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Modelling species level water requirements

Summary

Species level environmental water requirements are more nuanced than traditional discharge only flow rules. The hydrological requirements often need to occur in conjunction with other environmental drivers such as temperature or rainfall. Further, the requirements often have spatial dependencies such as longitudinal connectivity requirements to access refuge habitat for recruitment.

4 min read

Author: Zach Marsh

Environmental water requirements for species are nuanced

Environmental water requirements are typically captured as season, magnitude, duration, timing and count. This is entirely appropriate for considering the water requirements of ecosystems like wetlands. However, for an individual species, the water requirements are more nuanced. Consider the Mary River turtle, which requires bank wetting conditions (rainfall) suitable for egg laying, followed by periods of flow stability suitable for the eggs to develop and hatch within the aestivation period.

Eco Risk Projector provides a scalable platform for capturing and reporting complex habitat models

Eco Risk Projector is a web-based modelling tool, with a python-based computation platform that is designed to allow the rapid creation of species level flow-habitat models. To date, we have developed over 30 different models to capture habitat requirements at a single site and to combine these across sites. Habitat requirements are not limited to discharge, but often also include temperature, depth, rainfall and evaporation.

The python-based computation is open-source and can be used stand alone as a command line tool. The Eco Risk Projector web application delivers this computation via a highly scalable service which allows even the most complex models to be computed quickly and robustly. The models available are summarised below.

Flow assessment
Plugin	Description
Oversupply	For elevated flow conditions (also available in eFlow Projector).
Lowflow	For low flow conditions (also available in eFlow Projector).
Freshes	For high and intermediate flow conditions (also available in eFlow Projector).
Multiyear Freshes	For overbank flows that occur infrequently (also available in eFlow Projector).
Generalised and process models
Summary	Calculation of key flow metrics (mean, ARI, etc.)
Rating Curve	For habitat conditions defined by a continuous function related to flow
Low Flow Spawning Fish	Generic model for fish that spawn during stable low flow conditions
Offshore Reef Fishery	Based on a catch rate equation by Platten and Sawynok (2008) which relates annual freshwater flow to offshore reef catch rate
Waterhole model	For predicting the drawdown in a waterhole. Includes calibration (genetic algorithm) and run to empty tools.
Riffles	For predicting depth average velocity (and at depth velocity) based on discharge. Model contains 2 methods, the Abdulrahman (2017) width roughness method and the Dingman & Sharma (1997) cross section method.
Baseflow separation	Based on Lyne and Hollick (1979) digital filtering approach to separate hydrological data into baseflow and quickflow.
Colwells index	Calculate constancy, contingency and predictability based on the methods identified by Colwell (1974)
Spell analysis	Identify spell events in hydrological data and generate a number of summary statistics about the events.
Simultaneous spell analysis	Identify spell events that happen simultaneously across multiple sites in hydrological data and generate a number of summary statistics about the events.
Fish resilience through movement	Identify opportunities for fish to recolonise following period of no flow in intermittent streams.
Fish barriers and connectivity	Predict the frequency and duration of fish passage opportunities past barries in a river system.
Species specific water requirements
Ambassiz’s glassfish (Ambassis agassizii)	For identifying recruitment success for Ambassis agassizii, which spawn during stable low flow conditions in the Fitzroy River (QLD).
Banana Prawn (Penaeus merguiensis) Growth	Based on fisheries data that relates Banana Prawn growth to flow in the Fitzroy River (QLD).
Barramundi (Lates calcarifer) Growth	Based on a model by Halliday and Robins (2007) relating Barramundi growth to flow in the Fitzroy River (QLD).
Barramundi (Lates calcarifer) Juvenile Recruitment	Based on a model by Sawynok and Platten (2008) relating Barramundi juvenile recruitment opportunities to flow in the Fitzroy River (QLD).
Barramundi (Lates calcarifer) Year Class Strength	Based on a model by Halliday and Robins (2007) relating Barramundi year class strength to flow in the Fitzroy River (QLD).
Australian bass (Macquaria novemaculeata) spawning and juvenile movement	For identifying spawning events for Australian bass (flow, temperature, salinity and seasonal requirements). Based on coastal rivers south of the Mary River (QLD).
Carp Recruitment (Cyprinus carpio)	For identifying spawning events for Carp based on the frequency, duration and timing of over bank flows which fill floodplain wetlands.
King Threadfin Salmon (Polydactylus macrochir) year class strength	Based on a model by Halliday and Robins (2007) relating King Threadfin Salmon year class strength to flow in the Fitzroy River (QLD).
Leafy elodea (Egeria densa) growth and decay	For identifying the growth and decay of Leafy Elodea (using a rating curve approach) based on research in the Hawkesbury-Nepean River system.
Catfish (Tandanus tandanus) trigger for nest construction and egg survival	Based on research by Cockayne et al (2010), for identifying successful breeding events of Catfish.
Eastern snake-necked turtle (Chelodia lngicollis)	For identifying successful breeding events for Eastern snake-necked turtle, based on floodplain inundation and wetland dry out.
Northern snake-necked turtle (Chelodine oblonga)	Based on research in the Gulf plan area to identify the risk to Northern snake-necked turtle spawning due to unseasonal inundation.
Mary River cod (Maccullochella mariensis)	Based on research in the Mary River to determine spawning success of Mary River Cod, based on flow and temperature requirements.
Mary River turtle (Elusor macrurus) and White-throated snapping turtle (Elseya albagula)	Based on research in the Mary River to determine spawning success on Mary River turtle and White-throated snapping turtle, based on depth and rainfall requirements.

The Eco Risk Projector web application also stores flow data (including data preview and fixing tools), provides observed data fetching services, stores parameterised models (including version tracking) and visualises results (including all intermediate results).