Peel Estuary and Mandurah - Observations

The Peel-Harvey Estuary Tidal Movement I was unable to find any very useful reference on the Internet about the amount of tidal movement that was typical in the Peel estuary so I decided to take my own measurements at a time of Spring Tides, the new Moon of 2022/04/30. Six readings taken over a period of 22 hours at a period of Spring tides (new Moon, 2022/04/30-05/01) indicated a total range of about 20cm. This seems to be about a third of the tides on the coast. (Tide levels are available on the Internet for 'Mandurah' but where these levels apply to is not given. If they are in the estuary then they are probably substantially less than on the coast.) Home Top Index   This section added 2022/08/11 Water colour change The water in the Peel estuary is usually colourless, sometimes clear, sometimes - if there has been a lot of wind and sediment has been stirred up - cloudy. On this day we noticed it was clear but strongly coloured brown, probably from tannins that had washed in with the high flows in the Murray and Serpentine Rivers that feed into the estuary. Home Top Index I also noticed that the water tasted fairly fresh. It is normally about the same as sea water in salinity. It seems unlikely that the salt water in the whole 60 square kilometres of the Peel lagoon could have been replaced with fresh, so more likely that the fresh water had for some reason come over this side. The data I had from Dr Steve Fisher, Operations Manager, Science and Waterways, Peel-Harvey Catchment Council, showed some very low salinity readings had been collected in the past, so it was quite possible that this water was almost fresh. Photo iPhone 11 Pro, wide angle lens, 1.54mm, 2022/08/11 This panorama, which covered about 120 degrees, shows that the water in the Mandurah Quay harbour (on the left) was coloured by the tannins, while the water in the more open estuary (on the right) was colourless. The water in the harbour was not so strongly coloured as the water that I recorded above, on the previous day. I tasted the water on both sides of this photo. Both were somewhat saline, I couldn't be sure if there was any difference in the salinity between them. Photo iPhone 11 Pro, 2022/08/12   This section added 2024/10/05 Sand of the Peel lagoon

After microscopically examining, and testing with HCl (hydrochloric acid), some very white sand from the Peel lagoon beach and deciding it was almost pure quartz (SiO2, silicon dioxide) I had a look at some of the heavy sand (black in this location).   Not pollution Streaks of heavy sand such as this are common and quite natural. They are made up of naturally occurring minerals and are not, as some people seem to think, pollution.   I must take notice of the sands on the Indian Ocean beach next time I visit. I seem to remember some brown heavy sands in this area somewhere. Seems it must be ilmenite (FeTiO3, iron titanium oxide). It’s only very weekly magnetic, ruling out magnetite (Fe3O4, iron oxide). Another common heavy beach sand is rutile (TiO2, brownish, not black) and less common, zircon (ZrSiO4, zirconium silicate, lighter colours). It looks like there’d be some calcite (CaCO3, calcium carbonate, the yellowish translucent grains) in this lot, but I didn't test it with acid. I’ve always thought it odd that a heavier sand is often deposited on top of a lighter sand in this way. Sea shells are primarily calcite, which reacts strongly with acid. Photo 2024/10/05, iPhone 11 Pro, standard camera, 4.25mm fl.

This section added 2022/05/03 Dead and dying trees   Recently dead trees The trees in the photo on the right and many other trees in the SW of WA have died following an exceptionally long, hot, dry summer. In May of 2024 my wife and I have been noticing many dead trees scattered around the locality. Blind Freddy couldn't miss the connection between this drought, climate change, and the burning of fossil fuels. Also see The big dry: forests and shrublands are dying in parched Western Australia on the University of WA site. Home Top Index These, and the many other dead or dying trees that I have seen were in Andrew Hastie's electorate of Canning, where I live. Mr Hastie has chosen to oppose renewable energy and ignore the climate change problem (see on another page on this site) for the sake of political and personal advantage. CSIRO: Australia's changing climate; a quote... "The drying trend is particularly strong between May to July over southwest Western Australia, with rainfall since 1970 around 20 per cent less than the average from 1900 to 1969. Since 1999, this reduction has increased to around 26 per cent." (I have expanded on the climate change problem, particularly as it impacts WA, on another page on this site.)   This section added 2022/05/03 Dead trees in the Peel estuary

A very few of the thousands of dead trees in the Len Howard Conservation Park (there can be little doubt that the deaths are due to climate change). I think that these particular ones are in what I have called the Spoonbill Rookery near Mandurah Quay.

Home Top Index Anyone walking on the Len Howard Trail (through Len Howard Conservation Park) can't help noticing the number of dead trees in and near the small swamps and lagoons. It seems that the swamps were all once host to healthy Melaleuca trees, but they can no longer support them. The most obvious possible cause for this would be an increase in the salinity where the trees are. It is not easy to find out if this is definitely the cause. On another page I have noted tree deaths in Black Swan Lake, Lakelands, in the period from 2018 to 2024.   A summary The text in this section can be summarised as: It seems most likely that the tree deaths are due to increased salinity in the estuary and that the increased salinity is due to decreased runoff which itself is due to climate change. Salinity record On 2022/04/13 Dr Steve Fisher, Operations Manager, Science and Waterways, Peel-Harvey Catchment Council - Provided me with data from “the Marine and Freshwater Research Laboratories (MAFRL)  from five  sites in the estuary between the 1970s and mid 2001. From these data I found that the average of all the top salinity recordings at site #2 (near Dawesville and Falcon) from 1977 to 1994/04 (when the Dawesville Channel was constructed) was 25 parts per thousand (ppt), bottom salinity 27. After that time, up to mid 2001 when the data series ended, the averages were 32 and 35 respectively. From that, for what it is worth, the top salinity (having the greatest relevance for the trees) has increased by 28% since the construction of the Dawesville cut.   More dead trees Dead trees adjacent to the Len Howard Trail. Far more can be photographed by a drone. The fine-stemmed creeper on the left is, I believe, one of the obligately parasitic Cassytha species (that in SA, but apparently not in WA, is called snottygobble). The tree on the right is commonly called a paperbark, probably either Melaleuca cuticularis, salt water paperbark, or Melaleuca rhaphiophylla, swamp paperbark. Most of the dead trees are probably of the same species. Photo iPhone 11 Pro, 2022/05/05 From the above it does seem that the average salinity in the estuarine system has increased. My impression, again, for what it is worth, is that the increased salinity is likely more to do with decreased rainfalls since the 1970s (itself due to climate change) than due to the construction of the Dawesville Channel. Quoting from a Water Corporation publication, Climate change and WA - Climate and Southern WA: “A 20% drop in rainfall may not sound very dramatic until you understand the impact it has on streamflow – the water that runs off into our dams and other storages. The decline in rainfall throughout Perth and the South West has seen streamflow reduce by an average of over 80%!” It seems that rainfall and runoff is likely to continue to decline into the future. Quoting Climate projections for Western Australia; Rainfall projections published by WA department for Primary Industries and Regional Development: “The drying trend in the south-west will continue as greenhouse gas concentrations increase according to the modelling. The projected changes differ a little from the observed changes in recent years. There may be an increase in synoptic systems bringing helpful rainfall to the northern and eastern grainbelt and south coast, but the projected drop in the number of deep low-pressure systems means much less rainfall for the west-coastal regions and far south-west. The overall increase in atmospheric pressure over southern WA will likely drive a shift to a more settled weather regime, with more highs persisting for longer.” The reference was marked "Page last updated: Thursday, 15 April 2021." Seasonality of rainfall Just by the way, I have noticed that the annual rainfall in Mandurah is much more concentrated in the cooler half of the year, especially May to August than it was back in Clare, SA, where I used to live. In Mandurah 2/3 of the annual average rainfall occurs in the 1/3 of the year from May to August, 3/4 of the annual average rainfall occurs in the five months from May to September. Average rainfalls for Mandurah (from BoM) Jan Feb March April May June July Aug Sep Oct Nov Dec Total Mean rainfall 14.5 12.0 15.8 39.9 83.2 117.7 115.5 93.2 58.7 31.2 22.8 13.9 603.9 A very dry period In late 2023 and 2024 the official recorded rainfalls for Mandurah were: Dec 2023 Jan 2024 Feb March April Total Mandurah rainfall 0.6 0.0 1.8 1.2 0.8 4.4 I believe that this was a record low rainfall for the beginning of the year. The very dry period came to a sudden end on 2024/05/02 when I recorded 30mm, mostly in a very heavy downpour at around 3pm. The rainfalls that I recorded at Erskine were: Dec 2023 Jan 2024 Feb March April May June July August Erskine rainfall 0.6 0.0 1.9 0.9 0.0 97 117 173 144 The winter of 2024 was wetter than average, with a total of 528mm for the four months May to August. Home Top Index   This section added 2022/08/11 Len Howard Conservation Park Weeds in and near the LHCP   A fleabane outbreak in the BSPS I've written on another page about the infestations of invasive weeds into the Len Howard CP and nearby area and on my efforts to control several of the most conspicuous and invasive offenders. The patch of fleabane in the image on the right was in the southern part of the big seasonal paperbark reserve. Note that it is on a slight mound; I suspect that the surrounding area is seasonally flooded and that this kills any fleabane seeds in the soil. I sprayed this patch on 2023/01/05 Photo iPhone 11 pro, 4.25mm focal length standard lens, 2023/01/05 Lightning blasted and charred tree The photo on the right is of a lightning blasted Casuarina tree beside the concrete shared-use path adjacent to the Len Howard Conservation Park - on Glendart Court. Perhaps surprisingly this was not the tallest tree in the area, but it wasn't far off. I wonder why it was hit rather than another tree? Perhaps it was a better electrical conductor? The splitting of the bigger trunks and the charring of the top part of the tree are shown in more detail in the following photos. These photos were taken using a Cannon Ixus 190 on 2022/08/11 a few days after the lightning strike. Most of the tree was killed by the lightning strike, but a small section was still alive at the end of 2022. It had entirely died by early February 2023. Lightning blasted tree trunks Note that the largest trunks, on the right and left, have been split. I believe this is caused by the moisture in the tree flashing to steam due to the heating effect of the high electric current. The top part of the lightning blasted tree. Home Top Index To see the top part of the tree and the charring in more detail click on the image.   This section added 2023/06/11 Unnecessary and destructive widening of the paths in the Len Howard Conservation Park   An appropriate width for a path in the LHCP Photo iPhone 11 Pro, standard lens (6.25mm), 2023/06/08 Over a few days in early June 2023 the two paths running east from the car park to several hundred metres past the boardwalks were widened and sheeted, impacting on the adjacent native vegetation. They were quite wide enough before this. Where work was warranted was to the NE of the boardwalks where water puddles form in the low points of the path. Widening of the paths would have been justified if this was a recreation park, but it is supposed to be a CONSERVATION park! Surely conservations parks should be more about conserving nature than destroying it! The section of path in the photo is further east than the widened section. In wet weather there are many puddles such as the one here. The low points where puddles form could be filled by a couple of people with loam and wheelbarrows in a day, but I suspect that machinery is (over)used partly at least because it is less physically demanding.   A section of the widened path Photo iPhone 11 Pro, standard lens (6.25mm), 2023/06/11 The Parks and Wildlife Service, which is responsible for this park and presumably ordered the work, state that they "protect and conserve the state's natural environment". Yet here they are unnecessarily destroying a part of the natural environment. The Parks and Wildlife Service is a part of the Department of Biodiversity, Conservation and Attractions. I suspect that Len Howard, if he was still alive, would be disgusted with this operation. Home Top Index At the time of writing it remains to be seen how effective the widened paths will be, especially since they were graded flat, with no crowning in the centre to run the water off to the sides. No culverts were installed to run water under the paths where necessary. The improvement of the surface of the path is welcome, but the 'improved' part is twice as wide as it needs to be. I have written about a similar widening of a different part of the LHCP paths under A backward step on another page on this site.   Boulder placed to stop vehicles Photo iPhone 11 Pro, standard lens, 4.25mm, 2023/06/15 As the path was it was too narrow for vehicles. When widened the path became wide enough to tempt irresponsible people to drive illegally through the Len Howard Conservation Park, so this boulder needed to be put in place. I have spent many hours in removing invasive weeds and rubbish from the Len Howard Conservation Park and its vicinity (see another page on this site). This mismanagement of the park, by the organisation that should be protecting in, is very disappointing. A section of the path that needs attention   Pond and bog in the trail Photo iPhone 11 Pro, standard lens, 4.25mm, 2023/08/17 This part of the trail desperately needs attention from The Parks and Wildlife Service. It seems to be getting worse each winter. A small fraction of the amount of money that was spent on the unneeded path widening discussed above would have fixed this mess. It is in the LHCP adjacent to the Bridgewater Lifestyle Village. It is almost impossible to get passed dry shod. There are one or two other ponds in the path nearby, but this one is by far the worst. Home Top Index I contacted the Parks and Wildlife Service about this problem on 2023/08/17. Another page on this site discusses why so many people (including myself) are inclined to just walk by something that is not as good as it should be instead of doing something about it.   This section added 2022/07/26 The big seasonal paperbark swamp (BSPS) in the Len Howard Conservation Park

Photo iPhone 11 Pro, focal length 6mm (telephoto), 2022/07/24.

How the swamp came to be a reserve On 2022/08/08 I was told by an employee of the City of Mandurah that a condition of the development of the Bridgewater Lifestyle Village was that the swamp area had to be kept in its natural state as a reserve. Both areas were owned by the same people,   Responsibility for the BSPS The parts of the reserve outside of the paved paths are Council responsibility, the inner part is the responsibility of the Parks and Wildlife service.   Weeds I did not immediately realise how badly the BSPS reserve was infested with weeds, particularly fleabane and false onion weed. Some of Mandurah's parks are very well looked after, others are relatively neglected. I have made a project of removing these weed species to the best of my ability. This swamp, which doesn't seem to have a name (but should have) is either a part of the Len Howard CP or is at least adjacent to it (I've not seen a definitive map of the park). I have previously called it the 'big ephemeral paperbark swamp' but considering that it contains a significant amount of water for several months from winter onward it seems that 'seasonal' is more appropriate than 'ephemeral'. In 2022 Erskine had a wet winter, by my records there had been 129mm of rain in May, 148mm in each of June and July and about 70mm in the first third of August. Consequently by this time the swamp was full and overflowing into the main estuary pool. I've written elsewhere on these pages, with photos, on the swamp through the seasons. When was the big seasonal paperbark swamp (BSPS) empty, full, overflowing in 2022? I don't seem to have recorded when the swamp started overflowing, it was probably at least a couple of weeks before I took the photo above, that is, early July. Surface flow from the swamp into the estuary stopped on 2022/09/28.) Home Top Index Observations on water in the BSPS, 2023 The first part of the year was drier than normal, I recorded only 103mm up to the end of May, the BoM average to May is 170mm (2/3 of the annual rainfall usually falls in the four months from May to August and 3/4 in the five months from May to September). There are only two small water courses, that I have called gutters for want of a better name, leading into the BSPS. Both on the eastern side. 2023/06/06:11:30, water has just started flowing into the swamp through the northern of the two gutters. By my records there had been 41mm of rain in the previous week.   Filling without surface flow, 2023/06/17 This photo was taken on 2023/06/17. There had been very little rain to the beginning of June. In June there had been about 140mm, but there had been negligible surface flow into the swamp. Photo iPhone 11 Pro, standard lens 2023/06/10, 17:30, a trickle only in the northern most of the two gutters into the BSPS. The southern one was still dry. By my records there had been 103mm of rain in the previous two weeks. In the two and a half weeks to 2023/06/17 there had been about 140mm of rain but negligible surface flow into the swamp. Yet, as shown in the photo, there was a large pond in the centre of the swamp. 2023/06/21, 172mm of rain in June so far, 24mm in last 24 hours; a trickle in the northern gutter, southern one dry. There was a total of 177mm of rain in June, 115mm in July. The swamp started overflowing on 2023/08/15 following 70mm of rain to that date in August, 27mm of that in the previous 24 hours. At the time there was not much more than a trickle in the northern of the two drains; it seems that most of the water in the swamp either comes directly from rain or from groundwater. The swamp stopped overflowing within a few days one side or the other of 2023/09/08. Observations on water in the BSPS, 2024   A drone image of a part of the BSPS taken 2024/08/20 See here for more information. As mentioned elsewhere on this page in the five month period from December 2023 to April 2024 there was only 4.4mm of rain. According to my records this was followed by 94mm in May, 117mm in June and 173mm in July. On 31st July the BSPS was not overflowing, but the next day it was. There was a further 65mm or so over a couple of days in mid August and this resulted in very high water levels in the BSPS and a substantial flow out into the main lagoon. On 2024/08/23 I estimated the flow out of the BSPS at 10 litres per second. On the tenth of September is was down to 1.5L/sec., 12th about 0.5L/sec., 13th a small trickle, and by 2024/09/15 there was no visible flow.   This section added 2024/01/03 Observation on lack of undergrowth in the Big Seasonal Paperbark Swamp (BSPS) In the portion of the Len Howard Conservation Park that runs along the Peel lagoon the undergrowth, where it has not been cleared for paths, is so dense that it is very difficult to walk through. However, shrubby undergrowth is almost entirely absent from the BSPS. Home Top Index Local shrub species probably can't grow in the section of the swamp that is seasonally flooded (the flooded section of Marlee Reserve is similarly free of shrubby undergrowth). However, the lack of shrubby undergrowth in the other parts of the BSPS seems to me likely to have been due to heavy grazing before it became a reserve. Strange white algae in Len Howard Conservation Park This striking and strange fibrous material, that appeared to be a dried up algae, was left behind when the saline water from what was a shallow seasonal swamp within the LHCP dried away. The most likely cause for the death of the trees in this area, as discussed elsewhere on this page, is climate change resulting in increased salinities in the lagoons, but it is not a simple situation. I've also noted the impact of climate change in the Clare Valley of South Australia. Photo iPhone 11 Pro, wide angle lens, 1.54mm focal length, 2023/10/31 A close up of the white ? algae. The key is there for scale. Click on, or touch the image to see higher magnification. The fibres look quite glassy when magnified. Home Top Index The width of the field of this image is about 11cm. The width of the magnified image field is about 7cm. Photo Canon Ixus 190, 2023/11/02 The ocean beach at Mandurah I've placed photos of some of the ocean beaches on another page on this site, but this particular photo deserves a spot on this page of observations. Seaweeds are classified into green, brown and red types. It looks like all three could be in this tidal zone pool. Cottesloe Coastcare Association, a Perth group, has a page on seaweeds. Photo iPhone 11 Pro, standard lens, 4.25mm fl, 2023/11/03

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Wildlife Bandicoots   Southern brown bandicoot Southern brown bandicoot (Isoodon obesulus, another common name for it is Quenda) Photo Canon Ixus 190, 2022/02/28 There are bandicoots in the more densely scrubby areas along the lagoons of Mandurah. This one was near the Serpentine River in Greenfields. It was sitting quietly beside a path and a man was already sitting on the path when I arrived. I wonder if he had attracted the bandicoot by feeding it? I have since seen several more bandicoots in the Novara Beach Reserve. They seem most likely to be seen at dusk, dawn or night time. Generally, but not always, they are inclined to run into cover quickly after seeing a human. Kangaroos

Kangaroos at a feeding station that someone maintains adjacent to the Len Howard CP
Photo taken 2022/03/16, Canon Ixus 190

Home Top Index The kangaroos that live in the Len Howard CP are very relaxed around people. Many times we have seen them grazing on someone's front lawn. I've seen one hop through a front gate to do some grazing in mid morning. In the period at least from February 2022 to the end of 2022 there was a mob of 25 or more kangaroos resident in the BSPS. If anything these kangaroos are even more relaxed around people than those that use the feeding station mentioned above. The most relaxed one of them all is possibly the injured kangaroo mentioned elsewhere on this page.   Photo 2022/05/25   Photo 2022/08/13 Added comment Early this morning (2022/05/05), when there was hardly any daylight, I was walking through the little reserve at the western intersection of Silverton Crescent and Wattleglen Avenue on my way to do a fortnightly plasma donation when I saw a kangaroo in front of me. It casually did a couple of hops in the direction I was walking a couple of times then stopped, stood up to its full height - to intimidate me - and stood as I walked past about three metres away. At its full height it was only a little shorter than me (I am about 1.8m tall). Injured kangaroo - two photos on the right This kangaroo had a badly injured mouth, but was grazing peacefully when I photographed it. It is one of the big seasonal paperbark swamp (BSPS) mob. Home Top Index Photo iPhone 11 pro, telephoto lens, focal length 6mm, 2022/05/25 I happened across the same kangaroo again on 2022/08/13. The second photo on the right is the best I could get at the time. It looks like the injury has healed quite a bit, but the kangaroo's mouth is never likely to return to anything like its original form. Click for a more detailed image of the mouth area. Use back-arrow to return. Photo iPhone 11 Pro, telephoto lens, focal length 6mm. Updates I came across this kangaroo again on 15th August and 25th September 2022, 2nd of January and 2nd of February 2023. In January she was obviously carrying a large joey in her pouch, so she has done very well; in February the joey was following her around. The injury was still conspicuous, but not so much as it was in the earlier sightings. Oddly she seems tamer than most of the swamp mob, I wonder why. On the February sighting there was a young joey near her. I happened to see her again on 2023/05/12. I could not get a good photo, but I think her mouth looked much the same as it did in 2022/08/13. She did not have a joey following her. I happened across her again on 2023/08/11. She obviously had a fairly large joey in her pouch - the second one I've seen her produce. Again, her mouth looked much the same as it did in 2022/08/13. On 2024/02/26 I saw her again. Her second joey since the injury was still with her and about 2/3 grown. She seems to have gradually become less comfortable with me getting close to her. The first few times I saw her she was so tame that I had the impression she might have once been someone's pet. A cheeky kangaroo In my 78 years I've only once had a kangaroo threaten me. Home Top Index On 5th June 2024 this buck was grazing among the trees I had planted in the little reserve at the back of our house. I stopped to get a couple of photos. Then when I got my bike and started to wheel it past him he stood up to his full height (probably about 1.7m or so, almost as tall as me) and took a couple of little hops toward me. I just continued on my way. He didn't carry through with his threat. They can be dangerous if they rear back on their tail and kick with their hind legs. I've put a couple stout sticks nearby. If he does it again I'll wack him. Also see bird wildlife in my backyard on another page on this site.   This section added 2022/05/04 Lizards   Bobtail lizard (Tiliqua rugosa rugosa) Wikipedia, Tiliqua rugosa The lizard that I have always previously called the sleepy is generally called the bobtail in WA. The local variant is Tiliqua rugosa subspecies rugosa, the eastern variant is Tiliqua rugosa subspecies asper. This was the first lizard that I can recall seeing in the three months that I had been in WA, and to that time I had not seen any snakes at all. It was between Dampier Avenue and the scrub adjacent to the lagoon. Home Top Index Lizards of many species were common in SA, they seem less common in this area of WA. Update 2023/02/08 I have now seen three snakes, probably dugites (Pseudonaja affinis, also called the spotted brown snake) and there are many small skinks about, between about 4cm and 10cm, although they will not usually be noticed until they move for some reason. And I've seen at least one dragon lizard, perhaps a bearded dragon.   This section added 2022/07/26 Bats   Update January 2023 I still haven't seen any bats. While I have watched for bats on my frequent walks in the early morning and occasionally evening, I don't recall ever seeing a bat in the Mandurah area. With so many mosquitoes to provide food for microbats I would have expected bats to be quite common. I did wonder if the frequent aerial treatment, by helicopters, to reduce mosquito numbers had wiped out the local microbat population. But I read information sheets from the City of Mandurah stating that the mosquitoes numbers are controlled with very specific larvicides (S-methoprene) and Bacillus thuringiensis israelensis. So it seems unlikely that the mosquito treatments would account the the apparent low bat numbers. I've been told that some bat roosting boxes have been placed, so perhaps the low numbers are related to a lack of roosting sites - perhaps that may be connected to the great numbers of dead trees?   This section added 2023/08/03 Plants Sundews These sundews were among a number growing by the concrete path adjacent to Silverton Crescent on the edge of Len Howard Conservation Park. Home Top Index They are insectivorous plants that supplement the nitrogen that is available from the soil by capturing small insects and digesting them. Another plant on this page is the curious white algae of the LHCP. Yellow lichen On 2024/03/19 I took this photo of one of only a couple little patches of bright yellow lichen that I was able to find in the Big Seasonal Paperbark Swamp in Erskine, a Mandurah suburb. I suspect that this lichen is probably the yellow on the photo taken in Araluen Botanic Park. The small dark green buttons left of centre are interesting. Possibly very small lichen plants? The photo was taken using a Canon Ixus 190 pocket camera. It covers and area about seven centimetres across.   This section updated 2023/01/03 Dog water Home Top Index Many people walk their dogs around the Len Howard Conservation Park area. In the summer months there is very little or no fresh water available for dogs to drink in the area. Someone maintains a watering point mainly for kangaroos in the big seasonal paperbark swamp (I wish there as a shorter and generally accepted name for that) from about the end of the year until about May when water starts to become available in the swamp itself. I'm sure that dogs use it too, although it is difficult for small dogs to use because of the high sides of the container. There is also a tap at the car park near "Nature's Eye".   This section added 2022/05/06 Rubbish Just as around where I used to live in South Australia there is rubbish scattered carelessly around the Mandurah area. I intend to continue cleaning up this rubbish in my new neighbourhood. Today I picked up a bag full in the little reserve area at the western junction of Silverton Crescent and Wattleglen Avenue. It is common for people to dump garden waste in the local parks. Home Top Index I came across a shocking amount of rubbish in the patch of scrub adjacent to the Riverside Primary School on 2022/05/09, apparently left by someone who was sleeping rough. I made no attempt to pick it up. As discussed on another page on this site, there needs to be a noun for the type of careless, irresponsible, lazy people who do this sort of thing.   This section added 2022/06/26 Vandalism Senseless vandalism exists in Mandurah as it does in most other parts of the world. Some hundred or so of the plants I put into Crystal Brook Central Park back in SA were pulled up be one or more vandals. Fortunately, to the time of writing, few of the plants that I've put into a small park near my new home have been damaged by vandals. Dumping rubbish, discussed above, is a form of vandalism. Valdalism at the train station car park I noticed on 2022/07/03 that about a half dozen large recently planted trees adjacent to the new multi-story car park had been broken off. There was only one or two that had been left undamaged. By the 5th they had all been removed. Home Top Index Vandalism of my tree guards 2022/07/07; see the page on my projects in the Erskine area.   This section added 2022/07/29 Weeds As is the case with most of the public places with which I am familiar there are weeds in Mandurah, adjacent public paths and in parks and gardens. I find the unwillingness of the great majority of the local people to take part in the improvement of their public places puzzling.   Reprimanded for digging out weeds To my amazement on 2022/08/01 a ranger reprimanded me for digging out dune onion weed from one of the parks in Erskine. I've written on my efforts to remove some of them on my page titled Fleabane. I've speculated on how people look after their private gardens but don't bother with their shared places, and commented on Whatever happened to civic pride? in relation to the unwillingness of the general public to take part in improving their public spaces. And I've written on contribution on another page. I've written on another page of how the opportunistic dune onion weed (Trachyandra divaricata) invaded the area after the Halls Head Giant, Santi Ikto, was built. It took less than a year from the official opening of the Halls Head giant, in November 2022 for onion weed to become thoroughly established. Self or community? I suspect that selfishness is a factor in people's unwillingness to look after public parks and gardens, as it probably is in the unwillingness of many to donate blood (only some 3% of Australians donate blood or blood products). On the subject of selfishness, there are many private jetties in the Mandurah area, most have signs on them telling other people to keep off. Surely reasonable use by the public would be unlikely to harm the jetties or inconvenience the owners? Home Top Index Odd comments Why would anyone want to remove weeds from parks? I have made a project of working at improving the parks and paths in my local area. It seems to me only natural that I should want to do this. Yet I get the impression that many people find it hard to understand my actions or motivations. I, in turn, find it very hard to understand their lack of understanding; do they not think that we should care for our public places? Or do they just think, "It's not my job. Let somebody else do it."   Related work In addition to the onion weed removal that brought about this section, I've also pulled out fleabane and picked up rubbish. Perhaps the people who can't understand my work at controlling onion weed would find this equally inexplicable? About mid July 2022 I was hoeing out onion weeds adjacent to one of the paved trails in the big seasonal paperbark swamp east of my home when a man stopped and asked: "Why are you doing that?" as if my purpose was unimaginable to him. Was he unusual or would it be so incomprehensible to many that a person would want to remove weeds from a conservation park? 2022/07/24, another man stopped and said: "I've got to ask, why are you doing that?" I said something like "I'm digging out weeds; they have no place in a public park." Several other possible answers came to mind after I had thought about it for a while: Would you dig a weed out of your garden? Why then not out of a public park? Do you not care about weeds in your public places? I dig weeds out of my garden, why should I care less about a public park? If I am unwilling to try to improve our public places, why should anyone else? If no one cares for our parks what will become of them? If you have to ask you will probably not understand my answer. This is a beautiful park which the people of Mandurah are very lucky to have. Removing the most conspicuous, unsightly and invasive weeds can only improve it. Is caring for our shared environment such an uncommon thing to do? My page on contribution covers the point in depth. My notes on self or all and the rights and needs of future generations are also relevant. Home Top Index Primewest, Erskine shopping centre: a lost opportunity to reduce greenhouse emissions and increase profitability at the same time?   Prime West shopping centre, Erskine, WA A great opportunity lost. And a careless waste of electricity. In August 2022 car park shades were installed in the Prime West, Erskine, WA shopping centre car park. The shades were plastic mesh, not solar PV panels, a lost opportunity. Had solar panel shades been installed rather than simple shade sails most of the power consumption of the shopping centre could have been offset and a huge amount of greenhouse emissions avoided (most of Western Australia's power is generated by coal-fired power stations). I estimated that the area covered by the shade sails was 1,320m2, twice that of the Woolworths, Clare, shades, so had solar PV panels been used rather than shade sails the installed capacity would be around 280kW. Such a solar PV installation would generate about 490 megawatt-hours of electricity each year and that could reduce WA's greenhouse CO2 emissions by something like 400 tonnes each year. I've written a page on solar PV shade in car parks and other places elsewhere on this site. In 2022 solar PV panels typically pay for themselves in about five years. In this case where the cost of installing the shade cloth sails would have been avoided, the payback time would be shorter. PV panels also have the advantage of casting denser shade than shade cloth, so the cars beneath the panels would be cooler in summer. A waste of electricity for needless lighting too Note in the photo too that the lights beneath the shades are on, as are the two tall floodlights that can be seen in this photo. There were about 40 of each types of lights in the shopping centre car park. So far as I have been able to tell all were left on 24 hours a day. The shopping centre is open only from 8am to 6pm most days (Sundays 10am to 5pm, plus to 9pm on Thursdays) so outdoor lighting would only be necessary Thursday evenings and evenings in winter. On 2022/09/18 I emailed Prime West telling them about the lights being on all the time; I didn't ever receive a response. A letter to the editor and a result On 2022/09/30 I wrote a letter to the local newspaper on both the above points. It was published in at least one (Mandurah Coastal Times) a few days later. On 2022/10/12 I noticed that the car park lights were off.. One can hint and push but it is a rare thing to get a definite result such as this one. Having the car park lights on only when needed (if that is what happens in future) will reduce greenhouse gas emissions by something like 30 tonnes each year. Other shopping centre owners are far more progressive In Western Australia for example Northam Boulevard (article in The West Australian), belonging to Perdaman Group, 2,211 panels in total, 900 of these shading the carpark, and Dunsborough Centrepoint shopping centre (article in The West Australian).   Home Top Index In my home state, SA, there are big solar shaded carpark installations at Vicinity Centres (claimed to be the biggest in Australia at the time of construction, 1,400 panels on the car park alone) and Castle Plaza (430 solar shaded parking spaces). Also see my page on solar car park shades. Development? Progress? Mandurah is a fast growing city in what was, not so long ago, a mostly undisturbed area. It seems that the soil was too poor for it to be attractive for farming and whatever pastoralism there was didn't much impact the more coastal areas. However, development has come to Mandurah in a big way in the last few decades.   Seaside vegetation in its natural state I'm sure that there is a story in these three photos, but I can only guess at what it may be. This first image was recorded just south of the Dawesville Cut. It seems to be largely untouched native heath vegetation, outside of the shared walking/cycling path. The high-rise buildings are at The Cut Golf Course. Tree graveyard   Tree graveyard I didn't know what to make of this area when I first came across it, several hundred metres further south than the area in the photo above. It was the third photo (below) that gave a clue to what happened here.   Home Top Index These photos were all taken with my iPhone 11 Pro on 2023/08/03.   'Developed' golf course This golf course, "The Cut Golf Course", was on the inland (eastern) side of the foreshore dune and the above photo. I suspect that when the bush was cleared for the golf course the developers were not allowed to burn all the removed vegetation so they carted it over the foreshore dune and dumped in the 'tree graveyard'. Google Earth gives the impression that the 'tree graveyard' extends for the kilometre or more of the golf course. We can only hope that the heath will eventually recover where it has been so greatly disturbed by the machinery and the dumping of the ripped out bush. Note the kangaroos in the distance on the golf course. Why walk past, why not fix it?   A fence partly obstructing a path Thousands of people (including me) have walked past this fence in the more than a year that it has been in place and done nothing. Many people use that path every day. I’ve used that path many times. The fence was unnecessarily partly obstructing the path adjacent to a busy roundabout and shopping centre for at least a year. It made it harder for cyclists, pedestrians, people with prams, mobility problems, etcetera to pass each other; and there was the danger of a vehicle-pedestrian accident. Why were we all so unwilling to do something about it? I suspect it didn’t occur to most of us that we could do something about it. Why did the council allow the fence to encroach on the path when there was no need for it? Why did I put up with it for so long before I did something about it? Home Top Index I've written more on this subject on another page on this site.   This section added 2023/11/17 A fire in a reserve near my home I intend to observe the recovery of the bush in this area over the next few years.   The burned area Photo iPhone 11 Pro, wide angle lens, 1.54mm fl, 2023/11/15, the day of the fire There was a fire in a small reserve near my home in Erskine. I was informed by a firefighter who was there later in the day extinguishing smouldering remnants that it was not a controlled burn. It seems likely to have been lit by a fire bug. I have adopted some responsibility for removing invasive weeds in this reserve as recorded on another page on this site. I've called it the W/S (Wattleglen-Silverton) reserve for the adjacent roads and because it seems to have no formal name. About a quarter of the little reserve was burned.   Similar perspective as the above photo, ten months later Photo: iPhone 11 pro, 2024/09/19 There was another fire in a different part of the same little patch of scrub on 2023/11/18. I took the photo on the right partly because of the Xanthorrhoea flower spikes, partly because it was another record of this area as it recovered from the fires, but mostly because I thought it a very beautiful view. The tree in this photo is the same one as on the left in the photo above. Update, 2024/11/18 Home Top Index I noticed three burned patches in a chair that I had placed in the reserve a few months earlier. The chair was about 30 metres on the upwind side of the fire, so it would seem very unlikely that the burned patches were caused by sparks from the fire. I estimated that between the two fires two thirds of the reserve has been burned. I've heard that it was a 12 year-old boy who lit both fires and that the police had been informed. I've written about vandalism in other places in Mandurah elsewhere on this page.   This section added 2024/05/04 Regrowth in the burned area   After a long, hot, dry summer Photo iPhone 11 Pro, 2024/05/04 This photo was taken a couple of days after the first significant rain of 2024 following the very dry five months from the beginning of December 2023 to the beginning of May 2024. There was 4.4mm over the five months, and 30mm in the first few days of May. After the fires in 2023/11/15 and 18th there was ten millimetres of rain in late November then 4.4mm in the following five months. Remarkably, in spite of the long, hot, dry summer (one of the hottest and driest on record), there was a lot of regrowth in the little reserve. After having all been burned right down to ground level, as can be seen in the photo taken the day of the fire, some of the small yaccas had grown up to 90cm high. The top 10cm or so of leaves on many had died and gone brown, perhaps this was due to stress from the lack of moisture. Burned area drone image   Bush block on western intersection of Wattleglen Avenue and Silverton Crescent Image DJI Mavic Mini drone, 2024/09/07 The image on the right shows the bush part of the small reserve after several months of recovery. Home Top Index There had been a wetter than average winter, with 94mm of rain in May, 117 in June, 173 in July and 144mm in August, a total of 528mm for the four months. The grass trees (yakkas) were sending up many flower stalks at the time of the photograph. A period of exceptionally low tides   Lake Goegrup There was an exceptionally low tide in the few days around 10th December 2023. The local newspaper reported that two young dolphins were stranded in this lake, twice. It seems that the very low water levels were due to strong and persistent offshore winds. Photo iPhone 11 Pro, telephoto lens, fl 6.0mm; 2023/12/11, 08.52 A record of the tides; the black line on the graph shows what the calculated tide was expected to be, the blue line shows the actual recorded tide level. Home Top Index The red line on the lower graph shows the difference between the two. It reached a maximum of about 0.33m about 3am on the morning of Sunday 10th. It seems that the tide recording station in near the mouth of the Peel estuary, quite a way from Lake Goegrup. Climate change Climate change is hitting the SW of WA as hard or harder than most other places. The climate is drying significantly and the amount of run-off into reservoirs has declined enormously. In the Peel estuary there are huge numbers of dead trees and as I've written elsewhere on this page there seems little doubt that climate change is the ultimate cause. CSIRO: Australia's changing climate; a quote... "The drying trend is particularly strong between May to July over southwest Western Australia, with rainfall since 1970 around 20 per cent less than the average from 1900 to 1969. Since 1999, this reduction has increased to around 26 per cent." (I have expanded on this on another page on this site.) The WA Water Corporation has reported that "An average 20% decline in rainfall throughout the South West has seen streamflow reduce by over 80%." The WA government has announced the building of the state's third sea-water desalination plant. Just the first stage of this plant is expected to cost $2.8 billion. Do the people of Mandurah respond to this obvious and very important local change in the climate by changing their lifestyle in any way? It would seem not. Just one example: I've seen that at least on the one occasion that I made an observation and simple calculation, only about 1% of the local people use busses rather than driving. An aurora At a latitude of 32.6° aurora's are very rarely seen from Erskine (or Mandurah). All these photos were taken with my iPhone 11 Pro, using the standard lens camera, 4.25mm focal length 2024/05/11. For some reason the wide angle camera did not show the aurora at all; apparently lacking the sensitivity of the standard camera. Home Top Index We went to a car park on the Peel Lagoon near our home because it had a clear view toward the south and there were no large towns in that direction. When we first arrived we could barely see that there was a slight glow near the horizon. We immediately found that photos using our phones showed the aurora better than our naked eyes. This was the aurora at the time we arrived, 1712hrs. The green is from oxygen, purple, blue and pink are caused by nitrogen (from the Royal Museums Greenwich Web site). This photo was taken at 1924hrs. The town light glow in about the middle of this photo is probably from the small town of Waroona. The green glow seemed to only be visible close to the horizon. It seemed to not vary much, and became less easily seen at the red glow brightened. Looking more toward the east than the others in this group. The lights of Pinjarra can be seen on the horizon in the centre. The constellation of Scorpio (The Scorpion) is in the centre of the image. More easily seen in the high-definition version of the image (click on the image on the left). Sagittarius is right of top centre. 1928hrs This photo, taken at 1931hrs was about as bright as the aurora got while we were there. A few minutes later is was dimmer again. Home Top Index Probably Waroona lights on the far right horizon.   This section added 2024/09/06 Reserves and remaining bush nearby The patches of remnant bush in this section are all near my home in the border area of Erskine and Falcon. Clearing of a block of bush   Bush block on Wattleglen Avenue Image DJI Mavic Mini drone, 2024/09/06 Click on the image to see the bush area in higher definition. It seems that the patch of bush in the centre of this photo is privately owned. It has been in roughly its current condition since Denece and I moved to Erskine in February 2022. Some rubbish gets dumped in it, and some people 'test-drive' their SUVs around its sandy tracks, but apart from the vehicle tracks and the strip against the roads the native bush is not greatly degraded. Wattleglen Avenue is conspicuous on the left, Old Coast Road is just behind the service station and Binnar Crescent is in the right foreground. The Indian Ocean is in the distance. Home Top Index We noticed that temporary fences had been built around it a few days before this photo was taken. It seemed likely that this was in preparation for some sort of development. On enquiring at the Council office I was told that development permission for a self-storage installation on the eastern of the two allotments (about 40%) of the land had been granted. Update 2024/09/10   The cleared block Image DJI Mavic Mini drone, 2024/09/10 Click on the image to see it in higher definition. As shown in the photo on the right, almost all of the bush in the area was cleared. The work was done on 2024/09/09. Significantly it was the whole area that was cleared, not just the part that Council informed me had been granted a development approval. My family and I were saddened to see this bush cleared. There has been, and is continuing to be, a huge amount of bush being lost to 'development' in the Mandurah area and any loss so close to home will be a personal blow. Stormwater sump on Wattleglen   Stormwater sump and bush block on Wattleglen Avenue Image DJI Mavic Mini drone, 2024/09/06 The scrubby patch on the left with the pond is one of the stormwater sump reserves that are a part of the Mandurah landscape. This is one of the few that has not been fenced off. Home Top Index The scrubby block on the right is the one in the photo above. It was cleared three days after I took this photo. This stormwater sump does not usually contain any water, but it happened that this photo was taken just after a wetter than average winter. Also see the section on this page about a fire in a reserve near my home. That also involves a block of local native bush.   This section added 2024/11/11 A new bridge over the estuary

New bridge being built on the near side of the older bridge
Photo DJI Mavic Mini drone 2024/11/11

Estuary Bridge, several kilometres on the Peel Lagoon side of the Town Bridge, has been a traffic bottle-neck for several years, especially in the morning rush hour when there is only one lane to take the traffic toward Perth (there are two lanes taking traffic the other direction on this bridge). Home Top Index It is not easy to see what is happening with the duplicate bridge while driving across the old bridge, and nothing at all of the construction can be see from the walking-cycling path which is on the the north side of the old bridge below the vehicular traffic lanes. This overhead view may be helpful. I may take more photos as construction progresses. Construction started on the duplicate bridge in early 2024 and is due to be completed in late 2025. There are other drone photos from this vicinity on another page on this site.

A sunset: the last minute The following photos were all taken over a period of less than a minute on 2024/05/18 with an iPhone 11 Pro using the telephoto camera (6mm focal length) and digital zoom. Given that there are 360° in a full circle, the angular diameter of the Sun in our sky is about ½° and the Earth rotates (relative to the position of the Sun in the sky) a full circle in 24 hours, it can be calculated that the Sun appears to move its own diameter across the sky about every two minutes. So it is about two minutes from when the Sun first touches the horizon to the time it disappears below the horizon (it can be significantly longer if the Sun is 'moving' at a low angle across the sky). Home Top Index This photo was taken at 17:24:56 Western Australian Standard Time. We are lucky to have clearer air in the Southern Hemisphere than in the Northern Hemisphere because of far fewer people and far, far less air polluting industries. The Indian Ocean coast of Western Australia has particularly clean air because it comes, generally, from the west and the closest continent is Africa about 8,000 kilometres away (the island of Madagascar is about 7,000km away). The air on this day was unusually clear even for WA. I could not comfortably look at the Sun at any time while even a small part of it was above the horizon. Taken at 17:25:29 Taken at 17:25:35 Taken at 17:25:42, a few seconds after the Sun had gone below the horizon. Miscellaneous observations Catamaran with side-by-side masts

This is something I’ve never seen before, even in photos or drawings. The two masts are side-by-side, one on each of the catamaran’s hulls. The multiple masts I’ve seen previously have always been in line. I suppose this is more experimental than anything else; if a side-by-side mast system did turn out to be viable a lot of experimentation would need to be done to work out the best way of doing it. Home Top Index It was anchored at the Mandurah foreshore on 2023/08/13. I didn't see any name on the hull, but 'Ozone' was on one of the booms. A quick Internet search produced only one page that dealt with a side-by-side mast rig: Some reasons why I have chosen a side by side rig. The page is dated 2014 and pictures show a gaff rigged model; the full size boat may not have been built. Diagonal solar panels   Photo iPhone 11 Pro, 2023/07/20 These are the first solar panels that I can recall seeing that were installed diagonally. They were on the western side of the Big Seasonal Paperbark Swamp in Erskine and adjacent to the Bridgewater Lifestyle Village. The reason for placing these diagonally is obvious. Given the shape of the roof sections this was the best way that ten panels would fit. Why is placing them diagonally so rare? I don't know. They reminded me of the triangular solar panels that I saw in Japan where space was at a premium and it was important to use as much roof space as possible for a solar power installation.

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