cork flood defences

corkgsxr

Why dont they just dredge the river again. Thats the cause isnt it? They stopped dredging years back . Silt builds up river cant hold the volume.

sensormatic

are these people's our leaders so help me

pwurple

The cause is that Cork is built on a marsh. A flood plain next to a massive deepwater harbour.

I think we should embrace our watery overlords and get some canals and gondolas in.

RoyMcC

There's another viewpoint (certainly in the UK) that dredging increases the problem by making the rivers more efficient and rushing extra volume downriver into the populated areas.

corkgsxr

RoyMcC wrote: »

There's another viewpoint (certainly in the UK) that dredging increases the problem by making the rivers more efficient and rushing extra volume downriver into the populated areas.

But your doing the opposite here. Your dredging in the populated area and deep harbour. So it goes out faster

deRanged

I think the point is more that the river can only carry away a small percentage of the water landing in the floodplain. Even if dredging doubles the amount it can carry away, you're still only moving a small amount of the total, and what's left will still cause a flood.

That only accounts for rain/river flooding anyway, and tidal flooding is another story.

lostinsuperfunk

I saw the river being dredged near Horgan's Quay around a year ago. I even have a few photographs of it somewhere which I'll try and find and upload.

lostinsuperfunk

The recent floods in Cork were mainly due to a combination of high tides and storm surges. I am not sure, but I think dredging wouldn't help much with this issue. Perhaps it might help the flood to recede slightly faster, but I don't think it would reduce the size of the peak.

Pitcairn

Dredging the river won't prevent the tidal flooding that we had last week. The height of the tide is the height of the tide no matter how far down you dredge.

They only dredge the river channel for shipping purposes.

deRanged

there's a nice article on New Scientist explaining why dredging rivers doesn't work to prevent flooding.

The last paragraph is particularly telling.

murphym7

Pitcairn wrote: »

Dredging the river won't prevent the tidal flooding that we had last week. The height of the tide is the height of the tide no matter how far down you dredge.

They only dredge the river channel for shipping purposes.

Yip, this is the only reason the river is dredged, to keep the depth at the charted depths.

Red Nissan

corkgsxr wrote: »

Why dont they just dredge the river again. Thats the cause isnt it? They stopped dredging years back . Silt builds up river cant hold the volume.

Do you really mean the river?

The river is from the Dams to City Hall approx. No dredging was ever done on any scale in this section. Otherwise the river from The South Jetties and the sea lanes are dredged regularly.

Modern dredgers are very efficient and very fast and the general public would not be aware of their operation.

Calling for special dredging of the upper harbour might become an issue as the ports leaves town and all dredging commitments fall on City Hall, but that's a few years away yet. All new developments along the "Boggy Road" need flood defenses built in as the river will silt up as the commercial ship traffic moves to Ringaskiddy or Marino Point.

One may have heard in the media that the GAA's plans for O'Keeffe's Stadium development have been questioned, amongst the reasons, because they have NOT built in flood defenses, or adequately addressed the issue.

Red Nissan

RoyMcC wrote: »

There's another viewpoint (certainly in the UK) that dredging increases the problem by making the rivers more efficient and rushing extra volume downriver into the populated areas.

Indeed, the common thought process is for wide flood plains, this is what rivers do naturally and it is also the 'new' preferred coastal defense policy being introduced in the UK.

sensormatic

we all need to bottle the rainfall and use it in the house everyday