The Nagambie Lakes sub-region has several highly distinctive natural features which combine to produce a marked influence on the mesoclimate and therefore on the quality of the grapes grown and resulting wines made in the area. Soil The soils of the Nagambie Lakes sub-region get their distinctive red color from iron, more particularly from its high ferrous oxide content. This iron gives it a valuable granular structure, allowing them to both drain well and hold moisture well. Another attractive feature of the soil is that the top layer sets hard when dry, preventing erosion. This top layer varies in thickness from between 10 and 50 cm throughout the region. Much of this rich red soil lies over ancient river gravel and sand, tangible evidence of an older, now inoperative river system. Many of these rambling ancestral streams and underground aquifers are still flowing today. Some vignerons tap into them for supplementary water. Interestingly, their flow rates are strong - much faster than those of existing streams. Proximity to a water mass In all, six distinct lakes and lagoons make up the Nagambie Lakes water mass. They cover approximately 2000-2500 hectares of the 13,5000-14,5000 hectares region; about 15-20% of the total defined area. The moderating effect of being located close to a large water mass is evidenced in climatic data collected at the Mitchelton weather station. It shows, when compared to figures collated by the Bureau of Meteorology for the greater Goulburn Valley, that the region is less susceptible to frost and enjoys both a higher minimum temperature and lower maximum temperature during the growing season than the greater Goulburn Valley. This effect is highlighted by the fact that the Nagambie Lakes region is some 100 to 300 degree days cooler than the remainder of the greater Goulburn Valley. Further research has shown that this moderating effect becomes diluted, with less impact on the grape growing environment, the further one moves from the water mass. As a result, the specifications for drawing the boundary for the Nagambie Lakes sub-region have been stringently adhered to. At no point does it stray further than 3 km from the water mass, whether that be the lakes themselves, the river or its tributary streams, billabongs and lagoons. It is the only Australian wine region, and one of approximately six worldwide, where the meso-climate is so dramatically influenced by an inland water mass. The viticultural regions around the Great Lakes of America and Lake Como in Italy are two other such regions that are close to inland water masses of a similar size and scale. They too experience a mild and cooling influence on their growing conditions.