1
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