The most expensive proposal is to build two bridges and a tunnel through the slope on the north side of the canyon. That idea ought to be rejected by we Sierra folks before it gets any serious traction. The reason is it would destroy what is annually in our spring time, the most extenside single hillside with poppies in the whole Merced River canyon. For those that are not familliar with annual poppies in the Merced Canyon, those wildflowers bloom usually sometime late March to April covering the green grassy hillsides orange while redbud trees add deep rose color below. Here's a 4x5 pic I exposed this year of that slope that wasn't close to the best year's displays:
http://www.davidsenesac.com/Mariposa_3-07/07-I4-1w.jpgThe hillside that tunnel would harpoon is the one directly upstream from the current temporary upstream bridge. The reason some engineers probably prefer a tunnel instead of just improving the current temporary bridges is because the current temporary bridge positions require radically slowing down in order to negotiate the abrupt turning angles at the bridges and canyon bend. Some long vehicles can't negotiate the temp bridges at all. Of course all that could be dealt with by simply by crossing the river at an angle instead of a perpendicular. So I'm guessing the pricy tunnel idea is simply to allow vehicles to continue travelling at speeds well over the speed limit like many inconsiderate types seem to do now.
...David
http://www.davidsenesac.com
