, fieldwork was carried out involving a hydrocensus, geological mapping, drilling, aquifer testing and hydrochemical sampling. The analysis of these data revealed that the Sundays and Kamdeboo aquifer units are unsuitable for further development. The Moordenaars and Swart units, both of which produce good quality water, have a combined exploitation potential in the order of 30 000 m³ /d. / KMBT_363 / Adobe Acrobat 9.53 Paper Capture Plug-in

Thesis (M.Sc.(Geology)) -- University of Limpopo, 2022 / The Limpopo Province is largely underlain by crystalline basement rocks, which are characterised by low porosity and permeability. The climate in this province is arid to semi-arid, with scarce surface water for domestic and industrial use. As a result, groundwater is the prime source of fresh water supply for various uses. The complex geology, the impacts of climate change and man-made interactions with groundwater and surface water are the main threat to the availability of a sustainable source of fresh water in the province. In addition, despite substantial research efforts conducted by academic institutions and government organisations, there is still a gap in understanding quantitatively the dynamics of the hydrological systems in large parts of the Limpopo Province. The present study is therefore focused on the investigation of hydrological stresses that are applied to groundwater and surface water in one of the catchments situated in the Limpopo Province. In this study, a three-dimensional steady-state numerical model of groundwater flow was carried out at Mogalakwena Subcatchment, which is situated in the western sector of the Limpopo Province. The area is situated approximately 40 km northwest of Mokopane and 50 km west of Polokwane town. The research aims to understand the dynamics of the exchange between surface water and groundwater, and to assess the influences of these processes on the sustainability of water supply in the area. Hydrologically, the area falls within the boundaries of the Mogalakwena River Catchment, which forms part of the Limpopo River Basin. Previous studies suggest that there is a continuous decline in groundwater levels in the study area due to extensive use of groundwater for mining, irrigation, and domestic purposes. Furthermore, continued climate changes have altered the rainfall events during the last couple of decades, which consequently had an impact on groundwater recharge, quality, and availability. In addition, the complex geology of the area has an impact on the aquifers’ productivity resulting in variability in borehole yields throughout the study area. To achieve the aims of the research project, a three-dimensional steady-state numerical model of groundwater flow was implemented using MODFLOW NWT and ModelMuse v graphical user interface. The model domain covers an area of 5896 sq. km and was discretised with a grid cell size of 200 m by 200 m. The MODFLOW Packages used include DIS, UPW, RCH, EVT, WEL, GHB, RIV and UZF as well as the ZONEBUDGET. The conceptual model of groundwater flow consists of two layers, and it was developed based on drillhole logs, hydrochemical data, environmental isotopes, geological, digital terrain models, and other spatial data relevant for the conceptualisation of boundary conditions and hydrological stresses. The results of the steady-state simulation of groundwater flow show that recharge contributes 99.6% of inflow, followed by river leakage (0.36%) and GHB (0.08%). Among the outflow components, surface runoff takes the lion’s share (83.3%), followed by evapotranspiration (16.6%) and river leakage 0.02%. The zone budget was implemented to evaluate the interaction between surface water and groundwater by quantifying the amount of water that flows from one zone to the other. This was achieved by assigning zone numbers to the objects that represent boundary conditions (e.g., aquifer, river and dam). Zone 1, 2 and 3 were assigned to the aquifer, river and dam, respectively. The results indicate that the rivers gain more water than they supply to the aquifer. Similarly, the Glen Alpine Dam gain more water from the aquifer than it supplies to the aquifer. This implies that the interaction between surface water bodies such as rivers and dams have a significant impact on the aquifer, which consequently partly contributed to the shortage of water in the area. A predictive analysis of the aquifer’s response to an increase in abstraction rate, evapotranspiration rate and a decrease in recharge was carried out to investigate the future fate of water availability in the study area. The results suggest that as recharge decreases, the river inflow slightly increases to compensate for the declining water level due to the river stage exceeding the piezometric surface. In addition, the decrease in recharge rate is accompanied by a slight decrease in both surface runoff and evapotranspiration rate. Thus, a decline in recharge causes a significant drop in piezometric surface relative to the evapotranspiration extinction depth, which ultimately decreases the rate of evapotranspiration. Similarly, a decrease in recharge rate lowers the depth of the water level below the river stage, which consequently triggers water vi exchange from Mogalakwena River to the aquifer. In general, the water balance shows that as recharge decreases by 20% or more, the outflows exceed the inflows resulting in a continuous drop in water level, which may ultimately risk the availability of groundwater in the area. / Council for Geoscience (CGs)

Light Non-Aqueous Phase Liquids (LNAPLs) are used throughout the world for numerous applications, the most well-known being automotive fuels, such as petrol and diesel. The widespread production, distribution, storage and use of LNAPLs results in the ubiquitous occurrence of spillage to ground (Geller et al, 2000). Considering the hazardous nature of most LNAPLs due to their explosive and toxic characteristics, releases of LNAPLs to ground have well documented human health and ecological consequences. The occurrence of leaking underground and above-ground storage tanks at service stations and consumer installations is a common cause of contamination; and is described in literature for various countries of the world (Dietz et. al., 1986; Moschini et al, 2005; Mulroy and Ou, 1997; Harris, 1989; The Institute of Petroleum, 2002). Little failure data are however available for the South African context. In addition to this, data concerning the location and characteristics of sites storing LNAPLs in South Africa is similarly scarce. The study analysed data from three sources, namely the eThekwini Fire and Emergency Services data, GIS data and data from a local consultancy, in order to determine whether certain factors increased contamination risk posed by these facilities. The results indicated that contamination may be a result of numerous factors, but primarily line and tank failure. The type of installation was also found to have a significant influence on whether a site would be contaminated or not. In addition to the above, the results indicated that certain circumstances increase the severity of loss. The results indicated the need for more investigation to be performed into contamination as a result of LNAPL loss to ground, and the need for protective measures to be implemented for high risk sites where the likelihood and severity of a potential loss is high. Focus should then be centred on the probability of failure of non-ferrous pipework and GRP tanks to ensure adequate protective mechanisms are in place in the event of a failure of this newer infrastructure. In addition, a review of regulatory control of LNAPL storage in South Africa and the eThekwini Municipality, with reference to the international context, indicated the need for a specific department within the local government structure that manages LNAPLs with the objective of reducing contamination incidents. The continued use of underground storage of LNAPLs will always present a risk of failure/contamination due to the unseen nature of the installations and related infrastructure. It is this risk that requires regulatory management. Details of contaminated sites in South Africa should be within the public domain. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

MESHWR / Department of Hydrology and Water Resources / Siloam, a village in the Northern province of South Africa has groundwater reportedly characterised by concentration of fluoride greater than 1.5 mg/L permissible limit. Regional investigation has been done to determine the possible fluoride sources in the northern province of South Africa, but no localised investigation has been documented. The World Health Organization and South Africa National Standard permissible limit is 1.5 mg/L for a duration of time. Therefore, this study focuses on investigating the sources of fluoride in the groundwater of Siloam village in response to reported high incidences (80%) of dental fluorosis in Siloam village. This study also elaborates more on the hydrochemical and geochemical processes favouring the release of fluoride into the groundwater of Siloam village. Two (2) surface rocks, one (1) surface clay deposit, twelve (12) borehole cuttings and four (4) groundwater samples were used for this study. Temperature, total dissolved solids (TDS), conductivity (EC) and pH of the groundwater were determined using a combined multimeter because these parameters are proxy indicators of geogenic influence on groundwater fluoride concentration. Total fluoride in the groundwater samples and the leachates obtained during a leaching experiment were determined using Ion Chromatograph (IC) and Fluoride Ion Selective Electrode (FISE). X-ray fluorescence spectrometry is the most preferred method for rock analysis by earth scientists because it is faster and does not require ambiguous training on the part of the analyst, therefore, it is mostly the standard methods used in whole rock chemistry. Elemental composition and mineralogy were determined using X-ray Fluorescence (XRF) and X-ray diffraction (XRD), respectively. Clay, greywacke, argillaceous sedmients and basalt were analysed. Results obtained indicated that the groundwater fluoride concentration ranges from 3.92 to 4.95 mg/L, which are far above the WHO permissible limit and South African standard. Insitu temperature reading obtained ranges from 25 to 48°C thus classifying the groundwater to be hot and tepid. The groundwater pH ranges from 8.1 to 9.1 which indicates an alkaline water condition. The groundwater conductivity ranges from 330 to 730 μS/cm while the Total dissolved solids ranges from 130.12 to 423.07 mg/L. Groundwater proxy indicators showed geologic sources to be responsible for the high fluoride concentration in the groundwater of Siloam village. Hydrochemical investigation revealead that the mineralisation of groundwater in Siloam village is as a result of rock water interaction and the process of groundwater enrichment is through base ion exchange and reverse ion exchange. The dominant water type in the village was identified to be Na-Cl water type and the abundance of sodium (Na) is due to the heavy weathering of plagioclase of the parent rocks. Total fluoride content of the rocks and soils of the village ranges from 10 to 2000 mg/L. The leachable fluoride, however, ranged in concentration from 0.27 to 14.88 mg/L under induced temperature v and 0.05 to 10.40 mg/L without temperature. Mineralogical investigation revealed the abundance of smectite clay, which is known for its enrichment and leaching of fluoride into groundwater sources, thus, the research question and assumption about the possible source of fluoride and the assumption that fluoride increases downwards towards the aquifer were answered. Leaching experiments identified the main contributors of fluoride to groundwater in Siloam village as smectite clays and the muscovite present in the sandstone, greywacke and basalt. Time based leaching experiment, geochemical modelling and dating of different hydrogeological unit was recommended / NRF

Thesis (MScAgric (Soil Science))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The sandy soils of the Riverlands Nature Reserve, near Malmesbury, and the neighbouring farm were studied to determine the effects of long term invasion of the legume Acacia saligna on the soil nutrient content of a soil previously vegetated with fynbos. The effect of the removal of this alien legume on general soil properties and groundwater quality were also studied. The changes in nitrates and nitrites (NOX) due to the invasion and removal of the alien legume were investigated in more detail than changes in other soil nutrients. In addition to that emphasis was placed on the effect of vegetation clearing on groundwater quality, specifically relating to potential contamination with nitrates. This study was initiated after Conrad et al., (1999) found increased NOX concentrations in ground water while studying the effects of pig farming on ground water nitrogen (N) near a site cleared of Acacia saligna by Working for Water (WFW). Since many sites are scheduled for removal of this alien vegetation it was deemed necessary to study the effects that clearing alone had on groundwater quality. It was suspected that there would be an increase in soil and groundwater NOX with vegetation removal due to the inputs from the legume alien invader. Soil sampling was done continuously throughout the rainy season of 2007 (From May to December) on three adjacent sites separated by some 50 m of distance, consisting of a natural fynbos site and two Acacia saligna sites. The sites were selected approximately on the same contour line to prevent interaction through lateral water flow. One of the Acacia sites was cleared by the Working for Water programme in the usual manner leaving slash on the ground. Soil samples were collected at regular intervals throughout the season from all three sites (fynbos, Acacia and cleared site) using a Jarrett soil auger. They were airdried (to achieve full oxidation of mineral N) and sieved though a 2mm sieve. Soils were analysed by atomic absorption spectroscopy for basic cations and by ion chromatography for anions, including nitrates and nitrites. Total carbon and nitrogen was determined by combustion, pH (1M KCl and H2O) and EC (1:5 H2O) were also measured. The present study was part of a wider investigation into the quality of groundwater, modelling flow and contaminant transport (Jovanovic et al., 2008). The largest changes in soil properties were observed in the top (0-5 cm) layer. The fynbos site had a lower nutrient status by comparison to the Acacia site and the cleared site. The sum of cations from the soils of the fynbos site at a soil depth of 0-5cm was 100mg/kg and soils from the cleared and Acacia sites were about 190mg/kg. The Acacia site had a higher NOX status and experienced a larger NOX fluctuation during the rainy season than the fynbos site; minimum NOX values were similar (below 10mg/kg) but the Acacia site had a maximum NOX value of near 60mg/kg and the fynbos site just below 30mg/kg. There was little difference in general soil characteristics (exchangeable cations, pH and EC, total soil C and N) during the first season after clearing, between the Acacia and the cleared sites. The effect of soluble nitrogen changes due to alien legume invasion and removal on groundwater quality, relating to NOX, during the first season after clearing, was determined. It was found that the Acacia site had higher NOX concentrations than the fynbos site. At 0-5cm the fynbos site NOX was less than 30mg/kg and the Acacia site was between 30 and 110mg/kg for most of the season, with values lower than 30mg/kg for the last four sampling dates only. N concentrations on the cleared site behaved in a similar manner to the uncleared Acacia site, but generally N values were lower on the cleared site, there were only two sampling dates where the cleared site had higher NOX values than the Acacia site at 0-5cm. The average groundwater N in NOX under the cleared site was 4.34 mg/l, and under the Acacia site 3.78mg/l, these values are both below the level determined for water contamination with nitrates. However, the increase in ground water nitrate levels after A. saligna clearing was significant. It was concluded that there is a change in the nutrient status of soil with Acacia invasion and again with removal. NOX migrates to the groundwater to a larger degree once vegetation has been removed, although during this study the nitrate pollution threshold of 10 mg/l nitrate N was not reached. / AFRIKAANSE OPSOMMING: Die sanderige gronde van die Riverlands Natuur Reservaat, naby Malmesbury, en die aangrensende plaas was bestudeer om die effek van die langtermyn indringing van die peulgewas, Acacia saligna, op die voedingswaarde van ‘n voorheen fynbos begroeide grond, sowel as die effek van die verwydering van die indringer op die algemene samestelling van die grond en grondwater kwaliteit. Oplosbare stikstof veranderings (NOX) wat plaasvind as gevolg van die indringing en verwydering van die indringer peulgewas, was in meer diepte bestudeer as die ander elemente. Klem was ook geplaas op die effek van die verwydering van plantegroei op grondwater kwaliteit, met spesifieke verwysing na potensiële nitraat besoedeling. Die studie was beplan na Conrad et al., (1999) ‘n toename van NOX konsentrasies in grondwater ontdek het, tydens ‘n studie van die effek wat vark boerdery het op grondwater N naby ‘n area waar Acacia Saligna verwyder was deur Working For Water (WFW). As gevolg van die feit dat verskeie areas in die proses is om skoongemaak te word van Acacia Saligna, is dit nodig geag om die effek daarvan of grondwater kwaliteit te ondersoek. Die hipotesis was dat daar ‘n toename in NOX konsentrasies in grond en grondwater sal wees as gevolg van die verwydering van plantegroei. Grond monsters was deurlopend geneem gedurende die reën seisoen van 2007 (Vanaf Mei tot Desember) uit nabygeleë areas wat omtrent 50 meter uitmekaar is. Die volgende tipes grond was verteenwoordig: ‘n Fynbos begroeide grond sowel as ‘n grond begroei met Acacia saligna. Die areas was geselekteer ongeveer op die selfde kontoer lyn om interaksie tussen areas te voorkom as gevolg van laterale water vloei. ’n Gedeelte van die A. saligna area was skoongemaak deur die Working for Water program op die gewone manier deur die afgesnyde plant materiaal op die grond te los. Grond monster was geneem met gereelde intervalle gedurende die seisoen op al drie areas (fynbos, A. saligna, en skoongemaakte area) deur die gebruik van ’n Jarret grondboor. Die monsters was lugdroog gemaak (om volle oksidasie van die mineraal N te verseker) en toe gesif deur ‘n 2mm sif. Die gronde was analiseer deur atoom absorpsie vir basiese katione en deur ioon chromatografie vir anione, insluitende nitriete en nitrate. Totale koolstof en stikstof was bepaal deur verbranding terwyl pH (1M KCl en H2O) en EC (1:5 H2O) ook gemeet was. Hierdie studie was deel van ‘n wyer ondersoek na die kwaliteit van grondwater, vloei modelering en vervoer van kontaminante (Jovanovic et al., 2008). Die grootste veranderinge in die grond eienskappe was in die boonste grondlaag (0-5cm) waargeneem. Die bevinding was dat die fynbos area ‘n laer voedingswaarde het as die area begroei met die indringer sowel as die die skoongemaakte area. Die som van katione onder fynbos grond by ‘n grond diepte van 0-5cm, was 100/mg/kg en die som van katione by die ander twee areas was omtrent 190mg/kg. Die Acacia area het ‘n hoër NOX inhoud en het ‘n groter NOX fluktuasie ervaar gedurende die reën seisoen as die fynbos area. Die minimum NOX waardes was soortgelyk (minder as 10/mg/kg), maar die Acacia area het ‘n maksimum NOX waarde van omtrent 60mg/kg terwyl die fynbos area se maksimum net minder as 30mg/kg gehad het. Daar nie veel verskil tussen die algemene grond eienskappe (uitruilbare katione, pH en EC, totale C en N) van die Acacia en skoongemaakte areas gedurende die eerste seisoen na die indringer verwyder is nie. Die effek van oplosbare stikstof veranderings as gevolg van die peulgewas se indringing en verwydering op grondwater kwaliteit, met verwysing na NOX, gedurende die eerste seisoen na verwydering van die indringer was bepaal. Dit was bevind dat die Acacia area ‘n hoër NOX konsentrasie as die fynbos area het. Op ‘n diepte van 0-5cm was die fynbos NOX laer as 30mg/kg terwyl die Acacia area tussen 30 en 110mg/kg vir die grootste gedeelte van die seisoen was met waardes laer as 30mg/kg vir die laaste vier datums waarop monsters geneem was. Veranderings in N op die skoongemaakte area en die Acacia area was soortgelyk, maar oor die algemeen was N waardes laer op die skoongemaakte area. Daar was slegs op twee datums gevalle gevind waar die skoongemaakte area ‘n hoër NOX inhoud as die Acacia area gehad het by ‘n diepte van 0-5cm. Die gemiddelde N in NOX in die grondwater onder die skoongemaakte area was 4.34mg/l en by die Acacia area was dit 3.78mg/l; hierdie waardes is onder die drempel vir nitraatbesoedeling in grondwater. Die nitraat inhoud van die grondwater het wel beduidend toegeneem as gevolg van verwydering van A. saligna. Die gevolgtrekking was dat daar ‘n verandering plaasvind in die voeding status van grond met Acacia saligna indringing en weer met verwydering. NOX migrasie na die grondwater verhoog met verwydering van plantegroei. In hierdie studie was die nitraat besoedeling drempel van 10mg/l nitraat N nie bereik nie.

Thesis (MScAgric (Soil Science))--University of Stellenbosch, 2007. / South Africa is a water scarce country and in certain regions the quantity of surface water is insufficient to provide communities with their domestic water needs. In many arid areas groundwater is often the sole source of water. This total dependence means that groundwater quality is of paramount importance. A high nitrate concentration in groundwater is a common cause of water being declared unfit for use and denitrification has been proposed as a potential remedy. In groundwater of the Marydale district in the Northern Cape Province, nitrate levels are high enough to be of concern for domestic and livestock consumption. A review of the literature indicates that bacterial denitrification of groundwater can be achieved in situ by using a suitable energy substrate. The technology has been tested elsewhere in the world but more certainty is needed on whether it is a feasible option for local groundwater remediation using local, cost-effective energy substrates and exploiting bacterial populations present naturally in the regolith. The objective of this study was to perform denitrification experiments by laboratory incubation using soil and groundwater samples collected in Marydale in order to determine; 1) The effectiveness of different carbon sources; 2) The effect of using soil sampled at different depths; 3) The effect of C:N ratio of the carbon substrate; and 4) The quality of resultant water. Various experiments were set up using 10 g soil and 40 mL groundwater with different concentrations of carbon sources (sawdust, glucose, maize meal and methanol). All experiments were done under a nitrogen atmosphere to exclude oxygen and temperature was kept constant at 23 °C. Indicator parameters were selected based on literature review, and major cations and anions and some metals were analysed for initially and at selected times during each experiment to evaluate whether major ion chemistry was changing over time. Parameters analysed in supernatant solutions after varying periods of time to indicate progress of denitrification and reduction included nitrate, nitrite, sulfate, alkalinity, chloride, acetate, basic cations, ammonium, pH, electrical conductivity, dissolved organic carbon, heteThe Marydale groundwater in some boreholes is of predominantly NaCl type and the nitrate concentration of 19-32 mg/L as N exceeds ideal limits for drinking water of 6mg/L as N . Two soil materials were sampled at different depths from a red sand overlying calcrete (Plooysburg form, Family Py1000). The incubation experiments showed denitrification was complete within a period of between 1 and 6 weeks depending on the carbon substrate and C:N used. Higher rates of nitrate removal were achieved where greater C:N was used. Readily degradable carbon substrates e.g. glucose showed rapid denitrification, while sawdust, a slowly degradable substrate, effected slower denitrification, hence it was concluded that intermediately degradable carbon substrates e.g. wheat straw may prove more suitable. Use of shallower soil material containing initially higher nitrate levels resulted in better denitrification rates, however, both soil materials effected denitrification.. Heterotrophic plate counts increased with time, this presence and growth of heterotrophic bacteria confirmed that conditions were optimum for growth and denitrification and that inoculation with bacteria is not a requirement for in situ denitrification. Dissolved organic carbon (DOC) concentration could be directly correlated to the initial input of carbon substrate as soil and groundwater lacked organic material. Results showed that reaction products such as acetate and nitrite, and basic cation concentrations were elevated in the supernatant solution in preliminary experiments. This was interpreted to be attributed to incomplete oxidation of organic material and excess soluble and available carbon for reaction. Cation concentrations were interpreted to have resulted from a decrease in pH brought on by organic acids produced during denitrification. The method used showed specificity, as the only parameters affected by the denitrification experiment were DOC, alkalinity, nitrite, nitrate, and the heterotrophic plate count. The DOC and HPC did not comply with acceptable levels for drinking water. Removal of HPC by boiling or chlorinating is required to ensure that the resultant water composition is of potable quality. For further research with slowly degradable carbon sources it is recommended that a C:N ratio of more than 12 should be employed, and monitoring should focus on soluble carbon nitrate, nitrite, and heterotrophic plate count. The study confirmed that denitrification of this groundwater with a range of carbon sources is possible within a short period of anaerobic contact with local soil material. With sufficient knowledge of the characteristics of the soil and groundwater in the area, establishment of a working in situ denitrification plant is probably feasible.

This aim of this study was to improve the understanding and functioning of the Table Mountain Group aquifer system and contribute to the sustainable development of this potential source for water supply in the Montagu area.

This aim of this study was to improve the understanding and functioning of the Table Mountain Group aquifer system and contribute to the sustainable development of this potential source for water supply in the Montagu area.