Spelling suggestions: "subject:"groundwater -- south africa -- sandvik"" "subject:"groundwater -- south africa -- sandvikens""
1 |
Assessment of GIS-interpolation techniques for groundwater evaluation : a case study of the Sandveld, Western Cape, South AfricaMunch, Zahn 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2004 / ENGLISH ABSTRACT: The Sandveld, a potato growing area of the Western Cape is subject to significant
groundwater abstraction for both municipal and agriculture purposes. The climate is arid and
sensitive and important ecosystems in the area are showing varying degrees of impact.
Management measures are needed to ensure ongoing sustainable development of the area.
In this study, different interpolation techniques were evaluated to calculate values for
unsampled variables rainfall and groundwater elevation. Local deterministic techniques as
well as geostatistical techniques were used. It was found that geostatistical techniques,
especially with collateral information, such as topography, provided a more accurate result.
For environmental studies of this nature, Kriging is recommended as interpolation technique.
The underlying data will determine the selection of the particular type of Kriging.
Data was extracted from a customized relational database, geoMon, used for data capture,
retrieval, processing and reporting. Ease of data extraction facilitated analysis.
The interpolated grids were applied in two scenarios: Recharge calculations and quantification
as well as a new classification approach according to Resource Directed Measures (RDM).
Management classes were defined based on GIS-derived data. / AFRIKAANSE OPSOMMING: Die Sandveld, ‘n aartappelverbouingsgebied in die Wes-Kaap, ondergaan aansienlike
grondwateronttrekking vir beide munisipale sowel as landbou doeleindes. Die klimaat is dor
en droog en sensitiewe en belangrike ekosisteme in die area ondervind wisselende
impakvlakke. Bestuursmaatreëls word benodig om volhoubare ontwikkeling van die area te
verseker.
In hierdie studie is verskillende interpolasie tegnieke om onbekende waardes vir veranderlikes
gebruik in grondwater evaluasie te bereken, evalueer. Lokale deterministiese tegnieke sowel
as geostatistiese tegnieke is gebruik. Geostatistiese tegnieke, veral gebruik saam met
addisionele inligting soos topografie, bereken meer akkurate resultate. Vir omgewingsstudies
van hierdie aard, word Kriging aanbeveel as interpolasie tegniek. Eienskappe van die
onderliggende data word gebruik om die tipe Kriging aan te dui.
Data is onttrek uit ‘n gebruikersaangepaste databasis, geoMon, wat gebruik is vir
datavaslegging, onttrekking, prosessering en verslaggewing. Die gemak waarmee data
onttrek kon word het analise vergemaklik.
Geïnterpoleerde data is gebruik vir grondwateraanvullingsberekeninge en -kwantifisering
sowel as ‘n nuwe benadering tot klassifikasie volgens hulpbron gerigte maatreëls.
Bestuursklasse gebaseer op GIS-afgeleide data, is gedefinieer.
|
2 |
A spatial decision support system for groundwater abstraction impact assessment and licensingBasson, F. C. (Frederick Christoffel) January 2005 (has links)
Thesis (MSc)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: Water resources in South Africa are limited and groundwater plays an important role in
supporting basic human needs, sustaining ecosystems and enabling industrial and agricultural
development. Sound management practices are necessary to ensure sustainable development
of water resources. All groundwater usage must be licensed in compliance with the National
Water Act of 1998. A Spatial Decision Support System (SDSS) can be used to assist in the
groundwater usage licensing process of the Department of Water Affairs and Forestry
(DWAF).
The main aim of this study was to develop a SDSS, named Groundwater Abstraction &
Licence Evaluation Tool (GALET), that could assist in the process of allocating water use
licences and determining the local impact of abstraction, based on existing theory and data.
The development was done within ArcView 3.2 using the scripting language Avenue. The
Sandveld, an arid stretch of land along the west coast of South Africa that is heavily impacted
by groundwater abstraction, was the chosen study area. The data collected for this study
included existing borehole, recharge, rainfall and geological information.
GALET proved to be capable of calculating essential information needed to evaluate
groundwater abstraction, which included drawdown in the water table, zone of influence and
the possible effects on features such as rivers and wetlands. Targeted potential users regarded
GALET as a useful tool in the process of licensing and groundwater abstraction impact
assessment and plans are under way to implement GALET or a derivative thereof at the
DWAF regional offices. / AFRIKAANSE OPSOMMING: Waterhulpbronne in Suid-Afrika is beperk en grondwater speel 'n belangrike rol in die
ondersteuning van basiese menslike behoeftes, volhouding van ekosisteme asook industriële
en landbou-ontwikkeling. Betroubare bestuurspraktyke is noodsaaklik om die volhoubare
ontwikkeling van waterhulpbronne te verseker. Alle grondwatergebruik moet volgens die
Nasionale Waterwet van 1998 gelisensieer word. 'n Ruimtelike Besluitnemings
Ondersteuning Stelsel (RBOS) kan as 'n hulpmiddel gebruik word in die lisensiëringsproses
van die Departement van Waterwese en Bosbou.
Die hoofdoel van hierdie studie was om 'n RBOS, genoem Groundwater Abstraction &
Licence Evaluation Tool (GALET), te ontwikkel wat as hulpmiddel gebruik kan word in die
allokeringsproses van watergebruiklisensies en die bepaling van die impak van
grondwateronttrekking op die omgewing, gebaseer op bestaande teorie en data. Die
ontwikkeling is in ArcView 3.2 met die programmeringstaal Avenue gedoen. Die Sandveld,
'n ariede streek aan die weskus van Suid-Afrika wat onderhewig is aan grootskaalse
grondwateronttrekking, is gekies as die studie area. Die data wat vir hierdie studie ingesamel
is sluit bestaande boorgat, grondwateraanvulling, reënval en geologiese inligting in.
GALET was in staat om belangrike inligting aangaande die evaluering van
grondwateronttrekking te bereken, o.a. die daling van die grondwatervlak, die impaksone en
die moontlike effekte op landvorms soos riviere en vleilande. Die teikengroep potensiële
gebruikers het GALET as 'n nuttige hulpmiddel in die proses van lisensiëring en
grondwateronttrekking impakbepaling beskou en planne is onderweg om dit of 'n aangepaste
program by die streekskantore van die Departement van Waterwese en Bosbou te
implementeer.
|
Page generated in 0.0752 seconds