Yosemite Valley Bridges among the 11 most endangered.

Yosemite National Park. Located in eastern California between Lake Tahoe and Sacramento, this park is known for its seven mile long Yosemite Valley, The Half Dome, El Capitan and the 740 meter tall Yosemite Falls. It was the first park that preserved its natural scenery when the park opened in 1864. It is also famous for its eight rustic stone arch bridges, most of them were built over the Merced River and five of which were built in 1928 (the rest were constructed between 1921 and 1932). Four million people visit the park every year and in order to maintain the sustainable growth of tourist in the region, the National Park Service recently unveiled a management plan for the Merced River valley. Unfortunately, it may come at the expense of three of the stone arch bridges, as they would be removed.
Yet there is hope for the stone arch bridges. Each year, the National Trust for Historic Preservation nominates eleven of the most endangered historic places in the United States and its territories with a goal of providing support and offering alternatives to protect these places for generations to come. The bridges at Yosemite National Park were one of the 11 historic places considered most endangered for this year’s award. The eight bridge examples represent a major problem with managing the structures while at the same time, sustain the growth of tourism in the region. The goal with these bridges is to find a way to protect them from alteration as part of the modernization plan, while at the same time, raise awareness of how to protect these structures that are part of the National Wild and Scenic River Way.
To provide you with a better description of what the bridges look like, here is a summary of the eight bridges that one can see at Yosemite and hopefully will see in the future, should the National Park Service cooperate with other parties and organizations in preserving all of them:

The Yosemite Creek Bridge is the oldest, carrying the North Road and spanning Yosemite Creek below Yosemite Falls. Built in 1922, it spans 50 feet (15 m) in a single arch of reinforced concrete faced with granite. The bridge is 24 feet (7.3 m) wide, and was built at a cost of $32,000. The bridge originally featured lanterns on the buttresses at either end of the bridge.It replaced an earlier bridge, referred to as “the little red bridge.”

The Ahwanee Bridge was built in 1928 across the Merced with three arches, one spanning 42 feet (13 m) and the others spanning 39 feet (12 m), for a total length of 122 feet (37 m). The bridge is 39 feet (12 m) wide with a 27 feet (8.2 m) roadway, a 5 feet (1.5 m) sidewalk and a 7 feet (2.1 m) bridle path. It carries the Mirror Lake Road, framing a view of Half Dome for eastbound traffic. Cost was $59,913.09.

The Clark Bridge was also built in 1928 with a single 75.5-foot (23.0 m) semi-elliptical main span flanked by two round-arched subways for horse-and-rider traffic, 7 feet (2.1 m) wide by 11 feet (3.4 m) high through the bridge’s abutments. Cost was $40,061.22. The bridge carries the 27-foot (8.2 m) Curry Stables Road, a 5 feet (1.5 m) sidewalk and a 7 feet (2.1 m) bridle path.

The Pohono Bridge (1928) spans 80 feet (24 m), carrying the 27-foot (8.2 m) El Portal Road and a 5 feet (1.5 m) bridle path, at a cost of $29,081.55.

The Sugar Pine Bridge (1928), also historically known as the Kenneyville Bridge No. 2, spans 106 feet (32 m) at a five-degree skew across the river, with a 27-foot (8.2 m) roadway, a 5-foot (1.5 m) sidewalk and a 7-foot (2.1 m) sidewalk. It carries the Mirror Lake Road. The longest span of the eight bridges, the cost was $73,507.44. The bridge was named for a large sugar pine that grew to the north of the east bridge abutment.

The Tenaya Creek Bridge (1928) spans Tenaya Creek with a single 56.75-foot (17.30 m) arch at a 25-degree skew on the Happy Isles-Mirror Lake Road. The bridge carries the standard roadway, bridle path and sidewalk. Cost was $37,749.16.

The Happy Isles Bridge on the Happy Isles Road was built in 1929 with one span of 75 feet (23 m) and two equestrian subways in its abutments similar to those of the Clark Bridge, its near twin. The bridge’s total length is 126 feet (38 m). Cost was $46,673.03.

The Stoneman Bridge (1933) resembles the Clark and Happy Isles bridges, with a 72-foot (22 m) main span carrying a 27-foot (8.2 m) road and two 6-foot (1.8 m) sidewalks. The equestrian subways in the abutments were slightly enlarged in width to 8.5 feet (2.6 m) and were extended out from the surface of the wing walls for greater emphasis. It is located at the Camp Curry intersection. Cost was $71,675.08.The bridge replaced a wooden bridge that had carried the former “Royal Arch Avenue” to the Stoneman Hotel, which had been demolished by the 1920s. Construction on the bridge was built by Sullivan and Sullivan of Oakland, California, but was terminated when the Bureau of Public Roads lost confidence in the contractor’s ability to carry out the work. The bridge was completed by the Portland, Oregon firm of Kueckenberg & Wittman.

Note: Information courtesy of wikipedia. More details can be found here.
The Bridges of Yosemite are not the first bridges to be placed on the 11 Most Endangered List. Here is a list of past bridges that were listed as well as the report of what has happened to them.

Memorial Bridge at Portsmouth, New Hampshire:  This vertical lift bridge was nominated in 2009 but  was demolished in February 2012 to make way for a replica of the bridge. Completion is expected in 2013.

Amelia Earhart Memorial Bridge at Atchinson, Kansas: This continuous bridge was named after the first female pioneer pilot and was nominated in 2003. Sadly, this bridge is due to be demolished and replaced this year.

Bridge of Lions in St. Augustine, Florida: This unique bridge was nominated in 1997 as the bridge deteriorated to a point where demolition became an option. However, the citizens rallied for support for saving the bridge, which happened in 2011 through six years of extensive renovation.

Stillwater Bridge in Stillwater, Minnesota: A jewel for the city on the St. Croix, the bridge was nominated in 1997 which resulted in a resolution to convert the bridge into a pedestrian bridge upon completion of the new Stillwater Bridge 5 kilometers south of the city in 2016. A win-win situation for the city and its neighbor Houlton, Wisconsin.