The weekly wash-up (May 3)

The week that was in river and water news – May 3rd, 2013

Rainfall extremes were the main news this week as some parts of Australia head back into drought:

BHP’s river clean-up too slow for some   Miner BHP Billiton has been given until the end of 2016 to halt most of the pollution discharged from one of its coal mines into the Georges River south-west of Sydney. The NSW Environmental Protection Authority altered the pollution licence for BHP’s West Cliff and North Cliff collieries, requiring the miner to cut the salinity and heavy metals released into Brennans Creek and the Georges River.

georges river

The Georges River, south-west of Sydney

Great Lakes commission wants water levels in Huron, Michigan raised  Canada and the United States should look at building a new structure in the St. Clair River to raise water levels in Lake Huron and Michigan, the commission in charge of the Great Lakes says. Water levels in the lakes have remained below average for the past 14 years. The problem is often attributed to historical dredging in the St. Clair River, as well as long-term erosion, and sand and gravel mining. Those changes increased the flow through the river, lowering water levels in the lakes by an estimated 7 – 14 cms, according to the commission. But the biggest single contributor to declining water levels is changing climate patterns, which researchers estimate took 9 – 17 cms out of Huron and Michigan between 1963 and 2007.

A possible new way to manage water and snow in thirsty California  For the past few weeks, researchers from NASA and the California Institute of Technology’s Jet Propulsion Laboratory have been flying over the Tuolumne River Valley with sophisticated instruments that measure snow depth and area, as well as the amount of energy it absorbs from the sun. The new method provides an estimate of what the total volume of water is in the mountains. This will allow scientists to more precisely predict the volume of water that will come from the Sierra snowpack for 2.6 million people in the San Francisco area.

In Midwest drought abruptly gives way to flood  The midsection of the US, which was for months parched by severe drought, suddenly finds itself contending with the opposite: severe flooding that has forced evacuations, slowed commercial barge traffic down the Mississippi River and left farmers with submerged fields during a crucial planting time. It seemed a sudden, dizzying reversal for a region that had since last summer been contending with a drought that left water supplies in doubt, farm fields shriveled and water levels along the Mississippi River so low as to threaten, at times, to close down commercial traffic. By Thursday (Apr 25) , high waters and and the wreckage of more than 100 barges that broke loose from their moorings meant portions of the river were effectively closed.

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