Teacup in the Deluge: Climate Change and Your Yard
I’m writing a section for my next book about climate change predictions for the US by region. Wanna know what those predictions are? Look out the window. 2018 has been a real preview of the future, with above-average temperatures everywhere, soaking rains in the East, and drought and fire in the West. What matters is the long-term trend, not any individual year, but still, 2018 gives us a chance to see which everyday systems are not going to work for the warmer world. Ordinary things we take for granted. Like what happens in your yard when it rains.
Although I started my career as a landscape architect, full disclosure: I have always found stormwater management a little dull. These days precipitation of all kinds has become way more exciting, in the worst way, due to the increasing frequency of seriously scary storms. I write this with one eye on updates about Hurricane Florence inundating the Carolinas. My house up here in Connecticut has weathered nearly 50 years of coastal storms, including Hurricane Irene, in 2011, and Superstorm Sandy just a year after that. Average annual precipitation here is about 47”. In recent decades, the Northeast as a whole has seen a marked increase — more than 70% — in the amount of rain falling during storms. This is a surprise/not a surprise, because these more frequent, rainier storms are part of climate change predictions for the region. And climate change, as you know, is a show already in progress.
My house is in the woods between two seasonal creeks, with a walkout basement. The whole property is sandy soil full of New England rocks, so drainage would seem to be a no-brainer. The previous owners of the house certainly thought so, since this house came to us with its sole drainage strategy as standard gutters and downspouts. This utterly predictable set-up is supposed to catch the water as it runs down the roof, funnel it through to eight points around the base of the house, and dump it out on the ground there, at the end of the downspouts. Those downspouts? They end 8” from the foundation of the house. A few have splash blocks that carry the water 24” from the foundation, if they don’t overflow. An absolutely typical setup, found on countless houses, maybe even yours.
What’s wrong with this? It works as intended, which means all the water captured by the gutters is dumped right next to the foundation, at the end of those downspouts. There the water can infiltrate into that rocky, sandy soil and go on its way through the hydrologic cycle and out of my life, and that works fine — most of the time. The walls of our basement testify that it didn’t work fine once, maybe twice, in the life of the house, when a flooding event marked the walls a few inches above the floor. Hmm.
So we extend the downspouts, which is ugly, easy, and temporary. We need something more permanent, which would, in the past, have meant running those downspouts into a set of pipes to take that water, underground, to one of our creeks. The easiest way to route those pipes is across the driveway, which a landscaper suggested we do. You don’t really know what’s under a 50-year-old gravel driveway, but it’s probably not solid bedrock, a distinct possibility anywhere else in the yard.
But wait: think about that tried-and-true set of underground pipes and the gutters in 10” (Irene) or 20” of rain? (Sure, 20” is a lot of rain, but Hurricane Harvey (2017) dumped up to 60” of rain on Texas, so…) Simply: everything overflows, and everything backs up. Only so much water can fit through those pipes at once, then water starts to pool. Water coming from the house and backing up means way too much water around the house’s foundation, and that means way too much (ie any) water inside the house.
If you don’t want a lake in your basement, you need drainage meant to handle a deluge-worth of water. Yet it’s overkill to run the LA River through your yard. It’s hideous, and it’s right outside your house, and also: groundwater recharge is a thing. Sure, Connecticut’s had two badass storms in the last seven years, but it’s also just emerged from a two-year drought, because climate change is about weirder weather, not just warmer weather. Who wants to spend the next drought staring at a yard built for floods?
A layered system seems to be the answer: a normal rainy day system to work all the time, with a gullywasher system for the next epic storm. The gullywasher layer doesn’t have to work very often, but when it’s needed, it really has to work, because it’ll be that epic storm. When the deluge comes, you’ll need to get in and out. Maybe that’s the classic supermarket run for bread and milk, but it could be for emergency services to rescue you. It could even be for you to evacuate. It’s important, that rare thing in home landscaping that actually is life or death. So nope, keep that pipe away from the driveway, aka the sole route in and out. Look around and imagine a foot or two of rain, and give it somewhere to flood that isn’t where you’ll be or how you’ll get out.
My strategy is something like this: some of those underground pipes attaching to the downspouts, but with the ground surface sloped to form swales that will move the water away from the house and into the creeks when all hell breaks loose. An old idea, the dry well, may come into play here, too, as a way to provide a place for water to pile up, so to speak, in the epic storm, and a place for water to infiltrate the rest of the time. Circling back to that recent drought, this also could be a good place to install a cistern, if the next drought or the one after that is worse.
If climate change affects simple home landscaping to this extent, it really does affect everything. The strategy of layering everyday systems with ones for catastrophic events is a good one, and maybe one that can work elsewhere. Your yard seems ridiculously trivial, but aren’t you likely to shelter at home if/when the big one hits? A little planning can create a lot of resilience, or at least more than you’ve got now, exactly where you’ll need it when the storm comes.