Heth’s Run Bridge as seen today presents many mysteries.  Digging into the mysteries uncovers a interesting story.  I have crossed Heth’s Run Bridge many times, usually in a car on the way to the Zoo, but it was only in recent years that I realized it was a bridge.  When looking toward the zoo parking lot from the bridge (as in the picture below) it does not appear that the height of the road differs enough from the surrounding landscape to be a bridge.  However, in the view above (taken from the Zebra Ice Station parking lot on the river side of the road) it looks like a bridge.  The G.M. Hopkins Maps, one of my all-time favorite resources available on the Historic Pittsburgh website, explains the history of and the reason for this bridge.

The 1899 map identifies a bridge in this location called High Bridge, indicating that there was a significant difference in elevation at this point.  A 1912 photograph shows that this was indeed a high bridge, quite unlike the current bridge and its surroundings.  This would have been caused by a small stream called Haight’s Run which flowed under the bridge into the Allegheny River.  By 1911, most of this stream was covered over and Haight’s Avenue ran along its path.  The 1939 map shows no evidence of Haight’s Run, the name on the road and the bridge is now Heth’s, and the road is marked “not open.”  Also in this map, the bridge appears to be a different width than in the others, this is because the current structure was built in 1914, more technical and historical information about the bridge can be found here.  1939 is the most recent year for the G.M. Hopkins Maps.  I speculate that the bridge would still have been raised over the surrounding landscape at that time, based on the similarities in the surroundings between the 1911 and 1939 maps.  However, sometime between then and now, Haight’s/Heth’s Run was filled in and the zoo parking lots built on top, level with the height of Heth’s Bridge.

If I had not passed this way on foot, I doubt that would have realized that this was in fact a bridge or that once not long ago (in geological terms) a stream flowed along this way.  There is a tendency in urban areas for nature to be ignored or in this case built over, which sometimes causes catastrophic results.  Not far from Heth’s Run is Negley Run, another stream that was buried under a road.  The burial of this stream likely contributed to the tragic flood on Washington Boulevard last summer that resulted in several deaths.  I look forward to the day when all our roads and sidewalks will be made of permeable material, allowing for more natural absorption of rain water and reducing flooding.