40000 Daily Water Use Evapo T 250 35000 30000 200 25000 150 20000 100 15000 50 10000 0 5000 -50 0 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 -5000 -100 Year Figure 6 The Relationship of Water Consumption to Evapo-Transpiration in Blenheim Reference to Figure 7 show the average per capita water consumption in Blenheim has remained within the 650 - 750 litres/person/day throughout the period 1997-2006. The estimates after 2006 relied on population projections and will need to be updated following the 2013 Census. It is likely the projected population was greater than the actual and per capita consumption has been under–estimated. The per capita figures are based on gross consumption and therefore include the water used by industry/commerce, leakage, system losses and visitors to the area. Generally industrial and commercial properties are metered. Meter records were examined over a four year period and show that around 9.5% of the gross supply to Blenheim is used for business purposes. Per Capita Daily Water Consumption - Blenheim 1600 1400 1200 1000 800 600 400 200 0 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Av 744 732 638 647 664 619 677 596 671 661 714 685 665 692 617 Max 1480 1417 1415 1457 1422 1199 1455 1392 1326 1523 1,422 1,364 1,208 1,409 1,244 Min 495 440 416 437 434 432 429 436 466 457 508 509 508 460 453 Year Figure 7 The Estimated Range of Per Capita Water Consumption. Blenheim Page 38 )yad/3m(noitpmusnoC retaW yad/daeh/sertiL