Restoring Nature’s Hydraulic Pulse

Willow Warriors on the Nepean River. Photo by Kelvin Montague.

How many of us would choose to pave our driveways if we knew it was interfering with nature’s hydraulic pulse? How many of us understand the role of swamps, ponds, lagoons and the meandering of rivers and creeks in holding water in what is the driest occupied continent on the globe?

Water. It is the substance of life. We would panic if taps ran dry in our homes. It is equally concerning when a landscape runs dry. 

‘Nature is not a place to visit. It is home’. So writes Pulitzer Prize winning poet, Gary Snyder. It is also true that we are not simply in a landscape; we are ‘of it’, part of a common living being. This has particular resonance in our region, where our cities shares space with a World Heritage National Park and the rivers and tributaries that make up the massive Hawkesbury-Nepean water catchment. 

In the undisturbed natural environment, 85% of water falling during a rainstorm is collected and filtered by creeks, swamps and wetlands. However, land clearing, industry and a lack of understanding of these features compromises this system. In urban areas, where soil and vegetation are replaced with impervious surfaces, storm water is directed into large drains that bypass natural collection processes almost completely. Water rushes from high country to low, dragging with it sediment and pollutants, and leaving dry earth behind. Rushing water erodes riverbanks and flushes out the small creatures and microscopic plants that also play a role in filtering water and holding it in the landscape. 

A dry landscape is a landscape prone to bushfire. And the demise of water quality spells the demise of a vital tourism industry, not to mention the health and beauty of the home in which people live.

Addressing this issue takes action across government areas, as water does not flow according to administrative boundaries, and what happens upstream affects water quality below. 

Water flows from Lithgow in the west, through the Blue Mountains and down into Penrith and the Hawkesbury. Across these local government boundaries, community volunteers are working to restore nature’s plumbing. The results are heartening but there is no room for complacency. Those who make this their home can support these efforts by arming themselves with knowledge, monitoring the landscape as they would monitor their home, reporting when things don’t look right and participating in regeneration projects where they can. 

Upstream: A Natural Sponge

The temperate highland peat swamps surrounding Lithgow formed over thousands of years, as water seeped into pervious sandstone, was trapped in claystone layers and then gradually released through cracks. Peat formed on the surface and acts as a natural sponge. Surrounding plant life depends on this slow seepage of water, collecting and processing water as well.

Carne Creek Swamp, Newnes State Forest. Under threat with long-wall mining. Photo by Julie Favell.

Introduced animals, land clearing, fertilisers and weeds have destroyed most of these swamps, and today Lithgow has been home to two coal-fired power generation plants that use water from the catchment. Longwall coal mining is also present. Unlike room and post mining, where pillars are left to hold cavities, this technology uses a supporting spring to ensure a higher yield. When the spring is removed after extraction the ground collapses, fracturing the fragile sandstone required for the swamps. The mines also discharge wastewater containing sediment and heavy metals.

The Lithgow Environment Group (LEG) has been monitoring water quality in streams and rivers for years. It also watches the health of swamps. Findings of heavy metals and sediment in the water, that was confirmed by Water Scientist Dr Ian Wright, provided evidence to take action. The Wallerawang Power Station was required to put in a desalination plant to treat half of the water discharged from the Springvale and Angus Place Mines. But the Station and the plant have been decommissioned since then. The pressure for better practices continues. A proposal on the table at the time of going to press is the installation of a desalination plant at the remaining Point Piper Power Station, and the piping of mine wastewater to the plant to replace fresh water taken from the Colo River. 

Julie Favell, Natural Areas Project Officer with the Lithgow Environment Group, says communities should not be lulled into believing that industry self-regulation is enough.  She urges local people to remain alert to signs that indicate there are problems with our most valuable resource. This is their home. The personal responsibility lies here.

A Water Sensitive City

Further downstream Blue Mountains City Council is adopting an ambitious Water Sensitive City Strategy designed to mitigate the impacts of urban runoff on the downstream World Heritage National Park, earning the thumbs up from the United Nations Educational, Scientific and Cultural Organization (UNESCO).

Green rooftop harvesting of rainwater at the Blue Mountains Cultural Centre is a world first initiative. At Echo Point, stormwater harvesting allows the water to flow into a 150,000-litre tank that services nearby toilets visited by close to 3.5 million tourists annually. 

Geoffrey Smith, Environmental Scientist at Blue Mountains City Council, explains that capturing water and directing it toward multiple uses mimics Mother Nature. Other approaches to ensure water remains in the landscape include restoring the natural ‘chain of pools’ by creating check dams, and stabilising banks with bales of coconut mulch at strategic points in creeks; building raingarden bio-filtration systems at key nodes throughout the catchment; replacing concrete kerbs and guttering with grass swales; encouraging the uptake of slow drip water tanks in homes; and the installation of permeable driveways and carparks.

Inspired Youth

Lower in the catchment, young volunteers are restoring wetlands. Jade Paton, a recipient of the Young Landcare Leader Award, was introduced to wetland management as a Green Army participant, and assigned to the Hawkesbury Region in 2016. 

She considers herself lucky that Robin Woods of the Hawkesbury Environmental Movement (HEN) was the project’s host. “You cannot help but fall in love and learn to value the wetlands, if you have spent time with Robin,” she says. “They are important carbon sinks, reduce the risk of flooding and act as filters. They are also an important habitat for birds.”

Much of the work involved removing weeds and when the project came to an end the group couldn’t bear to walk away. “We had become attached to our sites and felt a responsibility to continue protecting them.”

During a team- building exercise the group dubbed themselves the Wetland Warriors and the name stuck. Participants now carry on as volunteers. Along with maintaining wetlands they educate the public and landowners about their value. They also work to attract more volunteers to ensure ongoing regeneration continues. 

Several of the warriors have found industry-related jobs and one is starting university because she wants to learn more about saving the environment. 

Harnessing the Adventure Brigade

Jeff Cottrell wasn’t a ‘Greenie’. He was just a man who wanted to paddle his canoe on the Colo River through Wollemi National Park, north of the Blue Mountains. He discovered he could gain access if he became part of a weed eradication team. 

Friends of the Colo was formed in 2000 to control weeds interfering with the natural ecosystems in Wollemi National Park and the Colo Catchment. Volunteers combine the excitement of bush walking, whitewater rafting and flatwater kayaking with weed control. 

One of the most invasive riparian (riverbank) weeds is black willow. The willow uses more water than other riparian native vegetation. Leaf drop sucks oxygen out of rivers and kills fish. Black willows also crowd out natural vegetation required by native birds. Their fine dandelion-like seeds can blow over 60 kilometres in the wind, spreading in leap frog fashion from areas bordering the Word Heritage area and into the National Park. 

Between 2000 and 2003, Friends of the Colo treated over 3,000 trees, using a bioactive poison. The trees die and break down. Borers enter the wood. Cockatoos chase the grubs and pull the trunks and branches apart. 

“Nature finishes the job, leaving piles of willow mulch,” says Jeff. “The natural vegetation grows in to fill the spot.”

Jeff uses his skills as a whitewater paddler and trip leader to manage the risk when mapping and treating willows in remote environments. Volunteers take photos and GPS readings to monitor patterns that lead to nearby seed sources or black willow galleries on areas outside the Park. 

Black Willow is under control in the Colo Catchment. Other weeds are being treated and work has spread to the Hawkesbury and Nepean Rivers, and Hawkesbury Floodplain with the help of volunteers from organisations such as the Springwood Bushwalking Club.

A travelling branch of the group, known as the Willow Warriors is replicating this approach in other whitewater rivers between Sydney and the Victorian border. The intent is to create buffer zones around national parks and in this way provide cost effective remote area weed control. 

Jeffery believes volunteers who are part of the outdoor adventure community can bring a variety of skills to conservation efforts. As a computer consultant he has spent his working life looking at process and applies this knowledge to systematically addressing weed control. 

He is now a convert to the conservation movement, and speaks of how a love of outdoor recreation translates into a passion to protect the environments that adventurers seek to enjoy.

It is this passion that is evident in the work of the Lithgow Environment Group, the Blue Mountains Conservation Society, the dedicated environment team at Blue Mountains City Council, the Hawkesbury Environment Network, the Friends of the Colo, and both the Wetland and the Willow Warriors. It is a passion for the importance of water to be shared.

Carol Major