Floating Wetlands

Ropes Crossing – Floating Wetlands Project – Autumn 2019 Update

Our on-going project for Blacktown Council at Ropes Crossing continues to progress well. The aim of the project is to remediate the water quality in a stormwater pond which was being affected by sediment and nutrient runoff from the nearby developing urban catchment. We previously installed three 56m2 rectangle floating wetlands parallel to one another, in order to intercept the stormwater flows to the pond. Our coir matts have done an amazing job encouraging the bacteria and microorganisms that are the basis of healthy water bodies.

We visited the site on the 26th March 2019 to check on the project and perform some standard maintenance work The photos shows the typical plant growth for the first 10 months after installation following a Spring/Summer growing season. More information on our innovative floating wetlands service can be found here.

Floating Wetlands

Ropes Crossing – Our Third Floating Wetlands Project for Blacktown City Council

We have previously worked with Blacktown City Council on commissions for two other floating wetlands projects. The first of these is the 440m2 wetlands we installed at Blacktown International Sports Centre in 2014 and the second is the 100minstallation at the William Lawson Wetland which we completed in 2017.

Our third floating wetlands project for Blacktown Council is at Ropes Crossing. The central issue that council wished to remediate was the water quality in a stormwater pond which was clearly being affected by sediment and nutrient runoff from the developing urban catchment. This is a common issue and one that our innovative floating wetlands design is perfectly suited to remedy.

The floating wetland we installed is 168m2 within the 5000m2 pond (as per the map on the right). We installed  three 56m2 rectangle floating wetlands parallel to one another, positioned to intercept the flow of stormwater flowing through the pond.

We did not install our bird protection cage because there are not many waterfowl apart from a few brown ducks. However, we did mitigate the risk of bird predation by installing our pre-planted coir mats, which we planted 18 months ago.  These mats are the ideal way to colonise the floating wetland with the bacteria and microorganisms required to the establish the wetland processes on the constructed floating wetland. We will continue to monitor the site and look forward to our next update which will show the clean water made possible by our floating wetlands.

Coir Mats

Coir Mats – The Ideal Way To Establish Wetland Plants on Ponds and Lakes

When it comes to establishing wetlands and recolonising areas around bodies of water, coir mats are an ecologically sound and highly efficient solution. They are ideal for golf courses, public parks, private ponds, stream and lake banks, tidal zones, stormwater ponds and rain gardens – they are also ideal for restoring wetlands.

The benefits of coir mats are many but the principle advantages lie in the microbiome of bacteria and fungi attached to the mats which boost the growth of the host plants and give increased resistance to pathogens. Where a site cannot be revegated due to flowing water, wave erosion or submerged slopes, coir mats can last for five years or more. Furthermore, unlike tubestock the mats can be established in shallow water and secured with rocks.

Our coir mats are all grown at our own aquatic nursery in Jamberoo. Each mat is planted out with nine plants and include a mixture of baumea articulata, schoenoplecus validus, eleocharis sphacelata and yyperus exaltus. The exposed roots of these hardy plants quickly grow into the submerged sediment and allow wetlands to be established or recolonised.

We have supplied coir mats to the Centennial Park Trust, Wollongong University and the Parramatta Park Trust. If you’d like to discuss the use of the mats or to get pricing and delivery information, please call us on (02) 4236 0954 or email us at or view our coir mats information page.

Waste Water Management

In-Situ Permeability Testing

IN SITU PERMEABILITY TESTINGToday our engineers were out onsite in the Shoalhaven to perform in-situ permeability testing using our constant head permeameter, a CSIRO developed synthetic wastewater and the methods described in AS1547.

The purpose of this field assessment was to determine the saturated hydraulic conductivity (Ksat) of the underlying local soil landscape, to a depth of 0.5m, at several test locations across a proposed rural subdivision.

This information was used to confirm our initial assumptions made when sizing the proposed subsoil effluent disposal areas and to further develop an understanding of the fate and transport of residual wastewater pollutants through the subsoil and how this might impact neighboring environmental receivers.

As opposed to using clean water, more accurate estimates of permeability were obtained by adjusting the composition of the test water to match that of raw untreated effluent. Synthetic wastewater was formulated using the methods described in (Toifl et al., 2014). This included the addition of Uminin Clay to replicate the total suspended solids (TSS), and inorganic materials added as salts (NaHCO3, KCl, MgCl2, NaCl, CaCO3) to match the ionic strength, pH, conductivity and alakalinity. Volatile or biologically degradable substances were excluded from the synthetic wastewater to avoid microbial and pathogenic activity.


On Site Wastewater Management for Challenging Sites

The challenging residential site plans.

Not all approvals are a tightly defined and straight-forward process. On challenging sites, the knowledge and experience of the onsite wastewater management specialist is crucial. For example, HEC were asked to prepare an On Site Wastewater Assessment for a client who was proposing to construct a 7-bedroom residential dwelling. This would normally be easily achieved for a 4300m2 property, however, when the owner also wanted a swimming pool, water tank on land that was needed for wastewater disposal. That’s when this became a complicated job.


Our cost-effective solution on this challenging site.

Why was this difficult?

Shallow soil and rock outcrop meant there was not much land available for wastewater disposal. Furthermore, Council requires a 6m upslope and 12m downslope buffer for soil absorption beds receiving secondary treated wastewater and a 100% reserve area in case the installed area fails.

Luckily, we did not have to ask the client to reduce the number of bedrooms or delete the pool from the plans.

We were able to overcome these constraints and obtain Council approval with the strategy shown on the attached drawings. There is already so much that can go wrong during the process of building a property that it is crucial that knowledgeable professionals are used for all assessments.

If you would like to discuss On Site Wastewater Assessments with Harris Environmental, please call us on 02 4236 0954 and we will be happy to assist.



Managing Lakes, Ponds and Wetlands with Sediment Maps

Previously, if a council or golf course (or other organisation responsible for a body of water) wanted to determine areas of sedimentation, monitor success of dredging projects or provide accurate volume calculations, their options were limited.

Our new bathymetry and sediment mapping service aims to solve that particular problem by providing a fast and accurate mapping service.

If the client has an existing baseline bathymetry map available, then it’s possible to provide an accurate map of the volume of accumulated sediment between the two survey events.

Harris Environmental Consulting can create bathymetry maps using an acoustic sounding device linked with global positioning systems (GPS). The surveys, which are carried out by kayak or motorboat (depending in part on the size of the body of water) provide a snapshot of the current water depth and sediment distribution and can be compared with past bathymetry surveys. After completing our survey we provide clients such as councils, golf course owners and land-owners with a visual image of the depth and contour of the water body in the forms of GPS surface mapping, bathymetry and colour 3-D contour imaging.

Some of the potential uses of this service including assisting in the design of wetland restoration works, assessing the effectiveness of fish stocking, aeration and chemical treatment calculations, assessing water safety hazards and in obtaining accurate volume calculations for water quality treatment and hydrologic balance assessments.

Amongst the many possible applications of this innovative new service are council stormwater ponds and wetlands

If the client has an existing baseline bathymetry map available, then it’s possible to provide an accurate map of the volume of accumulated sediment between the two survey events. The speed with which we can complete a survey is a major improvement on more conventional methods.

Amongst the many possible applications of this innovative new service are council stormwater ponds and wetlands, sediment basins for constructions sites and quarries, golf courses, recreational fisheries, estuaries and lakes, water storage reservoirs and recreational water bodies. For any of these situations we can provide colour, poster-quality maps in PDF format, printing options from letter size all the way up to large format wall maps and GIS shape files.

If you have any questions about our bathymetry and sediment mapping service or would like to obtain a quote, please contact Sean Harris at Harris Environmental on 0425 335 245 or email him at Details of the new service can be found on our Bathymetry page.


Camden Council Install Interpretation Signage at Floating Wetlands

Lake Annan suffered from severe water quality degradation and seasonal algal blooms and HEC were brought in to help improve the lake amenity both for environmental purposes and for the local community by installing floating wetlands.

The works undertaken at Lake Annan included modifications to the inlet of Lake Annan, as well as our innovative floating wetland system. Camden Council could see a need to explain why they installed the floating wetlands to the community, so they have now installed interpretation signage.


Harris Environmental Awarded .Eco Domain Name

The .eco domain is a new web address that is made available only to businesses, governments, non-profits or individual working towards a sustainable future for our planet. The top-level domain (an alternative to traditional purely commercial domains such as .com or is for those organisations or individuals who are committed to positive change for the planet.

The .eco domain is backed by more than 50 of the world’s most famous ecologically sound organisations including Conservation International, WWF, Greenpeace, Rainforest Action Network, Environmental Choice Australia and United Nations Global Compact. In order to use the domain, organisations needs to prove their ecological credentials and take a pledge regarding sustainability priorities that are based on the United Nations Sustainable Development Goals, a universal action plan to protect the planet, end poverty and grow prosperity.

Harris Environmental has been providing expertise, advice and integrated environmental solutions to clients in both the public and private sectors for more than 20 years. Kate and Sean Harris are both qualified environmental scientists and have grown the company with the intention of providing environmentally friendly and sustainable solutions to homeowners, councils, developers, architects, builders and surveyors throughout South East NSW.

You can find us at right now alongside our traditional domain name at and we are proudly displaying the .eco trustmark on our homepage.


Floating Wetlands

Centennial Park Installation

Installation and growth of our pre planted wetland coir mats for erosion control and wetland restoration at Centennial Park installed by the Harris Environmental team. This installation was a new design for bird protection using hooped poly pipe and netting.