Dam level, river flows hit new low

DOLPHIN sightings in the Clarence River have been on the increase as flow rates in the catchment hit record lows and residents prepare for water restrictions.

Water NSW data indicated the Nymboida Weir and Clarence River at Lilydale experienced some of the lowest flow rates on record on Thursday. Meanwhile Shannon Creek Dam dipped to its lowest levels since it was first filled in 2010, prompting Clarence Valley Council to introduce mandatory water restrictions.

"The community's water supply in Shannon Creek Dam is dropping every day," a council spokesperson said.

"The water level is now the lowest since the dam was first filled. When the dam drops to 80 per cent. Level 1 water restrictions start. This is likely to happen before Christmas."

For all areas supplied from the Nymboida River, water restrictions will be cancelled when water flows exceed 225 ML/day for 14 days.

Level 1 Water Restrictions:

▪ No outside garden watering between 9 am and 4 pm

▪ No sprinklers or unattended hoses

▪ Water efficient drip or spray systems - 15 minutes every 2 days

▪ Hand held hoses - 1 hour every 2 days

The graphic shows the steady flowrate decline at the Nymboida River weir during November, 2019.
The graphic shows the steady flowrate decline at the Nymboida River weir during November, 2019. Water NSW

Shannon Creek Dam harvests water from the Nymboida River, where the flowrate has steadily declined. The last significant rainfall event saw the flowrate spike to 2792 megalitres per day on July 6. It dropped to 122ML/d by September 17, rising back up to 301ML/day on September 23, then steadily declined down to 59ML/day last Friday, prompting 2GF presenter Richie Williamson to bring the low flows to attention on his breakfast program last Monday.

"The weir at Nymboida's been taking records since 1908 and on Friday it was the lowest ever flow over the Nymboida ... at just a shade over 50 megalitres," Mr Williamson said.

"In the 2013 flood it was 450,000 megalitres. I think highlights just how dry it is."

The flow continued to decline, dipping below 50ML/d for a short period on Thursday, to 49.36ML/day. After showers in the catchment on Thursday night, it returned above 50ML/day to 51.09ML/day at 2.10pm on Friday.

The record low for the Nymboida Weir is 18.2ML/d on February 4, 2003 according to NSW Water data.

The Clarence River at Lilydale has also experienced a steady decline since recordings in excess of 2000ML/d in early July and hit its lowest point of 35.9ML/d on Thursday. On Friday it had risen slightly to 42.4ML/day.

Coinciding with the low flowrates has been an increase in dolphin sightings in upper reaches of the river.

Leading Clarence Valley ecologist Greg Clancy said dolphins were an 'indicator species' of higher salinity in brackish waterways that have not experienced recent freshwater flushes.

"In our normal dry season we see greater salinity, which is indicated by different salt water species further upriver, including dolphins, which have seen as far upriver as Rogan Bridge," Mr Clancy said.

"They do tend to come up when there's more salt in the water.

"Without actually measuring the salinity in the water, we do have these indicator species, such as dolphins and crested terns, that give you an idea there is more salt in the water than wetter times."

"It's an incredibly dry season that we've got."

The Daily Examiner received a huge response from its followers on Facebook after we first heard reports of a pod of dolphins spotted in the vicinity of the Grafton Bridge:

Leah Bancroft: We have seen dolphins in the Clarence River in Grafton over the past few weeks. Lots of them!

Christine Lynch: There have been dolphins in the river in front of the B and B at Seelands as well.   Heidi Lolic: Have seen them past the ski lodge in Mountain View.

Janet Kleindienst: Husband and I saw a pod of dolphins heading up the river heading towards the bridge from the Fry St boat ramp. I was very surprised but Peter had seen dolphins in the river before.

Matt McLennan: Yes we do surf boat training on the river for Minnie Water Surf Club and we see them from time to time. We launch out of the sailing club.

Judy Wainwright: Been out front of South Club a few times in last few weeks.

Susie Anna: There were a heap of them at Corcoran Park a few weeks ago.

Nicko Campbell: At Kirshner St two weeks ago pod of six or so dolphins chased a school of mullet into the bank. Was an awesome sight.

Charlene Brooks: Near the Ulmarra Ferry a couple of weeks ago.

Racheal McIvor: Wow!! A couple of months ago we seen a massive sting ray on edge of Grafton Bridge.

Jamie Peterson: Racheal McIvor my mate caught one just down from the bridge.   Tony West I would be more concerned about the size an amount of bull sharks in the river at the moment.