Regional water resources assessments - Surface Water Management Area Lower Derwent

Regional Water Resource Assessment – SWMA

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Lower Derwent

Lower Derwent Surface Water Management Area is within Tasmania and is 1,611 km2

Results of the National Water Commission’s Framework for Assessment of River and Wetland Health for Lower Derwent SWMA

This page provides a summary of the results of the National Framework for the Assessment of River and Wetland Health (FARWH) for Lower Derwent water management area.

Table 1 Results of the National Framework for the Assessment of River and Wetland Health (FARWH) for Lower Derwent water management area

Component	Score	Notes
Biota	0.67	The Aquatic Biota Index provides a measure of the biological health of rivers using data on aquatic macroinvertebrates, native and exotic fish as presented in the Conservation of Freshwater Ecosystem Values Framework (CFEVF).
Catchment Disturbance	0.97	The Catchment Disturbance Index provides a measure of human caused changes that impact the river and wetland condition and the biota. For Tasmania the Catchment Disturbance Index is based the area of catchment land uses draining to a reach as presented in the CFEVF.
Hydrology Disturbance	0.83	The Hydrological Disturbance Index assesses the flow regimes change that result from river regulation and/or substantial flow diversion or extraction. For Tasmania the Hydrological Disturbance of rivers is based on the CFEVF data.
Physical Form		Physical Form was not presented for Tasmania because suitable data that met the requirements of the Framework for the Assessment of River and Wetland Health (FARWH) were not available.
Water Quality		Water quality assessment was not presented for Tasmania because suitable data meeting the needs of the FARWH were not available.
Fringing Zone	0.53	The Fringing Zone Index is a measure of the riparian vegetation condition as determined in the CFEVF.
Overall Score	0.7	The Overall Index for a Surface Water Management Area is a combination of the individual indices (Biota, Catchment Disturbance, Fringing Zone, and Hydrological Disturbance) to assess the overall health of the river. For Tasmania the indices are integrated at reaches using Euclidean Distance and weighted by reach length, then aggregated to give the overall Surface Water Management area score.

Figure 1 Results of the National Framework for the Assessment of River and Wetland Health (FARWH) for Lower Derwent water management area

Note: The ranges associated with the graph are described below.

Score	Condition
0.0-0.2	severely modified
0.2-0.4	substantially modified
0.4-0.6	moderately modified
0.6-0.8	slightly modified
0.8-1.0	largely unmodified

See the National Framework for the Assessment of River and Wetland Health (FARWH) report on the Publications page for details on the assessment method.

This page provides high level performance indicators of water management for the Lower Derwent surface water management area (SWMA) based on information provided by the government of Tasmania. It provides answers to a range of questions of relevance to the National Water Initiative (NWI), specifically in relation to:

Surface water management framework
Water resources caps
Surface water / groundwater interaction
Surface water sustainable yield
Environmental water requirements
Surface water diversions
Surface water entitlements
Protected terrestrial areas

Please note that a dash means that either the data was not available, not provided or that the question was not relevant for a particular area.

Surface water management area	Lower Derwent
Project ID	TAS_SW_20
Size of surface water management area	1,611 km²
NWC drainage division code	304.A
Drainage Division	Tasmania
State	Tasmania

Surface water management framework

What is the status of the water management plan for this surface water management area?	Statewide policy
If a final or draft plan has been written, what year was it completed?	-
If a final or draft plan has been written, does it consider groundwater explicitly?	-
If yes, how is groundwater considered?
Technical assessment	-
Management decisions	-
What percentage of the surface water management area is covered by the water management plan(s)?	-
Does your water plan specify water quality objectives to meet environmental and other public benefit outcomes?	-
Other items included in the management framework are:
Metering program for this area	-
Effluent recycling	-
Climate change	-
Aquifer storage and recovery	-
Household rainwater tanks	-
Efficient irrigation systems	-
Other	-
Management plan available at:

Water resource caps

Has a cap been placed on surface water usage / abstraction in this surface water management area?	Yes
Is the cap an absolute limit to allocation or provisional limit?	Provisional
If there is a cap, what year was it implemented?	2004
If there is a cap, is it considered to represent the sustainable surface water yield?	No
The following water usage types are included/not included under the cap:
Irrigation	Included
Urban supply	Included
Commercial / Industrial	Included
Minor catchment storages	Included
Minor on-stream storages	Included
Minor extracted water storages	Included
Stock and domestic	Not included
Mining / Oil and gas	Included
Forestry	Not included
Floodplain harvesting	Included
Drought supply	Included
Greywater use	Included
Effluent recycling	Included
Aquifer storage and recovery	Included
Does auditing of compliance with the cap occur?	No
Compliance report available at:

Surface water / groundwater interaction

Are surface water and groundwater managed as an integrated water resource in this surface water management area?	No
Reason or method:	Integration has not been assessed
Integrated management plan available at:

Surface water sustainable yield

The sustainable yield within this surface water management area for 2004/05 was:	Sustainable yield not assessed ML
The method used to determine the sustainable yield was:	Sustainable yield not assessed
Was the sustainable yield determined for the combined (i.e. surface water and groundwater) water?	Sustainable yield not assessed
Is the cap considered to be at or below the sustainable yield of surface water?	Sustainable yield not assessed
What is the level of entitlements relative to the sustainable yield?	Sustainable yield not assessed

Environmental water requirements

Have environmental water requirements been determined for this surface water management area?	Yes - complete coverage of water management area
If yes, what year were they completed?	2001
For regulated areas, how much of the mean annual flow is not available for allocation and provided for the environment? (percentage of mean annual flow at locality of river regulation)	100%
Are there formal environmental water provisions for regulated rivers?	No
If so, what method was used to determine environmental water provisions for regulated rivers?	-
For what percentage of the rivers are provisions made?	83%
Maps illustrating which rivers have provisions available at:
Do the environmental water provisions consider groundwater?	-
If yes, how?	-
Completed Environmental Flows Reports available at:

Surface water diversions

The total surface water diversion in the surface water management area for 2004/05 was:	<%DataBinder.Eval(Container.DataItem, "SSDVOLML_C", " {0} ML") %>
What percentage of surface water diversion is determined from metered data?	0 %
What is the level of diversions relative to the sustainable yield?	Unknown volumes or no data provided
For surface water diversion that is NOT metered, how was the surface water diversion determined for 2004/05?
Estimated from irrigated areas	No
Estimated from licence volume	Yes
Estimated from power usage for pumps	No
Estimated from models	No
Other	-

Surface water entitlements

Entitlements for surface water are required/not required for the following usage types:
Irrigation	Required
Urban supply	Required
Commercial / Industrial	Required
Minor catchment storages	Required
Minor on-stream storages	Required
Minor extracted water storages	Required
Stock and domestic	Not required
Mining / Oil and gas	Required
Forestry	Not required
Floodplain harvesting	-
Drought supply	-
Greywater use	-
Effluent recycling	-
Aquifer storage and recovery	-
Other	-

Protected terrestrial areas

Each of the following protection types cover a percentage of the surface water management area as detailed:
Habitat/species management area	-
Managed resource protected areas	2.94
National park	9.43
Natural monument	0.06
Protected landscape/seascape	-
Strict nature reserve	-
Wilderness area	-
Total	12.42

National Water Commission