Nutrient Truth: Best Practices in Developing Accurate and Realistic Nutrient Removal Rates from Stream Restoration and Stabilization
Ian C. Jewell
Freese and Nichols, Inc.
Winston-Salem, NC
In many localities where nutrient management and nutrient removal from waterways has become a priority focus for water- quality improvement, stream restoration and streambank stabilization has become a primary method of achieving nutrient reduction targets. The quantification of nutrient removal rates from these practices relies on determining the baseline nutrient concentration in streambank soils, bulk density as well as baseline streambank erosion rates. However, these baseline values, in particular existing erosion rates, are often based on values or regression curves developed from streams in entirely different hydrophysiographic regions and soil types. This creates the risk of stream restoration projects significantly overestimating or underestimating nutrient removal rates, and therefore failing to provide the degree of certainty needed to show progress towards meeting nutrient reduction goals in imperiled waterways. In this presentation, we present best practices towards estimating site-specific baseline nutrient loading rates from streambank erosion, with a particular focus on accurate estimates of erosion rates, using tools such as analysis of exposed tree roots to ensure that estimates of nutrient removal are based on a “best available data” approach. We present case studies of several stream restoration projects where these best-practices were employed and show the differences in estimation of nutrient removal rates using site-specific data versus published values or regression equations.
About Ian C. Jewell
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