Monitoring, modelling and remote sensing: WACE Year 12 Earth and Environmental Science
“Explain how monitoring, modelling and remote sensing inform sustainable resource management”
Monitoring collects data on the state of a resource over time, modelling uses that data to predict how the resource will respond to different management choices, and remote sensing gathers data over large areas from satellites and aircraft. Together they let managers set baselines, detect change, test scenarios and adjust decisions through adaptive management, so that sustainable yields and limits are based on evidence rather than guesswork.
What this dot point is asking
SCSA wants you to explain how these three tools support sustainable management of renewable resources at local, regional and global scales. The thread is evidence: you cannot manage what you cannot measure, and you cannot plan without predicting.
Monitoring
Monitoring is the systematic, repeated measurement of a resource and its environment.
- A baseline is the starting condition against which change is measured.
- Indicators are the measurable variables chosen to represent resource health, such as water-table level, fish stock size, vegetation cover or water quality.
- Repeated measurement reveals trends, distinguishing real change from natural variation.
For example, groundwater management on Perth's Gnangara Mound relies on a network of bores monitoring water-table levels over decades.
Sustainable limits such as a sustainable groundwater yield or a fishing quota are only as good as the data behind them. Monitoring provides the baseline and trend information that turns a management target into an evidence-based decision rather than a guess.
Modelling
A model is a simplified representation of a system used to predict its behaviour.
- Models take monitoring data and project how a resource will respond to different scenarios, such as different extraction rates or rainfall futures.
- They let managers test choices safely before acting, for example estimating whether a quota will allow a fish stock to recover.
- Model reliability depends on data quality and on how well the model captures the real system, so predictions carry uncertainty.
Remote sensing
Remote sensing collects data from a distance, mainly using satellites and aircraft.
- It covers large and inaccessible areas efficiently and repeatedly.
- It tracks changes such as land clearing, vegetation health, water extent, algal blooms and sea-surface temperature.
- It complements ground-based monitoring, which provides detailed local measurements that calibrate the remote data.
Monitoring: repeated measurement of a resource over time. Baseline: the reference condition before change. Indicator: a measurable variable representing resource health. Model: a simplified representation used to predict behaviour. Remote sensing: collecting data from satellites or aircraft. Adaptive management: adjusting decisions as new data arrives.
Putting it together: adaptive management
The three tools form a cycle. Monitoring measures the current state, models predict the outcome of options, a management decision is made, and continued monitoring checks whether the prediction held. If it did not, the decision is revised. This adaptive management cycle lets managers respond to uncertainty and change, and it operates across scales, from a single mine site or aquifer, to a regional fishery, to global monitoring of forests and oceans.
For a managed resource, name a suitable indicator and baseline, state how you would monitor it (field measurement or remote sensing), explain how a model would predict the resource's response to a management option, and describe how repeated monitoring would feed back to adjust the decision. Showing the full adaptive cycle earns the marks.
How remote sensing actually works
It helps to know the principle behind remote sensing. Sensors on satellites and aircraft measure electromagnetic radiation reflected or emitted by the surface across different wavelength bands. Healthy vegetation strongly reflects near-infrared light, so combining infrared and visible bands into a vegetation index lets analysts map plant health and detect clearing or drought stress over whole regions. Thermal bands measure surface temperature, used to track sea-surface temperature and bushfire hotspots, while specific bands reveal water turbidity and chlorophyll, allowing algal blooms to be mapped. Because satellites revisit the same area regularly, change can be measured automatically over years. The trade-off is resolution: broad coverage often means coarser detail, which is exactly why ground truthing with field measurements is needed to calibrate and verify what the imagery shows.
- Confusing monitoring and modelling
- Monitoring measures the present; modelling predicts the future.
- Treating model predictions as certain
- They depend on data quality and simplifying assumptions.
- Forgetting remote sensing needs ground truth
- Field data calibrate and check satellite data.
- Leaving out the feedback loop
- Adaptive management revises decisions as new monitoring data arrives.
Exam-style questions
Questions in the style of SCSA exam questions on this dot point, each with a worked answer. They are written by ExamExplained unless tagged "Past paper"; the year shows the paper a question is modelled on.
WACE 2022-style6 marksBore monitoring of the Gnangara Mound shows the water table has fallen by an average of 0.3 metres per year over 20 years. Explain how monitoring, modelling and remote sensing together could be used to manage this groundwater resource sustainably.Show worked answer →
A 6 mark answer should weave the three tools into a management response to the data.
- Monitoring
- The bore network establishes the baseline and the falling trend (0.3 m per year over 20 years equals about a 6 m decline), distinguishing real depletion from seasonal variation and quantifying the problem.
- Modelling
- A groundwater model uses this data to predict how the water table would respond to different extraction rates and rainfall scenarios, so managers can test what abstraction limit would halt the decline before acting.
- Remote sensing
- Satellite data tracks vegetation health and surface-water extent across the whole mound and detects land clearing that affects recharge, complementing the point measurements from bores.
- Together
- Monitoring measures, modelling predicts a sustainable yield, a reduced abstraction limit is set, and continued monitoring checks whether the decline stabilises, revising the limit if not (adaptive management).
Markers reward use of the data, a distinct role for each tool, and the adaptive feedback loop.
WACE 2020-style6 marksExplain why model predictions used in resource management always carry uncertainty, and discuss how monitoring helps manage that uncertainty.Show worked answer →
A 6 mark answer needs sources of model uncertainty plus the role of monitoring.
Why uncertainty. A model is a simplified representation of a complex system, so it cannot capture every process. Predictions depend on the quality and length of the input data, on assumptions built into the model, and on uncertain future drivers such as rainfall, climate and economic demand. Errors in any of these propagate into the prediction.
Role of monitoring. Continued monitoring tests model predictions against reality: if the measured outcome differs from the prediction, the model and its assumptions can be refined and the management decision revised (adaptive management). Monitoring also improves the data the model is built on, narrowing uncertainty over time, and provides early warning if a system behaves outside the modelled range.
Markers reward at least two genuine sources of uncertainty and a clear explanation that monitoring validates and refines models within an adaptive cycle.