Nutrients and nutrient-related pollution are a leading cause of impairments to US waters, and environmental agencies are very actively engaged in designing management programs to address these impairments. In some situations, increased nutrient loadings to streams brought about by human activity is the primary cause of these water quality impairments. For this reason much current agency activity is devoted to development of water quality targets (criteria) for algae, phosphorus, and nitrogen.
Understanding and preventing stream impairments related to nuisance algae and excessive aquatic plant growth is difficult because of the number of variables that can contribute to this condition and the interrelationships between them. A further complexity is the fact that nitrogen and phosphorus (potential causal variables themselves) are required components of healthy aquatic systems. Numerous studies have shown that the accumulation of algae and other aquatic plants is governed by many stream characteristics including shade, bottom substrate, water depth, water velocity, water clarity, nutrient concentrations, temperature, and others. In cases where nutrient concentrations are known to be the limiting factor controlling populations of algae and aquatic plants, it is appropriate to manage the load of nutrients in a system to avoid excessive algae and plant population. In cases where other stream factors are limiting aquatic plant growth, management of nutrients may be less important.
NCASI has prepared a number of technical resources that can be used by member companies to enable knowledgeable management of timberland and mill wastewater treatment systems so that these operations do not cause nutrient impairments in ambient waters. The NCASI staff has also prepared resources that will help members effectively engage in state or regional initiatives to develop stream criteria for nutrients and regulate the release of nutrients from point and non-point sources.