Clean Water and Environmental Health
Clean water is precious, but in the cities of the developed world most of us take it for granted and complain about it when it is disrupted as though it is a god given right. For some, spiritually (Ganges) it is a God-Given-Right and culturally it is central to many indigenous people’s beliefs and lives. Without it we would all die of thirst within a matter of hours and yet most of us don’t really appreciate it or respect it! Clean water is also critical to our health e.g. hygiene for our ablutions, for our food e.g. aqui / horti / agri / permo- ‘culture’, and for cleaning our homes; but is it a right?
Like many ‘rights’ there should also be responsibilities and this is central to my discussion below.
Only in this century has Australia placed any controls on how much water can be extracted from stormwater (SW) catchments/drainage basins (DB) or groundwater (GW) from artesian basins e.g. the Great Artesian/Australian Basin (GAB), one of the world’s top three in size covering 20% of Australia. There were no real controls on who could install a well/borehole (BH), how they were installed or maintained, how much water was extracted (pumped) or how it was tested (monitored).
Ironically, the greatest contribution to understanding the GAB has come from the coal seam (bed methane- CH4) gas (CSG) industry by way of competency standards for BH drillers, installation, monitoring, maintenance and cumulative environmental impacts (∑EI). Of course it is in the interests of the CSG companies to extract as much gas as possible from every well and not lose it in the process (fugitive emissions) and at the same time in order to do this they need to manage the precious water. Ironically also is the fact that when the water first came on stream for users it was no longer required. After a period of several years of drought, even Toowoomba was looking at recycling wastewater like many cities in the world even though the filtration technology is well proven the herd came out and torpedoed this future proofing possibility. Another downside for many was that the CSG requirements shone a light on all the sub-standard operators/operations that must be equally applied to all drilling activities wherever water, gas or oil is extracted.
If a mining operation, particularly coal mining, conducts drilling and pumps down water or removes gas to make mining safer by removing dangerous (flammable or combustible) gases then that needs to be controlled by the same standards that are applied to the CSG industry. In the process of removing gases from a coal mine there should be a requirement to capture any gases and not just vent / flare them to air. Not only is it a valuable resource but it is also a major contributor to greenhouse gases (CH4 GWP = 25 x CO2). Coal mining should fund mobile tankers to capture CH4!
In processing any water from these previous shallow seawater basins there is a high level of salinity (35ppm) and the salt needs to be removed if used for drinking water. Now that the three Queensland based CSG JV companies (QCG, APLNG and Santos) are water, gas and salt producers they have considered all potential alternatives for disposing of the huge volumes (ML) of saline water e.g. irrigating salt tolerant plantations (Chinchilla White Gum, and even mangroves was suggested). However, this creates a long-term problem by increasing the salinization and sterilization of soils that are already sterilizing large areas in Australia. Given the necessity to build massive sealed (neoprene and bentonite) ponds is an opportunity to consider moving into the aquiculture business or better still biofuels from algae. Who knows this could provide a major carbon offset of their massive carbon footprint but without a carbon market would they?
That aside, and unfortunately from hard won personal experience, it is easier to manage a saline than a freshwater pond system. I am unsure if this is due to the difficulty in managing the typical Australian ephemeral (intermittent) brackish water bodies e.g. Lake Eyre, or because it is easier to enable flushing (solution to pollution is dilution?) with seawater into coastal ‘lake’ systems! Having lived and worked in the tropics for a decade and been the ‘Guardian of the Lakes’ for Townsville City Council (TCC) for several ‘challenging years’ I believe I have a good handle on what makes a good lake / lagoon / pond / waterway-course / billabong tick! I hope this discussion will help any environmental guardian understand some of the issues in managing water bodies?
Most lakes were artificial/‘man-made’ engineered structures designed for flood retention and protection purposes. In the latter case this is not only by capturing and slowing the release of water to the sea during times of high rainfall in the catchment but also when times of higher tides prevent the release of water (tide determines flood discharge) and by excavating drainage basins the ‘soils’ are then used as fill to build-up the surrounding flood prone land. Such land is common in most of Australia’s coastal areas due to the low eroded topography and shallow catchments.
Many coastal soils north of the temperate zone consist of potential or actual acid sulphate/sulfate soil (P/AASS) that are formed from the reaction of iron sulfides common to this red rusty continent (FexOx). Ancient Archaean algae known as acidi(c)-thio(S)-bacillus ferro(Fe)-oxidans (ATBFO) are able to extract sulphur and produce sulphuric acid (H2SO4) as a by-product. ATBFO analogues have been found at Deep Ocean (black smokers) and surface geothermal vents (geysers) where they ‘consume’ sulphur rather than oxygen in non-oxygenated environments (anaerobic). Any excavation less than (<) 5m below mean sea level (MSL=AHD) is likely to encounter ASS and therefore miners/developers are required to treat (neutralise) acids from forming by the addition of agricultural lime (aglime). As an example any ASS with 1% oxidisable sulphur (Sox) content requires 50kg of aglime per cubic meter (1% Sox: 50kg/m3 CaCO3) to neutralise it. Although 1% may seem low it is in fact very high and not uncommon in marine sediments e.g. soils excavated by CSG companies during the excavation of their LNG pipelines around Gladstone Harbour. In excavating saline saturated fine grained (sand/silt) marine sediments the density or specific gravity of the soils are generally around 1.85 kg/m3 thereby effectively doubling the aglime required to neutralise these soils e.g. 100m3 AASS = 1tonne aglime!
This standard neutralisation process needs a large land area to treat the ASS, creating an ongoing need to stockpile treated soil and in the process creates large quantities of carbon dioxide. This is an impost on the local community due to land-use requirements and carbon emissions. It is therefore preferable, despite anti-dredge disposal protagonists, to deposit the soil below the turbulent zone or aeration/oxidation zone where the soils could be retained, when properly constructed, within the deepest parts of a retention basin! Without entering into debates about the need for maintenance dredging or dumping, other than to say that all land purchased in South East Queensland’s coastal zone requires ASS treatment (if you’re unable to grow anything in your garden it could mean that the soils were not properly treated and there is salt and/or acid present!). Without focusing on soils in this module, even though it’s difficult to artificially separate soil quality (SQ) from impacts on WQ; I’ll leave that discussion to another module on SQ. Most soils require some form of treatment in order to make them favourable to grow plants and provide protection against erosion/dispersion, and consequently sedimentation causing water pollution. This is especially critical if those soils have been used to reclaim or build-up land in South East Queensland’s (SEQ) Gold Coast!
Once lakes are established with surrounding plants and play areas they then become attractive places for people to live and therefore pay a premium price to live near, as the impression created is that they are natural and will be environmentally healthy and aesthetically pleasing places to live. However, if there aren’t sufficient controls put in place to capture pollution before it goes into these waterbodies then they then become traps for pollution, algal and noxious weed/water plants and potentially lead to dead wildlife e.g. fish, birds, reptiles, mammals, and even pets! As an example; in Townsville’s main Lake Curralea, in the lee of Castle Hill, no natural environment was established around the lake when it was first constructed other than grass and widely separated trees that provide little shade over the lake. The lake is 7.5ha in area and 2.5m deep (150ML) however by early 2002 it had over (>) 10 tonnes of dead aquatic species, including 50 female Barramundi (Barra). I know this because at 6am on 23rd January I was called out to the lake on a calm and warm sunny Monday morning to discover that all the 20 aquatic species it provided habitat for had died and completely covered the surface of the lake! It was one of those times in my life when I was deeply shocked. The lake had become anoxic after a massive algal (blue-green cyano-bacteria) bloom over the weekend that removed all the dissolved O2 (DO) as it died off. Of course, not everything in the catchment can be controlled by local government and hard engineered end-of-pipe solutions e.g. SWQ Interception Devices (SQID) or traps not designed to remove all pollutants e.g. nutrients and give rise to algal blooms. Instead, it is up to the whole community to protect these lake systems. I call it SQID, because like an Octopus, its many tentacled arms capture things that come close!
Community Responsibility:
1. Education- these lakes are the last trap for pollutants and garbage that will otherwise be flushed out into the sea and impact beaches and fisheries along the coast and the values of the beautiful waters of the Great Barrier Reef World Heritage Area (GBRWHA). Given the high proportion of beachfront (The Strand and Rowes Bay etc.) users e.g. people walking and with pets, undertaking sport, including fishers and those in direct contact such as swimmers, snorkelers and divers; means that everyone has a role to play, and especially pet owner swimming pets;
2. Pet waste- this is a food source for micro-organisms and as pet ownership is high with over 3,000 registered dogs and probably an equivalent numbers of cats in the Lakes DB. Pick-up after your pet is necessary to avoid ..it getting into the lakes. Sewage is separately piped as it is required to be tertiary treated in the GBRWHA. Unfortunately, during times of flood, sewers can overflow and create health hazards and downstream impacts e.g. turbidity or ‘turdidity’?
3. Greenwaste- this should be collected and if not composted or mulched should be disposed at landfill for turning into the same. Unfortunately many people just throw the waste over their fence, including grass cuttings and leaves*1 onto adjacent land i.e. public land and in some cases directly into drainage channels. Of course nothing happens until the next major storm event when the blocked off channels not only become dams and cause flooding of other people’s properties but waste eventually gets deposited into the nearest water body. A greater surface area of waste allows faster microbial decomposition and DO*2 removal. Leaf blowers are one of the worst things ever invented as everyone blows there green-waste into the street and apart from blocking the drains causing flooding, it eventually gets flushed along the SW gutter, into the drains and via the pipes into the lakes or out into the sea!
4. Oil/chemicals- loss/disposal into the SW drain or from a leaking engines / containers onto sealed areas means that slicks or poisons will be flushed to kill wildlife, pets and potentially swimming children or elderly who ingest it and have a greater sensitivity to pollution!
5. Nutrients- disposing detergents (containing Phosphorous) down the SW drain rather than onto the grass, or the overuse (as prescribed on the packaging) of fertiliser means that excess nutrients (N-P-K) are flushed into the lakes and cause algal blooms;
6. Transport- many loads are improperly secured or sealed and are lost at times other than in road accidents simply by falling off or overflowing their containers. Unfortunately even where there is no immediate fire danger the Fire Service generally flush substances down the SW drain;
7. Sediments- fine sediments in particular will smother aquatic organisms, corals and seagrasses. Also nutrients frequently attach themselves to sediments and, as above, are flushed through the SW system. I once received a call from an irate lake front landowner that there were weeds growing at the bottom of their revetment/rock wall and was trapping rubbish and was unsightly. Given that there was no long-shore drift, SW drain outlet pipes or other transport source, I asked if they had conducted landscaping to which the landowner went quiet, because they had created the problem and they needed to rectify it not the local council!
8. Plants- people complain about trees blocking their view but given the importance of trees during storms, providing they are pruned and able to establish deep root systems as many are planted in shallow holes or have damaged roots from construction activities within the drip line and become top heavy and topple over in high winds e.g. Brisbane’s Roma Street Gardens during the Gap Storm. They are able to stabilise and de-salinize (by draw-down of GW levels) soils while slowing SW and GW flows. For those who live near the coast, the natural protection provided by healthy mangroves was demonstrated during the Asian Tsunami (villages left intact). Trees also provide shade stopping weeds and cooler conditions provide shelter for aquatic nurseries;
9. Overstocking- too many fish with too little food and no way of escaping when conditions deteriorate. In the Australian tropics the ‘Wet’ is when the first Monsoon rains come and not only flush all the stuff sitting in the catchment into the lakes but also allow adult fish to migrate back to where they were first conceived. If the fish subsequently can’t escape when water levels drop or barriers stop them then they become trapped. When the 50 ‘Barra’ died, as noted above, they were the top predators in the muddy water system and were all over 0.9m long ‘Big Mothers’ as they had changed to the breeding stock for future ‘Barra’;
10. Please refer to my ‘Fish Kill Chart’ for a quick summary of potential reasons for fish kills.
Monitoring
The lakes were monitored from a boat three times per week at three different depths in order to establish environmental baseline data. However, it is essentially only four factors that determine WQ and those are: temperature (T oC), dissolved oxygen (DO ppm), salinity (EC) and acidity (pH).
1. ToC- conditions that affect aquatic species and the ability of the water to dissolve;
2. *DO- aeration from a balanced plant/algal life and surface mixing by wind or aeration pump;
3. EC- salinity from salt or other dissolved minerals e.g. when there has been little rain during a drought and there is insufficient seawater exchange lakes can become hypersaline; and
4. pH- neutral conditions (6-9) means that WQ is balanced i.e. acidity vs alkalinity.
All the other parameters can be checked by taking water samples to a NATA accredited laboratory for more detailed analysis. However, we also need to consider the climatic conditions existing at the time of monitoring and recording. As discussed in AQ Mod. I the Weather Office (Bureau of Meteorology/BoM) records at critical locations e.g. airports, and the data can be accessed online, or be obtained from a simple neighbourhood weather-station where records of rainfall, wind, cloud/smoke/dust cover and ToC, and in fact any other environmental effects that are relevant e.g. tides, and the location and time of measurement/monitoring. It is only by personally observing and understanding the air movements in your own neighbourhood that you will be able to decide whether the wind records (“roses”) are relevant to where your lake is and can be used to judge the impacts on local WQ!
As an example, there had been the usual suite of monitoring tests conducted at 6am on a weekday morning and they had come back without flagging any issues e.g. immanent WQ deterioration / collapse. I graphically recorded monitoring results in order to highlight trends within the lakes and saw a concerning trend (the trend is your friend). I never applied the Airport BoM data directly to the location of the lakes because they were in the lee of the 300m high granite dome of the aptly named Castle Hill. This meant that unlike the airport that was on a coastal plain exposed to the predominant sea breezes the lakes were generally sheltered from these aerating, mixing and cooling breezes. I immediately went to the lakes and observed that the conditions were still and warm and that the water was greening and starting to smell. I immediately returned to the office and sent out emails to the Deputy Mayor and all relevant department heads to be on standby for the imminent collapse of the lakes as an algal bloom developed and a potential fish kill could result on its collapse. Some of the staff who had conducted the survey and their superiors disagreed with my assessment of the situation and believed I was unnecessarily raising concerns and that I should withdraw my red flag! Within a matter of hours a massive algal bloom developed and the lab provided the necessary evidence that supported my concern. The lakes DO subsequently collapsed and the fish kill that resulted the following morning was cleaned up by my well trained Emergency Response Team before the media arrived, and without photos of dead fish to report there was no story!
I only give this as an example to illustrate that there is no substitute for personal field observation and an unbiased assessment of the data gathered. I subsequently sat down with one of the Environmental Officer‘s (EO) responsible for monitoring and used this real life example as a way to illustrate how an on-ground understanding of the environmental conditions can not only give greater insight into how these lakes function but also be the basis for gaining an understanding of any water system worldwide (from LinkedIn, the EO (now PM) has worked for TCC for >15 years).
I have not included information on more unlikely extreme issues that could create WQ problems!
My Background
I completed a Post Graduate Diploma in Environmental Science in Hydrogeology (contamination of aquifers), Environmental Engineering (including microbiology) and Law (Marine Pollution) in 1993.
I have worked as an Earth Scientist for governments, companies and consultancies for 30 years.