Namoi ecological Hydrological Response Variables (HRVs)

## **Abstract** 

The dataset was derived by the Bioregional Assessment Programme from multiple datasets. The source dataset is identified in the Lineage field in this metadata statement. The processes undertaken to produce this derived dataset are described in the History field in this metadata statement.



Ecologic Hydrologic Response Variables (HRVs) are the hydrological characteristics of the system that are instrumental in maintaining and shaping ecological services and can potentially change due to coal resource development. These data refer to the ecologic HRVs for the Namoi subregion for the 54 simulation nodes.  The nine ecologic HRVs were computed under CRDP and Baseline conditions, respectively and the ACRD is the difference between the Baseline and CRDP.

The nine ecologic HRVs are as follows:



1. FR1 = R0.3 This is the volume of flow that is assumed to result in the over-bench flow. It is defined as the peak daily flow in flood events with a return period of 3 times per year as defined from the modelled flow in the reference period (1983-2012).  This HRV contributes to the variable SFLR.



2. FR2 = (R3.0) This is a volume of flow that is assume to result in "over-bank" flow.  It is defined as the peak daily flow in flood events with a return period of once every three years as defined from modelled flow in the reference period (1983-2012). This HRV contributes to the variable SFLR.



3. FR3_NumberofDays (Low flow, days)  The mean number of days per year with "low" streamflow during a thirty year period.  The low streamflow is defined as any modelled streamflow below 1 ML/d.  It is assumed to represent minimum flow that is sufficient to flow of riffle and gravel bar structures and thereby maintain connectivity between pool habitats within streams.



4. FR3_Max_Spell Maximum spell of low flow days.



5. FR3_Mean_Spell  Mean spell of low flow days.



6. VOBF (Volume of overbank flow) = Cumulative daily streamflow in excess of the overbank threshold over the duration of an event. Overbank flow is defined as a daily streamflow with an event return period of 1 in 3 during the historical simulation period.



7. ZF_NumberofDays= The mean number of days per year with "zero" streamflow during a thirty year period.  The zero streamflow is defined as any modelled streamflow below 0.1 ML/d.



8. ZF_Max_Spell Maximum spell of zero flow days.



9. ZF_Mean_Spell Mean spell of zero flow days.

## **Purpose** 

This is the dataset used for the receptor impact modelling to evaluate additional coal mine and coal resource development impacts on receptors at 54 simulation nodes.

## **Dataset History** 

The description of how the resource was created can be found in a readme file in the dataset itself.

## **Dataset Citation** 

Bioregional Assessment Programme (2017) Namoi ecological Hydrological Response Variables (HRVs). Bioregional Assessment Derived Dataset. Viewed 11 December 2018, http://data.bioregionalassessments.gov.au/dataset/d2da0bc3-2eb8-408b-9d12-13f5c1d6d683.

## **Dataset Ancestors** 

* **Derived From** [Historical Mining Footprints DTIRIS NAM 20150914](https://data.gov.au/data/dataset/fb0a43f1-9022-4844-b5b5-b91f72a1d9f9)

* **Derived From** [Namoi AWRA-R model implementation (post groundwater input)](https://data.gov.au/data/dataset/8681bd56-1806-40a8-892e-4da13cda86b8)

* **Derived From** [Namoi AWRA-L model](https://data.gov.au/data/dataset/0d58109a-f3b3-4f3a-9bc0-f8d8398d4da8)

* **Derived From** [Namoi Environmental Impact Statements - Mine footprints](https://data.gov.au/data/dataset/493a47cd-4228-4dec-bb72-bcf4495fa306)

* **Derived From** [Namoi Surface Water Mine Footprints - digitised](https://data.gov.au/data/dataset/fa0a0d09-3780-498a-a412-242b25130291)

* **Derived From** [River Styles Spatial Layer for New South Wales](https://data.gov.au/data/dataset/06fb694b-d2f1-4338-ab65-a707c02f11d7)

* **Derived From** [National Surface Water sites Hydstra](https://data.gov.au/data/dataset/f7edc5e5-93ee-4527-bed5-a118b4017623)

* **Derived From** [Namoi AWRA-R (restricted input data implementation)](https://data.gov.au/data/dataset/04fc0b56-ba1d-4981-aaf2-ca6c8eaae609)

* **Derived From** [Namoi Hydstra surface water time series v1 extracted 140814](https://data.gov.au/data/dataset/10fc9dd2-fc95-4357-86f1-c59e69678c5c)

* **Derived From** [GEODATA 9 second DEM and D8: Digital Elevation Model Version 3 and Flow Direction Grid 2008](https://data.gov.au/data/dataset/ebcf6ca2-513a-4ec7-9323-73508c5d7b93)

* **Derived From** [Namoi Existing Mine Development Surface Water Footprints](https://data.gov.au/data/dataset/d4875816-4184-4579-8194-8aff6efe7d9a)



Tags: Namoi subregion, inlandWaters
Organization: Bioregional Assessment Program