Page Comparison

Introduction

The Environmental Demand Model (EDM) in Source operates on a daily basis generating demands and extracting water to meet these demands using the environmental demand and supply point node. This model is used to define environmental water requirements at the project set up phase and then applies a series of heuristic routines in order to define the water required to achieve the specified environmental water requirements. It can can be applied in both regulated and unregulated systems.

Info

icon	false

The EDM is modelled using the environmental demand node in Source. Refer to Environmental Demand node for details on configuring the node.

In Source, the environmental demand node is used to model environmental demand, which can be set up in two ways:

As an in-stream requirement (In-stream requirement); or
To act as a floodplain (Floodplain).

...

Table 1. Commonwealth Environmental Water Holder Framework for determining environmental watering actions 2009

...

	Extreme dry	Dry	Median	Wet
Ecological watering objectives	Avoid damage to key environmental assets	Ensure ecological capacity for recovery	Maintain ecological health and resilience	Improve and extend healthy and resilient aquatic ecosystems
Management objectives	Avoid critical loss of threatened species Maintain key refuges Avoid irretrievable damage or catastrophic events	Support the survival and growth of threatened species and communities including limited small scale recruitment Maintain diverse habitats Maintain low flow river and floodplain functional processes in sites and reaches of priority assets	Enable growth, reproduction and small-scale recruitment for a diverse range of flora and fauna Promote low-lying floodplain-river connectivity Support medium flow river and floodplain functional processes	Enable growth, reproduction and large-scale recruitment for a diverse range of flora and fauna Promote higher floodplain-river connectivity Support high flow river and floodplain functional processes
Management actions	Water refugia and sites supporting threatened species and communities Undertake emergency watering at specific sites of priority assets Use carryover volumes to maintain critical needs	Water refugia and sites supporting threatened species and communities Provide low flow and freshes in sites and reaches of priority assets Use carryover volumes to maintain follow-up watering	Prolong flood/high-flow duration at key sites and reaches of priority assets Contribute to the full-range of in-channel flows Use carryover to provide optimal seasonal flow patterns in subsequent years	Increase flood/high-flow duration and extent across priority assets Contribute to the full range of flows including over-bank Use carryover to provide optimal seasonal flow patterns in subsequent years
Key goal	Damage avoidance	Capacity for recovery	Maintained health and resilience	Improved health and resilience

...

The following assumptions are made when EDM is configured in Source:

Water requirements are not additive - A basic assumption used in the EDM is that environmental water is not consumed and, as such, flow rule water requirements for more than one environmental asset can potentially use the same water in accounting for the success of their flow rules being met. For example the minimum flow requirement for fish passage is not necessarily a separate parcel of water from the minimum flow required to prevent an algal bloom;
Flow rules can be co-dependent: A flow rule can be conditionally contingent on another flow rule also being met;
Flow rules should only be attempted if their requirements are likely to be met: The EDM determines the daily demand, however before passing the demand for this day, the EDM checks to see if the total water required to complete the rule is available; and
The highest priority environmental water demand is for environmental flow rules which have commenced but not yet completed. If an environmental flow rule has started to be met, then the continuation of meeting this flow rule requirement has precedence over commencing water ordering to meet a new flow rule.

...

Versions Compared

Old Version 10

New Version 11

Key

Introduction

Table 1. Commonwealth Environmental Water Holder Framework for determining environmental watering actions 2009