Water flows downhill. As rainfall and snowmelt morph into runoff, this water travels overland and then into ditches, channels, streams and rivers of ever-increasing size. The process continues to the sea unless flow is retarded by obstructions or the volume exceeds the capacity of the channel. The water surface rises until water is able to flow downhill in another direction. The result is the overflow of stream banks and encroachment of water on to highways, structures and other locations where it is not wanted.
The Wyoming Valley had a front row seat to this process once again last month. This time it was water in solid form that flowed down the Susquehanna until its volume exceed the capacity of the river. The jammed ice caused the river to rise to a crest of 35 feet and overflow its banks in West Pittston. When the jam broke, water rushed down to the Veterans Memorial Bridge in Wilkes-Barre where it briefly spiked to a depth of 27 feet. In a situation reminiscent of 2011, “We dodged a bullet,” according to Luzerne County Emergency Management Director Lucy Morgan.
Unsurprisingly, West Pittston residents responded to the recent flood with renewed calls for their own levee. Let me put an end to the myth that the last round of levee raising and extensions did not include West Pittston because residents did not want to lose their riverfront views. The economics simply did not justify it. This was confirmed in a 2016 Corps report that the estimated benefit to cost ratio is 0.37. Remember, it would take an act of Congress to get this project going. The consensus across the country is that the Corps’ levee building days are over.
Levee building in the Wyoming Valley has been ongoing since the Flood Control Act of 1936. Whenever the levees were overtopped, the response has been to make them higher and longer. The 2001-2006 levee raising was designed to provide protection from a flood of magnitude equal to that of Hurricane Agnes in 1972. In 2011, rainfall from Tropical Storm Lee resulted in new record flows along the Susquehanna. In response, FEMA tasked USACE Baltimore District (Corps) to conduct a basin flood data assessment as well as update its 2003 model to include the hydrologic and hydraulic changes that have occurred and produce a revised flood model for the Wyoming Valley.
The results are startling. For the Wilkes-Barre gauge at Market Street, 100-year flow increased from 265,000 to 296,500 cubic feet per second while 100-year water surface elevation rose 3.5 feet. These increases occurred over just a 10-year period. There are many reasons for this, but climate change is perhaps the most significant. According to the Corps, five major flood events have occurred in the Wyoming Valley since 2003. These observations are consistent with predictions that climate change will result in the more frequent occurrence and intensity of storms in our region, resulting in greater flooding.
The Corps follows FEMA rules and guidance in its flood frequency analysis. Historical flows are plotted and fitted to a frequency distribution pattern or function. That pattern is then extrapolated to predict the 1 in 100, 1 in 500-year, etc. flood events. If the magnitude and frequency of floods are increasing, then this approach will be forever playing catch-up with reality. Levees and other flood mitigation measures that are designed to protect communities from major floods will ultimately fail.
Complicating that task is the fact that the Trump administration has largely been hostile to discussions of global warming. In August 2017, a week before Hurricane Harvey made landfall in Texas, President Trump rescinded an Obama-era executive order that urged federal agencies to take into account climate change and sea-level rise when rebuilding infrastructure. The result is a situation akin to the military building an army to fight the last war.
The level and duration of any particular flood is a function of many factors beyond total rainfall. These include antecedent soil moisture, the timing of rainfall over the watershed, flows entering the Susquehanna from side streams and the water content of any snowpack. The flow in the river may be altered by debris blockages at chock points, leaking or overtopped levees and, as we observed recently, ice jams. The flood mitigation structures and practices are based on standard “design storms” which never occur. Every flood is different, and the lessons learned from one event are applied to preparations from the next.
Flood mitigation structures consist of levees, diversions, pumps, and gates. Emergency responses include monitoring of water levels, opening and closing of gates, turning on pumps, placement of temporary berms, issuance of watches and warnings and, if necessary, evacuation orders. These practices have proven effective for moderate and some of the major flooding that Wyoming Valley residents have experienced. Ultimately, they will fail when the really big storm hits as there is no way to completely stop the downhill flow of water. No one can predict when this will happen, but it will. No amount of preparation can guarantee 100% protection from Susquehanna floodwaters.
The alternative approach is to look upstream and address the sources of flow. The Susquehanna River begins in Cooperstown, New York. From there, it travels 250 miles downstream to Wilkes-Barre. At this point, the drainage basin includes 9,960 square miles. Any drop of water entering the basin at any location has the potential to cause flooding in the Wyoming Valley. Reducing flow volumes and peak flow rates at the sources is usually easier and less expensive than addressing them at the point of impacts.
The regulatory justification for such a strategy is the Waters of the United States (WOTUS) rule. This rule defines the waters that fall under the jurisdiction of the Clean Water Act as it is administered by the EPA, Department of the Army and the Corps among other federal agencies. The WOTUS rule broadly defines waters to include any body of water who’s “use, degradation or destruction of which could affect interstate or foreign commerce”.”While this definition has a sound environmental basis, it is hotly contested by the Trump administration and our senator Pat Toomey.
On Feb. 28, 2017, President Trump issued an executive order directing the EPA and the Department of the Army to reevaluate the WOTUS rule. It calls for a revised rule to be implemented in accordance with Supreme Court decisions, agency guidance and longstanding practice. It is frequently cited as an example of “regulatory overreach” and “burdensome regulation.” If the WOTUS rule is significantly revised, many existing requirements that reduce peak flows throughout the watershed may be rescinded, resulting in higher Susquehanna River flows during storms.
What does all this mean for the Wyoming Valley? The probability of acquiring federal funding for more levee construction is close to nil. If available, it would require a local match that would most likely be unaffordable. Flood insurance premiums will continue to rise. Portions of the Wyoming Valley Levee System are at risk of losing FEMA accreditation due to insufficient freeboard. Climate change will lead to more frequent and larger floods that our infrastructure will not be able to contain. Regulatory relief may result in even higher peak flows. New federal funds for road and bridge infrastructure projects may restrict construction such that they are resilient to anticipated flooding.
Meanwhile, life in the areas protected by the levee continues. Wilkes University and King’s College pursue their growth plans. Economic development continues, oblivious to the risks of construction in the natural floodways. Residents who live in these areas can move or make their homes flood resistant. For many, these are both impactable options. We can only watch the water flow downhill and hope for the best.