8.3 Rice
crop management
8.3.1 Rice
area measurements
CICL monitors rice area and rice water use within its operational
area. The rice areas are measured using scanned aerial photographs and ArcView
Geographic Information System (GIS) software. The aerial photographs are taken
during December-January each year. 163 photographs at
a scale of 1:50,000 were used for rice area measurement during the
2000/2001 season.
Coleambally LWMP Area
The Coleambally LWMP Area is the most developed rice growing
area in CICL’s operational area. Total rice areas and water deliveries to rice
for the last 16 years
are shown in Figure 8.6. This chart shows
that total rice areas have increased this year, and that total rice water usage
has also increased.
Figure 8.6 Historical rice areas and total water used
for rice growing in the CIA
Rice water usage for the last 16
years can be seen in Figure 8.7. This chart also shows the
16-year average rice water usage for the CIA (13.4ML/ha). The average annual
rice water usage for 2000/2001 is less than the sixteen-year average.
Figure 8.7
Historical rice water usage in the CIA
Kerarbury Channel and Outfall District LWMP Areas
CICL has been monitoring rice
areas and water use in the Kerarbury Channel and Outfall District LWMP Areas
since 1997. Total rice areas in these LWMP areas for the past four seasons can
be seen in Table 8.6
Table 8.6
Rice areas in the Kerarbury Channel and Outfall District LWMP Areas
The total rice area grown in the KCA has increased
slightly each year since 1997. The COD has had a considerable increase in total
rice area from the 1999/2000 season to the 2000/2001 season. This is largely
due to another property being included in the total rice area calculation for
the COD LWMP Area. This property is a
customer of CICL, but rice growing on the property was administered in the past
by DLWC. In the 2000/2001 season the property grew 760 ha of rice.
Table 8.7 shows a comparison of rice areas
and rice water use in CICL’s area of operation. The CIA has the largest total
area of rice grown and therefore the largest total surface water use. The KCA
has the highest average surface water use (ML/ha).
Table 8.7
Total rice areas and surface water use in CICL's area of operation
8.3.2 Coleambally
Rice Environmental Policy breaches
In the past rice water usage has been calculated on a farm
basis. However since 1997/98 CICL has been calculating rice water usage on a
block basis. A farm can be comprised of one or more blocks. A block is defined
as a parcel of land that, while being included in the farm title, is separate
from other land parcels (or blocks) within that farm title. Each block has a
separate water supply point, which enables identification of crop water usage
for individual blocks. 137 farms, or 37 percent of all farms in the CIA
(including horticultural farms), are comprised of two or more blocks.
In 2000/2001 rice was grown on a total of 372 blocks in the
CIA. The average water usage was 11.8ML/ha, which was less than the
sixteen-year average of 13.4ML/ha.
Table 8.8
presents a summary of the rice surface water usage for the last three seasons.
This shows that the majority of blocks (67 percent) are using between 10 and 16
ML/ha. In total, 33 blocks exceeded 16 ML/ha for rice water usage, of which six
exceeded 19 ML/ha.
Table 8.8
Comparison of rice water usage for blocks in the CIA over the last three
seasons
Table 8.9 presents a summary of the rice
water usage in CICL’s area of operation. This does not include the COD, as DLWC
carried out the COD’s rice administration for the 2000/2001 season.
Table 8.9
Summary rice water usage CICL's area of operation 2000/2001
The majority of high rice water usage blocks occurred
towards the north. A study of the groundwater dynamics in northern Coleambally
has been completed by CSIRO Land and Water. This study shows that the excess
water used in the northern area flows in a north-westerly direction towards the
KCA and surrounding bore blocks. The
findings of this study and the NRM approach are being incorporated into CICL’s
rice policy, which is currently under review.
The Coleambally Rice
Environmental Policy was implemented throughout the CIA and KCA by regional
staff for the 2000/2001 season. The following table presents a summary of the
breaches of the Coleambally Rice Environmental Policy in each region. Most high
rice water use breaches occurred in the Boona Region, which may be attributed
to the deeper watertables.
Table 8.10
Breaches of the Rice Policy during 2000/2001
As can be seen in Table 8.11, the number of
Coleambally Rice Environmental Policy breaches for 2000/2001 is the lowest it
has been since 1996/1997, with a total of 54 breaches.
Table 8.11
Breaches of the Rice Policy since 1994/1995
The following table shows a summary of the Rice
Environmental Policy breaches in the CIA and KCA, and the actions that have
been taken.
Table 8.12 Summary of Rice Policy breaches in the CIA
and Kerarbury area
8.3.3 Rice water use testing
No
rice water use testing was carried out during the 2000/2001 season.
|
