The COHERENT Collaboration has made the first observation of the Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) process on both CsI and LAr detectors using neutrinos produced in the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). CEvNS measurements will have significant impact on many areas of physics, motivating COHERENT to perform precise measurements utilizing a variety of target nuclei. Precision measurements at COHERENT require a reduction in the largest systematic uncertainty of 10% on the neutrino flux. Taking advantage of the well-understood charged-current interaction of electron neutrinos on deuterium, we are deploying a heavy water detector to directly measure the neutrino flux. This poster will present an overview of the heavy water detector, as well as simulation results and near-term plans.