Biological assessments are a requirement for ESA and evaluate the potential affects on listed species caused by construction activities. Biological assessments for invertebrates pose unique challenges due to: difficulty in sampling aquatic environments, patchy distributions and project scale. A case study will be discussed which goes through the biological assessment process including: project background, site location, selection of site specific sampling methods and potential problems with large river sampling. We will look at the results from the sampling and what this means for consultation with the U.S. Fish and Wildlife Service. We will also look at possible outcomes from this consultation, whether the project will be proceed and the steps are used in this process.