Sustainable Watersheds for Carbon Offsets: Biomass harvesting for phosphorus capture, habitat renewal and carbon emissions reductions

The report details IISD's Bioeconomy project (2017-2019) focusing on harvesting unconventional biomass from water retention sites and roadside ditches in Manitoba. It argues that this practice removes phosphorus to protect Lake Winnipeg, improves habitat health, and provides a low-carbon alternative to fossil fuels or a means of soil carbon sequestration. The document analyzes harvesting methods, the shift from bioenergy to livestock bedding and compost, and evaluates global and North American carbon market verification methodologies to identify frameworks suitable for these watershed management activities.

• Harvesting cattails and other grasses from managed watershed areas removes phosphorus before it enters lakes, which can then be recovered for use as agricultural fertilizer, while also improving biodiversity and reducing flood impacts.
• A pilot project demonstrated that harvesting rural roadside drainage ditches is a viable alternative to conventional management methods such as mowing, herbicides, and excavation, as it improves water flow and removes contaminants.
• In 2018 and 2019, the demand for harvested biomass shifted from bioenergy toward livestock bedding and compost to improve soil health and carbon storage, which is more efficient and cost-effective than burning for energy.
• Urban harvesting in the City of Winnipeg diverts up to 500 tonnes of material annually from landfills to compost facilities, removing approximately 350 kg of phosphorus and reducing GHG emissions by over 200 tonnes.
• The use of blended cattail, wood, and grass fuel pellets in Hutterite communities and other facilities provided a low-carbon alternative to coal, improving heating efficiency and air quality in pig barns.
• Economic analysis based on the 2014/15 MAFRD Farm Machinery Custom and Rental Rate Guide estimates the total cost of harvest, baling, and forage at CAD 49,452, resulting in an estimated cost of CAD 34 per bale or CAD 56 per tonne.
• There is currently no specific literature on using harvested cattails as organic fertilizers, but analogous research on woody biomass suggests that a one-year observation period is insufficient to determine impacts on soil health.
• The report identifies a lack of a standard national or international carbon offset market in Canada, noting that the federal Pan-Canadian Framework on Clean Growth and Climate Change puts a price on carbon starting at CAD 10 per tonne, increasing to CAD 50 by 2022.
• A review of carbon market verification methodologies found that most are focused on forested land or synthetic nitrogen fertilizer reduction in the US, with few directly applicable to cattail harvesting, though some Alberta protocols for biomass waste to energy are close matches.

APA

Grosshans, R., Viswanathan, B., Gass, P., & Grieger, L. (2019). Sustainable Watersheds for Carbon Offsets: Biomass harvesting for phosphorus capture, habitat renewal and carbon emissions reductions. International Institute for Sustainable Development. https://www.iisd.org/system/files/publications/sustainable-watersheds-carbon-offsets.pdf

Chicago

Grosshans, Richard, Bala Viswanathan, Phil Gass, and Lorne Grieger. Sustainable Watersheds for Carbon Offsets: Biomass harvesting for phosphorus capture, habitat renewal and carbon emissions reductions. International Institute for Sustainable Development, 2019. https://www.iisd.org/system/files/publications/sustainable-watersheds-carbon-offsets.pdf.

Wikipedia

{{cite report |last1=Grosshans |first1=Richard |last2=Viswanathan |first2=Bala |last3=Gass |first3=Phil |last4=Grieger |first4=Lorne |title=Sustainable Watersheds for Carbon Offsets: Biomass harvesting for phosphorus capture, habitat renewal and carbon emissions reductions |publisher=International Institute for Sustainable Development |date=August 2019 |url=https://www.iisd.org/system/files/publications/sustainable-watersheds-carbon-offsets.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{grosshans2019sustainable, author = {Grosshans, Richard and Viswanathan, Bala and Gass, Phil and Grieger, Lorne}, title = {{Sustainable Watersheds for Carbon Offsets: Biomass harvesting for phosphorus capture, habitat renewal and carbon emissions reductions}}, institution = {International Institute for Sustainable Development}, year = {2019}, month = aug, url = {https://www.iisd.org/system/files/publications/sustainable-watersheds-carbon-offsets.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }