The differences among the Platte, the Republican and the Niobrara rivers demonstrate just how unique each system can be. The Republican and the Niobrara have cut streambeds down to bedrock, as opposed to the Platte, which comes through the state essentially on a ridge. Streamflow sources differ as well. Groundwater inflow contributes nearly half the discharge of the Platte, and the Niobrara would probably disappear during drought years without the inflow of groundwater. The Republican, however, is primarily fed by overland runoff, Goeke said.
Diversions also plays a role in the characteristics of river sytems.
Much of the Platte is diverted for irrigation, particularly in Dawson and Phelps counties, he said. Besides significantly reducing the flow of the Platte, diversions has caused a rise in the groundwater levels in some areas due to seepage. Management standards can't be applied to one system without affecting another. Lincoln citizens depend on the Platte to recharge the Ashland wellfield adjacent to the Platte for their water supply. The Platte, however, would ge greatly reduced at Ashland without the discharge of the Loup and Elkhorn rivers, Goeke said.