Transcript 04 GIS User conference_sabeto catchment

LANDUSE MAPPING IN THE SABETO
CATCHMENT, NADI, FIJI
Pacific GIS/RS Conference, 2013
SPC – Land Resource Division
Introduction
• SPC, with support from USAID are assisting communities to manage their
food resources and strengthen their resilience to the effects of climate
variability and climate change
• In partnership with MOA, SPC undertook vulnerability and adaptation
assessments in the Sabeto catchment, Nadi. Assessment tools include
PRAs, HIES
• GIS, land use and vegetation mapping have been used to identify
adaptation measures
• The survey was an activity for the SPC’s Enhanced Climate Change
Resilience of Food Production Systems for selected PICTs (Fiji, Kiribati,
Samoa, Solomon Islands, Tonga and Vanuatu) USAID Project.
Locality
Sabeto catchment covers 13819 ha and is located about 8km from Nadi town. The
Sabeto road turnoff is about 5 minutes north of Nadi international Airport. The
catchment is located in the Ba Province, Viti Levu and comprises of Sabeto,
Nalotawa, Nadi, Vuda and Vaturu districts.
Objectives
• Collect biophysical and baseline data for the
catchment;
1. Collection and preparation of soil maps, land use
capability maps and land tenure maps for the
catchment.
2. Preparation of the current(November, 2012) land
use map for the catchment after the survey.
OBJECTIVE 1: COLLECT AVAILABLE DATA
AND BASELINE MAP PREPARATIONS
Soils data
• Obtained from the Landuse Section, Ministry of
Agriculture.
• Digitized soil map of Fiji.
• Data includes all soil taxonomy of Fiji. (eg. Soil
names, soil type and properties, etc.)
• The data provided us with baseline information of
the type of soils present and the production of the
soil map of Sabeto catchment.
Sabeto Soils
Major Soil type in the
area
Nigrescent
Description
Area(ha)
%
5010.81
36.26
3624.09
26.23
2456.13
17.77
1146.20
8.29
679.26
4.92
Marine marsh
Dark soils, moderately
fertile to fertile
Highly leached, acidic
and not very fertile soils
Yellow brown sandy soils
covered with shrubs and
grassland
Soils of the floodplains,
fertile soils
High clay content and
poorly drained
Saline soils
571.10
4.13
Beach strands
Sandy soils
169.96
1.23
Ferruginous latosolTalasiga
Degraded humic
latosols, highly
weathered.
161.59
1.17
Humic latosol
Red-yellow podzolic
Recent alluvium
Gley soils
Soil map
Land use Capability(LUC)
• The systematic arrangement of different kinds of land according to those
properties that determine its capacity for sustained production, where
capability is used in the sense of suitability for productive use. Capacity
depends largely on the physical qualities of the soil and the environment.
• LUC for Fiji is categorized to 8 classes.
• Data made available by the Landuse Section, Ministry of Agriculture
LUC Classes
• Classes I to IV – Comprise of land suitable for
arable cultivation.
• Classes V to VII – Land not suitable for arable
cultivation but suitable for pastoral or
forestry use.
• Class VIII – Land suitable only for protective
purposes. (eg. Forest reserves, mangroves)
Sabeto LUC
Land class
Slope (degrees)
Area(ha)
%
VI
21 - 25
4584
33
VII
25 - 30
3149
23
II
0-7
3103
22
III
8 - 11
1422
10
IV
12 - 15
948
7
VIII
>30 or peat or
marshland areas
571
4
V
16 – 20
42
0.31
Cont.
• The catchment has some good (39%) arable land
(classes II-IV) with slope ranging from 0-15 degrees
(flat- rolling slopes).
• Majority of the land(56%) is land classes V – VII with
slope ranging from 16-35.
• Much of the land classes in the catchment relate to
the physiographic characteristics and the terrain.
Sabeto LUC Map
Sabeto Land Tenure
• Taken from Cadastral data of Fiji by the Lands
Department.
• 96% of the catchment is native land and 4% is
freehold.
• Landowners’ consultation are vital before any
development takes place in the area.
Sabeto Tenure Map
OBJECTIVE 2: SABETO FIELD SURVEY
Fieldwork
• Involved driving and walking around the area
and plot the types of landuse boundaries onto
the printed 1:10,000 scale Worldview2
images.
• Use of GPS as well.
Some land use observed and activities of the survey
GIS Integration
• Mapping software was ArcGIS9.3
• Took 2 months after the survey to complete
the digitized Sabeto catchment land use
shapefile.
• From the data we were able to determine the
common land use types and practices and the
amount of area they cover within the
catchment boundary.
Results
Major
Landuse
Area(ha)
Percentage
cover (%)
Forest
5549.96
40.16
Grassland,
shrubs
3628.39
26.26
Cultivated
land
2339.17
16.93 where
<2% is
agriculture
Residential,
School
1034.55
7.49
Pasture,
grazing
718.50
5.20
Mangroves
406.35
2.94
Unused land 142.07
1.03
Cont.
• Upper catchment is dominated by forests and
upland grasslands.
• Farming(sugarcane) are done on the mid
section(rolling slope lands) to the lower
section(flat to gently slope areas) of the
catchment.
• Most flat lands are mainly used for residential,
commercial and recreational purposes.
• Less than 2% of the catchment is used for
agriculture.
Community Based Adaptation
• Vulnerabilities identified
– Food insecurity and reliance on imported and less
nutritional food
– Limited communication and access roads
– Increased incidence of disease outbreaks
– Increased incidence of landslides
– Increased flooding of food gardens
– Reduced crop yields
Community Approach
• Because of the catchment’s vulnerabilities an
agroforestry demo-farm was established in the
catchment.
• Overlaying soils and LUC data made it easier to predetermine the soil properties and land use capability of
the demo-farm. Although soil testing was also done on
sight as well as slope measurements for more accuracy.
• As a result some all year round crops were selected and
planted to help diversify food productions and
sustainable land management was also practiced on the
farm because of the sloping-terrain.
• Other adaptation measures
– Promotion of livestock diversity
– Improve farming practices through community
training on plant propagation, nursery
management, climate ready crops, crops and
livestock management
– Improve pest and disease control
– Increase community disaster preparedness
Agroforestry Model Farm, Vaturu District School, Nagado.
Acknowledgements
• Ministry of Agriculture for their help in the
assessment and Soils data.
• SOPAC for the WorldView2 satellite images.
Vinaka
Tuvuki Ketedromo
[email protected]