Small Engineered Wetland & Climate Change

The Global Power of Wetlands: The Absorption of Carbon

There is a lot of data about the importance of wetlands. In fact they’re critical to the safety and future of the planet. However, there is little emphasis placed on the ability of wetlands to capture carbon. Wetlands absorb carbon at a higher rate than more dry land for a few reasons.

First, the plants that thrive in wetlands grow at faster rates. Plus, their growth is carbon reliant. That is to say the structures that wetland plants create to help them grow fast are carbon heavy structures. In this they’re much like skyscrapers built of steel (a high carbon substance). Wetland plants need to be built tough to withstand the pressures of living in wet environments.

The second reason is that wetlands are usually anaerobic environments. The microbes in these  the lack of oxygen deficient environments are prevented from creating gaseous CO2. As a result, much of the carbon stays locked up in the soil.

According to this report published in 1999 wetlands carbon sequestration abilities are explained in the following excerpt.

.. wetlands are the largest terrestrial carbon reservoir in Canada, covering 14 per cent of the land surface but containing about 60 per cent of the carbon stock (approximately 150 Gt C).

Clearly wetlands are a powerful tool in the fight to reverse global warming.

The Local Power of Wetlands: Cleaning Water, Lowering Risks of Floods, Reducing Water Costs, & Tax Expenditures

Wetlands stack a lot of functions into small spaces. When properly employed both surface wetlands and sub-surface wetlands perform a myriad of tasks. These include cleaning water that’s been tainted from domestic and industrial chemicals. Additionally they slow stormwater, dealing with it where it falls. This saves municipal water authorities money both in treatment and infrastructure costs.

Wetlands can and should be included in all new developments. Our legislatures should be looking at ways to incentivize the installation of new wetlands.

For example, in the city where miles of stormwater pipes need to be maintained wetlands lower costs. By replacing pipes with wetlands billions of dollars are saved. They also save time, further reduce carbon footprints and reduce the use of concrete.

Wetlands increase land values by adding beautiful nature to the urban landscape. Plus, they help cool and even clean the air while providing habitat for small animals creating an ever expanding chain reaction of positive results.

Automobiles create more than just air pollution. They leak oils and other fluids that wetland microbes can breakdown. Additionally, many property owners spray a wide array of chemicals. These include chemical lawn treatments and pesticides. While wetlands may be damaged by large amounts of these chemicals they often filter out these chemicals in small quantities.

Stormwater that otherwise runs in concrete pipe is filtered by wetlands. This makes the water that eventually finds its way into the drinking supply cleaner.

The Power of Balance That Wetlands Bring

As we’ve heated and continue to heat the planet we’re going to face less predictable weather, more storms, more droughts, more rapid changes of more extreme weather. Wetlands have a calming and balancing effect.

In both water rich and water poor areas wetlands can help to balance out seasonal changes by holding onto water through dryer times and catching water and keeping it from running off too quickly in wet times. Wetland plants protect that water and further increase the stability of the local water supply by reducing usage, by slowly sinking cleaned water into aquifers, and by providing a source of humidity via evaporation that can cause more frequent rain events.

Clearly wetlands are a good idea but what about for individual property owners? What is the motivation for a suburban family to give up part of their lawn and or garden to a wetland?

The Power of Food Producing Wetlands

If you’re interested in the grow food not lawns movement don’t shy away from including wetland areas on your property. After all, they are super productive. In fact, wetlands can be extremely productive beyond your garden.

Typical garden plants might not grow in wetlands. This presents the opportunity to experiment with plants that like to. Additionally wetland fill up with organic material over time. As a result, they need that rich organic soil removed periodically. This soil is excellent for potting. As a result it saves you the trouble of buying potting soil that’s been trucked in from who knows how far.

If you’re not interested in growing food in a wetland you can still plant items that are useful for pollinators and other beneficial insects in your wetland. If your wetland is engineered properly you can use it to help keep the rest of your garden watered.

Our Wetland Plans

Our property is a sloping hillside but in the winter there is a steady flow of water running across it. Starting near the top of the property water runs down to an area that keeps eroding. We’re properly planning to redirect this in a more positive way. Additionally we have neighbors at the bottom of the hill. As storms are going to be more powerful we don’t want to see our land beating down their front door.

We’ve thought about swales for some time but do to the slopes and terracing that we already have I’m leaning more towards keyline contour ditches that are at the back of the terraces so that the terrace in front of them can slowly absorb that water but wherein there may often be quite a lot of pooling. In these ditches and very small ponds we will plants clumping grasses, wild rice, reeds, and other water productive loving plants.

We’re planning a series of these along with a living roof and back yard space that can drain into a cistern and a larger pond or subsurface wetland on the lowest part of the property with a large basin that can catch and slow large amounts of water in a torrential situation without creating large problems for our neighbors in the valley.

I’ve got a design that I’ve worked up in Sketchup but it may not be true to the land so I’m hesitant to post it but when we do the actual work I’ll take loads of photos and will be sure to post about it. If you have any questions please contact me.