The health of our creeks and other waterways should be important to us all. The river and all its tributaries are jewels in the area’s crown.
In our city, responsibility is shared between Hawkesbury City Council, various statutory bodies such as National Parks, the EPA and Sydney Water, and another body you may not have heard of, Hawkesbury River County Council. I was pleased to be elected in 2016 by my fellow Councillors to one of the two positions as delegate from Hawkesbury council to the County Council, which is a joint effort covering the LGA’s of Hawkesbury, Penrith, Blacktown and the Hills Shire.
The County Council’s responsibility is largely related to weed control in and near our waterways. Since coming on board, I’ve been impressed at the practical and professional approach shown by its leadership and workers. My perception is that it’s a tight ship, and the people know and love their jobs.
Recently, a Hawkesbury resident approached me and expressed concern about the health of Currency Creek. The creek runs east from Tennyson, through Glossodia, Ebenezer and Sackville where it joins the river.
The picture was alarming:
Concern was also expressed on social media:
I took up the issue at our HRCC committee meeting last night.
I was informed that upper sections of the 15km length of Currency Creek are frequently reduced to a series of standing ponds. Sometimes 200 or 300m long, sometimes shallow and sometimes 6-8 feet deep. The green scum is Duckweed, and blooms of it can cause the underlying water to become anaerobic “black water”.
Low flows in the upper reach of creeks are a natural consequence of rainfall patterns. It was not the opinion of HRCC staff that nutrient levels here are higher than normal because of identifiable agricultural runoff. The presence of dead fish (mostly Carp) arose from the combination of low oxygen and warm water. Carp like cool conditions. In weather like this, they “cooked”.
In terms of what might be done, HRCC’s mandate concerning weed control is limited to waterways traversing non-private land. Any waterway on freehold land is not subject to HRCC control. Spraying is not advised in this case because the subsequent biomass decomposition would exacerbate precisely the conditions causing the fish death. Many water plants such as Azolla (which, for example, my neighbour’s dam is full of where I live in Oakville) fix Nitrogen directly from the air, and return nutrients to the environment on decomposition. In fact, this is a strategy actively used by the Chinese to fertilise rice paddies for centuries. The Duckweed is not something that can readily be reduced, either mechanically or chemically.
However, there’s good news: This section of creek, although less than healthy now, is isolated and a single rainfall event will flush such blooms out. Here’s a picture taken recently of the same creek only 5km further downstream.
Here, the water is clean and healthy, and shows the spectrum of biodiversity of a healthy creek. The whole creek isn’t sick, just small sections. It’s the height of Summer, and no creek flows freely at all times and places.
Concerned locals should also note that groundwater monitoring occurs continuously in the same are. The monitoring station pictured below is very close to the location of the concerned resident’s video, and the health of our waterways are always under review.
In my new role at HRCC, I have been pleased to witness a new GPS-based logging and reporting system that has seen the number of property inspections for weeds rise through 2,500 per year and keep increasing. This requires a data sharing arrangement with member Councils and I have been supporting the dialogue required to make this happen. The HRCC makes good use of volunteer and vocational programs for its on-the-ground workers, and gains an increasing share of its income from commercial activities and government grants, placing a smaller burden on contributions from member councils.
If the concerned resident was worried that “no one cares” when he comes across the distressing scene of a sick waterway and posts video of it on Facebook, then I can assure him that the HRCC noticed, and discussed the matter at length within 48 hours of his post. The HRCC must operate within its’ mandate, but if other environmental agencies need to be engaged, then they will be.
If you’re a Hawkesbury resident and are concerned about the health of a waterway in your area, or about a noxious weed control matter that may fall within HRCC’s remit, contact me and I’ll forward your concerns.