Not exactly 40 but the original plans sat quiet for 30 years until about 2008. A friend and I went up there a few times and the first time only the spillway was started and nothing on the dam. We got a tour of the spillway and power generating section from an engineer. Security was very loose back then but they won't let you near it now. When hurricane Jova came through all the work they had done was washed down river. Another time they had a cement base about half way across the valley. Just found this article from late last year and they have made progress.
Colima, Mexico, Advanced (18-12-2015) .- For over forty years, farmers in the region of Manzanillo and Cihuatlán have expected a reality of the promise of building a dam on the banks of the River Marabasco, but after countless obstacles, setbacks and unfulfilled government commitments, currently the work has not even reached 50 percent of its construction.
The first project, called El Naranjo, was drafted in 1971 but remained stagnant over thirty years.
In 2003, the theme was taken up by the federal deputy Roberto Preciado Cuevas under the name El Naranjo II, and a year later was adopted by Governor Gustavo Vazquez Montes, but both died in February 2005 when the state government plane crashed in Michoacan, while returning from Mexico city.