Stormwater Harvesting
The video tells the story of Orange’s pioneering and award-winning stormwater harvesting system.
Water experts knew that urban areas produce much more water run-off than rural environments. But could the water be ‘cleaned-up’ so that it could make a useful contribution to a regional city’s water needs? That was the challenge taken on and explored by Orange City Council in the wake of a record drought.
The water which runs through Orange’s stormwater channels, to be harvested in different ways, has become an integral part of the city’s water supply.
Blackmans Swamp Creek Stormwater Harvesting Scheme
The Blackmans Swamp Creek stormwater harvesting scheme is the first large scale, indirect-to-potable stormwater harvesting project in NSW, if not Australia.
This project is capable of providing around 1300 ML of additional water into the Orange’s raw water supply each year from the city’s stormwater system, meeting around 25% of the city’s total water needs.
Orange’s journey with stormwater harvesting began in the wake of the Millenium drought.
Water flowed over the spillway of Orange’s main water storage dam, Suma Park Dam, in late 2005. But, continued dry conditions in the following years and well below average run-off led to the city’s water storages dropping to levels never previously encountered. By late 2007 the storages were below 40% and forward rainfall projections were less than positive. At their lowest levels in August 2008 the storages reached 26.7.%
Prompted by the scale of the crisis, Orange City Council began to explore a number of options to develop alternative sources of water, but a key prospect was stormwater harvesting.
This project evolved from concept to operational reality within 18 months at a cost of $5 million involving extensive consultation with the community and government authorities and detailed analysis to satisfy concerns about the safety, reliability and capacity of the scheme.
At the same time, the Council began investigating a range of options aimed at both reducing water consumption as well as investigating opportunities for developing new water supplies.
At the outset, the approach taken was not just to apply a short term solution to get through the current emergency in the hope that it would rain again and the problem would go away. In contrast, it was recognised that a much more long-term strategic solution was necessary.
This package of responses included a range of demand management and system operating solutions such as :
- best practice pricing,
- water restrictions,
- education programs,
- water loss improvement strategies,
- working with high water users to reduce their water use and
- installing water efficient devices across the city.
As a consequence of these and other initiatives, water usage in Orange dropped to less than 4390 ML in 2008, a drop of around 38% from the high of 2002.
A range of measures were also investigated during this time with the aim of sustainably adding to the city’s water supply. These included investigating new sources of groundwater and re-connection to the city’s old water supplies.
From these origins, Orange now has two stormwater harvesting systems, based around two local creeks.
Blackmans Swamp Creek
The basic concept of the Blackmans Swamp Creek stormwater harvesting system involves capturing a portion of the high flows in Blackmans Swamp Creek during storm events, and transferring these into the nearby Suma Park dam to add to the city’s water supply.
Harvesting stormwater emerged as a viable option because of :
- the close proximity of Blackmans Swamp Creek to Suma Park dam,
- the availability of key existing infrastructure and
- the very high level of water quality treatment that was able to be provided by Council’s main water filtration plant at Icely Road, which treats the raw water from Suma Park Dam.
This water quality treatment included ozone treatment to destroy pathogens and biologically-activated carbon filtration to consume the remnants of the compounds destroyed by the ozone.
The high likelihood of flows in Blackmans Swamp Creek was also a key element. This creek runs through the urban environment of Orange, and because of the roads, footpath, car parks and other sealed surfaces in this catchment area, reliable runoff occurs after every rainfall event.
A key tool to assist in the consultation process was the development of the Review of Environmental Factors (REF) for this project, which included a series of operating rules to provide a clear outline of how the project will work. These involve :
- establishing flow trigger points when harvesting could begin,
- maintaining base flows,
- and establishing ongoing stakeholder engagement once the project became operational.
Water quality
A critical issue throughout the development of this project was the need to ensure the harvested stormwater mets the appropriate standards of the Australian Drinking Water Guidelines. This was achieved through the creation of many barriers within the water supply system to eliminate possible contamination.
Orange City Council worked closely with key state authorities, such as
- NSW Health,
- the Department of Environment and Climate Change (DECC) and
- Department of Water and Energy (DWE), including conducting a two day Hazard and Critical Control Point Analysis (HACCP) workshop with representatives of these and other agencies.
The REF provided a comprehensive outline of the project, neatly summarising thousands of pages of analysis as well as clearly determining that the project would not cause undue impact to the downstream environment.
On the contrary, the work actually improved the existing situation through the removal of suspended solids via a series of Gross Pollutant Traps (GPTs), as well as reducing peak flow levels, thus reducing the likelihood of erosion and damage during high flow events.
The public reaction to drinking harvested stormwater was also tested through a series of community consultations, including on-line surveys where the predominant response was not one of concern about water quality but of urging Council to get on with the work as soon as possible.
The first stage can deliver 1300 megalitres annually. Orange’s long term average water usage has been around 7000 megalitres a year. However in recent years, thanks to efficiency measures and education programs, this has fallen to below 5000 megalitres annually.
Council has broken new ground in the development of this large scale, direct-to-potable stormwater harvesting project. Given the current focus on innovation in managing the security of urban water supplies, it is the right project for its time.
It has been developed from idea to reality within a very short space of time while giving proper consideration to the necessary legislative, environmental and community consultation processes. The project demonstrates that with support, local government can use local resources to solve local problems.
The Scheme was officially opened by the NSW Minister for Water, Phillip Costa on 27 August 2009.
Ploughmans Creek Stormwater Harvesting Scheme
Orange City Council is pursuing an integrated package of both structural and non-structural programs to help secure the City’s water needs. The Ploughmans Creek Stormwater Harvesting Scheme is one of these initiatives and follows on the heels of the multi award winning Blackmans Swamp Creek Stormwater Harvesting Scheme. This scheme will transfer a portion of the storm flows from the Ploughmans Creek catchment into Suma Park Dam where it will supplement the City’s raw water supplies.
Urban development, through the creation of impervious surfaces, provides a valuable resource in terms of certainty of stormwater generation. Urban development in the Ploughmans Creek catchment has increased the average volume of runoff by 880ML per year. Available data indicates that the quality of this water compares favourably with typical values for an urbanised catchment.
A drier future, albeit with more extreme storm events, makes stormwater harvesting from an urbanised catchment a sensible option to consider. The challenge is to adaptively manage the scheme’s use so that the downstream impact is not significant and that the needs of downstream users and the aquatic environment are not compromised. The urbanisation of the Ploughmans Creek catchment, compared to its natural condition, has generated additional stormwater runoff. The harvesting scheme, as proposed, has been designed and will be operated to capture and use this extra runoff.
The Ploughmans Creek stormwater harvesting scheme was constructed and will operate without risk of serious or irreversible damage; without degrading the health, diversity and productivity of the environment for future generations; and without jeopardising biological diversity or ecological integrity.
The Review of Environmental Factors (REF) placed on public exhibition in November/December 2009 concludes that the construction and operation of the scheme is unlikely to result in a significant adverse environmental impact.
The Ploughmans Creek Stormwater Harvesting Scheme comprises four (4) wetlands to provide stormwater quality and quantity controls and two (2) small V-notch weirs and associated pumps to pool and harvest stormwater flows. The average volume harvesting by the scheme under current catchment conditions is estimated at 700ML/year however, when the catchment is fully developed this is estimated to increase to an average of 800ML/year.
Wetlands
The wetlands that are part of this scheme are the Somerset Park wetlands, the Cargo Road wetlands, Burrendong Way wetlands and The Escort Way wetlands.
Somerset Park Wetlands
All planting of the wetlands has taken place with the following plants, but due to the Orange climate, all plants are currently dormant and Council is looking forward to spring when these plants emerge and flourish, greatly enhancing the appearance of the wetlands and surrounds.
Wetlands Planting Information
Ecotone Zone 1
Lomandra longifolia, Pennisetum alopercuroides
Ecotone Zone 2
Gahnia sieberiana, Juncus usitatus, Juncus aridicola, Poa labillardieri
Fringing Zone
Baumea articulata, Bolboschoenus fluviatilis, Phragmites australis
Mudflat Zone
Carex appressa, Carex fascicularis, Juncus aridcola, Juncus usitatus
Deep Water Zone
Ottelia ovalifolia, Eleocharis sphacelata
Download the Overview Plan and Review of Environmental Factors (REF)
Floodplain Management Plan
The NSW Government’s Flood Policy is directed at providing solutions to existing flooding problems in developed areas, and ensuring that new developments are compatible with the flood hazard and do not create additional flooding problems in other areas. Under the Policy, the management of flood prone land remains the responsibility of local government. To facilitate this, the Government provides funding in support of floodplain risk management programs.
The policy provides for a floodplain risk management system comprising the following sequential stages:
- Flood Study – Determines the nature and extent of the flood problem.
- Floodplain Risk Management Study – Evaluates management options for the floodplain with respect to both existing and future development.
- Floodplain Risk Management Plan – Involves formal adoption by Council of a plan of management for the floodplain.
- Implementation of the Plan – Involves construction of flood mitigation works, where viable, to protect existing development. – Uses planning controls to ensure that future development is compatible with flood hazards.
- Review of Plan – Review of plan to ensure it remains current and appropriate. A review is normally carried out after 10 years.
Orange City Council is responsible for local planning and land management in the Blackmans Swamp Creek floodplain. Council proposes to develop a floodplain risk management plan in accordance with the NSW Floodplain Development Manual (2005).
Floodplain Risk Management Community Committee
Floodplain risk management plans are formulated under the guidance of the Floodplain Risk Management Community Committee (FRMCC) which was formed by Orange City Council in March 2000 and consists of representatives from Council, State Government agencies, the local community and Central West Catchment Management Authority. The charter of the FRMCC is to identify the main issues affecting the floodplain and progress the preparation of a management plan to address any identified flood problems.
Study Area
The Blackmans Swamp Creek floodplain affects a significant proportion of the urban area of the city of Orange including the CBD. The city of Orange is located in the Central West of NSW about 260 km west of Sydney. The study area comprises the waterways and adjacent low lying lands of Blackmans Swamp Creek and its tributaries including Rifle Range Creek and the East Orange Creek and adjoining floodplains.
Some development within the catchment including the CBD is prone to flooding with potentially high hazard and damage. Large floods in recent history occurred in 1984 and 1999.
Objectives
The overall objective of the study is to develop a floodplain risk management plan for the study area that addresses the existing, future and continuing flood problems, in accordance with the NSW Government’s Flood Policy, as detailed in the NSW Floodplain Development Manual. It is envisaged that the study will be undertaken in 2 stages as indicated below.
Floodplain Risk Management Study
The objectives of the floodplain risk management study are listed as follows:
- Examination of the relationship between Council’s current flood policy and strategy with Council’s environmental planning policies and instruments (including Council’s long-term planning strategies for the Blackmans Swamp Creek floodplain) and identifying any conflicts. Identified conflicts are to be addressed and strategies developed.
- Examination of the present level of flood awareness and current evacuation plans in the context of the NSW State Emergency Service’s developments and disaster planning requirements.
- Facilitation of a public consultation program to ensure effective community consultation and participation throughout the study.
- Recommend appropriate flood planning levels.
- Identification of works, measures and restrictions aimed at reducing the social, environmental and economic impacts of flooding and the losses flooding caused by development and the community, both existing and future, over the full range of potential flood events. Council is looking for innovative solutions to the management of the flood hazards in the Blackmans Swamp Creek floodplain with an emphasis on planning options and that can be integrated in the Land use Strategy as part of the review of Council’s LEP.
- Assessment of the effectiveness of these works and measures which may reduce the effects of flooding on the community and development, both existing and future.
- Consideration of whether the proposed works and measures might produce adverse effects (environmental, social, economic, or flooding) in the floodplain and whether they can be minimised.
- Identification of modifications that are required to current policies in the light of investigations.
Floodplain Risk Management Plan
The objectives of the floodplain risk management plan are listed below:
- Reduce the flood hazard and risk to people and property in the existing community and to ensure future development is controlled in a manner consistent with the flood hazard and risk.
- Reduce private and public losses due to flooding.
- Protect and, where possible, enhance the river and floodplain environment.
- Be consistent with the objectives of relevant State policies, in particular, the Government’s Flood Prone Lands and State Rivers and Estuaries Policies and satisfy the objectives and requirements of the Environmental Planning and Assessment Act, 1979.
- Ensure that the floodplain risk management plan is fully integrated with Council’s existing corporate, business and strategic plans, existing and proposed planning proposals, and policies that meet Council’s obligations under the Local Government Act, 1993 and has the support of the local community.
- Ensure actions arising out of the management plan are sustainable in social, environmental, ecological and economic terms.
- Ensure that the floodplain risk management plan is fully integrated with the local emergency management plan (flood plan) and other relevant catchment management plans.
- Establish a program for implementation and a mechanism for the funding of the plan and should include priorities, staging, funding, responsibilities, constraints, and monitoring.
Preparation of the Floodplain Risk Management Study and Plan
Lyall and Associates Consulting Water Engineers have prepared the Draft Floodplain Risk Management Study and Plan and submissions from the public have been received. These were considered in the compilation of the final report which was adopted by Council on 1 October 2009.
Blackmans Swamp Creek Floodplain Risk Management Study and Plan – Vol 1
Blackmans Swamp Creek Floodplain Risk Management Study and Plan – Vol 1 Pt 2
Blackmans Swamp Creek Floodplain Risk Management Study and Plan – Vol 2
Stormwater Management Plan
The Stormwater Management Plan for the City of Orange aims to develop a coordinated stormwater management system to improve water quality within the urban catchment of Orange. The Plan provides detail on the catchment, historical water quality monitoring, current issues and strategies for addressing identified issues.
The implementation strategy is intended to ensure that management options are carried out according to the vision and aspirations of the community and stakeholders.
Stormwater Management Plan - Appendix A
Stormwater Management Plan - Appendix B and C
Sections of the East Orange stormwater channel are currently being upgraded in a long-term project. These images show progress.
Orange’s network of stormwater drains and channels are a major, usually unseen infrastructure asset. This network is made up of around 233 kilometres of storm drains and channels.
The location of each part of this network is shown on the map below.
Zoom-in to the Orange locality to find a channel near you. The locations of the stormwater pipes are approximate only. If you need more detailed information please contact Council. Engineering staff for further details.
Ploughmans Valley & North Orange Dual Water Scheme
This is an important initiative which aims to reduce consumption of drinking water in the Ploughmans Valley & North Orange area by 40%. Instead of using drinking-water, residents can use stormwater collected from the city’s wetlands to irrigate gardens and flush toilets.
This Fact Sheet answers a range of questions from – can I give the water from the purple tap to my pets? Can I wash the car using the purple tap water? Or can I use it to fill the swimming pool?
All houses in the Ploughmans Valley & North Orange area built since 2005 are required to be equipped with a ‘dual water’ plumbing system. Beginning at the distinctive purple-coloured water meter at the front of your property, your house is designed to have two sets of plumbing: one that supplies water to toilets and outdoor taps, and one for all other uses (drinking taps, hot water, washing machines, showers, baths, etc).
Because of the drought, the NSW government gave Orange City Council permission to postpone connecting newly-built houses to the recycled water system until the storm water wetlands were constructed and a second set of water mains were completed.
