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SURFACE WATER HYDROLOGY OF THESURFACE WATER HYDROLOGY OF THERINGAROOMA RIVER CATCHMENT

Bryce GrahamDepartment of Primary Industries, Parks, Water and Environment

Ringarooma catchmentgCatchment area of ~922 km2

Originates in Mt Maurice

Major upper catchment inputsfrom Dorest, New, Cascade, Weld, Frome , Wyniford ,Maurice and Ledgerwood

Minor Tributary input from Amber, Ruby & Marsh Creeks, y

Department of Primary Industries, Parks, Water and Environment

Ringarooma catchment Rainfall and Evaporation

Rainfall Range 600 to 1800mmRainfall Range 600 to 1800mm

Mean Annual Rainfall is 1100 mm

i h i iHighest regions occur in Dorsetupper reaches of Ringaroomaand Cascade catchmentsand Cascade catchments

~67% of region lies within>=1100 mm

Department of Primary Industries,Parks, Water and Environment


5 year moving average indicatesaverage indicates a general decreasingrainfall trend

Last 15 years, 10 years have beenyears have beenbelow AAR of 1100mm

Evaporation remainedconstant ~ 1000mmPer year.



Distinct seasonalpattern throughoutthe catchment

Rainfall generallyRainfall generally exceeds evaporation during the months ofgApril to September

North of the catchmentreceives less rainfall than southern regionthan southern region


Ringarooma Stream Flow MonitoringFlow Monitoring

Majority of historical sitesrecords are for short periodsrecords are for short periods

Moorina site only long termsite suitable for historical Flow analysis

Cascade site only other site with >10 yrs record.with 10 yrs record.

2 new sites at Ledgerwoodand Branxholm installed 2008


Stream Flow CharacteristicsStream Flow Characteristics

Ri Ri @ C d Ri /Statistic

Ringarooma River@ Moorina

Cascade River u/s Cascade Dam

Annual Ave Flow (ML/Day) 741 52( / y)

Annual Ave Volume (ML) 270643 18924

Mi i A l A V l (ML) 128235 11974Minimum Annual Ave Volume (ML) 128235 11974

Maximum Annual Ave Volume (ML) 398861 29500


Stream Flow Characteristics Ringarooma @ Moorina Annual Yield (ML)Ringarooma @ Moorina Annual Yield (ML)

450000

Ringarooma @ Moorina Annual Yield (ML)

350000

400000

450000

Ringarooma @ Moorina Annual Yield (ML)

Annual Average (ML)

250000

300000

ield

(ML)

mate

150000

200000

Ann

ual Yi

Esti

0

50000

100000

0

Year


Rainfall Reminder

Text


Stream Flow Characteristics Ringarooma @ Moorina Monthly Volume (ML)Ringarooma @ Moorina Monthly Volume (ML)


Stream Flow Characteristics Flow Duration

Flow duration curve of the monthly mean flow at Ringarooma River @ Moorina


Stream Flow Characteristics Floodingg


Stream Flow Characteristics Flooding


Estimating flow forungauged areasungauged areas

Only 3 current gauges

Cover Ledgerwood and Ringarooma, no other areag

Estimates required ford hun‐gauged catchments

Hydrological model allowsHydrological model allowsestimates of yields in un‐gauged catchments


RingaroomaH d l i l M d lHydrological Model


Hydrological Model Calibration1Poor, R2<0.65; Fair, 0.65<R2<0.70; Good, R2>0.70

Calibration Period (Year)

Coefficient of Determination (R2)

Performance Rating

1978 2009 0 83 G d1978 – 2009 0.83 Good2009 0.93 Good2005 0.89 Good1995 0 83 Good1995 0.83 Good1985 0.77 Good

Poor R2<0 65;Poor, R2<0.65; Fair, 0.65<R2<0.70; Good, R2>0.70


Modelled Yields @ Moorina GaugeModelled Yields @ Moorina Gauge

Gauged Annual Average Flow (ML)

Modelled Current Annual Average Flow @ Moorina (ML)

Last 10 yrs average

252461 237365

Last 10 yrs 257637 231837

ymedian

257637 231837


Modelled Catchment Yields


Distribution of Yields in the Ringarooma Catchment

Specific Yields (ML/km2)

Area (km2) Summer Winter Annual

Ringarooma Catchment 922 89 360 449

Wyniford 61 103 359 461

Weld 51 164 576 740

Cascade 39 89 384 473

Legerwood 60 92 466 558

Dorset 120 144 566 709

Upper Ringarooma 146 131 613 744


Climate Changeg

Two major projects for Tasmania to establish potential impact of Climate Change on water resourcesof Climate Change on water resources.

CSIRO Tasmanian Sustainable Yields Project, released jDecember 2009 and

ACE CRC Cli F f T i P j d lACE CRC Climate Futures for Tasmania Project, staged release of reports started, Water and catchments in final review.


Climate Changeg

CSIRO Tasmanian Sustainable Yields Project

The sustainable yields project modelled four climate impact scenarios across the Ringarooma catchment. The main gobjective of this scenario modelling was to estimate changes in flows in river systems. The four scenarios modelled were:


Climate Changeg

Scenario A: historical climate (1 January 1924 to 31 December 2007) and current development2007) and current development

Scenario B: recent climate (data from 1 January 1997 to 31 ( yDecember 2007 were concatenated to make an 84‐year sequence) and current development

Scenario C: future climate (84‐year sequence scaled for ~2030 conditions) and current developmentconditions) and current development

Scenario D: future climate (84‐year sequence scaled for ~2030 conditions) and future development.


Climate ChangegScenario A Scenario B Scenario

CwetScenario Cmid

Scenario Cdry

GL/Year Percentage change relative to Scenario A

Inflows

From catchment runoff

464.5‐17% (386.4)

‐4% (445.9)

‐9% (422.7)

‐14% (399.5)

runoff

From flows downstream of na na na nahydro schemes

Total (inflows) 464.5 ‐4% ‐9% ‐14%

Source: Ling etal 2009.


Climate Changeg

Mean monthly end‐of‐system flow and daily flow duration curves under scenarios P, A and Csce a os , a d


Climate ChangeFuture Development

entire Pipers‐Ringarooma region projected to increase byprojected to increase by approximately 147 km2 from 2528 km2; 6% incfrom 2528 km2; 6% inc by 2030

Pipers‐RingaroomaCatchment wide 25% to 27% in 203027% in 2030


Climate Changeg

Assessing the impact of this increase in the RingaroomaAssessing the impact of this increase in the Ringarooma catchment under a median future climate showed the end of systems flows to reduce by 1.3% relative to Scenario C mid, y ywhich has the potential to reduced the access to water for extraction by 2.5%.


Summary

High rainfall regionMajor contribution to flow from upper Ringaroomacatchments Predictable flow regime with distinct seasonal signalRelatively high base flowModel developed to establish yield estimates in un-gauged

i f t h tregions of catchmentFuture climate shows potential reduction in yields out to 2030 9% under a mid future climate scenario2030, ~9% under a mid future climate scenarioThe impact of climate change and future forestry has potential to reduce end of system flows by a further ~1 3 %potential to reduce end of system flows by a further ~1.3 % compared to Tas SY scenario C mid.


References

DPIPWE (2010). Surface Water Hydrology of the Ringarooma River Catchment. Water Assessment Hydrology Report Series, Report No. WA 10/11 Water and Marine Resources Division, Department of Primary Industries, Parks, Water and Environment, Hobart, Tasmania.

Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, Post DA and Marvanek S (2009) River modelling for Tasmania. Volume 3: the Pipers‐Ringarooma region. A report to the Australian Government from the CSIRO Tasmania S i bl Yi ld P j CSIRO W f H l h C Fl hi A liSustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Australia.

HEC 2005. NAP Region Hydrological Model Ringarooma Catchment. Report 118784‐2. Hydroelectric Corporation: Hobart, Tasmania.

Website: www.dpiw.tas.gov.au/water


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