BIG models using Source to model 5 000

BIG models- using Source to model 5, 000 farm dams e. Water Source conference 1 st December 2020 Katherine Szabo Dr Phillip Jordan, Dr Keirnan Fowler, Ella Guthrie

Overview § Background ▫ Farm dam modelling ▫ Case study § Model development ▫ Challenges ▫ Tips and Tricks § Model verification § Scenario modelling 01/12/2020 2

Farm dam modelling STEDI/CHEAT § Farm dams typically lumped for subcatchments § Assumes even spatial distribution of runoff across catchment § Back-calculation algorithm to calculate natural flows Farm dam assumptions in STEDI (SKM, 2011) 01/12/2020 3

Farm dam modelling e. Water Source § Individually represent each farm dam with spatial distribution § Target individual dams with management strategies § Model the chainage of farm dams more accurately than a lumped model § Integrate catchment and river systems modelling § Environmental flow compliance analysis at different locations along farm dam impacted watercourse § Climate change modelling of farm dam impacts § Tools available to increase modelling efficiency 01/12/2020 4

Case study: Seven Creeks catchment § Part of the Murray-Darling Basin § Flows into the Goulburn River § ~5, 000 farm dams What is the most effective management strategy to maximise autumn and summer low flows, by reducing the impact of farm dams? 01/12/2020 5

Seven Creeks catchment 01/12/2020 6

Model development Derive partial natural inflows DELWP farm dam distribution layer 10 m Digital Elevation Model 01/12/2020 STEDI back calculation algorithm Natural inflows for each subcatchment Climate and demand Farm dam model in e. Water Source Tau. DEM process in Arc. GIS e. Water Source Farm Dam Plugin 7

Model development 01/12/2020 8

Model development 01/12/2020 9

Model development: challenges § Spatial analysis § Processing time and power required for farm dam plugin § Run time for ~5, 000 farm dams § Ensuring all farm dams are correctly distributed by the DEM and connected by up the Farm Dam Plugin 01/12/2020 10

Model development: Tips and Tricks! § Copy and paste function in Source § Linked analysis § Export summary to check linkages 01/12/2020 11

Model development: Tips and Tricks! § Scenario input sets for climate change modelling 01/12/2020 12

Model development: Tips and Tricks! § Feature tables for easy update of farm dam configuration 01/12/2020 13

Verification results FDC verification at Seven Creeks at Kialla West 01/12/2020 14

Scenario modelling Management options: § Decommissioning § Low flow bypasses Target individual farm dams: § Top 5% by total upstream catchment area § Top 5% by farm dam volume § Top 5% by location 01/12/2020 15

Scenario modelling 01/12/2020 16

Scenario modelling § Unimpacted flow scenario showed impact of farm dams in catchment § Impact of farm dams on cease to flow events § Environmental flow compliance assessment § Impact of climate change on farm dam impacts 01/12/2020 Low flow compliance during drought years 17

Groundwater springs contribution § 100% baseflow supplied by groundwater springs § Decommissioning or bypassing of farm dams based on location downstream of groundwater springs 01/12/2020 18

Summary § e. Water Source used to model 5, 000 individual farm dams § Model integrates both catchment and river system modelling § Able to use to efficiently undertake scenario modelling to determine effective management strategies § Utilise for climate change modelling 01/12/2020 19

Katherine Szabo Email: katherine. szabo@harc. com. au Ph: 0437 340 015 01/12/2020 20