Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search


Many rivers are low and could go lower

Many rivers are low and could go lower

NIWA’s National Centre for Water Resources is warning water managers and users to be prepared for low water levels in rivers, hydro lakes, and groundwater over the summer.

‘Mean river flows for spring were the lowest on record for large parts of the South Island, and for parts of the North Island,’ says NIWA hydrologist Charles Pearson. ‘Last month, we saw a sharp contrast in the North Island between record high river flows in Gisborne, and record low river flows in parts of Taranaki, the central plateau, Wellington, and the Wairarapa. In the South Island, river flows were the lowest on record for November in much of Marlborough and Nelson, and in parts of Canterbury and Otago.’

Over the next three months, the water resources outlook is for normal or near-normal soil moisture and river flows in the north and east of the North Island but generally dry conditions for the rest of the North Island and all the South Island.

‘There’s a high probability of below normal river flows and soil moisture in coastal Canterbury and east Otago. This is likely to exacerbate the low groundwater levels already reported by Environment Canterbury. Irrigation may well continue to be under pressure in the east,’ says Charles Pearson.

The snowpack in the Southern Alps is below normal levels due to poor snow in winter, which is contributing to the below-normal hydro lakes.

Water quality is likely to be poorer than normal in unusually low flowing rivers and in the lakes and coastal environments they feed. This increases the risk of algal blooms.

‘During low flows, the river is not as effective at scouring algae off the riverbed. This is exacerbated by the reduced dilution of nutrient-rich groundwater getting into rivers, and by increased water temperatures. Filamentous green algae love these conditions,’ says NIWA river ecologist Dr Barry Biggs.

‘The algae smother bed sediments needed for insect and streambed life. We’ll also see low dissolved oxygen levels, leading to stress or death in invertebrates on which adult fish feed. As rivers dry up, fish become confined to deeper pools and experience stress from high temperatures and low dissolved oxygen levels,’ says Dr Biggs.

© Scoop Media

Business Headlines | Sci-Tech Headlines


Nurofen Promotion: Reckitt Benckiser To Plead Guilty To Misleading Ads

Reckitt Benckiser (New Zealand) intends to plead guilty to charges of misleading consumers over the way it promoted a range of Nurofen products, the Commerce Commission says. More>>


Half A Billion Accounts: Yahoo Confirms Huge Data Breach

The account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (the vast majority with bcrypt) and, in some cases, encrypted or unencrypted security questions and answers. More>>

Rural Branches: Westpac To Close 19 Branches, ANZ Looks At 7

Westpac confirms it will close nineteen branches across the country; ANZ closes its Ngaruawahia branch and is consulting on plans to close six more branches; The bank workers union says many of its members are nervous about their futures and asking ... More>>

Interest Rates: RBNZ's Wheeler Keeps OCR At 2%

Reserve Bank governor Graeme Wheeler kept the official cash rate at 2 percent and said more easing will be needed to get inflation back within the target band. More>>


Half Full: Fonterra Raises Forecast Payout As Global Supply Shrinks

Fonterra Cooperative Group, the dairy processor which will announce annual earnings tomorrow, hiked its forecast payout to farmers by 50 cents per kilogram of milk solids as global supply continues to decline, helping prop up dairy prices. More>>



Meat Trade: Silver Fern Farms Gets Green Light For Shanghai Maling Deal

The government has given the green light for China's Shanghai Maling Aquarius to acquire half of Silver Fern Farms, New Zealand's biggest meat company, with ministers satisfied it will deliver "substantial and identifiable benefit". More>>


Get More From Scoop

Search Scoop  
Powered by Vodafone
NZ independent news