Nature-based Innovations for Wise and Enduring Environmental Solutions

As our Erosion and Sediment Control (E&SC) industry continues to evolve, many practices and product technologies have come and gone, while others have persisted. What may have been a revolutionary idea years ago may not seem so great today when compared to more modern technologies and practices. We see this phenomenon across many industries.

Take, for example, straw bales. At one time, they were routinely used as a form of sediment control placed around project perimeters, at the bottom of slopes or perhaps in low flow channels. In reality, they were “flow blockers” and simply re-routed and concentrated the flow of water to perhaps cause even greater issues. However, they did capture some sediment and were readily available while there were few other options available. Enter the silt fence in the 1980s and later fiber rolls and wattles in the 1990s, and straw bales became quickly relegated to being shredded through choppers and blowers for use as a dry-applied mulch over seedbeds to this day.

Then, consider hard armor solutions such as rip rap and gabions and later, cast in place and articulating concrete block revetments. The use of rip rap and gabions dates back thousands of years. Time proven, all these techniques have performed well in more aggressive hydraulic conditions, but at what cost to the environment. Depending upon their relative level of imperviousness, do they simply deflect hydraulic energy, accelerate runoff and send it downstream or to adjacent properties to cause even great issues? Do they allow for groundwater recharge and establishment of cooling vegetation versus natural solutions that reduce both surface and water temperatures? Also, what is the amount of energy required to extract, produce, ship and place these materials? In today’s terms, what are their carbon footprints and levels of CO2 emissions?

Next, consider ways in which we can increase the amount of carbon in depleted soils. Traditionally, topsoil has been employed to increase organic matter and biological activity in disturbed or sub-soils. When topsoil is not readily available or is too costly to import, what are our next best options? Organic rich compost likely comes top of mind, but its availability and cost are limitations especially when projects are located away from sources. What has become more mainstream is the concept of manufactured “topsoil” where a “sub-soil” is blended with compost or other source of organic matter to create a “faux” topsoil to meet weak specifications.

Assessing the complete environmental impacts of harvesting, production, shipping and placement of topsoil, manufactured “topsoil” or even compost must also be considered. The consistency, uniformity and purity of these materials can also be suspect. How can the harvesting of “topsoil” from a candidate borrow area really ensure consistency if each truckload is not tested for conformity to specifications and the potential presence of contaminants such as heavy metals, plastic, pathogens, and weed seeds? The compost industry is plagued with contamination issues with its inability to control and monitor inputs from waste streams such as plant and food waste, recycled organic materials, and manure. Quoting A1 Organics, a leading Colorado compost supplier, “Contamination is the number one challenge our industry faces… “.

Beyond purity we must assess the safety of materials employed for erosion and sediment control. For example, the US Environmental Protection Agency (EPA) in their most recent 2022 Construction General Permit (CGP), recommend using erosion materials that are considered “Wildlife Friendly”. These products should be composed of loose weave nettings from natural fibers or be 100% biodegradable as opposed to “non-wildlife friendly” products that contain square, non-movable nettings derived from non-biodegradable plastic sources. Copious research by the US Fish and Wildlife Service, US Forest Service, US Natural Resources Conservation Service and numerous state agencies has documented the dangers of wildlife entrapment and entanglement in plastic nettings. Moreover, the breakdown of these nettings is contributing to mounting concerns over the accumulation of “microplastics” in our environment.

Thus, we must holistically look at any material’s environmental impact and safety from cradle to grave when assessing or considering its employment for E&SC as well as improving soil health via increased organic matter and biological activity.

This presentation by subject matter experts will delve more deeply into these considerations and offer alternative innovations that are truly wise and enduring “Nature-based” Solutions for the protection of our environment.