About six months ago I was standing on the shore of the Mississippi River, rendered speechless by its power. The river was swollen with water from recent severe thunderstorms, and even though I was in Minneapolis, over a thousand miles from the river’s delta, the power and force of the river was immense. The river roared over the human-created dam without much hesitation – the same river that in some form carried much of a continental ice shield to the sea after the last Ice Age, the same river that carries rock, in little pieces, from the Rocky Mountains to the sea – and quickly calmed downstream, as if to ready itself for the journey ahead of it.
We all know the Mississippi is no stranger to floods. In fact, less than two years ago it was so swollen with rain and snowmelt that it threatened to shift course and abandon New Orleans completely. The mood of the river has changed much since then. Unfortunately, despite the temperamental nature of this enormous river, the mood swing is not entirely natural. While we humans can’t truly ‘tame’ the Mississippi we do seem to be able to worsen its notorious mood swings.
Instead of raging with floodwaters, the mighty Mississippi has been impacted so heavily by drought that it has receded to record low water levels. The Mississippi River is still a very important shipping corridor, and the water has gotten so low that it may be impossible to continue to run barges down its course. The situation has become so dire that people are literally exploding rock reefs under the river to try to deepen it. Some people are calling for more water to be released from reservoirs on the Missouri River in South Dakota, but there are legal barriers, and those who live in the arid lands near and west of the 100th meridian will not send water downstream without a fight. And, with a deep freeze settling into the northern parts of the vast Mississippi watershed, we won’t be seeing much relief for the river any time soon. Even if heavy storms strike the Northern Plains, we won’t see much snowmelt any time soon, at least not if the current indications are right.
I mentioned earlier that we humans have worsened the mood swings of the Mississippi. One way we have probably done this is through increasing the variability and frequency of extreme weather events by releasing massive amounts of carbon dioxide and other greenhouse gases into the atmosphere. This is a global problem that requires a global solution and is a subject of intense political ‘debate’ that I tend to avoid in this blog. However, there is another issue, one not often discussed, that cuts to the heart of the problem. I’m of course talking about the ‘fast water’ engineering that rushes water away instead of letting it infiltrate into groundwater – the main subject of this blog.
Countless acres of wetland once covered the Great Plains and other parts of the Mississippi’s watershed. In drier areas, grasses with deep roots intersected water and channeled it to the thirsty soil. today we instead channel water into the river quickly and ‘efficiently’ using gutters, tile drains, and levee-lined riverbanks. This system undoubtedly worsened the flooding we experienced two springs ago. But that isn’t all it does. All that water that was channeled away would have otherwise soaked into the ground, replenishing aquifers. If we allowed more water to soak into the ground or linger in wetland complexes, the river wouldn’t be running so low that barges are scraping their bottoms on shoals and submerged sand bars. We obviously need the ‘bread basket’ of the Great Plains and Ohio River watershed for food production, but we could be doing more. We could be restoring and constructing wetlands, daylighting urban streams like Four Mile Run in Pittsburgh, and returning the rivers to at least part of their floodplains. Every drop of water that soaks into the ground is a drop that isn’t destroying homes and roads during floods, and every drop of water that soaks into the ground and reemerges in a spring during a drought will be readily welcomed by those who rely on the river for their livelihood. With an uncertain future including the likelihood of even more extreme weather in the future, every little bit makes a difference.