The Rivanna was hardly the most impressive of Virginia's many rivers, nor the most commercially viable. In the heat of the summer the Rivanna sometimes became little more than a trickle; in spring and fall heavy rains often caused floods that damaged mills and inundated fields. However great these obstacles, residents of central and northern Albemarle perceived the river in terms of commercial promise: a source of power for local mills and a means of cheap transportation for tobacco and other crops. Thomas Jefferson, whose Monticello estate was a stone's throw from the Rivanna's banks, organized the first of many attempts to tap the river's economic potential. After surveying the Rivanna in 1765, Jefferson concluded that clearing a series of small obstructions could convert the stream into a navigable waterway. The young planter secured an act from the colonial assembly that authorized a trusteeship to undertake the “laudable and useful” enterprise. Jefferson and other prominent gentlemen became trustees, collecting voluntary subscriptions and then paying local contractors to remove the obstructions. The trusteeship was not a complete success – a series of navigation and canal companies would attempt to build more permanent improvements over the next 100 years – but Jefferson took considerable pride in his public-spirited efforts.