I'm going to show my maturity and rise above the obvious snark*:
Representative Michele Bachmann, the conservative Republican running for president, has little in common, ideologically, with her fellow Minnesotan, Senator Al Franken, a Democrat.
But when it comes to fighting for federal approval of a big bridge project -- in this case, a $700 million freeway-style span over the St. Croix River between Minnesota and Wisconsin -- they are joined at the hip.
Such a proposal would not normally command national attention, but critics of Ms. Bachmann have seized on it to say that it is hypocritical of her to support such a huge public project in her district while attacking government spending otherwise. The bridge in question would be mostly paid for by the taxpayers of Wisconsin and Minnesota. But it needs a federal exemption from the Wild and Scenic Rivers Act to get the go-ahead, and former Vice President Walter Mondale, a Minnesotan, and environmentalists have argued that the project would essentially gut the law. They have proposed a scaled-down replacement bridge instead.
Does it make sense to build the bridge as planned?
The bridge currently carries 18,000 passengers a day and is a safety risk. Just considering the financial aspects, a $10 toll would raise about $66 million each year (assuming there are no substitute routes). Discounted revenue at 3% for 12 years would cover the $700m construction cost but a billion dollar bridge (assuming about 50% cost overruns) would not be financed until after 19 years. The key seems to be the environmental benefits of the wild and scenic river:
The National Wild and Scenic Rivers System was created by Congress in 1968 (Public Law 90-542; 16 U.S.C. 1271 et seq.) to preserve certain rivers with outstanding natural, cultural, and recreational values in a free-flowing condition for the enjoyment of present and future generations. The Act is notable for safeguarding the special character of these rivers, while also recognizing the potential for their appropriate use and development.
Sanders, L.D, Walsh, R.G, & Loomis, J.B. (1990). Toward Empirical Estimation of the Total Value of Protecting Rivers. Water Resources Research, 26 (7), 1345-1357.
The purpose of this paper is to develop and apply a procedure to estimate a statistical demand function for the protection of rivers in the Rocky Mountains of Colorado. Other states and nations around the world face a similar problem of estimating how much they can afford to pay for the protection of rivers. The results suggest that in addition to the direct consumption benefits of onsite recreation, total value includes offsite consumption of the flow of information about these activities and resources consumed as preservation benefits. A sample of the general population of the state reports a willingness to pay rather than forego both types of utility. We recommended that offsite values be added to the value of onsite recreation use to determine the total value of rivers to society.
Using their average willingness to pay estimate for eleven study rivers and inflating to 2011 dollars gives a wild and scenic river value of $19 per user/nonuser. If 1 million people hold these values and the new bridge reduces them by 50% then the increased cost is about $100 million after 12 years and $150 million after 19 years, pushing the breakeven point out to 14 and 24 years.
Insert your own assumptions, but this is how the analysis should go.