From the hydrologic records of over 50 years on a watershed with an area of 500 km2, the average annual rainfall is estimated as 850 mm and the average annual runoff as 350 mm. A reservoir in the basin, with an average surface area of 1700 hectares, is planned at the basin outlet to collect available runoff for supplying water to a nearby community. The annual evaporation over the reservoir surface is estimated at 1300 mm. There is no groundwater leakage or inflow to the basin. Determine the available average annual withdrawal from the reservoir for water supply.