The Assessment of “Existing Lawful Use” of Groundwater ... - eWISA

THE ASSESSMENT OF “EXISTING LAWFUL USE” OF
GROUNDWATER USING REMOTE SENSING AND
GEOGRAPHIC INFORMATION SYSTEMS
Johan Wentzel 1 , Julian Conrad 2 , Abdulla Parker 3 and Bayanda Zenzile 3
1 DWAF - Department of Water Affairs and Forestry, Private Bag X313, Pretoria, 0001. Tel: 012-336 8073.
Fax: 012-328 6397. E-mail: wentzelj@dwaf.gov.za
2 GEOSS - Geohydrological and Spatial Solutions, Stellenbosch.
3 DWAF - Department of Water Affairs and Forestry, Bellville.
ABSTRACT
The Department of Water Affairs and Forestry (DWAF) is responsible for the registration and
licensing, if necessary, of a number of water related issues including the abstraction of
groundwater. The National Water Act of 1998 states that water rights that were exercised in
October 1998 are to be considered as existing lawful use. On the receipt of applications for further
groundwater abstraction, it is often stated that a certain volume abstracted is “existing lawful use”.
The Department of Water Affairs and Forestry needs to be able to verify the claims made and they
are busy determining the most suitable method to carry this out. An approach that is currently
being tested is making use of 1998 satellite imagery with remote sensing technologies and
geographical information systems for assessing existing lawful use.
This approach is being tested extensively in the northern Sandveld (Olifants-Doorn Water
Management Area), with good success. However, there are a number of critical issues that need
to be taken into account. These issues include the importance of ground truthing the current
satellite imagery, the variation in the types of crops used, the variabilities associated with the water
sources used for crop irrigation, and the costs associated with acquiring current imagery.
INTRODUCTION
The National Water Act of 1998 (1) states that water rights that were being exercised in October
1998 would in future be regarded as existing lawful use. This implies that irrigators could continue
their activities unless there is reason to believe that the resource is over allocated. In such an
instance, the Department of Water Affairs and Forestry would implement a process of Compulsory
Licensing. This process is carried out in conjunction with the irrigators and will not be discussed
further in this paper. If users want to expand their existing activities, requiring increased water
usage, then they must apply for a license to do so.
REGISTRATION
In order to assess the water use situation and to quantify the amount of water actually used, a
process whereby all water users were required to register their use was initiated. This information
is needed to assess the current use of the water resource and will also be used for billing
purposes. This process is not the same as the licensing process. The registration information,
which includes the user’s personal details as well as their water use, was subsequently captured
electronically and a database called WARMS (Water Authorisation and Registration Management
System), was created within the Department of Water Affairs and Forestry to manage this
information.
Proceedings of the 2004 Water Institute of Southern Africa (WISA) Biennial Conference 2 –6 May 2004
ISBN: 1-920-01728-3 Cape Town, South Africa
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VERIFICATION
The most cost effective way to verify irrigator’s registered usage is by making use of colour aerial
photography and satellite images that have been georeferenced and have a high enough
resolution to identify irrigated land with a fair degree of accuracy. The Department of Water Affairs
and Forestry is currently using LANDSAT TM images for the verification process. The first
LANDSAT satellite was launched in 1972 and the latest, LANDSAT 7, was launched in April 1999.
Although satellite images taken before 1984 did not have a very good resolution, the images have
subsequently improved enough to allow their use for the verification process. The resolution with
LANDSAT 7, for instance is 30 m (multi-spectral) and 15m (panchromatic). Satellite images consist
of multi-spectral bands, where a band is a slice of wavelengths from the electromagnetic spectrum.
All objects that reflect green light for instance, will be captured in one band. (The colour per se is
not captured, only the frequency). These spectral bands can then be manipulated electronically to
highlight certain features on the earth’s surface, such as centre-pivots.
The WARMS database information was linked to the national farm coverage data supplied by the
Department of Land Affairs. Figure 1 illustrates farm boundaries superimposed on a LANDSAT 5
image.
Figure 1. A 1998 LANDSAT satellite image showing centre pivots. Farm boundaries are shown in yellow.
By linking WARMS data and using computers to display satellite imagery, one can now select a
particular farm, know immediately who the owner is and view his registration details. Satellite
imagery captures the actual pivots and the area irrigated by the pivot can be calculated. (Since
most crops in this study area are potatoes, calculations carried out presume that the crop being
studied will also be potato). Using known irrigation usages for potatoes (per season), water usage
per pivot can be calculated. Results obtained can then be compared with the value registered by
the farmer. Figure 2 shows a 1998 satellite image with electronically captured centre pivot areas
superimposed. Green circles indicate active circles, and yellow denotes inactive areas. This image
was captured in 1998 and partially reflects the existing lawful use.
In order to quantify the expansion that has taken place since 1998, information obtained from more
recent satellite images has been subjected to the same process as discussed before. Figure 3
illustrates the differences between 1998 and 2002 agricultural activities.

Figure 2. GIS captured irrigation areas, classified according to irrigation. The
1998 image provides an assessment of “existing lawful use”.
While pink circles appeared on the 1998 satellite images, all circles coloured green have been
developed since then. As described before, having linked the WARMS database to Department of
Land Affairs information, it is possible to identify farms where expansion has taken place. If
follow-up investigation finds no justification for the expansion, the irrigator will be requested to stop
his activities immediately or face prosecution.
DISCUSSION
Figure 3. Agricultural expansion subsequent to 1998 (indicated by the green circles).
DWAF are currently receiving more and more reports of the illegal development of irrigation and
building of unauthorised dams in all parts of the country (Wessels, 2003) (2) . DWAF is obliged to
follow up on these reports and legally sound procedures have been developed for this purpose.
The key activities are verification of registered water use and verification of existing lawful water
use. The verification of water use registration is the initial process. This involves an audit of
WARMS data and using appropriate remote sensing data / maps / aerial photography or any other
relevant information. Verification of existing lawful use is a more complex process and fraught with

practical, legal and technical consequences. DWAF’s Directorate of Water Utilisation is well aware
of these consequences and is currently developing procedures and directives for dealing with the
verification process. A flow diagram is included (Figure 4) of the proposed procedures and the
required documentation developed (i.e. letters 1 to 5 in Figure 4) should there be non-compliance
issues.
Yes
•Satellite imagery
•Aerial Photos
•Reports from area
•Departmental officials
set 35(3)(b)
Sufficient
information
Letter 1
Yes
Determine extent
and lawfulness
sec 35(4)
Possible unlawful
water use
Notice to user to apply
for Verification
sec 35(1)
No
Letter 3
Was application
received in time
sec 35(2)(c)
Yes
Request additional
information
sec 35(3)(a)
Yes Is existing
No
use lawful?
Confirm existing
lawful use
Note
Indicates written
actions requiring
standard documents
Yes
Letter 5
Letter 2
No
Late application
condoned
sec 35(6)
•Application form
•Return date
•Entitlement w ill lapse if no
application received
•Deliver personally or registered mail
sec 35(2)
No
Inform user to stop
water use
sec 35(5)(a)
Give applicant opportunity
to make representations
sec 35(3)(d)
Was the
representation
successful
No
Issue directive to stop
unlawful use
sec 53(1)
Letter 4(a)
Letter 4
Figure 4. Flow diagram of procedures and actions to be followed in the verification of existing
lawful water use.

The described method in this paper is currently the most cost effective way to verifying water
usage and of keeping pace with continuing development. It must be noted that in the study area a
single crop type predominates and the assumption is made that all irrigated areas are for potatoes.
The irrigation requirements for potatoes are known for different times of year and the amount of
water being applied can thus be calculated. No testing was carried out to see if crop types could be
differentiated and identified. In addition, there are typically two growing seasons for potatoes per
year and this issue must be kept in mind. The land after a potato harvest is then left fallow for 3 to
5 years. Thus a single image only provides data for a particular time and extrapolation of the active
crop areas and water consumption to an annual figure must be carried out carefully. At least two
images per year (ideally six months apart) should be assessed to determine annual figures.
Although Landsat TM was used there are a number of other sensors and images that can be used
and further investigation should be carried out to determine the most cost effective solution for
addressing the assessment of existing lawful use and current status.
CONCLUSION
Based on the procedures and directives developed by DWAF’s Directorate of Water Utilisation, and
the testing being carried out in pilot areas across South Africa, including the northern Sandveld,
Olifants-Doorn Water Management Area, the continued illegal use of water for irrigation purposes
and the building of unauthorised dams will be addressed, challenged and terminated. These
activities need to be particularly swiftly dealt with in the “stressed” dry regions that are currently
widespread throughout South Africa.
REFERENCES
1. DWAF, The National Water Act (Act 36) (1998).
2. J.J. Wessels, Briefing notification of registered water use and procedure for dealing with
unauthorised water use. DWAF Internal Communication. File B191/1 (2003).