Date of Award

Spring 2017

Document Type


Degree Name

Master of Science (MS) in Biology




This project focused on highly impacted streams at Turnbull National Wildlife Refuge, Cheney, WA to evaluate the health status and ecosystem integrity of the water bodies. Turnbull National Wildlife Refuge contains over 3,000 acres of wetlands, and provides high quality habitat for migrating and breeding waterfowl. However, these wetlands are impacted by both high nutrient levels (Davidson and Rule 2006) and invasive fish (Scholz et al. 2003). This project focused on stream sections of the Company Ditch (CD) and Pine Draw (PD) watersheds. Company Ditch historically had very high nutrient levels and low water quality. Water quality may be improving since closure of a nearby dairy operation in 2008. Pine Draw includes several springs and the only perennial stream habitat on TNWR. This stream has high densities of invasive brook stickleback, and experiences nutrient loading from an unknown source.

Both streams were assessed using benthic macroinvertebrate surveys in 2007, 2008, 2010, 2011, 2013, and sampled again 2016. Benthic macroinvertebrate communities are widely used in monitoring ecosystem health. Physical habitat characteristics and water quality parameters were also measured. Water quality clearly improved in the Company Ditch during 2008-2011 following the closing of the dairy. Water quality has declined in one seasonal Pine Draw site, but remained more consistent in the permanent Pine Draw sites.

Included in

Biology Commons