Hello Warin61

I agree that the DCS NSW Base Map shows this area as water but that map is not always correct and, as I recall reading in a recent post on talk-au, we don't want OSM to be just a copy of the Base Map. When I looked at satellite imagery from various sources I could see little water. I agree that there is sometimes water there but it seems to me that surface water is so infrequent in this stream (unlike other streams in the vicinity) that natural=wetland better describes the actual situation. 

I have been researching water in the Lachlan and Murrumbidgee areaa as a personal interest. One significant document published a couple of decades ago, "A history of the ecology and flows of the lower Lachlan River and its distributaries" from https://www.researchgate.net/publication/324559709 (author was Patrick Donald Driver of NSW Department of Planning, Industry and Environment, dated January 1999) does not even mention Coolyamba Creek. This creek does not carry the more significant water that appears in nearby waterways such as Merrowie and Merrimajeel Creeks. I have visited the area and travelled on Alma Road and Cobb Highway but I have no recollection of anything significant at Coolyamba Creek.

As I said above, I do not see the DCS Base Map as always accurate. Natural=wetland was my best judgement for the area along Coolyamba Creek. I'm doing my best but you are possibly more experienced and better informed than me. If you think it best to re-map these areas as intermittent water, then please do so.

Thanks for contacting me.
