Scientists have dated sharp-edged flakes of stone found in the fine-grained sediments of a dry riverbed in the Afar region of Ethiopia to between 2.52 and 2.60 million years ago.

科学家们已经确定，在埃塞俄比亚阿法尔地区干燥河床的细颗粒沉积物中发现的具有锋利边缘的石片存在于252万至260万年前。

They dig out nests in the riverbed and lay their eggs.

它们在河床上挖巢产卵。

As a result of fluvial scouring and aggrading the riverbed, the alluvial layer is fluid-saturated porous medium.

由于河流冲刷和河床加积，沉积层多饱和多孔。