as fuel. First all the peat down to the groundwater table was dug away. In the 16th century a method was developed to dig peat below water, using a dredging net on a long pole. Large scale peat dredging was taken up by companies, supported by investors from the cities. These undertakings often devastated the landscape as agricultural land was dug away and the leftover ridges, used for drying the peat, collapsed under the action of waves. Small lakes were created which quickly grew in area, every increase in surface water leading to more leverage of the wind on the water to attack more land. It even led to villages being lost to the waves of human-made lakes. The development of the polder mill gave the option of draining the lakes. In the 16th century this work was started on small, shallow lakes, continuing with ever-larger and deeper lakes, though it wasn't until in the 19th century that the most dangerous of lakes, the Haarlemmermeer near Amsterdam, was drained using steam power. Drained lakes and new polders can often be easily distinguished on topographic maps by their different regular division pattern as compared to their older surroundings. Millwright and hydraulic engineer Jan Leeghwater has become famous for his involvement in these works. Control of river floods Three major European rivers, the Rhine, Meuse, and Scheldt flow through the Netherlands, of which the Rhine and Meuse cross the country from east to west. The first large construction works on the rivers were conducted by the Romans. Nero Claudius Drusus was responsible for building a dam in the Rhine to divert water from the river branches Waal to the Nederrijn and possibly for connecting the river IJssel, previously only a small stream, to the Rhine. Whether these were intended as flood control measures or just for military defense and transport purposes is unclear. The first river dikes appeared near the river mouths in the 11th century, where incursions from the sea added to the danger from high water levels on the river. Local rulers dammed branches of rivers to prevent flooding on their lands (Graaf van Holland, c. 1160, Kromme Rijn; Floris V, 1285, Hollandse IJssel), only to cause problems to others living further upstream. Large scale deforestation upstream caused the river levels to become ever more extreme while the demand for arable land led to more land being protected by dikes,