Megafauna mega-find: the extraordinary discoveries at Diamond Valley Lake

Construction of a huge Californian reservoir had just begun when bones started to emerge - and turned out to be a vast treasure trove of Pleistocene fossils

In the early 1990s, the Eastside Reservoir project - eventually simply referred to as Diamond Valley Lake - was announced. Planners intended to create an enormous reservoir to act as Southern California's emergency water supply. It would require a huge excavation, and accordingly, an Environmental Impact Report (EIR), a requisite before construction could commence, was commissioned.

When complete, the EIR indicated there would be few fossils of any significant scientific value; should any fossils be found, they would be fragmentary at best. Construction was therefore given the green light, and the heavy machinery moved in.