What the heck needs environmental protection in Nebraska?
Its frozen prairie.
The stated concern is that a leak will contaminate the Ogallala aquifer. It's a strawman argument meant to divert the real purpose which is to prevent the US from taking advantage of the crude oil in tar sands.
It's true that a leak might contaminate a small area (on the order of acres if it reaches the groundwater). The size of the aquifer in Nebraska is on the order of 64,400 square miles. And contrary to the common opinion of it being an underground lake, its main composition is sands and gravels. A single truckload of crude oil crashing into a lake, stream or river has the potential to contaminate a much greater volume of surface water than a pipeline leak, especially with today's instrumentation and inspection procedures.
It's unfortunate that the state's Republican governor and US senator have bought into the environmentalist argument and are happy to have the pipeline delayed and moved. In the meantime more water from the aquifer is being used to grow corn to produce ethanol or biodiesel for use in motor vehicles instead of human consumption. And the final irony is that the water is essentially irreplaceable; the ratio of pumping to recharge is about 10:1. So in the guise of protecting the water, the nimbys have actually endangered more groundwater than would be impacted by a pipeline leak. But who says politicians are smart anyway; it's all about maintaining power, isn't it?