UPDATE: One of the signs is missing while the boardwalk is being upgraded. Here is the sign until it is replaced. (That should make it easier 
)
Where does the Water Come From?
This spring is associated with a massive limestone formation that extends north of Katherine and to the Queensland border. Although outcrops of the rock can be seen along the highway between Mataranka and north of Katherine, most of the limestone is below ground. Wet season rainfall absorbed into the porous limestone is heated by the earth before being released as crystal clear spring water.
Rainbow Spring and other springs of this region have long been known by local Mangarrayi / Yangman people. However it wasnt until WW2 when soldiers stationed at Mataranka dammed the spring, turning it into a relaxing swimming pool.
The secret of the Roper's flow.
The secret of the Roper River's constant flow lies in vast basins of water under the ground.
Huge reservoirs of water, 30 to 100 metres underground are heated to the temperature of the ground at this depth. The springs in Elsey National Park are not true hot springs in that there is no underground "hot spot" heating the water, just the normal temperature increase with depth.
At Mataranka's Rainbow Spring, water flows through the pool, out into the Waterhouse River and on into the Roper River.
Water flows underground from surrounding higher country down towards Mataranka and Roper River. Water that fell perhaps thousands of years ago and hundreds of kilometres away has collected in cracks and caves in the limestone here. Each summer, the wet season tops up these huge underground tanks.
Where the land surface has been worn away and cuts the underground water level, water flows out of the ground as springs.
Questions:
Please email me the answers and do not put them in your log entry.
Question 1 - What temperature is the water heated to?
Question 2 - How many millions of litres of water flow through the pool each day?