Charcoalkultur

Infiltration berms belong at the public works level, but a comparable practice for us masses is hugelkultur. I attended a talk last year at the Mother Earth News fair comparing biochar to hugelkultur and discovered that hugelkultur is generally easier and less chancy than making and applying biochar. Yet, a hugelkultur bed will not be as long-lived as one with a load of biochar.

Hugelkultur is the practice of piling soil and organic material on top of a bunch of logs and sticks to form a mound (mainly on contour) which can capture runoff in order to grow plants like a super high raised bed. +paul wheaton published a DVD about it and  +Sepp Holzer put some good instructions on Paul's richsoil website.

I've been using hugelkultur to augment swales in order to reduce erosion on the back slope of my property. My previous post about infiltration berms brought me to consider hugelkultur not as an alternative to biochar, but as another opportunity to put biochar to good use. Filling the gaps with biochar (or some percentage thereof) while building a hugelkultur bed is one way. Biochar could also be applied in areas where there is a need for extra moisture.

Such was the case with my wife's hydrangea which she wanted planted in a sloped area that normally would not stay moist enough for this plant. Yet, there is a roof downspout nearby which spills out onto the slope (via a splash plate) once the rain barrel fills up. I built a quasi-hugelkultur bed to direct the overflow to the hydrangea and loaded the outlet with unground biochar in order to slow the flow of water and hold it close to the plant.

There is enough of a dam behind the biochar to keep it from being washed away. Over time the biochar will break down into small particles and leach into the soil where it can do even more good.

I can see using biochar in a similar fashion on the uphill toe of a hugelkultur bed in order to reduce the tendency of the toe to erode where runoff sheetflow meets the mound. For highly steep slopes (> 25%), a deep swale on the uphill side of the hugelkultur mound containing some percentage of biochar could serve the same purpose.

Swales are an approved ESD practice in the Maryland Stormwater Manual. Hugelkultur beds aren't, but there may be enough latitude in the specs and descriptions that it would fit without requesting special approval. Beyond these practices, terracing is the next step for reducing runoff on steep slopes. For that, heavy equipment is needed, so it's better in most cases to think in terms of swales and mounds.

A Way to Plant Free Trees

The erosion control project that I am advocating for my church is to block surface runoff from eroding the topsoil into our detention pond by building a hugelkultur mound on the upper rim of the excavated area. This mound would be planted with a cover crop for at least one season, but after that, it would get some perennials or even trees in places where they wouldn't interfere with future building plans.

I hope we can get started with our preparations soon because we might be able to get help from The Alliance for the Chesapeake's Trees for Sacred Places program, which offers not only free trees, but technical support, training, and religiously-oriented motivation. You just need to have room to plant 60 or more trees. This may be possible, but it would surely fill up our open ground (outside the future building footprint). Teaming with another church congregation to make a total of 60 tree plantings may have to be our approach.

Alliance for the Chesapeake has partnerships with an organization called Interfaith Partners for the Chesapeake, which includes the tree planting program and a new program called RiverWise which looks at stormwater management more broadly, similar to the Watershed Stewards program, and even provides substantial financial assistance to correct problems.

It makes sense to involve church congregations in these efforts. They already have many diligent members who want to be contributors to improving their local communities, but starting with their own properties is a necessary first step.