Tumut

 

Atmosphere & Weather | Biodiversity | Catchments | Resources Use

A cloudy future for the Tumut River ?

This "snapshot" profile celebrates a recent environmental initiative within this LGA.

After the Snowy Mountains Hydro Scheme commenced, the Tumut River was destined to have an artificial and inverted flow regime. The Scheme captures and stores most of the snowmelt, and then releases it through the hotter months to maximise electricity generation and water supply to the Murrumbidgee, supporting the food bowl of NSW.

So, the Tumut River runs fast and high in summer, slow and low in winter and its exaggerated high and low flows create erosion and channel changes. To date, $27 million has been spent to maintain channel capacity through snag removal and realignment, and rock armoring of the banks in areas of aggressive erosion.

This late June 2008 photo shows the extreme low flow levels now associated with winter. The Tumut River was running at 200 megalitres per day compared to the 9,000 megalitres it can reach on high flow days.

This late June 2008 photo shows the extreme
low flow levels now associated with winter.
The Tumut River was running at 200 megalitres
per day compared to the 9,000 megalitres
it can reach on high flow days.

Climate change is likely to reduce snow and rainfall and, hence, water availability. Recent Tumut rainfall appears to bear this out, being 67% of an average year in 2005, only 38% in 2006, 81% in 2007 and 2008 again heading below average. Tumut’s figures reflect the full Snowy Scheme with storages around their lowest levels since construction.

In an attempt to improve water supplies, the Snowy Mountains Authority has been running a cloud seeding trial. Seeding technology is not new but the experiment will gauge its efficacy in the Snowy Mountains: there is some indication that seeding to date may not have made a significant difference. Low water in the Snowy catchments will lead to higher supermarket food prices and lower farm incomes until the drought abates.

Historically, little consideration was given to the Tumut River's combined Social, Economic and Environmental values. The NSW Department of Water and Energy’s draft Tumut River Management Plan aims to redress that by managing the river to incrementally improve its environmental values while improving social and economic values. In a time of climate change, funding constraints and competing management priorities, the Plan’s integrity will be tested.

 

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