Through a carefully controlled sequence, semi-desert lands planted first to grasses and then to shrubs and trees can be protected against wind erosion. As vegetation flourishes it increases dew formation and rainfall. Plant roots prevent runoff and retain the water in gulleys and low places. Evaporation builds up moisture content in the atmosphere.
A ride of fifteen miles through a finely wooded country brought us to the Lake Eleanor dam-site and the municipal camp, where general preparations are being made and runoff records are being taken. In a comfortable log house two assistants to the engineer spent the winter, keeping records of rainfall and other meteorological data.
Half an hour later he'd filled his emergency containers with a day's worth of drinking water and settled Tarlac as comfortably as possible into the runoff stream. It wasn't ideal, but at least it would keep the fever down and the injuries mostly clean while he did what he could to make the cave defensible. He discovered quickly that he could do very little.