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DEVELOPMENT OF FUTURE MANAGEMENT OPTIONS FOR THE HAWKESBURY RIVER

Associate Professor Bruce Simmons, Dr Uthpala Pinto, Dr Jennifer Scott and

Professor Basant Maheshwari University of Western Sydney, NSW, Australia, Ku-ring-gai Council, Sydney, NSW, Australia.

The Hawkesbury River StoryA history of development, impact and response.

Development

River Impacts

Community Concerns

Community Responses

Outcomes

Evaluation

Sydney’s Population Growth (based on Flood 2003 and ABS 2013)

1750 1800 1850 1900 1950 2000 2050 21000

1000000

2000000

3000000

4000000

5000000

6000000

7000000

Year

Population

Development and River Impacts.

The Hawkesbury River – Development PatternsTime Flow Development Activity

1793-50

Flood till 1820 drought

Early European Settlement

Food Production, River Transport, Macquarie Towns

1850-1900

Flood Opening up of Catchment

Road, Rail, Clearing, Farming, Grazing

1900-1950

Drought Water Supply Dam Building,Irrigation

1950-1990

Flood Growth of Sydney

Instream Aggregate Extraction

1990- Drought Expansion of Sydney

Urbanisation

The first 22 farms on the Hawkesbury River, 1794 (in Barkley & Nichols, 1994, attributed to University of Sydney Cartography).

The Settlement on Green Hills, Hawkesbury River, NSW 1809(watercolour attributed to George William Evans. Original held at State Library of NSW)

Land Clearing (Pictorial History Hawkesbury Publ.)

The Purple Noon’s Transparent Might (a painting of Freemans Reach by Arthur Streeton 1896. Original held by the

National Gallery of Victoria

Dam Building 1900-1960 Warragamba Dam Sydney Morning Herald February 10, 2008. photo: Anthony Johnson.

www.smh.com.au/.../2008/02/09/1202234227091.html

DredgingMean depth of the Hawkesbury River (SPCC 1984)

Riverbank collapse at North Richmond 1967(photo RAAF Richmond, in Barkley & Nichols 1994)

River Bank Collapse at WindsorCouncillor Ted Books WISER Community Consultation Presentation 2007

Nutrient Pollution. Ortho-phosphorus concentrations

Hawkesbury River in the 1940s and 1979–81 (SPCC 1983)

Blue-green algal bloom at Windsor (SPCC 1984)

Egeria densa beds in the Nepean River (photo Simmons 1996)

Responses of the Hawkesbury River to Human Activity

Time Activity Response Indicators1893-1850

Farming, River trade

Bank erosion NavigationBank collapse

1850-1900

LandClearance

Extensive siltation

Navigation Shoaling

1900-1950

Dams, irrigation.

Flood scouring, reduced flows

Bank collapse. Flow records.

1950-1990

Extraction STW eff.

Bank scouring, WQ, ecology

Change in Depth Increased nutrients

1990- Urban Dev Recreation

Turbidity, Nutrients.

Aquatic weed problems

Community concerns and responses.

A Chronology of Community Concerns

These include: River bank clearance 1800s • Silting and navigation issues 1880s• Sewage Pollution (Health) 1900s• Turbidity 1930s• Noxious weeds 1940s• Algal Blooms (Blue Green) 1980s• Weed Blooms 1990s

Hawkesbury River First Recorded Management Response (1803)

Recent actions to improve waterway quality of the Hawkesbury River include:

Policies/Acts/RegulationsSydney REP No. 20-Hawkesbury-Nepean River (No. 2-1997)

Hawkesbury-Nepean River Act 2009 No. 14 (repealed 2012)

Hawkesbury-Nepean Catchment Management Trust Regulation (1999-2003)

Catchment Management Authorities Act 2003

Recent actions to improve waterway quality of the Hawkesbury River include:

Organisations Established1983 Joint Councils Hawkesbury River Committee1989 Nepean-Hawkesbury River Catchment Management Committee1993 Hawkesbury-Nepean Catchment Management Trust2006-2011 Office of Hawkesbury-Nepean

2011-2013 Hawkesbury Nepean CMA now part of Sydney CMA

Recent strategies/programs to improve waterway quality of the Hawkesbury River include:

1986 Nutrient Removal Program - (MWS&DB)1996 Phosphorus Action Program HNCMT1997 Erosion & sediment control program HNCMT

2001 Strategic Management Plan for the H-N Catchment & River System. (By HNCMT).2006 River restoration project. HNCMT. (Erosion, bank restoration)2007 H/N Catchment Weed Management Strategy OHN2009 Hawkesbury Nepean River Recovery Program. OHN2012-2023 Hawkesbury-Nepean Catchment Action Plan. HNCMA

Outcomes

Control of Nutrient Pollution

1940 1950 1960 1970 1980 1990 2000 2010 20200

0.5

1

1.5

2

2.5

3

3.5

4

Nutrient Data, Wilberforce mg/l (CSIRO, SPCC, SCA)

Nitrogen Total (mg/L) Phosphorus Total (mg/L)

Control of Nutrient Pollution

1940 1950 1960 1970 1980 1990 2000 2010 20200

5

10

15

20

25

30

35

40

45

50

Suspended Materials, Wilberforce (SPCC, SCA)

Chlorophyll-a (ug/L) Suspended Solids (mg/L)

Summary

Time Event Response Status

1793-50

Bank Clearance

Collapse Continuing

1850-1900

Catchment Clearance

Sedimentation Largely Stable

1900-1950

Dam Construction

Bank ErosionFlow impact

Status quo

1950-1990- 2030-

Urban Growth Sewage PollutionUrban Runoff

Controlled?

Expanding

Post-European settlement of Sydney. Department of Planning and Infrastructure (2006). ‘Draft Sydney Metropolitan Strategy 2006’).

Pre 1917. 1917-1945. 1945-76. 1976-2005. 2005-

Conclusions• Responses in waterway condition can be linked

to catchment activities and actions to improve river health.

• Many actions or management practices have not been or are not capable of assessment.

• The development of a framework to assess future management proposals for protection and remediation is recommended.

• This should include: 1. capability of benefit cost assessment 2. investigation of legal rights for the river .

Thankyou