The Happy Valley Water Control Board (HVWCB) will undertake an irrigation project which will provide 10 million gallons of water annually to 100 wheat farms of 100 acres each. The HVWCB will charge $0.02 per gallon for the water, which will be distributed equally among the 100 farms. It is estimated that:

i land rent in Happy Valley will rise by $70 per acre per annum;

ii 50 farm labourers will be attracted to work on Happy Valley farms, at the market wage of $2000 per annum, from the vineyards of nearby Sunshine Valley;

iii production of wheat on Happy Valley farms is subject to constant returns to scale.

Assuming the Referent Group is the economy as a whole, work out the annual Referent Group benefit of the irrigation project in terms of areas defined by demand and supply curves for output or inputs. Explain your answer.