Stream tales

Midsummer blues (or browns)

Since October last year I have been concerned about the new dams built upstream from us in Grimwade Road, Balingup. It was apparent that there were changes to the way the stream flowed as it left the property on which the dams were built and made its way to the properties below, including mine which I call Montaza.

The rate of flow in the watercourse at my place was considerably less than in previous years at the same time of year and there was a lower response to the smaller rainfall events probably because the dam water levels would need to reach a certain height before the water spilled over.

I decided to document the changes with that useful tool, the iPhone. The resolution is better than the digital camera I bought several years ago and the images transfer automatically to my computer.  Easy!

Here are a couple of sample records of the health of the watercourse in January this year, 2018.

IMG_7289

This image taken on 10 January 2018 shows part of the lower pond at my place, Montaza. It’s of a bay in the stream not quite on the main channel. Here the water has become stagnant because of the very low rate of flow. Leaves are almost stationary on the surface, scum has formed and bubbles suggesting lack of oxygen are on the surface. It looks very  off-putting. This is unprecedented since I bought the property in 2006.

The video of the lower pond was taken on the same day and shows just how unattractive the stream had become with its stagnant, slow moving current that allows debris to build up. A faster rate of flow would improve oxygenation and carry away surface material.

Over the entire warmer weather months we experienced the side-effects of the lower rates of flow, ie scum build up, high sediment levels and other forms of pollution.

Heavy rain brought some relief. There were several occasions when water was released suddenly because heavy rain was forecast and there were possibly concerns about the dam walls breaching. Some of this water may have been from the bottom of the dams which would be low in oxygen with rotting vegetation.

In the early hours of 25 May we received heavy rain and with the cooler weather the rate of flow increased. Cooler water temperatures also meant that algal blooms were reduced and the clarity of the water improved. Will there be an improvement in water conditions by next October when the warmer conditions return? We don’t know.

Most of the powers-that-be seem unable or unwilling to assist. Shire, state government agencies, politicians and other bodies have all been approached, but we’re still short of a solution.

All in all an unsatisfactory situation especially as there seems to be no way of achieving a round-table discussion with all parties, nor having anything like a management plan in place between us downstream landowners and the owners of the dams property.

Footnote: The banner photo at top is of the stream at Montaza taken in July 2006. I call the area near the handrail and steps up the hill The Knoll. Rhododendrons are now planted there. It had been very cold that year and some plants were damaged by frost. The steps are still in place and the handrail is about to be restored. Although we had very late rains that year, the stream was still flowing, clear and healthy.