Five Next Steps for Green Infrastructure
It’s time we think about constructing nature — not just restoring it.
Why is this good time to take stock of what we know and still need to know about green infrastructure?
- Built infrastructure is failing, both worldwide and in the United States. (See my piece last year on the Michigan dam failure.)
- This trend will only worsen in the face of widening flood-and-drought extremes driven by climate change.
- There are many starry eyes in the environmental community about the ability of natural infrastructure to step in as a replacement for built infrastructure. A more realistic stance: Retrofit the built infrastructure that’s failing to make it work better and supplement it with natural infrastructure, often in ways beyond the usual restore-a-wetland thinking.
- Mainstream thinking about what “natural” infrastructure is hasn’t evolved beyond “let’s restore nature in place to provide benefits in that place alone.” It’s past time for us to think about nature as part of a full engineering and infrastructure strategy and to think about how natural infrastructure can and should provide benefits beyond its immediate siting (see below for a prime example).
The criticism that “nature’s nice, but it’s not going to protect us” is often true today precisely because of the inadequate scale and strategy we’re putting into restoration. Next steps (which I begin to articulate below) would be a) developing a strategic roadmap for construction of natural infrastructure (as opposed to simply trying to restore to a historical baseline) and b) coordinating these assets with existing built infrastructure.
1. Aquifers: Can They Be Game Changers in an Age of Increasing Drought and Flood Extremes?
What is known: There is vast potential to store water underground in empty aquifers — and in an age of increasing drought and flood extremes due to climate change, we will need that storage potential.
Arizona has put more than 12 km3 of surface water underground — the equivalent to one-third the full-capacity storage of Lake Mead mas o menos. There are many more Lake Meads of recharge potential available in the overdrawn Ogallala, California’s Central Valley, and in Pakistan, which has an aquifer the size of England.
What needs further thought or investigation: Whether we can get the water back and drink it once we’ve stored it and put it down there.
Groundwater is out of sight & out of mind because it is underground and hence, invisible. Add to this:
- We have no science that tells us how much we have.
- We have no idea how much is down there.
- Groundwater doesn’t just stay put, it moves — very slowly — underground both vertically and horizontally.
Fortunately the science is pretty robust in terms of knowing how much we remove from groundwater — on an annual and large scale with the GRACE satellites and on a daily and finer scale with InSAR. The science is also robust in terms of knowing where groundwater can and will flow with geophysical models and calibration by satellites and wells.
There is disconnect between this science and policy, though: We lack strategic recovery plans that take into account losses due to movement beyond recovery infrastructure (well fields) and cross contamination by infiltration of agricultural return flows and/or urban pollution, including non-point septic systems.
Finally, there’s generally more planning about how much we can put in the aquifers, but little planning about how much it will cost and what the GHG implications are for pulling it back out of the ground to use later. We need coherent, science-based standards and strategy for recovery.
2. Wetlands & Equity: Can Strategically Restored Wetlands Serve Everyone?
What is known: The services provided by coastal and inland wetlands have a global monetary value of $47.4 trillion per year in terms of flood protection, water filtration and carbon sequestration. Of course, more than 64% of all wetlands have been lost since 1900. Restoration and construction of strategic wetlands could generate enormous economic value.
What needs further thought or investigation: Value for whom — the wealthy, or everyone? Big, centralized water infrastructure has disproportionately benefitted the “haves” with little improvement for the “have-nots” [see my interview with Catherine Flowers]. If you need evidence, think about Flint. Think about water infrastructure on Indian reservations. Natural infrastructure is distributed, natural water-cleaning technology and flood protection. In some cases, it also brings co-benefits in terms of recreation and property value. Can these benefits be distributed in ways to improve water resilience for a broader cross-section of society than centralized built infrastructure has in the past? More broadly, what is the basin-scale blueprint for building out wetlands that achieve this broader societal mission?
3. The New Normal Rainfalls: Can We Take Advantage?
What is known: Our current mix of built infrastructure is failing to take advantage of the “boom” part of boom-bust rainfalls. Super typhoons, atmospheric rivers and hurricanes like Harvey are the new normal. They cause epic damage — but they also deliver impressive quantities of water that if stored strategically could come in handy later.
What needs further thought or investigation: Whether coordination of built and natural infrastructure can allow us to game the extremes better. One example: In California, state agencies in collaboration with the Army Corps of Engineers are exploring a concept called Forecast-Informed Reservoir Operations (FIRO). Simultaneously, the same state agencies are designing managed aquifer recharge (MAR) programs in the Central Valley that take floodwater and use it to recharge thirsty aquifers. What if we coupled FIRO and flood-MAR to capitalize on moisture from atmospheric rivers and store it underground?
4. Forest Management for Water Supplies: Can We Stop Drinking from a Hot Firehose?
What is known: Forests are burning down all around us. Cali, Australia, the Amazon. Seriously?
What needs further thought or investigation: Is there a measured strategy to saving the ones that are vital for water supplies? The current approach is drinking from a hot firehose — reactive, not strategic thinking. Do we continue — in true Teddy Roosevelt form — to try to save all the national forests exactly the way they are? Or can we take an alternative, more utilitarian approach — restoring those tracts that science shows revive function and give value?
From a water perspective, the measured approach would mean intentionally linking source water protection for cities and farmlands directly to the health of upstream forests. Yes, we have done some good work in this space already — but it is far less strategic than it needs to be to a) save the essential tracts of intact forest, b) replant essential tracts that have already burned and c) do thoughtful, science-based M&E on the outcomes downstream. And a), b) and c) should together be the standard.
5. Gulf of Mexico Dead Zones: Can We Expand Our Definition of ‘Natural’ Infrastructure to Address the Problem?
What is known: Farms in the Midwest contribute significantly to nitrogen inputs and dead zones in the Gulf of Mexico.
What needs further thought or investigation: Whether data and technology can allow us to strategically manage the timing of fertilizer application at scale to mitigate continental non-point source pollution. What we think of as “natural infrastructure” can and should go beyond its value as on-site conservation. It can include farmland. There, I said it. It can also be data and technology — and we need to think about what it can do for nature on a larger scale. If we fold farmland into the concept of natural infrastructure it becomes a giant on the scale of China — once you mobilize it at that scale, you’ve got a lot of power to make a difference toward a goal (like global decarbonization and basin scale restoration for a river this size of the M.I.S.S.I.S.S.I.P.P.I).
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