¾¨Ó㴫ý

When rains came that melted snow the last week of February, the floods of our area were bound to happen.  Rain at the Field Station Saturday and Sunday amounted to only 1.27 inches but its rate of accumulation, snow melt and heavier rains in the upper watershed contributed to the flood on Monday. 

By noon Feb. 28, the Little Neshannock was cresting at the green footbridge that connects the Frey Nature Trail of the Field Station to the main campus of ¾¨Ó㴫ý.  Two days later, March 2, the water level was back to normal.

What is normal?  That is the average water level maintained in a river channel.  Flood stage is defined by the U.S. Weather Service (a branch of the National Oceanic and Atmospheric Administration) as the point when the water level exceeds the lowest bank of the basic channel and begins to spread out beyond the bank.

The footbridge over the Little Neshannock Creek is our current benchmark for documenting flooding.  This span of about 50 feet was constructed the summer of 1983 by a team coordinated by Dr. Floyd Zehr, now professor of physics emeritus.  To secure the state permit before building the bridge, Dr. Zehr had to determine the 100-year high water level mark for the creek from local and regional records and then plan to build above that by at least one foot.  Determining that fact was not easy, but abiding by it has paid off over the years.

Trail walkers to the Field Station may be interested in knowing that the green bridge sits on eight pilings sunk into the banks and has sides that were trusses from a building demolition project in Youngstown, Ohio.  Digging the holes for the four pilings on each end of the future bridge was done by hand.  That, and getting the trusses into position and connecting them below with horizontal I-beams, required skills that have become the slogan of much physical labor at the Field Station:  "Brute force and awkwardness." 

Henry Wilson, former staff member in the Physical Plant, "pushed" trusses one at a time with a Ford tractor. They were scooted from the west over wooden scaffolding Dr. Zehr had constructed in the creek basin.  I, on an Allis-Chalmers tractor, "pulled" them from the east.  We managed to get the job done without incident.  An Amish man with acetylene torch welded trusses to the I-beams that provided support for planks of treated lumber.  At that time the Field Station had been in existence only three years.  There was no boardwalk on the trail, just a grassy and wetland path between the field east of the lake to a barn and other buildings on the Fayette-New Wilmington Road.

Mike Heasley, class of 1984, who as a student worked on the bridge's construction, recently recalled that summer's project.  "We had quite a time putting in those posts and not slipping into the water," he said.

The 100-year high water level has been matched or exceeded at least three times since the footbridge was constructed:  April 1994, July 2003 and February 2011.  Each of these has been documented by observations made at the footbridge: flotsam from downstream collected on the I-beams that had been positioned "one foot above the 100-year high."  In 2003 the bridge was hit by a massive floating pile of logs and brush that left a slight bend of the trusses in the downstream direction. 

On Feb. 28, a visit to the trail and bridge from both east and west gave opportunity to once more photograph the flood of the Little Neshannock.  About one-fourth of the boardwalk had been covered and the flotsam was accumulating on the bridge's I-beams.  By estimate from a satellite photo, the creek at the Field Station consisted of a flowing body of water one-fourth mile wide.  

Animals and plants of a wetland are adapted to flooding of their environment in a variety of ways. They make it through tough times.  As I inspected the partly submerged path of the Nature Trail during the peak of flooding, I spotted a small insectivore, the least shrew, swimming feverishly across a span of flood water to a patch of emergent grass.  Rabbits, too, can swim but most of the time they simply avoid the water by staying "high side."  Rooted vegetation may get broken up and washed away, as I saw on parts of the trail, but that will grow back when conditions dry.

On March 2, virtually all the floodwaters had dissipated and the creek was at its normal level, about seven feet below the planks of the footbridge.  Inspection that day showed no obvious damage to the bridge.  It was built to be sturdy.  We are, however, having the bridge formally inspected as a precaution.

This brings us to the present moment.  What is the future of the green footbridge that serves as a vital link from ¾¨Ó㴫ý to the Field Station?  In the 1980s, I registered an off-the-cuff assessment that "if we get 20 years of service from that hand-built structure, that will be great."  In 2002, in a report on the Field Station, I highlighted the need to consider replacing the footbridge.  We are now approaching the 28th "birthday" of the bridge and need to take stock.  Age plus "wear and tear" have weighed in on the structure.  The original construction, minus labor, cost the College about $3,000.  Oh, that we could replace it today for that amount!  Estimates are that number tenfold or more.

Clarence Harms, Director
Field Station
724-946-6001
harmsc@westminster.edu

Little Neshannock Creek and footbridge from the west, Mon., Feb. 28

Trail leading to the boardwalk from the east, Mon., Feb. 28

Footbridge after flooding, Wed., March 2

Dr. Floyd Zehr during bridge construction, Aug. 1983

Little Neshannock Creek and footbridge from the west, April 7, 1994