Tuesday, July 28, 2009

The Power of Water

Damaged bridge in Wilket Creek Park

The storm from this past weekend was strong enough to severely damage a pedestrian footbridge in Wilket Creek Park. Just south of Edwards Gardens, the storm water washed away the stone and gravel from around the footings of the bridge. The bridge is anchored by 4 steel pillars and that is all that is left standing. The power of the water flow is evident in how the armour stones placed along the stream banks were knocked around like pebbles.

All but the bridge footings have been washed away

2 tonne armour stone blocks tossed around like pebbles

A similar bridge just downstream shows where the armour stone is supposed to be

This type of storm damage now occurs about once a year. About a year ago, a similar storm caused similar damage to bridges in this ravine. Fortunately the bridge is well anchored so it's only a matter of reconnecting the bridge to the path to fix it up. However, problems like this are likely to reoccur until the underlying problem of too much stormwater runoff is resolved.


steve s said...

The temporary crossing at the Forks also washed out completely this weekend. The last time it did that was the first weekend in May during a big storm. We watched it happen.

Donwatcher said...

I saw that too but that temporary bridge is only made up of sand and gravel. Any over topping of water from the creek would wash it away. The Wilket Creek flood was similar but was powerful enough to move the armour stone. Now that's impressive!

Anonymous said...

Was this one of the bridges the City rebuilt after the last flood? If so they clearly need to rethink their designs as these kinds of flash-floods are not going to stop any time soon.

Donwatcher said...

Given the amount of water that flows during storms and the addition of woody debris carried by the flood waters, I don't think there is anything reasonable the city can do to solve the bridge problems on this very popular footpath. The best way to solve the problem is to prevent the storm water inputs into the creek. Until that happens I suppose we'll just have to learn to live with it.

Anonymous said...

If it's the same stretch of creek that's south of the Civic Garden Centre, that creek has blown out every year for the past 10 years and was rebuilt every time. They have to do a much better job of rebuilding as well as stormwater control or they're just wasting our money.