One of the challenges of generating electrical energy with a hydrokinetic turbine in Alaska rivers is the detrimental effect of woody debris in the water column. In order to mitigate this problem the questions of describing what types of debris might be encountered, the frequency of occurrence, the force of impact, and location in the water column need to be answered. The University of Alaska Fairbanks (UAF) Alaska Hydrokinetic Energy Research Center (AHERC) designed, constructed, and tested a mechanical debris detection device (MDDD) for Ocean Renewable Power Company (ORPC). The MDDD was intended to be deployed in the Tanana River at Nenana, Alaska, to assess the debris conditions at the location and depth at which ORPC was planning to deploy a hydrokinetic turbine demonstration project. The MDD was mounted on ORPC’s anchoring system that was designed to hold their turbine support structure in place during turbine operations. Due to difficulties in trying to deploy the anchoring system the MDDD was not deployed during the project period. This report summarizes the design, testing and operating instructions for the MDDD. Technical specifications and information are contained in the appendices.