Course: BFM 101 Biofuels Fundamentals

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Sustainable Management for Biomass Production
Biodiversity and Wildlife

Ground and Surface Water
Ground and Surface Water

Harvesting forests or crops for bioenergy, and the associated development and use of infrastructure (i.e., roads, trails, and landings), can lead to soil erosion and runoff that may affect water quality and hydrological processes. Water quality is also affected by use of chemical fertilizers and herbicides, and by release of wastewater from processing facilities into surface waters. Water quantity is affected by irrigation practices and water withdrawals for conversion processes. Additionally, water flow and soil saturation are affected by residue management practices.

Water Quality and Quantity

The use of chemical fertilizers and pesticides in today’s intensive row crop production has led to contaminated drinking water and pollution in lakes and streams. The construction of roads and trails for biomass harvest can cause erosion, resulting in sediment movement to streams. Biomass harvesting and site preparation operations also increase the risk of erosion and sediment flow to surface waters [6,7]. Soil erosion increases in a non-linear, exponential manner with declining residue cover [3], which in turn reduces water infiltration and increases water runoff.

Production of short-rotation woody crops through monoculture plantations (e.g., willow, poplar) can deplete groundwater resources, especially if irrigation is required [8]. Power plants processing this biomass usually require water for steam production and cooling. If water used in the conversion process is released untreated into lakes or rivers, it can negatively affect water quality due to the chemicals used during the conversion process.

Water Erosion and Soil Saturation

Removing vegetation and litter during biomass harvesting can increase the risk of higher rates of soil and water erosion.  It also allows more water to fall directly on the soil surface and infiltrate to groundwater, resulting in a higher water table that could lead to soil saturation and a loss of productivity [9].

Best Management Practices

There are a number of best management practices that could be employed to minimize the effects of biomass harvesting and utilization on water quality:

- Minimize the number of roads and trails on a site, and close areas to traffic once the harvesting is completed;
- Monitor carefully the use of herbicides and fertilizers in biomass production (including recycled ash) and adhere to prescribed guidelines for their use. The removal of above ground-ground biomass for bioenergy crops may require more frequent fertilization for subsequent crops. Care should be exercised to ensure that fertilizer materials are not transported into streams, wetlands and lakes at levels that could impair water quality;
- Avoid establishing short-rotation woody crop plantations in areas where long-term regional groundwater availability could be a concern;
- Provide adequate crop residues or slash on the ground to enhance higher infiltration and minimize run-off;
- Encourage power plants  to re-use water during energy conversion. If water is to be released to lakes or rivers, plants should secure and comply with permits from appropriate regulatory agency.

Resources provided by the eXtension Farm Energy Community of Practice at http://www.extension.org/ag+energy

Sustainable Management for Biomass Production
Biodiversity and Wildlife