During the Second World War, gravel was extracted from these pits for the construction of local wartime air fields. With time, the pits flooded and the reserve is now a Site of Special Scientific Interest for its many species of flora and fauna. The lakes are one of the best places for dragonflies and damselflies in Bedfordshire, with no fewer than 18 species known to have bred here. The nearby River Great Ouse brings in even more species, with adults hunting over the water and grassland.
Wildfowl congregate on the open water including great crested grebe, teal and tufted duck, while grey heron hunt along the banks. Chiffchaff, reed bunting, and sedge and willow warblers can all be found on site.
In deep water areas, rare plants such as whorled water-milfoil and bladderwort have established, while the shallower margins are dominated by reed and common bullrush. Islands that were formed by extraction now support alder and yellow and purple loosestrife.