05.18 MDT Megaload Hearing: Let’s Talk About Floodplains
- Posted by Trish Weber
- News
From yesterday’s article in The Missoulian:
Robertson, a professional engineer, explained why he found erroneous the EA’s conclusion that the project would have no significant impact on the floodplain. Imperial/Exxon must build or enhance several turnouts on U.S. Highway 12 west of Lolo and elsewhere. One proposed turnout is roughly 13 miles up Lolo Creek, at mile marker 20.3. It’s at a spot where, according to Robertson, the floodplain reaches all the way across the highway. That’s based on revised federal floodplain rules prompted by Hurricane Katrina, he explained. Floodplain maps updated in 2009 with the new regulations don’t consider highway fill as levees, Robertson explained. “Highway embankments can’t function as levees, so it’s not certified as one here,” Robertson said. The environmental assessment didn’t identify milepost 20.3 as encroaching on floodplain, he added. “In fact, nowhere along Highway 12 did it identify that.”
What exactly does this mean? I wasn’t sure when I read it, so I started asking questions - a benefit of working for a Civil Engineering firm. Turns out: that this is a really big deal.
There are two different issues at stake here - one is environmental and the other is engineering-related.
First, the environmental issue. When fill dirt is placed in a floodplain - a necessary step in constructing a highway turnout - it alters the hydrology of the river when it is in flood stage. Essentially, because the dirt is in a place where a certain amount of water would normally go in a flood, that same volume of water has to go somewhere else. Where does it go? That is always the question, and why hydrology studies are often required before a permit is issued to place the fill. The water could go somewhere else where it would cause additional erosion, which can damage stream health, endanger existing structures, amid other risks. Without a hydrology study indicating that placing fill in the floodplain is going to cause problems somewhere else, it is not reasonable to conclude that there is no significant impact on the floodplain. Hence, the need for an Environmental Impact Statement which would include, amont other things, said hydrology study. This is what the lawsuit is about - the need for an EIS.
There is also the second issue, which is the engineering. It turns out that, as testified by Mr. Robertson, after Hurrican Katrine, the Federal Emergency Management Agency (FEMA) changed the rules which had previously allowed roadway fill to be classified as a levy. They used to be considered levies, now they are not. Why does this matter? That was my question. Well, because levy construction standards are signficantly stricter than highway construction standards. Existing highways that are in a floodplain, for example Highway 12 at MP 20.3, do not need to be moved out of the floodplain or altered to meet the new standards - a condition known as being “grandfathered in”. However, any new highway construction - including turnouts - that are located in floodplains DO need to be constructed to levy standards.
Mr. Robertson has testified that the highway embankment as designed would not be certified as a levy. Therefore, the construction of the turnout at US 12 MP 20.3 would not, as designed, meet federal standards.
This is another example of the KMTP placing our federal highway infrastructure at risk. From what I’m seeing in the newspaper, it looks like Western Montana is looking at some flooding conditions right now, no? This is a very real issue - not academic at all. And if/when that turnout got washed out in a flood because it was not built to federal standards, guess who would foot the bill to fix the damage? Hint: not ExxonMobil.
It seems to me that this is something that the FHWA should find interesting. And by “interesting” mean “worth investigating”.