As a stormwater engineer I always feel strong emotions when the news turns to flood disasters anywhere in the world. As we wait for the latest severe Typhoon named Usagi to approach Hong Kong and watch the cleanup in Colorado, my thoughts turn to flooding and how we exacerbate the damage.
This past week Colorado – which had just faced devastating wildfires and drought not two years ago, faced an event similar in rainfall to what Hurricane Irene dumped onto New England and NJ a year before Superstorm Sandy. Even NJ had rarely seen 14 inches of rain in one day before Irene hit. Colorado is now dealing with the effects of a storm, like Vermont did, with no ocean anywhere in sight. Most folks don’t realize that in a hurricane, most damage occurs not from the water rising from the ocean, although in Sandy it was devastating, but from water falling from the sky. A ”weak” storm can stall in one place dumping many inches of rain before moving on. The surge can be devastating, but the rain can turn deadly as it makes the rivers swell.
The devastating nature of the Colorado storms was made worse by manmade laws of the state. Water rights laws in Colorado make it illegal for a homeowner to have a rain barrel to collect stormwater. Residents are not allowed to detain runoff in any way unless they have a permit. In contrast, New Jersey stormwater retention (seeping into the ground) called recharge or stormwater detention (slowing it down ) is a required part of construction plans. Low Impact Design is the latest in stormwater management.
Engineers used to think it was wise to get runoff to the nearest creek as soon as possible, making manmade straight concrete channels to do it – but that put downstream neighbors in peril of a rapidly rising waterway. We learned only recently the best way to prevent major flooding is to keep natural water hydrology as close to natural as possible. Keep the stormwater close to where it falls as long as you can. Let it seep slowly and recharge into the ground. Keep those windy bends in the river. Keep swales and river edges vegetated, to slow down the water while still clearing downed trees that block flow. Un-pipe waterways to give them room. Return the hydrology to what was there before you built anything. The lakes and rivers and aquifers will naturally recharge as the water moves underground to the nearest spring, or waterway.
As Colorado has been built up, just like all over the world, laws have not kept pace with the new reality of over-development. In NJ, we still have work ahead of us, but when we have flash floods ALL of the runoff does not wind up in the creek at once. Water rights laws in Colorado and Western states were designed for dry conditions and very little development, where not having enough water was usually the case. But when a storm can dump as much rain on Boulder as it can in Newark, we have a serious, deadly problem.
What we have been doing for centuries is no longer working in a crowded, overdeveloped, impervious world. We are discovering that a decentralized approach works best in stormwater management as a tiny rivulet is easier to deal with than a raging river. As a bonus, the counterintuitive argument for doing it this way is that stormwater management prepares us for inevitable periods of drought. We are preventing flooding while filling our aquifers at the same time.
Our love affair with drilling is also costing us – in terms of forested cover loss and new impervious sources of runoff – like well drilling pads and hard packed roads from heavy truck traffic. I haven’t even addressed the contribution of fossil fuel to a warmer world and more severe storms. The untold story of the Colorado floods are that natural gas drilling areas in the flood plain are exposing Colorado residents downstream to the toxic spills of fracking fluid as well as leaking oil tanks damaged by the floods. Pollution always goes hand in hand with flooding and erosion. Colorado is no exception. They now have to deal with mud, and toxic fracking fluid and oil as well. That is another human contribution to the epic misery.
When the rain falling from the sky does not care who owns it as it sweeps your home off its foundation, the concept of water rights and drilling rights, need to take a back seat to protecting the lives and property of everyone.
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