CE–QUAL–W2 water-quality models for Klamath Straits Drain recirculation scenarios, Klamath River, Oregon, 2006–15

A hydrodynamic, water-temperature, and water-quality model (CE-QUAL-W2; Wells, 2020) of the Link-Keno reach of the Klamath River (Oregon) was used for calendar years 2006–15 to run a series of base and recirculation scenarios. These model runs were implemented to test alternative scenarios for routing some of the Klamath Straits Drain discharge into Ady Canal. The model scenarios were configured for baseline conditions and three different sets of recirculation scenarios, including the maximum year-round recirculation without discharge limits (scenario 1), limited year-round recirculation fixed by the current pipe flow configuration from Klamath Straits Drain into Ady Canal (scenario 2), and limited seasonal recirculation (May-September), also fixed by the current pipe flow configuration (scenario 3). For calendar years 2012–15, a separate CE-QUAL-W2 model for the Klamath Straits Drain was used in lieu of the Klamath Straits Drain as a tributary directly into the Link-Keno reach of the Klamath River CE-QUAL-W2 model. Original calibration and simulation of the Klamath Straits Drain model was documented in Sullivan and Rounds (2018). Original calibration and simulation of the Link-Keno reach of the Klamath River was documented in Sullivan and others (2011). These recirculation scenarios will be used by the United States Bureau of Reclamation to better understand the effects of recirculating Klamath Straits Drain discharge into Ady Canal on constituent loads of total nitrogen, total phosphorus, and the 5-day biochemical oxygen demand (BOD5).