In May 1998 an Ethiopian farmer refused to drain water from upstream plots over his land. He blocked the flow and drained the water down the slope along the boundary of his plot. As soon as the first heavy rains of the season fell a month later, a gully was created 300 metres further down the hill. In the 15 years that followed, this gully grew 230 metres long, 70 metres wide and 8 metres deep, eating away the plots of six households; and it continues to grow.