Showing posts with label Stormwater. Show all posts
Showing posts with label Stormwater. Show all posts

29 November, 2011

Eeewwww!!

Up to now I haven't really looked at the environmental issues which affect the Barwon River, however with Saturday's deluge of rain, pollution has suddenly become a hot topic - well, for the next few days. The Geelong Advertiser informs me that for several days it will be unsafe to swim in either the river or Corio Bay. The reason for this is that the recent downpour caused the sewage system to overflow into the stormwater drains as well as sending a great deal of rubbish into the drains,  meaning that output from the stormwater drains may be contaminated. Not only is this bad news for humans who can suffer a range of unpleasant symptoms, but it is also a problem for the river environment in general.
Stormwater drain near Queen's Park
Large influxes of "nutrients" combined with the right weather and low water levels create ideal conditions for outbreaks of blue green algae along the course of the river. So what is blue green algae? It is actually a type of cyanobacteria, which as a group may well be the most successful micro-organisms on the planet. These tiny bacteria are thought to have given rise to the process of aerobic metabolism used by all higher life forms as well as forming the basis of chloroplasts - the part of a plant which it uses to make food. Cyanobacteria convert water into oxygen and energy by photosynthesis and it is through their actions some 3.8-2.5 billion years ago that Earth's oxygen-rich atmosphere developed. Cyanobacteria are also able to "fix" nitrogen and carbon. That is, they use the nitrogen found in nitrates, nitrites, ammonia and urea as well as carbon as part of their growth cycle.
Jerringot Wetlands
Whilst these effects are vital for the planet as a whole, contributing significantly to a reduction in greenhouse gasses, in a river system such as the Barwon, they can have negative effects. This is because the cyanobacteria use the chemicals which wash into our waterways to multiply. The result is an algal bloom which can result in a reduction in the amount of oxygen available in the water (eutrophication), which harms fish and other fauna. At the same time, cyanotoxins are produced which are toxic to humans and animals which live in and along the river.
Symptoms of poisoning in humans can include skin irritation, dizziness, numbness around the mouth, tingling in fingers and toes (produced by neurotoxins). Longer-term effects can include nausea, vomiting, diarrhoea and liver dysfunction. Animals can experience weakness, staggering, difficulty breathing and ultimately death.
So what are the "nutrients" in question and where do they come from? The primary chemical culprits are nitrogen and phosphorous. In urban areas they can be found in pollutants such as leaf litter from exotic trees (particularly in autumn), human sewage, animal waste, grass clippings, paper, detergent and industrial byproducts while in rural areas crop fertilizers can also impact on the levels of nitrogen and phosphorous in the water.
Pollutants on the surface of water at Jerringot Wetlands
...at Jerringot Wetlands
Other threats to river health and to its flora and fauna come from various sources. Pesticides used to control weeds or insect infestations in crops can be carcinogenic to humans if allowed to build up in drinking water supplies whilst non-biodegradable rubbish can cause physical harm or poison river users and wildlife.
Rubbish in the Barwon near Breakwater
Grass and other rubbish washed up during the recent rain
There are some factors however, which work to counteract the effects of pollution on the river system and one of the most important is the reed beds which filter stormwater runoff before it reaches the river. In the case of the Barwon, this includes not only the reeds and other aquatic plants which line the riverbanks themselves, but also the plant life in the wetlands adjacent to the river.

Reed beds at Balyang Sanctuary
Aquatic plants at Jerringot Wetlands
I have looked at a number of these in previous posts. Much of the stormwater from Belmont is collected by Jerringot Wetlands, whilst that from Newtown flows into Balyang Sanctuary. Most of Leopold's runoff drains into Gateway Sanctuary and Ocean Grove's into Blue Waters Lake. All of these wetlands ultimately drain into the Barwon River. In many places however, Geelong's stormwater flows directly into the Barwon with no intervening wetland to reduce the level of pollutants entering the river.

19 October, 2011

Another hidden gem

Today I rediscovered a lake which I had not visited for more than ten years; and in the bright sunshine of our first 30 degree day of the season, Blue Waters Lake in Ocean Grove did indeed sparkle like a jewel - a sapphire.
Blue Waters Lake, Ocean Grove
This very pretty little lake is another of the wetlands which drains ultimately into Barwon River. It has been substantially developed in recent decades, but was originally a natural lagoon. Like Balyang Sanctuary, Jerringot Wetlands and Gateway Sanctuary, it now filters stormwater, trapping harmful pollutants before they can end up in the larger river system. A City of Greater Geelong council report from 2003 acknowledges the vital importance of the lake in collecting and treating a significant proportion Ocean Grove's stormwater runoff and looks at ways to improve water quality. It also recognises the value the local community places on the lake as a recreational facility.
Hardhead Duck
Like the other wetlands along the river, Blue Waters is home to a sizable bird population. Today I noted at least a dozen species after only a cursory check, including quite a number of Hard Head Ducks. The only other place I have seen hard heads was a pair at Jerringot Wetlands a few months ago. Aside from a tendency to dive every time I attempted to take a photo, they were reasonably unconcerned by the presence of people.
Unlike the other wetland areas along the river, Blue Waters has a substantial number of non-native plantings, which whilst probably not helpful environmentally, make the lake significantly more attractive. These include quite a number of large willows at the water's edge which along with interspersed native plantings screen out many of the houses which border the lake.
Today's walk did not see us complete a lap of the lake, so I will return in the not too distant future to take a few more snaps and count a few more birds.

29 September, 2011

Rain, rain come again!

...and boy did it rain! I had intended to go for a run all day and for a variety of reasons, wasn't able to get out there until late afternoon. The weather was overcast but still quite mild. There had been a little rain on and off during the day, but nothing too major.Of course, as soon as I changed into my running gear, the lightning started. But as there was little rain about and whilst overcast, it looked to be clearing from the south, I headed out anyway, following my usual route down to the Barwon. Clearing? Who was I kidding? By the time I got about 5km into my run, it was pouring. We haven't had rain like that in ages - big, heavy, wet drops and it didn't let up. It was however, probably the best time to be running. The temperature was still remarkably mild, there wasn't much wind and the rain was keeping me cool.
It felt later than it was - more like 6pm than 5pm - but I wasn't the only one making the most of the conditions. I passed the odd cyclist and a couple of intrepid walkers as well as several other runners - with one exception all male.
This got me thinking about two things. Firstly, I wondered as I often do, about the optimum conditions for running. Over the years, I think I've encountered most of them, such as they are in this part of the world, and my conclusion is that if it is too cold to start running, then I am more likely to have a good run. However, if it is not so cold that I don't want to start running, then I will very soon find it too hot to run comfortably. Great! Either I won't run because it's too cold, or I can't run because it's too hot. My current solution to this problem seems to be running during thunderstorms. Any breeze is cooling, but not freezing, the rain is refreshing and perhaps all those extra ozone molecules zinging about add some extra bounce to my step - assuming of course, I don't get hit by a stray lightning bolt.
Stormwater runoff
The other downside to running in the rain which became increasingly apparent on this occasion, was the issue of water runoff across the path. By the 7km mark, my ultra lightweight running shoes were anything but, by the 9km mark I could hear squelching noises with every step and then, at around the 11km mark I landed in a pothole which meant one foot was now completely saturated as high as my ankle. Regardless of this, I finished the run in reasonably good shape and hit the shower to dry off - let's face it, it was wetter outside at that point!
But what do the experts say about weather and running? From what I can see, the "optimum" temperature range for distance running is between about 5-10 degrees Celsius. Great! I'd rather be home in front of the heater! But I do have to admit that they are pretty much correct. Assuming I can drag myself out there, my best times tend to be in the cooler weather - anything below about 15 degrees will do, except in the case of rain for the reasons I outlined above. Some experts contest that running in cold weather can actually hamper the ability to run as performance is compromised by the need to generate heat to warm the body, however I suspect they have cooler temperatures in mind than those along the Barwon.
Yesterday a torrent, today a trickle
Heat of course, is a detriment to running. Too hot and you run the risk of hyperthermia (elevated core body temperature) leading to heatstroke and organ failure, dehydration and electrolyte loss through sweating, or sometimes even hyponatremia (decreased body sodium levels) due to over hydration. None are a good alternative and as I have trouble drinking and running at the same time - water is not useful when inhaled - I tend to avoid running in the heat. Either I go early, late or not at all unless I misjudge the temperature, in which case I suffer.
The other thing which was glaringly obvious as I made my way round the river was the water runoff. Not only for the fact that most of it seemed to be happening via my ASICS, but also because of the very apparent volume of water which was making its way into the river. As I neared Queen's Park, I passed a stormwater drain which was discharging water with the velocity of a small train. On my way back, I noticed a similar drain on the opposite side of the river had taken on the proportions of a waterfall and then, as I neared King Lloyd Reserve, there appeared to be a small geyser spouting from the lawn - perhaps a pipe had ruptured under the weight of the deluge.
Balyang Sanctuary
Along this section of the river, the water collected from surrounding catchment areas, just feeds back into the river itself and joins the larger flow, however on other parts of the river, stormwater plays an important role in maintaining local eco-systems. Balyang Sanctuary and Jerringot Wetlands are both excellent examples of habitat maintained by storm water runoff. Balyang takes its water from 70 hectares of surrounding residential land, whilst Jerringot is supplied from a large area extending up the Belmont Escarpment as far as Roslyn Road. The careful planting of native flora at Balyang Sanctuary - and presumably also Jerringot - contributes to a significant improvement in the quality of stormwater reaching the Barwon