Land use (nutrients)

Find further information on the Conservation of Freshwater Ecosystem Values (CFEV) Program and its data at www.dpipwe.tas.gov.au/cfev.

Spatial data

TitleLand use (nutrients)

CustodianWater and Marine Resources Division, Department of Primary Industries, Parks, Water and Environment

CreatorGIS Unit, Information and Land Services Division, Department of Primary Industries and Water (DPIW)

DescriptionEstimation of excess nutrient input to freshwater-dependent ecosystems.

Input data

Land Information System Tasmania (LIST) Land use data layer (version May 2004), DPIW

Lineage

The land use (nutrients) data layer was developed by selecting LIST land use categories which are likely to result in excess nutrient input to freshwater-dependent ecosystems, particularly waterbodies and wetlands. Each land use category from the LIST data was given a score based on the relative impact it is likely to have on nutrient yield to freshwater-dependent ecosystems, either as 0.5 (moderate impact) or 0 (high to severe impact). A list of the selected land use categories and their assigned scores is given in Table 1. Areas of the state containing none of the LIST land use categories shown in Table 1 were assigned a nutrient score of 1 (no or very little impact). The land use (nutrients) data was attributed to each of the waterbody and wetland spatial units using the rules outlined below.

Table 1. Land use categories and their land use (nutrient) impact score.

Primary	Secondary	Tertiary	Nutrient score
Production from dryland	Grazing modified pastures	Pasture legumes	0.5
Production from dryland	Grazing modified pastures	Pasture legume/grass mixtures	0.5
Production from dryland	Grazing modified pastures	Sown grasses	0.5
Production from dryland	Cropping	Cropping	0
Production from dryland	Cropping	Cereals	0.5
Production from dryland	Cropping	Beverage and spice crops	0.5
Production from dryland	Cropping	Hay and silage	0.5
Production from dryland	Cropping	Oil seeds	0.5
Production from dryland	Cropping	Sugar	0
Production from dryland	Cropping	Cotton	0.5
Production from dryland	Cropping	Tobacco	0
Production from dryland	Cropping	Legumes	0.5
Production from dryland	Perennial horticulture	Perennial horticulture	0.5
Production from dryland	Perennial horticulture	Tree fruits	0.5
Production from dryland	Perennial horticulture	Oleaginous fruits	0.5
Production from dryland	Perennial horticulture	Tree nuts	0.5
Production from dryland	Perennial horticulture	Vine fruits	0.5
Production from dryland	Perennial horticulture	Shrub nuts fruits and berries	0
Production from dryland	Perennial horticulture	Flowers and bulbs	0
Production from dryland	Perennial horticulture	Vegetables and herbs	0
Production from dryland	Seasonal horticulture	Seasonal horticulture	0
Production from dryland	Seasonal horticulture	Fruits	0
Production from dryland	Seasonal horticulture	Nuts	0
Production from dryland	Seasonal horticulture	Flowers and bulbs	0
Production from dryland	Seasonal horticulture	Vegetables and herbs	0
Production from irrigation	Irrigated modified pastures	Irrigated modified pastures	0.5
Production from irrigation	Irrigated modified pastures	Irrigated woody fodder plants	0.5
Production from irrigation	Irrigated modified pastures	Irrigated pasture legumes	0.5
Production from irrigation	Irrigated modified pastures	Irrigated legume/grass mixtures	0.5
Production from irrigation	Irrigated modified pastures	Irrigated sown grasses	0.5
Production from irrigation	Irrigated cropping	Irrigated cropping	0
Production from irrigation	Irrigated cropping	Irrigated cereals	0.5
Production from irrigation	Irrigated cropping	Irrigated beverage and spice crops	0.5
Production from irrigation	Irrigated cropping	Irrigated hay and silage	0.5
Production from irrigation	Irrigated cropping	Irrigated oil seeds	0.5
Production from irrigation	Irrigated cropping	Irrigated sugar	0
Production from irrigation	Irrigated cropping	Irrigated cotton	0
Production from irrigation	Irrigated cropping	Irrigated tobacco	0
Production from irrigation	Irrigated cropping	Irrigated legumes	0
Production from irrigation	Irrigated perennial horticulture	Irrigated perennial horticulture	0.5
Production from irrigation	Irrigated perennial horticulture	Irrigated tree fruits	0.5
Production from irrigation	Irrigated perennial horticulture	Irrigated oleaginous fruits	0.5
Production from irrigation	Irrigated perennial horticulture	Irrigated tree nuts	0.5
Production from irrigation	Irrigated perennial horticulture	Irrigated vine fruits	0.5
Production from irrigation	Irrigated perennial horticulture	Irrigated shrub nuts fruits and berries	0.5
Production from irrigation	Irrigated perennial horticulture	Irrigated flowers and bulbs	0
Production from irrigation	Irrigated perennial horticulture	Irrigated vegetables and herbs	0
Production from irrigation	Irrigated perennial horticulture	Irrigated seasonal horticulture	0
Production from irrigation	Irrigated perennial horticulture	Irrigated fruits	0.5
Production from irrigation	Irrigated perennial horticulture	Irrigated nuts	0.5
Production from irrigation	Irrigated perennial horticulture	Irrigated flowers and bulbs	0
Production from irrigation	Irrigated perennial horticulture	Irrigated vegetables and herbs	0
Intensive uses	Intensive horticulture	Intensive horticulture	0
Intensive uses	Intensive horticulture	Shadehouses	0.5
Intensive uses	Intensive horticulture	Glasshouses	0.5
Intensive uses	Intensive horticulture	Glasshouses (hydroponic)	0.5
Intensive uses	Intensive animal production	Intensive animal production	0
Intensive uses	Intensive animal production	Dairy	0
Intensive uses	Intensive animal production	Cattle	0
Intensive uses	Intensive animal production	Sheep	0
Intensive uses	Intensive animal production	Poultry	0
Intensive uses	Intensive animal production	Pigs	0
Intensive uses	Intensive animal production	Aquaculture	0
Intensive uses	Manufacturing and industrial	Manufacturing and industrial	0.5
Intensive uses	Residential	Residential	0.5
Intensive uses	Residential	Urban residential	0
Intensive uses	Residential	Rural residential	0.5
Intensive uses	Services	Services	0.5
Intensive uses	Services	Commercial services	0.5
Intensive uses	Services	Public services	0.5
Intensive uses	Services	Recreation and culture	0.5
Intensive uses	Transport and communication	Airports/aerodromes	0.5
Intensive uses	Transport and communication	Roads	0.5
Intensive uses	Transport and communication	Railways	0.5
Intensive uses	Transport and communication	Ports and water transport	0.5
Intensive uses	Transport and communication	Navigation and communication	0.5
Intensive uses	Waste treatment and disposal	Waste treatment and disposal	0
Intensive uses	Waste treatment and disposal	Stormwater	0.5
Intensive uses	Waste treatment and disposal	Landfill	0
Intensive uses	Waste treatment and disposal	Solid garbage	0
Intensive uses	Waste treatment and disposal	Incinerators	0
Intensive uses	Waste treatment and disposal	Sewage	0
Water	Reservoir/dam	Evaporation basin	0.5
Water	Reservoir/dam	Effluent pond	0
Water	River	River - intensive use	0.5
Water	Marsh/wetlands	Marsh/wetland - intensive use	0.5
Water	Estuaries/coastal waters	Estuary/coastal water - intensive use	0.5

Data limitations

The land use (nutrients) data inherits all the limitations of the input data, and also relies heavily upon the expert assessment of the relative impacts of each of the land uses.

Date createdSeptember 2004

Scale and coverage1: 25 000, Statewide

Attribute data

TitleLand use (nutrients)

Column headingWB_NUTRI, WL_NUTRI

Input data

CFEV Land use (nutrients) spatial data (described above)
CFEV Mean Annual Run-off attribute data
CFEV River Section Catchments spatial data
CFEV Waterbodies spatial data
CFEV Wetlands spatial data

Type of dataContinuous but also exists in a categorical format (see Table 2).

Number of classesWaterbodies = 5, Wetlands = 5

Assigning values to ecosystem spatial units

A land use (nutrients) score (continuous number between 0 and 1) was assigned to each waterbody and wetland spatial unit using the following process.

Firstly, the land use (nutrients) spatial data layer was intersected with the RSC data layer and for each RSC (which sometimes is a waterbody catchment) and wetland catchment, the percentage area of the catchment containing each nutrient score (0, 0.5 or 1) was calculated. Note in the case of wetlands, the catchment may be made up of more than one RSC. A single score for the catchment was then calculated using an area-weighted average. A further step involved taking this value and assigning a final nutrient score for the catchment according to the following rules:

If value is ≥0 and ≤0.25, then assign nutrient score as 0 (high impact).
If value is >0.25 and ≤0.75, then assign nutrient score as 0.5 (medium impact).
If value is >0.75 and ≤1, then assign nutrient score as 1 (low impact).

This value was known as the land use (nutrients) score for the local catchment. For wetlands, this score was assigned directly to the wetland spatial unit as WL_NUTRI.

Nutrient scores for the waterbodies, however, were accumulated for all upstream RSCs, (including the local waterbody catchment) and weighted by the current MAR. In this accumulation, the boundaries of the upper catchment stopped where a RSC was directly downstream of a waterbody or a wetland of area >1 ha. This allowed for the influence of a waterbody/wetland acting as a sink for catchment-derived sedimentation (illustrated in Figure 1Figure ).

Figure 1. Illustration of catchments showing the local and upstream RSCs contributing to the calculation of the catchment disturbance scores. Dotted lines show RSC boundaries.

The calculation of upstream accumulated land use (nutrients) score for a given waterbody catchment is given by the following equation:

Where:

RSC_ANUTRI = Accumulated land use (nutrients) score for the RSC (waterbody catchment)

RSC_NUTRI (1…n) = Land use (nutrients) score of the upstream RSCs

RSC_MAR (1…n) = Current MAR value of the upstream RSCs

RSC_NUTRI = Land use (nutrients) score of the local RSC (waterbody catchment)

RSC_MAR = Current MAR value of the local RSC

RSC_AMARNM = Accumulated current MAR value for the RSC (includes the MAR of the local RSC)

The upstream accumulated land use (nutrients) score for the waterbody catchment was then assigned directly to the relevant waterbody spatial unit. The overall land use (nutrient) scores range from 0 (poor condition – high nutrient input) to 1 (natural or near-natural condition – low nutrient input).

Each of the waterbody and wetland spatial data layers had the continuous land use (nutrients) data categorised according to Table 2. The categorical data was used for reporting and mapping purposes.

Table 2. Land use (nutrient) categories for waterbodies and wetlands.

Category	Waterbodies (Min to max values)	Wetlands (Min to max values)
1	0	0
2	>0 to <0.05	>0 to <0.05
3	0.05 to <0.95	0.05 to <0.95
4	0.95 to <1	0.95 to <1
5	1	1

CFEV assessment framework hierarchy

Waterbodies>Statewide audit>Condition assessment>Naturalness score (WB_NSCORE)>Sediment quality-surrogate (WB_NUTRI)
Wetlands>Statewide audit>Condition assessment>Naturalness score (WL_NSCORE)>Water quality (WL_WATER)