Here, instead of
installing refrigeration systems at two Tualatin River treatment plants
(at a cost of $60 million). the wastewater utility paid upstream
farmers to plant shade trees in the riparian areas (at a cost of
$6 million). The total maximum daily load (TMDL) for water temperature
reduction is closely monitored by the EPA and Oregon Department
of Environmental Quality (ODEQ) and although future
temperature reduction and temperature credits will depend on
shade from riparian trees, the temperature credit calculation is
based on the robust Shade-a-Iator model developed in Oregon
(Lambrinos, 2010; ODEQ, 2010).