b'Lakes, Rivers,The Ohio River is the primary riverand Forests of Ohio. It forms more than 400 miles of the states boundary. At one time,When a glacier moved into an area it was a major highway heading west, where the ground was soft, it often carrying canoes and flatboats for scooped out some land. Then when the Native Americans, explorers, traders,ice melted, it filled the low area with and settlers. water, making a lake. This can happen on Ohios rivers also provide power anda large or small scale. The Great Lakes, resources. Streams and rivers poweredthe largest surface fresh water system the areas mills and later, factories.in the world, were formed this way. Lake Cities and towns grew near the riversErie has been important in Ohio for because of this, and because riverstransportation, fishing, and recreation. allowed them to travel and trade.Other smaller lakes in Ohio were also Agriculture was strong in river areas.formed by glaciers. There are not many Drinking water was plentiful, both fromdeep lakes in Ohio, and the largest lakes streams and underground sources, suchof inland Ohio are all man-made. They as springs. Over the years, pollution ofwere made to handle the extra water Ohios water has been a problem.that was needed during Ohios canal era. Pollution controls have been establishedNow they are mainly used for recreation. to clean up Ohios lakes, rivers, andWhile Ohio is not known for having underground water sources. many lakes, it is knownfor its great riversystems [see graphic(L)] . Streams andrivers run for morethan 44,000 miles inthis state. Geologistsknow that Ohios riversat one time flowed tothe north, but the gla-ciers blocked them, sothe water forced itsway along new paths.Flowing water is a pow- Ohios streamserful force and can cut and rivers run for morethrough land, even than 44,000bedrock. miles.Graphic (L)page 5'