This collaborative grant between Oregon State University (PI: Selker) and the University of Nevada Reno (PI: Tyler; EAR-1128999), supports a three year continuation and enhancement of national multi-user facility support for the Center for Transformative Environmental Monitoring Programs (CTEMPs). CTEMPs was established in 2009 with initial support through the American Recovery and Reinvestment Act (ARRA; EAR-0943682). CTEMPs offers community support for planning, training, equipment lease and field implementation using distributed fiber optic methods including Raman backscatter Distributed Temperature Sensing (DTS) to allow for unprecedented observation of the spatial and temporal distribution of temperature for environmental applications including but not limited to, snow, groundwater and watershed hydrology, aquatic and terrestrial ecology, karst geology, soil science (including permafrost studies), atmospheric boundary layer turbulence and glaciology. Data collected using the CTEMPs DTS systems will be integrated into the CUAHSI Hydrologic Information System (HIS) and CTEMPs will become a Hydrologic Measurement Facility (HMF) Node of CUAHSI. CTEMPs plans training workshops and field deployment for up to 26 research projects a year with this support. CTEMPs currently maintains five DTS system, one of which is high resolution, and 27 km of fiber optic cable. High resolution DTS systems allow for near continuous (0.25 m) and precise (+/- 0.3 deg C) observations of river bottom, lake, or estuary bottom, snow pack, soil horizon or atmospheric temperatures over distances as great at 8 km at high temporal frequency (1 Hz). Temperature precision of +/ 0.01 deg C can be achieved when observation are sampled hourly. When placed in a stream or river, fiber optic DTS allows for observation of the location, temperature, and flux of each groundwater inflow, calculation of an exact heat budget to determine hyporheic exchange, and observation of micro-thermal habitats critical to successful larval fish recruitment. DTS systems were originally developed for applications in the oil industry and for fire detection in high rise buildings. Support for CTEMPs will make this developing technology available to broader scientific community for marginal instrument lease costs and applications for instrument use will be prioritized by an advisory committee with external representation.