Neighbourhood catchments: using GIS to achieve ownership and change in stream and catchment management
1 Natural Resources and Mines, P.O. Box 19, Emerald, Qld., 4720
Phone: 07 4987 9304, Fax: 07 4987933, Email: Cameron.Dougall@dnr.qld.gov.au
2Natural Resources and Mines, P.O. Box 736, Rockhampton, Qld., 4700
Phone: 07 4938 4240, Fax: 07 4938 4010, Email Chris.Carroll@dnr.qld.gov.au
3Natural Resources and Mines, LMB 1, Biloela, Qld., 4715
Phone: 07 4992 9104, Fax: 07 4992 3468, Email: Scott.Stevens@dnr.qld.gov.au
The Fitzroy Basin is a large catchment in which complex ranges of natural resource management issues occur. Impacts from landuse are often far removed from the source and difficult to quantify, study and visualise. The Neighbourhood Catchment approach proposes that local sub-catchments are an appropriate size to address resource management issues.
Two 'focus’ Neighbourhood Catchments' have been established in the Fitzroy. Geospatial information on land management and catchment condition is first captured, and using a Geographical Information Systems (GIS), linked to produce a spatial database. Sediment yields and water quality results are then analysed within the GIS and the impacts of changes in stream and land management practices are assessed.
Information generated from the approach is used to create ownership for lanholders and promote change in land and stream management at a sub-catchment scale and larger. A GIS has been pivotal in this process, aiding in the communication of findings to landholders, community groups and government agencies
The Fitzroy Basin is the second largest coastal catchment in Australia (142 000 Km2), and is dominated by grazing (82%), cropping (7%), irrigation (0.6%) and mining (0.4%) (Calvert et al., 2000). The Population is ~170 000, with the majority of people living in towns. Land management and condition is the predominant responsibility of farmers. Indicators of unsustainable landuse within the Fitzroy include high turbidity, pesticide and nutrient levels, toxic algal blooms and widespread occurrence of exotic weeds and threatening habitats, in particular flood plains and riparian areas (Jones, 2000; Fabbro et al, 1996; Telfor, 1995; Henderson, 2000). Other indicators include possible isolated outbreaks of salinity (Gordon, 2001, pers. comm.) and an estimated 4 million tonnes of sediment discharging annually from the Fitzroy Basin into the Great Barrier Reef Lagoon of Keppel Bay.
In a catchment the size of the Fitzroy it is difficult for individuals and groups to easily see the relationships between land management practice on farm and resultant offsite impacts such as algal blooms, pesticide contamination and salinity. Consequently it is proposed that stream and land management be considered at both a local property and sub-catchment or ‘Neighbourhood Catchment’ scale. At this scale property owners, researchers and community groups are more able to study, visualise, quantify, and understand the relationships between land management practices and offsite agricultural impacts.
Figure 1: Sediment plume cyclone joy 1991
In the Neighbourhood Catchment approach, we propose that the local catchment is an appropriate scale that can integrate and engage landholders, and achieve ownership and promote change in resource management practices in the Fitzroy. Geographical Information Systems (GIS) are a pivotal part of the Neighbourhood Catchment approach allowing monitoring, analysis, modelling and visualisation of relationships between land management and its impacts at various scales. This paper will outline the role of a GIS in achieving ownership and change within the context of the Neighbourhood Catchment approach.
A Neighbourhood Catchment consists of a group of properties, or parts of a property, that are located in a common sub-catchment, hence the term ‘neighbourhood’. This scale is then used as a building block to create ownership of land and stream management at a sub-catchment scale and larger.
Two ‘focus Neighbourhood catchments’ (300 km2) have been established in the Fitzroy to help understand and determine the impact of land management on sediment and water quality (Figure 2). The Spottswood catchment is dominated by grazing (89%), whereas the Gordonstone catchment has an even mixture of cropping (51%) and grazing. Sediment, nutrient and pesticide loads are measured from a paddock through to progressively larger scales in the two catchments. Spatial information on the catchments is sourced from property plans, aerial photographs, satellite imagery and existing departmental databases.
Monitoring of catchment condition, and resultant water quality was conducted in the two focus catchments. This data enabled feedback to landholders on the impact that land management had on sediment movement and water quality. The 50 landholders in turn provided records on their land management practices, including crops grown, tillage operations, stocking rates, and fertiliser and pesticide applications. All data was linked to a GIS which enabled land management within the catchments to be related to sediment movement and water quality data.
Figure 2: Gordonstone and Spottswood ‘focus’ Neighbourhood Catchments
To aid in the extension of improved land management practice and the Neighbourhood Catchment approach, relevant information was collated into a visual presentation. The resulting presentation covered areas such as long-term soil fertility declines, soil erosion, water use inefficiency, compaction, stubble effects and their relationships to catchment health. It integrated information from grazing, dryland and irrigated cropping, mining, concluding with an introduction to the Neighbourhood Catchments project. Data was exported visually from the GIS into the presentation, allowing analysis and visualisation of the Neighbourhood Catchment concept. The extension audience was broadly split into three groups; landholders, community groups and government organisations.
All landholders were initially visited at their homes with the PowerPoint TM presentation. A vast majority of property owners chose to be involved in the approach. These owners were given digitised property plans and paddock scale record keeping sheets. Discussions with the landholder enabled a baseline record of adoption and awareness of best management practice to be produced. The opportunity to use the property plan as a platform for aiding environmental accreditation was also discussed.
The communication power of a GIS was demonstrated with the simple analysis of two similar rainstorm events (127 and 100 mm; and 30 minute intensities of 14 mm/hr) at the Gordonstone catchment. These storms offered the ideal opportunity to highlight the importance of land management practices that retain soil cover in reducing sediment movement.
In February 2000 event, an average sediment concentration of 1.1 g/l was measured at the Gregory Highway sampling site when only a third of the catchment had adequate soil cover levels (>30%) to control erosion. In contrast, in the April event there was a 65% reduction in sediment concentration (0.39 g/l), after sorghum and sunflower had been planted, and when almost two-thirds of the catchment had soil cover >30%. The reduction in sediment movement due to soil cover at a 50km2 scale is similar to findings found by Carroll et al. (1997) at a 10 ha paddock scale, and show that land management practices can translate to a reduction at a Neighbourhood catchment scale.
To simplify the information contained in the storm events, data on ground cover was entered into the GIS. Using the ArcView 3d analyst extension ground cover was classed and extruded vertically. The following PowerPoint slide was produced (Figure 3).
Figure 3: Surface cover and examples of sediment concentrations at Gregory highway section of Gordonstone creek for two similar rainstorm events (100mm, 127 mm; and 30 minute intensities of 14 mm/hr) in February, and April 2000
In this approach the emphasis was not on telling landholders “how” to farm, but “what we have learned about farming”. The relationships between ground cover, rainfall infiltration and water quality were more easily seen. Positive results were recorded, many times we were asked to stop the presentation, allowing others to be called into the room.
Schools, Landcare and Community based natural resource management organisations
Many schools and community groups seek a broad overview of natural resource issues within the Fitzroy catchment. Again, GIS information was used as the delivery mechanism for presenting facts on the Fitzroy catchment and the Neighbourhood catchment approach.
The presentation animates broad scale coverages on landuse in the Fitzroy Basin to set the scene. Locations of areas being impacted by landuse are highlighted (Figure 4), as well as research activities conducted into improving land management practices. Positive feedback was received from students and teachers. Several teachers expressed an interest in seeing some of the presentations becoming core components of learning modules on catchment management within the region.
There has been as increasing demand by the community for Neighbourhood catchment multimedia material. Web development has been earmarked as a solution to this problem. The planned development will incorporate GIS based extension material, allowing users to access the information in PDF format.
Importantly, the Fitzroy Basin Association who represents the key stakeholders in the region have endorsed and adopted the Neighbourhood Catchment approach to devolve funding grants and deliver on-ground works in the Fitzroy catchment. This achievement would not have been possible without using GIS as an effective extension tool.
Figure 4: Animated broad scale landuse coverages
Several departmental agencies have been engaged with material from the Neighbourhood Catchment presentations through the Queensland launch of the National Action Plan for Salinity and Water Quality. Community feedback has been encouraging with the importance of working on a sub-catchment scale to address natural resource management issues being recognised (Newsbrief: National Plan for salinity and water quality 2001).
The application of the Neighbourhood Catchment approach to date has been in ‘focus catchments’. The next target is change at a Fitzroy scale.
It is intended that the Neighbourhood Catchment approach will be used to achieve change in five adjacent Neighbourhood Catchments. The land management principles learned from research in the focus catchments, and in other areas, will be used to model the impact of land and stream management practices in the expanded area. In this way Neighbourhood Catchments become building blocks for improved water quality at a Fitzroy catchment scale.
The modelling will be GIS based, with the Soil Water assessment Tool SWAT (Arnold, et al. 1999) being used through an ArcView interface. Information generated will again be extended through spatial outputs generated from the GIS such as maps, tables and charts.]
Use of a GIS has allowed the visualisation of the current state of the landscape, and observation of the downstream impacts of unsustainable landuse on water quality and aquatic environments. Within the Neighbourhood Catchment approach, it enables baseline data and changes in the condition of land management to be recorded, and for landholders to assess and improve their management practices. GIS has been shown to be a valuable extension tool aiding in property, catchment, and regional scale change.
Arnold J.G., Williams J.R., Srinivasan R., & King K.W. 1999. SWAT Soil and Water
Assessment Tool . USDA Agricultural Research Service, Texas A&M University, Blackland Research Centre.
Carroll, C., Halpin, M., Burger, K., Sallaway, M.M., and Yule, D.F. (1997). “The effect of crop type, crop rotation, and tillage practice on runoff and soil loss on a Vertisol in central Queensland.” Australian Journal of Soil Research 35, 925 – 939.
Calvert, M., Simpson, J., and Adsett, K. (2000). “Land use mapping of the Fitzroy catchment -Theme 5”. National Land and Water resources Audit. Queensland Department of Natural Resources. www.nlwra.gov.au/
Fabbro, L. D., Sheil, R.J., and Duivenvoorden, L.J. (1996). “Plankton (Phytoplankton and Zooplankton).” In: Noble, R.M., Duivenvoorden, L.J., Rummenie, S.K., Long, P.E., and Fabbro, L.D. Downstream Effects of land Use in the Fitzroy Catchment. Queensland Department of Natural Resources, Brisbane.
Gordon, I. (2001), Queensland Department of Natural Resources and Mines.
Jones, M. (2000). “Fitzroy Implementation Project Queensland. Technical Report 3, Theme 7- Catchment Health.” National Land and Water Resources Audit. Queensland Department of Natural Resources. www.nlwra.gov.au/
Newsbrief: National Action Plan for Salinity and Water Quality, (May 2001). Queensland Government. http://www.dnr.qld.gov.au/water/salinity
Noble, R.M., Duivenvoorden, L.J., Rummenie, S.K., Long, P.E., and Fabbro, L.D. (1997). “Downstream Effects of land Use in the Fitzroy Catchment.” Queensland Department of Natural Resources, Brisbane.