other estimates in the literature end up around the same level eg fischer et al to fraiture et al for the manufacturing sector and for electricity production oecd calculations were used as the starting point while water use in different industrial sectors can vary significantly an overall average relationship with total industrial value added was assumed per geographical region according to assumed regional structure of the sector and technological level over time this relationship was adapted according to assumed structural sector shifts and technological progress a water balance can be established for each grid cell see chapter taking account of landuse patterns natural vegetation crop distribution and management climate parameters temperature precipitation and co concentration and soil parameters this shows the resulting runoff per grid cell ie the amount that ends up in river systems lakes and dams and the volumes available for downstream extraction