Water water everywhere, but where do we store it?

Water storage has been on my mind a lot lately. With the multiple storms tracking across the country dumping rain and snow this past month, flooding communities and/or creating dangerous traveling and living conditions, we’re dealing with lots of water on our landscapes this winter.

The question then invariably follows: how can we take advantage of such storms by storing this water and saving it for when we need it? Especially in drought-ridden areas like California and the West (or even here in Minnesota where we’ve seen persistent drought the past couple summers), having an ‘atmospheric river’ come through dumping water from the sky and not figuring out how to store it for later use seems like a missed opportunity.

Of course, in reality, it’s not that easy. While scientists might be able to provide some guidelines for timing, magnitude, and duration of such events based on past records, we also have a changing climate that throws a monkey wrench into all of those predictions. We are seeing more extreme storms more frequently, and our infrastructure is just not well positioned to consistently manage extra water.

The past few winter/spring seasons, “Lake Chipotle” in Minneapolis has become an unlikely tourist attraction, reflecting what can happen when the capacity of our stormwater infrastructure is overwhelmed.

And let it be said, while we humans can build some absolute marvels of engineering, it’s really hard to try to engineer a solution when we don’t know what we don’t know – do we design infrastructure to handle a 500-year storm? A 1000-year storm? The goalposts of how much more water we should expect are changing and the costs associated with building new infrastructure skyrockets as you consider trying to capture more and more water.

This is one of those situations where I fall back on my absolute most favorite educational graphic of all time:

Sometimes a picture IS worth a 1000 words. Credit to creator arvoreagua

What’s the point? Sometimes we engineer ourselves into problems when we don’t pay attention to the landscape. Our tendency to cover areas with impervious surfaces and restrict the movement of our rivers and lakes works against us, and it prevents nature from doing a lot of the hard work of infiltrating, moving, and storing water for us. We need to work more with natural systems versus against them.

Case in point: I recently came across a great article that made the case of using ‘paleo valleys’ for water infiltration and storage. During the last ice age, ancient rivers and glaciers carved up the landscape across much of the country and moved and deposited coarse sand and gravel into low-lying valleys. That sand and gravel makes for a very porous medium that can infiltrate water exceptionally quickly. These features essentially act as huge natural storm drains – they quickly move water underground and off the surface where we have to worry about it.

Plus, aside from the benefit of quickly removing water from the surface, you’re also helping recharge your groundwater supply, which is another big concern and issue we’re dealing with these days. Nature for the win!

Of course, this approach means we need to make sure we preserve and protect these types of geologic features from development. That can be a tall order when local governments are looking to expand their footprint and tax base. Still, prioritizing and protecting our natural systems is good business – every dollar invested in buying undeveloped land to help manage stormwater can save from $2 – over $5 in avoided flood damage. That’s a pretty decent return on investment.

In Minnesota, where groundwater supplies 75% of our drinking water and 90% of agricultural irrigation, there’s already a huge push to identify and protect areas that can serve to infiltrate water and recharge our aquifers. In our corner of east-central Minnesota, the glacial history here has left plenty of areas capable of strong infiltration and recharge.

Our area of the world is mostly darker yellows and greens thanks to our geologic history – our landscapes are built to capture water. Source: USGS

We need to remain very aware and sensitive of that, especially as developmental pressures increase in our area: our landscape’s natural engineering is already performing these stormwater management and infiltration services for us – let’s be SMART about how we develop and use the land.

Aside from land protection of undeveloped areas, many farmers in our watershed have gotten the memo when it comes to extreme storms – using management practices that build soil health means increased infiltration and less of their soil washing off into the nearest river or lake. In more developed areas, a large stakeholder group in recent decades put together a package of stormwater ordinance materials that local governments can adopt to help manage development in a way that ‘keeps the raindrop where it falls.’ Several communities in Washington County have already adopted these Minimal Impact Design Standards (MIDS), and over the coming years, I get to work with several of our partners to help encourage other of our Lower St. Croix watershed communities to consider adopting MIDS. It’s good, necessary work.

When I look at the piles of snow on our landscape right now, I can’t help but think about where that water is going to go when it melts. Instead of trying to just direct it to the nearest river or lake where then flooding becomes a concern and potentially huge expense to deal with, let’s capture that water on our landscapes – slow it down – infiltrate it – so we can use it later when we need it. Taking advantage of the stormwater infrastructure that nature has built and provided for free? That’s smart thinking, and it will only serve us well into the future.