Preface: advances in hypolimnetic oxygenation

Abstract

Wagner KJ. 2019. Preface: advances in hypolimnetic oxygenation. Lake Reserv Manage. 35:225–228. Hypolimnetic oxygenation systems (HOS, here taken to mean techniques that add oxygen to the bottom layer of a lake or reservoir without disrupting stratification) have been in use for over half a century. However, issues of theoretical understanding, equipment, implementation, monitoring, and cost have limited widespread application of what is a potentially very effective means of improving water quality. Advances of the last two decades have pushed HOS to the forefront of water supply management, with some application in recreational lakes as well. Key advances include demonstration of long-term improvement of water quality, including higher concentrations of oxygen and lower concentrations of reduced compounds and algae, better predictability of results, including greater understanding of oxygen demand and its expression, and characterization of capital and operational costs, including likely changes over time as oxygen demand is satisfied. The application of additional management techniques in many cases limits our ability to ascribe all positive results to HOS alone, but the value of HOS as a lake management tool has been clearly demonstrated. More applications with careful monitoring and documentation of results are expected to advance this approach further.