This Earthcache will take you to the Hepburn Springs area.

For this cache you will start at the Wyuna Spring.

Wyuna Spring

Wyuna ‘spring’ is actually a ‘bore’ that was first drilled near the eye of Wyuna Spring during the 1930s. The existing hand pump belongs to Wyuna bore, which is located about 5-10 m from the eye of the actual natural Wyuna Spring and was drilled in 2002–3. The original Wyuna Spring (New Spring), is also referred to as ‘New Domed Eye’. It emerges from the plane of a thrust fault probably associated with Milkmans Reef. The special significance of the original Wyuna Spring eye was that it stopped flowing in the period 1910–1912 due to reef mining activity further to the south. Flow recommenced gradually after the North Frenchman’s mine was closed in January 1912 and the water levels in the bedrock aquifer gradually recovered. Mineral water from the original Wyuna spring was piped down the valley to the bottling cellar at Pavilion Spring. At this time and later Pavilion Spring was supplemented by water from Locarno Spring. Wyuna contains reasonably high levels of sodium and the highest amount of gas of the Hepburn springs.

Where do Mineral Springs come from

The hydrologic cycle All water forms part of a process known as the hydrologic cycle. Water evaporates from the sea, clouds form and eventually the water falls as rain. Much of the rainwater evaporates again fairly quickly. Some of it seeps into the ground and it may be thousands of years before it emerges to become part of the cycle again. This depends on how far it sinks and how slowly it is moving through the aquifer (where it is stored).

The aquifer Water in the aquifer does not flow freely as in a stream, but fills up all the holes, cracks and cavities in the rock and flows very, very slowly. As rock is made of tiny grains of different minerals, so the water naturally absorbs some of these.

Groundwater All groundwater therefore contains some minerals. The wrong balance of minerals makes the groundwater brackish. The right balance makes it excellent drinking water as the lack of air underground means there is no bacteria in the water. This means the quality is excellent even though it may be extremely old, like the bore water at Sale or Portland. So why is the mineral water around Daylesford different to other drinkable groundwater? The essential ingredients that makes it so special are not only the unique balance of minerals that give the water its special taste but also the carbon dioxide. Carbon dioxide Carbon dioxide is gas that comes from deep within the earth and is probably volcanic in origin. It rises up through cracks and where it can get through to the aquifer, it mixes with the water making it effervescent. The mineral springs are also always cool and refreshing. This is because they maintain a constant temperature in the ground.

How mineral springs are Formed

(see diagram)

The water in mineral springs starts out as rain. Much of the rain water evaporates again fairly quickly or runs off into our streams to be eventually carried back to the sea.

Some of the water, however, seeps into the ground to enter an aquifer - consisting of fractured rock which holds water - where it is stored.

This groundwater in the aquifer flows very slowly, percolating throughout all the cracks and holes in the rock eventually come out at a natural spring.

Read question 1 below, and now take a walk over to the Sulphur Spring at S 37° 18.723 E 144° 08.569 (wp2) for the next part of this Earthcache.

Sulphur Springs

Sulpher Springs is approximately 120 m downstream from the Wyuna Spring. The original spring had a 5 m deep bore drilled and equipped with a pump in 1930. Landscaped with semi-circular free stone rock surrounds, Sulphur is located beside a rustic stone bridge on the other side of the creek. The new bore was drilled in 2006 and is equipped with a ‘bilge’ style pump. Between Sulphur and Locarno the creek flows underground through a pipe providing public circulation space and picnic and play areas in an otherwise relatively narrow valley. Upstream from Sulphur the valley of Welshmans Gully narrows slightly and mineral water can be seen seeping along the cracks and slab separators in the concrete paths between Sulphur and Wyuna bores. .

Log the Cache

To Log this EarthCache, please send an email with answers to the following questions to our Geocaching.com account.

1. Your caching name and the EarthCache name

2. At the Wyuna Spring have a taste test of the mineral water, also note the level of sodium and Sulphate in the water.

3. Have a taste test of the water at the Sulphur Spring, which spring has the stronger Sulphur taste?

4. Why do you think the different levels of Sulphate occurs.

5. Ignoring the man made structures at the 2 Springs (pumps and rock walls), what natural feature differences are there?

6. If you like include a photo of yourself at GZ, but please don’t include a picture of any of the questions as we will need to delete the photo.

    

   Sources:-

   http://web.archive.org/web/20130303180450/http://www.mineralwater.vic.gov.au/history/where-do-mineral-springs-come-from/

   http://web.archive.org/web/20120331141249/http://www.mineralwater.vic.gov.au/regions/otway-basin/