- Bioregional Assessment Program
- Assigning receptors to water-dependent assets
A large part of this submethodology is superseded by advances in methods for the bioregional assessments (BAs). Specifically, there is now no need to either generate receptors as spatial points across the landscape or to collate them into a receptor register. Instead, receptors are addressed spatially by the asset and landscape class spatial features (polygons, lines and points) and covered conceptually through the development of the landscape classes (product 2.3 (conceptual modelling)), the causal pathways (product 2.3 (conceptual modelling)) and the receptor impact modelling (product 2.7). They are then assessed spatially during the impact analysis using a regular grid of assessment units. Potential impacts on receptors are reported in aggregate via landscape class and asset profiles in product 3-4 (risk and impact analysis) and delivered as spatial datasets at data.gov.au.
As a consequence there is no requirement for a BA to produce a point-based receptor dataset or a receptor register. However, Chapter 3 of this submethodology is still relevant to conducting a BA as it refers to the conceptual basis and criteria for assigning receptors, which informs the relationship between receptors and other parts of the BA process. Chapter 3.2 provides the basis and approach to BA landscape classification, which is then applied to produce the landscape classes in product 2.3 (conceptual modelling).
This submethodology provides a framework for assigning receptors in a subregion or bioregion for each bioregional assessment (BA) in a complete, efficient and representative manner that is fit for purpose and in accord with high standards of professional scientific practice. It defines receptors; outlines the role that receptors play in the broad context of a BA; and describes the documentation and development of the receptor register required for each BA.
A receptor is a point in the landscape where water-related impacts on assets are assessed.
The process of assigning the location of receptors is the primary mechanism for focusing a BA on the location of potential water-related impacts associated with coal resource development and for addressing risks to ecological, economic and sociocultural water-dependent assets within the subregion or bioregion. While the process is highly interdependent with other BA activities, it is important to note that this submethodology initially focuses on the preliminary placement of the receptors across the subregion or bioregion. The receptors will be subsequently updated with further information produced by other BA activities. For example, identification and refinement of critical relationships and impacts for each receptor will occur during the conceptual modelling and receptor impact modelling in Component 2: Model-data analysis.
Each receptor is a unique entity. It has coordinate attributes in two dimensions, latitude and longitude. Information and data can be recorded at a receptor including depth-related information. The coordinate attributes are recorded in the receptor register. The receptor register is a simple and authoritative list of receptors in a specific bioregional assessment. The list includes a unique identifier, the location of each receptor and the relevant landscape class. For BA purposes, a landscape class is an ecosystem with characteristics that are expected to respond similarly to changes in the groundwater and/or surface water due to coal resource development. Note that there is expected to be less heterogeneity in the response within a landscape class than between landscape classes. They are present on the landscape across the entire BA subregion or bioregion and their spatial coverage is exhaustive and non-overlapping. Conceptually landscape classes can be considered as types of ecosystem assets, which are ecosystems that may provide benefits to humanity and are spatial areas comprising a combination of biotic and abiotic components and other elements which function together. The receptor register, when finalised, is stored as a spatial dataset in the Bioregional Assessment Repository and a snapshot extract may be obtained at any particular point in time in spreadsheet format – for example, for publication purposes.
The process for compiling the receptor register is described in this submethodology (broadly illustrated in Figure 7). In broad terms, receptors are selected to be representative of, and linked to, assets in the water-dependent asset register and the potential impacts upon them. A number of methods can be employed to achieve this end and they are described in this submethodology. To ensure that the distribution of receptors across the landscape captures the impacts of potential coal resource development within the subregion or bioregion, receptors also need to be defined with reference to the coal resource development pathway (CRDP) and hazard analysis. Where there is limited or no additional coal resource development in the CRDP, receptors are generally only required to be allocated for defined landscape classes (described in Section 3.2). In other cases, receptors may already be available from pre-existing work.
Given the potential for very large numbers of assets within a subregion or bioregion, a landscape classification approach is used to reduce the complexity of the task of assigning receptors across the landscape while retaining the information necessary for the assessment. The rule set for defining the landscape classes is underpinned by an understanding of the geology, geography, ecology and hydrology (surface water and groundwater) of the subregion or bioregion. Different subregions and bioregions might use different landscape classes. The landscape classification improves the efficiency in defining the required conceptual models for multiple assets and in the subsequent assignment of:
- hydrological response variables, the hydrological characteristics of the system that potentially change due to coal resource development (for example, drawdown or the annual streamflow volume)
- receptor impact variables, the characteristics of the system that, according to the conceptual modelling, potentially change due to changes in hydrological response variables (for example, condition of the breeding habitat for a given species, or biomass of river red gums).
Once the preliminary distribution of receptors within the subregion or bioregion has been determined, receptors are linked to the assets and landscape classes via causal pathways defined by the conceptual modelling and the receptor impact modelling activities of Component 2: Model-data analysis. This is to ensure that the distribution of receptors is complete and representative of the subregion or bioregion’s assets. Each receptor may be associated with more than one asset and, as some assets are very large, each asset may be associated with more than one receptor. At this stage, gaps or biases in the distribution of receptors across assets can be assessed. If needed, additional receptors can be assigned to address these gaps or receptors removed where redundancies exist.
The process of assignment and distribution of receptors within a subregion or bioregion must be conducted in consultation with ecology, hydrology, hydrogeology and risk discipline experts working on the BA. They also must be assigned according to the guiding principles outlined in this submethodology (Section 3.1), which require that the placement of receptors is representative, efficient and complete.
Product 1.4 (description of the receptor register) summarises the landscape classification and point to the reasoning and evidence used to select the location of the receptors given the relevant knowledge available about the subregion or bioregion (noting that the conceptual models that underpin this reasoning are documented in product 2.3 (conceptual modelling) and product 2.7 (receptor impact modelling), whereas the landscape classification is presented in full in product 2.3 (conceptual modelling)). The preliminary receptor register should be reviewed by relevant domain expertise and those with local knowledge to enable feedback and clarification on the receptor placement, landscape classification, conceptual models and, when known, hydrological response variables and receptor impact variables. After this, any changes, such as additional receptors, can be incorporated into the preliminary receptor register and an updated receptor register produced.
Once the receptor register is compiled, the BA progresses to assess potential impacts of coal resource development on receptors found within water-dependent assets.
METHODOLOGY FINALISATION DATE
- 1 Background and context
- 2 Defining receptors
- 3 Assigning receptors
- 3.1 Overview of process for assigning receptors
- 3.2 Landscape classification
- 3.3 Process for assigning receptors across the landscape
- 3.3.1 Hydrological response variables and receptor impact variables
- 3.3.2 Spatial distribution of receptors across the landscape
- 3.3.3 Criteria for evaluating receptor assignment
- 3.3.4 An example of surface water receptors for the Namoi subregion
- 4 Developing a receptor register
- Contributors to the Technical Programme
- About this submethodology