Fresh water dune pools a mystery

AN interesting discovery of freshwater dune pools has been made by a Bushman's River resident.

Dennis Laubscher, a mining and geo-mechanics consultant, said he had found the pools about 100m to 200m from the high water mark.

"These pools are the result of water seeping some 400m under sand hills up to 49m high, covered with coastal forests and bush,” Laubscher said.

He explained that heavy rainfalls in the area in July and August last year resulted in the formation of a "lake” inland of the sand hills. The dimensions of the lake are about 1500m east to west by 300m north to south, with a bay extending north-west some 400m and a depth of up to 3m.

By September he observed seepage in low lying areas on the seaward side of the sand hills and pools started to form in the low lying areas between the dunes.

In January some of the pools measured up to 20m x 5m and 0.7m deep with small steams flowing into the pools.

On February 1 and 2 Bushman's River recorded 130mm of rain with the result the "lake” rose by some 400mm. A few days later the pools had risen 300mm.

"What is extremely interesting is the presence in the pools of amphibious insects and frogs. Where did they come from in what was a sterile environment?” he pondered.