[talk-au] Lakes around Mungo National Park

Mon Feb 21 11:19:49 UTC 2022

I don't think "sand" is the right tag. When I visited Lake Mungo, there was vegetation on the lake bed and some parts would have been too soggy to drive on - the National Parks track crosses part of the lake but I think they had to survey it carefully to avoid the wetter sections. On the eastern side there was a sand beach - it really looked like a beach except there was no water. But the lake itself did not appear as sand.  Satellite imagery might be a good guide for the moment.

I do not have a photograph of Lake Mungo but I have just uploaded one of my pics of Lake Garnpang to Flickr if you wish to have a look. The lake bed was covered in vegetation and I think this is similar to my recollection of the other lakes in the Willandra area.  You can't zoom in very far when looking at Flickr but if you download the image in high resolution, you can zoom in and get a good idea of the appearance of the lake bed.  If it didn't occasionally get wet and boggy, I'd think of tags such as "scrub" or "grassland".  But our mapping need to recognise that it does sometimes get soggy. Remembering that wetlands are not necessarily wet all the time, perhaps natural=wetland + wetland=wet_meadow or wetland=marsh would be more accurate for these particular lakes.  

This link to pic of Lake Garnpang: 
https://flickr.com/photos/157067200@N03/51894707756/in/photolist-2n4KWCC-2inizwF-6hZHhz-6iGY24-6iGTAD-6iM7oY-6iMb1b-6i4PxQ-6i4Q4b-6i4S3y-6hZJx6-2ing4fe-2injKcg-2injK9W-2inizAP-2ing4dR-85TtMN-2m6cARv-TMAatS

On Mon, 21 Feb 2022, at 8:53 PM, Warin wrote:
> On 21/2/22 19:51, cleary wrote:
>> I too have struggled with correct tagging. I live in the city but I have enjoyed visiting western NSW and I have an interest in the waterways of the Murray-Darling river system. I have seen areas temporarily flooded on some occasions and the same areas dust-dry at other times. I think I am probably the person who mapped Lake Leaghur, among  others but not Mungo.  I have also mapped areas including up to Ivanhoe, so I may have been the person mapping other areas that Warin has mentioned.
>> 
>> One of the issues is the frequency of water in the rivers and lakes. Quite some time ago I proposed the key 'ephemeral' as being less frequent then 'intermittent' .. but then other suggestions came up and I put it on 'the backburner'.. 
> I recently add a time limit on the water presence to the proposal. I 
> think that puts it out of 'usefulness' for European mappers and may 
> lead to its rejection, if they cannot use it they don't like it.  
> I am inclined to add the tag 'ephemeral=yes' to much of Australia 
> inland water things. I recall the indigenous rangers at Lake Mungo 
> saying that the Lake has not been covered with water for about 15,000 
> years (when the Lachlan River forged a new course and a much reduced 
> volume now flows down what we know as Willandra Creek).  I am not 
> certain but I think none of the lakes of the Willandra Lake region has 
> been seriously submerged for many many years. Water flowing into the 
> lakes can make them soggy but not enough that one might contemplate 
> using a boat. I know NSW DCS Map shows the lakes as water but I recall 
> a national parks officer telling me that every year people arrive with 
> their boats based on what they see on maps but are disappointed as 
> there is never enough water even to swim, much less launch a boat. The 
> default OSM render does at least show 'intermittent'. I was not aware 
> of the 15,000 years, perhaps forgotten, makes water=lake be very wrong! 
> From the above I am incline to simply map them as sand areas with any 
> relevant names, and perhaps 'was:natural=water' with 'comment=water 
> 15,000 years ago'. 
> ?? Any objections? OSM is supposed to map the now not the history. 
> As I remember 'Lake Mungo' it had no suggestion of being a 'wetland' 
> there being nothing I could see that would suggest the plant growth I'd 
> associate with any wet area, 
> so I'd be reluctant to use the tag wetland. There is an area tagged 
> with some 'protected zone' to the west of Lake Mungo .. that on hte DCS 
> map (I don't recall which) has some small areas with 'dry' wetland  
> mapped. 
> Dry wetland out here to me means wetland with key intermittent=yes and 
> possibly ephemeral=yes too. For the above reasons,I would certainly 
> like to see Lake Mungo and other lakes in the Williandra Lakes region 
> NOT be tagged as natural=water (and, given the vegetation on the lakes, 
> I I think surface=salt would be incorrect). I know that "intermittent" 
> is open to interpretation but I think the absence of water cover for 
> 15,000 years is stretching the interpretation.  
>> 
>> As the areas do get soggy, support plant and animal life but would never be suitable for building etc. I think natural=wetland is the best tag for these areas.  Wetlands is a broad term but it generally applies to areas that are occasionally inundated and remain wet for extended periods but may also be dry at some times.  I have also visited areas such as the Gwydir Wetlands and Macquarie Marshes which are also along tributaries of the Darling and I see more similarities than differences. Wetland also apples to areas of permanent water too. 
> And I have mapped wetland areas that do have buildings on them - stumps 
> I would think would be used. These areas are shown on the DCS maps .. 
> the building there with the wetland and on the imagery. Many of the 
> areas are on private land and not easily accessed from public roads, 
> although there is a road through the middle of Lake Leaghur and Lake 
> Garnpang. I have used my occasional visits, brief conversations with 
> locals where possible, satellite imagery and DCS NSW Maps to try to tag 
> these areas as accurately as I could but people with more knowledge of 
> the area may be able to do better. There are two DCS maps - the 'Base 
> Map' that is fairly clear to map from and the 'Topographic Map' with 
> generally coarse features, this is the one than has the difficult to 
> interpret mapping of these 'lakes'. 
>> On Mon, 21 Feb 2022, at 6:25 PM, Warin wrote:
>>> Hi,
>>> 
>>> There are inconsistencies in tagging of 'lakes' around Mungo national 
>>> Park...
>>> 
>>> The DCS base map show them as lakes ...
>>> 
>>> I am not certain what the DCS Topo map is showing .. but they all the 
>>> same. I think it is 'intermittent lake' over 'sand'?
>>> 
>>> 
>>> A water lake one -
>>> 
>>> name     Lake Mungo
>>> 
>>> natural     water
>>> 
>>> surface     salt
>>> 
>>> water     lake
>>> 
>>> intermittent     yes
>>> 
>>> 
>>> vs the others e.g.
>>> 
>>> name     Lake Leaghur
>>> 
>>> natural     wetland
>>> 
>>> 
>>> Similar inconsistencies extend out to at least Ivanhoe.
>>> 
>>> 
>>> To my way of thinking they are lakes, dry most of the time, not wetlands.
>>> 
>>> 
>>> Thoughts? In particular the rendering of the DCS Topo map ... what is 
>>> their meaning?
>>> 
>>> 
>>> DCS Topo Legend 
>>> https://raw.githubusercontent.com/mholling/nswtopo-legends/master/nsw.png
>>> 
>>> 
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