Sunday, June 28, 2009


We've been looking at the water catchment area near our home. We had a great walk to the source of our local stream (see left for source of Puhinui Stream) and then walked downstream where we noticed other 'feeders' swelling the flow of the stream. Pretty boggy in parts, wet feet when we got home, but good fun and great to be outdoors. Intrigued by how water collects and then forms into a stream we decided to create an aquifer at home in an old fish tank.

Creating the aquifer was quite easy. First make a layer of sand at the bottom of the tank with a bit of a hill in one corner. Next spray water onto the sand until it starts to pool. Don't pour water onto the sand, but spray and be patient as the water needs to soak through.

With wet sand lay two pieces of clay on top of the sand. The gap between the clay pieces will represent a river. Make holes in the sand and push drinking straws through. These straws will be trimmed later and represent boreholes or wells. On top of the clay put some small stones or pebbles and then trim off your straws. (Full details can be found in Mary Gardner's book Investigating New Zealand Waters).

Next we sprayed water on the pebbles and noticed how the water made its way to the river. We also "polluted" the area by dropping food colouring into the bore holes or onto the stones. It was fascinating to see how quickly things became "polluted", the area affected and how difficult it was top clean it up afterwards. It was good to get water from a bore hole and see how our pollution of the area affected the quality of water we obtained from the bore. Very interesting and rather worthwhile I thought.

This week is the bird survey week I mentioned previously. We've been entertained by the silver eyes on our makeshift bird feeders. We strung a wire between the house and a tree and then hung inverted plant pots from the wire. Using this technique we've been able to get some feeders very close to the house which enables us to get a good close look at the feeding birds. The silver eyes are sufficiently acrobatic to get the food from the feeders, the sparrows wait on the ground for bits to fall off. Great fun, very entertaining and educational :-)

A few more pictures of the silver eyes are here. In case you're interested it was quite a dull day. Shots taken at ISO 3200, focal length of 300mm in 35mm speak, f5.6 and 1/320sec. Images have been cropped slightly. Let me know what you think.

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