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.)
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.
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
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
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.
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.
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.
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."
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
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.
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.
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.
I suspect that Len Howard, if he was still alive, would be disgusted with this operation.
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.
One wonders, how long will it be before someone drives around the boulder?
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 vandalism of the park, by the organisation that should be protecting in, is very disappointing.
It is in the LHCP adjacent to the Bridgewater Lifestyle Village.
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.
Photo iPhone 11 Pro, focal length 6mm (telephoto), 2022/07/24.
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.
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.
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.
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.
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
Click on, or touch the image to see higher magnification. The fibres look quite glassy when magnified.
Photo Canon Ixus 190, 2023/11/02
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
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 at a feeding station that someone maintains adjacent to the Len Howard CP
Photo taken 2022/03/16, Canon Ixus 190
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.
Added commentEarly 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 rightThis 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.
I did not see this kangaroo again in the next two months, at least I did not see a kangaroo that I recognised as this one.
I happened across the same kangaroo again on 2022/08/13. This is the best photo 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.
UpdatesI 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 so as it was in the earlier sightings. Oddly she seems tamer than most of the swamp mob, I wonder why. On the February siting 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 mount looked much the same as it did in 2022/08/13.
Also see bird wildlife in my backyard on another page on this site.
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.
Update 2023/02/08I 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.
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?
Another plant on this page is the curious white algae of the LHCP.
There is also a tap at the car park near "Nature's Eye".
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.
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.
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 parkI 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.
Vandalism of my tree guards2022/07/07; see the page on my projects in the Erskine area.
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:
Primewest, Erskine shopping centre: a lost opportunity to reduce greenhouse emissions and increase profitability at the same time?
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 tooNote 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.
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 progressiveIn 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).
Also see my page on solar car park shades.
However, development has come to Mandurah in a big way in the last few decades.
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.
It was the third photo (below) that gave a clue to what happened here.
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 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?
I've written more on this subject on another page on this site.
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.
Photo iPhone 11 Pro, wide angle lens, 1.54mm fl, 2023/11/15, the day of the fire
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
It seems that the tide recording station in near the mouth of the Peel estuary, quite a way from Lake Goegrup.
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.)
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.
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.
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.
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.
On this site...Bowman Park, Crystal Brook, South Australia
Cleaning up roadside rubbish
Climate change, the world's great threat and challenge
Destruction of roadside vegetation by a body that should be protecting it
Gleeson wetlands, Clare, South Australia
Offshore wind farms in Australia, why the world needs them and how to find reliable information on them.
Specific to WAA photographic record of a visit to the South of WA
Fleabane, my efforts to remove it in and near the Len Howard Reserve, and similar local environmental improvement projects
Mandurah volunteer workers; keeping in touch
Mandurah, a note on conspicuous consumption
On this page...Abbreviations and names I've used
Big Seasonal Paperbark Swamp, in the Len Howard Conservation Park
Observations on water in BSPS, 2022
Observations on water in BSPS, 2023
Catamaran with side-by-side masts
Dead trees in the Peel estuary
Diagonal solar panels
Water colour change
Fire in a reserve near my home
Len Howard Conservation Park
Lightning charred tree in Len Howard CP
Section of path needing attention
Letter to the editor and a result
Names and abbreviations I've used
Ocean beach at Mandurah
Path widening in the Len Howard Conservation Park
Primewest, Erskine shopping centre, a lost opportunity
A period of exceptionally low tides
Pond and bog on trail
Swamp, seasonal, in the Len Howard Conservation Park
Seasonality of rainfall
Section trail that needs attention
Self or community?
Solar panels, diagonal
Swamp, how it came to be a reserve
A period of exceptionally low tides
Lack of undergrowth in the BSPS
Water colour change
Weeds in and near the LHCP
Weeds; Odd comments
White algae in Len Howard Conservation Park
Why walk past, why not fix it?
Why would anyone want to remove weeds from parks?
Widening of the path in the Len Howard Conservation Park