[talk-au] Lakes around Mungo National Park

[cleary]

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. 

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. 

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. 

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. 

Some lakes are farmed, although not in protected areas such as Willandra Lakes. The frequency and amount of water varies in different locations. In parts of the Darling system, periodic inundation provides rich silt deposits and farmers tolerate the occasional flood. In some areas, farmers use drainage or irrigation to manage the moisure on the farmed areas so that, while once wetlands,  these areas are now rarely inundated and I mapped them as landuse=farmland. In some areas, the farmland does get inundated more frequently so that I have mapped them as both farmland and either water or wetland, based on the best interpretation I could make of available information. Lake Tandou, near Menindee, was one of the more challenging.







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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