Channel erosion and deposition is a natural process for creeks of all sizes. However in many urban areas, land use change and development put extra pressure on local creeks. There are a number of general rules to help maintain a natural balance of erosion and deposition.
Maintain riparian vegetation
Plants growing on the banks and in the channel are important for stability. Any area not modified with hard engineering, must have a stable, established ground cover covering the banks to minimise erosion and deposition downstream.
Maintain trailing plants and woody debris
Where fallen branches or growing plants accumulate in a creek, try to avoid removal. These features slow water flow and decrease its erosion potential. In some circumstances, these features can become flood hazards or cause localised scour, which may threaten infrastructure assets. In these cases, the debris may need to be removed. This should be discussed with Council to assess the risk and action.
Use "soft engineering" to stabilise channels
In certain circumstances it may be necessary to stabilise an eroding channel through re-grading the banks, adding vegetation and/or strategically placing natural features such as logs.
Works of this kind that require any re-engineering or contouring of the creek bank should be designed and constructed by qualified professionals and have a development application. Superficial works such as re-vegetation or other surface erosion controls may be carried out without a development application. Contact us if you are unsure if your planned works are suitable.
Use "hard engineering" to stabilise channels
"Hard engineering" includes works such as rock lining, channel re-alignment and/or other significant work which is sometimes required to stabilise a channel. These works should always be designed and constructed by qualified professionals and require a DA.
Any significant work within a channel must be in accordance with the Riparian and Water Management controls in Council’s relevant Development Control Plan.
Outlet protection
Sound engineering design requires extra protection at pipe and culvert inlets and outlets. A range of energy dissipaters can be used, including rough surfacing, basins, large protruding structures and graded spillways. Any of these structures should be designed by a qualified engineer using suitably sized natural materials and constructed in a manner that complements the receiving environment.
Further information can be found in the fact sheet guidelines for controlled activities - outlet structures from the Department of Water and Energy.
Water quality monitoring
Council undertakes biannual water quality monitoring of these waterways to track conditions and alert to any influencing factors up stream.
Steep terrain and ridge-top development have led to the major flood risk within Ku-ring-gai resulting from flash flooding along headwater streams and drainage depressions. Ku-ring-gai’s flood risk management program is based on the requirements of the NSW Floodplain Development Manual and Flood Prone Land Policy.
The primary objective is to allow the appropriate use of flood prone land while reducing the impact of flooding and flood liability on individual owners and occupiers of flood prone property and to reduce the private and public losses resulting from floods.
Current studies
Lane Cove Northern Catchments Flood Study
Ku-ring-gai Council has recently received funding for the Lane Cove Northern Catchments flood Study through the NSW Government Floodplain Management Program grants 2020-21.
The study area includes Coups Creek, Water Dragon Creek, Peppermint Creek, Avondale Creek and Quarry Creek as well as smaller tributaries of Lane Cove River.
These waterways are in the suburbs of Wahroonga, Warrawee, Turramurra, South Turramurra, Pymble and West Pymble.
For more information about this study please read the community newsletter(PDF, 2MB).
Middle Harbour Northern Catchments Flood Study
Council has received funding for the Middle Harbour Northern Catchments flood study through the NSW Government Floodplain Management Program grants 2019-20. The catchment area includes Middle Harbour Creek (and associated tributaries) in St Ives and Rocky Creek (including Stoney Creek and High Ridge Creek) in Gordon/East Killara which flow into Middle Harbour. This flood study commenced in 2020 with the draft report expected in 2022.
For more information about this study please read the community newsletter(PDF, 2MB).
Middle Harbour Southern Catchments Flood Study
Council has received funding for the Middle Harbour southern catchments flood study through the NSW Government Floodplain Management Program grants 2018–19. The Middle Harbour Southern Catchments Flood Study area consists of five catchments. These include Echo Point and Moores Creek in Roseville, “Wellington Road” and Gordon Creek in Lindfield and “Northern and Southern Creeks” in Killara, all flowing into Middle Harbour.
For more information about this study please read the community newsletter(PDF, 220KB).
Flood Risk Management Committee
This advisory group is the first formal step in the floodplain risk management process.
They act as both a focus and forum for the discussion of technical, social, environmental, cultural and economic issues during the development of flood studies and flood risk management plans. Its membership consists of representatives from Council (elected representatives and staff), relevant government agencies including Office of Environment and Heritage, National Parks and Wildlife Service NSW, Sydney Water and the State Emergency Service, as well as representatives from the local community.
Council’s Floodplain Risk Management Committee (established in 2015) is currently overseeing implementation of the floodplain risk management process for sub-catchments in the LGA, in partnership with the NSW Office of Environment and Heritage.
There are currently 6 community representatives on the committee in addition to Chair Deputy Mayor Barbara Ward and Deputy Chair Councillor Greg Taylor. Community representatives for each term are nominated following the Council elections.
Meetings of the Committee are held as required. Meeting agendas and minutes are published on Council's website.
Please read the Terms of Reference(PDF, 229KB).
Completed studies, reports and mapping
Blackbutt Flood Risk Management Study and Plan
Blackbutt Creek Flood Risk Management Study and Plan was completed in August 2016.
This report builds on the findings from the Blackbutt Creek Flood Study (2014) and outlines measures to mitigate flooding including land use planning, community awareness, flood warning and infrastructure changes and upgrades.
Blackbutt Creek Flood Risk Management Study Report(PDF, 445KB)
Preliminary Floodplain Management Measures(PDF, 3MB)
Floodplain Risk Management Plan and References(PDF, 50KB)
Appendix A Locality Plan, Pipe Network and Vulnerable Locations
Appendix A Locality Plan(PDF, 2MB)
Appendix A Pipe Network Capacity(PDF, 4MB)
Appendix A Vulnerable Locations(PDF, 2MB)
Appendix A Emergency Response Classification Maps
Appendix A AEP Emergency Response Classification Maps(PDF, 7MB)
Appendix A PMF Emergency Response Classification(PDF, 4MB)
Appendix A Flood Risk Precinct 20% & 5% AEP
Appendix A Flood Risk Precinct Maps 20% AEP Proposed True Hazard Classification(PDF, 5MB)
Appendix A Flood Risk Precinct Maps 5% AEP Proposed True Hazard Classification(PDF, 5MB)
Appendix A Flood Risk Precinct 1% and AEP
Appendix A Flood Risk Precinct Map 1% AEP Proposed True Hazard Classification(PDF, 5MB)
Appendix A Flood Risk Precinct Map PMF Proposed True Hazard Classification(PDF, 5MB)
Appendix A Flood Modification Options
Appendix A Flood Modification Mitigation Options(PDF, 5MB)
Appendix B Assessment of Changes in the Blackbutt Creek Catchment
Appendix B Assessment of Changes in the Blackbutt Creek Catchment(PDF, 3MB)
Appendix C Draft Flood Planning Matrix – Appendix D Sensitivity Memorandum
Appendix C Draft Flood Planning Matrix(PDF, 39KB)
Appendix D Sensitivity Memorandum(PDF, 189KB)
Appendix D Sensitivity Memorandum Map(PDF, 5MB)
Blackbutt Creek Flood Study
The Blackbutt Creek Flood Study is the first of a series of detailed flood studies to be undertaken in Ku-ring-gai. This study used historical information, landscape survey, stormwater pipe data and computer modelling techniques to indicate areas likely to be impacted by flooding. The original Flood Study was completed in December 2014.
Final Report Blackbutt Creek Flood Study, Appendix A- B Community Consultation Survey and Summary
Final Report Blackbutt Creek Flood Study – Appendix A – B Community Consultation Survey and Summary(PDF, 4MB)
Appendix C- Flood Depth Mapping
Appendix C – Flood Depth Mapping(PDF, 10MB)
Appendix D- Flood Level Mapping, Appendix E- Summary of Peak Flows, Appendix F- Hydraulic Categories Mapping
Appendix D Flood Level Mapping – Appendix E Summary of Peak Flows – Appendix F Hydraulic Categories Mapping(PDF, 9MB)
Appendix G- Provisional Flood Hazard Mapping
Appendix G Provisional Flood Hazard Mapping(PDF, 6MB)
Appendix H - Flood Planning Area Mapping, Appendix I- Preliminary Flood Emergency Response Classification of Communities, Appendix J- Climate Change Impact Mapping
Appendix H Flood Planning Area Mapping – Appendix I Preliminary Flood Emergency Response Classification of Communities – Appendix J Climate Change Impact Mapping(PDF, 5MB)
Lovers Jump Creek Flood Study Review Report
The Lovers Jump Creek Flood Study Review Report (2018) was adopted by Council in November 2018.
Lovers Jump Creek Flood Study Review Report 2018
Lovers Jump Creek Flood Study, November 2018
Final Report(PDF, 2MB)
Appendix A- Historic Rainfall Data, Appendix B- Community Consultation, Appendix C- Questionnaire Responses and Verification of Model Flood Behaviour, Appendix D- Flood Depth Mapping
Appendix A - D(PDF, 5MB)
Appendix E- Flood Level Mapping, Appendix F- Summary of Peak Flows
Appendix E - F(PDF, 3MB)
Appendix G- Hydraulic Categories Mapping, Appendix H- Provisional Flood Hazard Mapping, Appendix I- Flood Planning Area Mapping, Appendix J- Preliminary Flood Emergency Response Classification of Communities
Appendix G - J(PDF, 6MB)
Appendix K- Climate Change Impact Mapping, Appendix L- Impacts of ARR 2016 and At-Site Design Rainfall on Flood Behaviour
Appendix K - L(PDF, 3MB)
Lovers Jump Creek Flood Risk Management Study and Plan
Council completed the Lovers Jump Creek Floodplain Risk Management Study and Plan in June 2019. Options such as land use planning, community awareness, flood warning and infrastructure changes and upgrades have all been investigated.
Lovers Jump Creek – Final Floodplain Risk Management Study and Plan
Lovers Jump Creek Flood Risk Management Study and Plan -Table of Contents and Forward Information(PDF, 6MB)
Lovers Jump Creek Flood Risk Management Study and Plan - Page 1 - 48(PDF, 5MB)
Lovers Jump Creek Flood Risk Management Study and Plan - Page 49 -91(PDF, 10MB)
Lovers Jump Creek Flood Risk Management Study and Plan - Page 92-131(PDF, 2MB)
Appendix A- Flood Mapping – Sensitivity to Recent Catchment Changes
Lovers Jump Creek Flood Risk Management Study and Plan - Appendix Part A(PDF, 5MB)
Appendix B- Flood Planning Mapping, Appendix C- Community Consultation
Lovers Jump Creek Flood Risk Management Study and Plan - Appendix B Part 1(PDF, 6MB)
Lovers Jump Creek Flood Risk Management Study and Plan - Appendix B Part 2(PDF, 4MB)
Lovers Jump Creek Flood Risk Management Study and Plan- Appendix B Part 3 & Appendix C(PDF, 4MB)
Appendix D- Emergency Response Mapping
Lovers Jump Creek Flood Risk Management Study and Plan - Appendix D(PDF, 9MB)
More information
Email floodriskmanagement@krg.nsw.gov.au or call Sophia Findlay, Water and Catchments Program Leader on 9424 0853.
Household stormwater drainage systems
Property owners must maintain the stormwater system from their house, garage and other structures to the kerb and gutter or other approved discharge point.
Maintenance of a property stormwater drainage system may include removing build-up of leaves and debris in gutters and drains, repairing holes in roof gutters and downpipes, removing blockages in pits and stormwater lines and repairing and replacing damaged sections of stormwater pipes. A plumber or other suitably licensed contractor will need to be contacted to undertake repairs.
Regular maintenance and the removal of leaves are required to help prevent blockages and the deterioration of the stormwater drainage system. Damaged and deteriorated stormwater drainage systems can result in the surface flow of stormwater over the property creating a nuisance or flooding.
When Council can take action
Council investigates and takes action on stormwater drainage complaints only where it relates to the flow of surface water from one property across the common land boundary onto another property, and where all of the following criteria is met:
- surface water is the result of defective roof drainage from a dwelling or outbuilding;
- evidence is provided that substantiates the surface water has caused or is likely to cause physical damage to land or building on the other land;
- surface water has been directed to and/or concentrated in a particular area by a man-made structure or drain.
Natural overland flow of rain water
Rain water may run off areas like gardens and bushland because of factors such as the slope of the land, the volume of rain, presence of rock shelves and the ability of the soil to absorb rain water. If you reside on a sloping site, you should be aware that natural surface water run-off flows down the slope following the contours of the block.
Property owners are responsible for taking steps to protect their own property against the natural overland flow of rain water. Any diversion of natural overland flow must be carried out in a way that does not have detrimental impacts on other properties. A licensed plumber or other suitably qualified contractor should be engaged to carry out any works.
Seepage water
Natural underground water is a common cause of seepage, particularly after periods of heavy rain. Seepage can often be seen where sloping blocks have been excavated to obtain a flat yard, through retaining walls and rock shelves and may continue for many days following rain.
It is not the responsibility of uphill property owners to control natural seepage water. Downhill property owners are responsible for protecting their own property if affected by seepage. This can be achieved through installation of subsoil drainage. Subsoil drains are intended for the drainage of ground water or seepage from the subgrade and/or the subbase in excavations. Advice should be sought from a qualified civil/hydraulic engineer and a licensed plumber or other qualified contractor should be engaged to carry out any works.
Private Inter-allotment drainage easement
Private inter-allotment drainage easements and their maintenance are the responsibility of the respective beneficiaries of the drainage easement. There can be many properties burdened and benefitted by a private inter-allotment drainage easement and the on-going maintenance and any necessary repairs needs to be co-ordinated between all of the responsible property owners.
If there is a drainage easement on your property, it will be identified on the certificate of title, provided when you purchased the property. Inter-allotment drainage records are held by NSW Land Registry Services and additional information about private drainage easements and how to obtain further records is available here.
When Council can’t take action
Officers have the discretion to take no action or are unable to take action in circumstances where:
- the surface water is natural run-off from the property or properties above due to the topography and isn’t redirected in any manner
- the water is subsurface seepage or water seepage as a result of ground water
- overflow occurs due to exceedance of the design capacity of an approved drainage system in extreme rainfall events
- the drainage problem involves private inter-allotment drainage easement infrastructure
- the location of a dwelling or outbuilding impacts on surface run-off
- surface water is a result of overflows from stormwater absorption pits where contours of land and lack of access prevent direct connection of a building’s roof water to the council’s stormwater drainage system
- the run-off is from new development work that is the subject of a development consent and has been constructed in accordance with that consent.
For emergency help in flood events, contact the State Emergency Service on 132 500.
If your concern is of a nature that Council can't assist with, the NSW Government's Community Justice Centres may be of help. These centres provide free, confidential mediation and conflict management.
Steps to take before lodging a complaint
You should try to contact your neighbour before taking formal steps to report a concern about the overflow of stormwater. Be tactful when bringing the concern to your neighbours notice as they might not realise there is a problem. In order to maintain neighbourly relations it could be beneficial to discuss the problem directly and enable your neighbours to undertake works such as clear blockages and engage plumbers to resolve the matter without involving Council in the process.
When reporting a stormwater drainage concern on private land, please provide the following information:
- what is occurring;
- when it occurred and on how many past occasions;
- what is happening on the neighbouring property to cause the overflow;
- how your land and/or building are being damaged and if possible include a written report from a hydraulic engineer, licensed plumber or other suitably qualified person stating the land or building is likely to or is being damaged;
- what discussions you have had with your neighbour about the issue;
- photographs and/or videos of the stormwater overflow as it is occurring.
To report a concern contact us on 9424 0000 or krg@krg.nsw.gov.au.
Household wastewater systems
The majority of homes within Ku-ring-gai are connected to Sydney Water’s sewer main system. Sewer mains are owned and maintained by Sydney Water and convey household wastewater from bathrooms, toilets, kitchens and laundries to wastewater treatment plants.
Property owners are responsible for the maintenance of the private wastewater pipes on their properties up to the connection point to the sewer main. The connection point is not always at the property boundary and it may be under the footway, roadway or across the street. More information about maintenance of private wastewater lines is available on Sydney Water’s website.
If there is a blockage or overflow at your property, you should contact a licensed plumber. Sewer service diagrams show private sewer pipes on a property and are available through Sydney Water’s Tap In online service.
If you notice a wastewater leak in a public area such as on a road, park or footpath, you can report a leak online to Sydney Water or by calling them on 13 20 90 or send an email with details of the location and a photograph to faults@sydneywater.com.au.
If your home is not connected to a Sydney Water sewer main, you may have an on-site wastewater management system, such as a septic tank, composting toilet or aerated system.
There are special regulations that apply to these systems. As the owner of the property, it is your responsibility to ensure that the system has been approved by your local council and that it is working properly.
Council approval is required for all on-site wastewater management systems. To install a new system you will need to obtain two approvals from Council.
WaterNSW has more information for home owners about on-site wastewater management systems.
Our Nature Play programs offer weekly nature-themed activities, designed to develop curious minds and playful spirits. They involve a fun morning of play-based investigation and discovery in nature led by our experienced Environmental Ranger:
Bouncing into the year of the rabbit: Hop on into the Wildflower Garden to dig around and discover all about what makes this years Lunar New Year animal twitch. This year is the year of the Rabbit.
Wetland wonderland: Come explore our amazing wetland environments and learn about the special creatures that live there.
Bush chefs: It’s time to fire up the BBQ for some cooking inspired by native bush tucker plants.
Yoga in nature: Let’s get inspired by the trees dancing on the breeze and the lounging lizards at the Wildflower Garden for some fun kids’ yoga.
Clean up the garden day: Get involved with Clean Up Australia Day at the Wildflower Garden by cleaning up in unexpected places and getting crafty with rubbish!
Bush walk adventure: Get ready for a big bush walk to our favourite park where we’ll play some games and discover new places.
Mini rangers: Our animals need lots of care and attention to help them stay happy and healthy. We’ll learn how to feed, handle and care for our animal friends.
A home among the gum trees: It’s Eucalypt Day and we aim to celebrate the important place that these iconic trees hold in our hearts by discovering who calls them home and seeing which ones we can identify.
Autumn colours: Did you know there are native deciduous trees? We’ll discover the changes plants and animals go through during this pivotal season.
The Easter hunt: Join our rangers for a journey as we hunt for clues and fill our baskets with surprising facts about our favourite Aussie animals.
Activities cost $20 per child with one parent/carer admitted free of charge. All activities are COVID-19 safe and bookings are essential as spaces are limited. For more information visit our Nature Play page.
Benefits of Nature Play
Nature play significantly improves all aspects of early childhood development – physical, cognitive, social and emotional. Playing outdoors in nature grows resilience, self-confidence, initiative and gross-motor skills.
Ku-ring-gai Wildflower Garden
Set on 154 hectares of urban Sydney Sandstone bushland at St Ives and adjacent to Ku-ring-gai Chase National Park, Ku-ring-gai Wildflower Garden boasts some of Sydney’s best Wildflower trails, Duffys Forrest and Coastal Upland Swamp as well as 18 threatened species of Australian Flora and Fauna and 2 endangered ecological communities providing learning experiences in the natural environment.
Our Nature Play programs offer weekly nature-themed activities, designed to develop curious minds and playful spirits. They involve a fun morning of play-based investigation and discovery in nature led by our experienced Environmental Ranger:
Lunar New Year: Join the Festivities of the Chinese New Year with lanterns, games and a traditional treat.
Leaf litter critters: It’s time for a bug hunt. Let’s see what creatures we can find amongst the leaf litter.
Day time and night time: While we’re asleep in bed, other creatures are coming out to play. What nocturnal creatures do you know?
The little seed: Plants are so clever! We’ll learn about all the ways plants move their seeds around without taking a single step!
Nature heroes: Let’s get involved in Clean Up Australia Day! We’ll be sorting and learning all about rubbish to find out what’s the big deal.
Teddy bear's picnic: To celebrate Parks Week, we will roll out the rug in our favourite spot at the Wildflower Garden and enjoy stories, songs, and picnic goodies with our favourite Teddy Bear.
Grug and the grass tree: Everyone loves Grug! We’ll be reading our favorite Grug stories and learning all about the grass trees he came from.
Water play: For World Water Day we’ll have some wet and watery fun and learn lots of ways to save this precious resource.
Room on the broom: We will be reading Julia Donaldson’s Room on the Broom and taking an adventure through the Wildflower Garden.
The Easter bilby: A time to celebrate these gentle, shy creatures that inhabit the Australian bush. Come on an Easter Hunt of a different kind!
Activities cost $20 per child with one parent/carer admitted free of charge. All activities are COVID-19 safe and bookings are essential as spaces are limited. For more information visit our Nature Play page.
Benefits of Nature Play
Nature play significantly improves all aspects of early childhood development – physical, cognitive, social and emotional. Playing outdoors in nature grows resilience, self-confidence, initiative and gross-motor skills.
Ku-ring-gai Wildflower Garden
Set on 154 hectares of urban Sydney Sandstone bushland at St Ives and adjacent to Ku-ring-gai Chase National Park, Ku-ring-gai Wildflower Garden boasts some of Sydney’s best Wildflower trails, Duffys Forrest and Coastal Upland Swamp as well as 18 threatened species of Australian Flora and Fauna and 2 endangered ecological communities providing learning experiences in the natural environment.
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Ku-ring-gai spans three of Sydney's major catchments, encompassing 171km of creeks. Most creeks remain in a semi-natural/natural condition in private easements, parkland and bushland reserves.
Council participates in two Coastal Management Program (CMP) projects, setting the long-term management strategy for our coastal environments.
Waterways plans and policies
Our Water Sensitive City Policy and Strategy have both recently been updated and work together to enhance the liveability of Ku-ring-gai. They provide a framework for responding to the issues of water conservation and security, flooding, degradation of urban waterways, ecological health and rising temperatures in a way that enhances the liveability of Ku-ring-gai.
Water Sensitive Cities Policy(PDF, 352KB)
Water Sensitive Cities Strategy(PDF, 11MB)
Water monitoring
Our staff are actively testing various waterways throughout Ku-ring-gai. View more information on the results.
Wetland communities
Ku-ring-gai has two important wetland endangered ecological communities which are important natural features within our catchments.
Water pollution
If you notice water pollution such as sediment, paint or chemicals in a local waterway or see someone dumping rubbish or garden waste into or near a waterway call Council 9424 0000 or email krg@krg.nsw.gov.au.
If you notice sewerage in a waterway or overflowing from any infrastructure, contact Sydney Water on 13 20 90.
Get involved
For only an hour a month you can volunteer your time to help collect environmental data in our local waterways.
Find out more about Streamwatch.