High resolution temperature observations to identify different runoff processes
Creators: name: Westhoff, M.C.(Martijn)
Publisher: name: TU Delft
Year: 2011
Subjects: DTS
stream water temperature

description: Headwater catchments are important contributors to streamflow. They are small, but all combined they influence river flow significantly. To be able to make proper runoff predictions under different climate conditions and changing land use, it is important to have detailed understanding of the discharge processes in the headwater catchments. In this rersearch the possibilities of fibre optic Distributed Temperature Sensing (DTS) are explored to obtain more insight in temporal and spatial discharge dynamics during stormflow. DTS is a technique capable of measuring temperature with high spatial and temporal resolution. The technique relies on short laser pulses that are sent through a fibre optic cable. Throughout the fibre optic cable small parts of the pulses are reflected by disturbances in the glass fibre, of which the exact position is obtained by measuring the travel time of the reflected light. All experiments were done in the Maisbich: a 565 m long, first order stream in Central Luxembourg. Parent StudyAll studies Measuring instrumentTemperature sensor 1209363_Mai6A (T 414m inflow), Maisbich LUXTemperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of lateral inflow at 414 m downstream of V-notch weir Q4 Measuring instrumentTemperature sensor 1209365_Mai171 (T 350m inflow), Maisbich LUXTemperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of lateral inflow at 350 m downstream of V-notch weir Q4 Measuring instrumentTemperature sensor 1209368_Mai11 (T 178m inflow), Maisbich LUXTemperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of lateral inflow at 178 m downstream of V-notch weir Q4 Measuring instrumentTemperature sensor 1209369_SPOT (T 104m inflow), Maisbich LUXTemperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of lateral inflow at 104 m downstream of V-notch weir Q4 Measuring instrumentTemperature sensor 1209370_road, Maisbich (Luxemburg)Temperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of stream water at ca 280 m from V-notch weir Q3 Measuring instrumentTemperature sensor 1239545_SPOT_upstr (T 104m up), Maisbich LUXTemperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of stream water just upstream of lateral inflow at 104 m downstream of V-notch weir Q4 Measuring instrumentTemperature sensor 1239546_coolbox, Maisbich (Luxemburg)Temperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of water in a box. In the same box ca 30 m of DTS fiber optic cable measues temperature. Measuring instrumentTemperature sensor 1239547_M11_upstr (T 178m up), Maisbich LUXTemperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of stream water just upstream of lateral inflow at 178 m downstream of V-notch weir Q4 Measuring instrumentTemperature sensor 1239550_SPOT_downstr (T 104m down), Maisbich LUXTemperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of stream water just downstream of lateral inflow at 104 m downstream of V-notch weir Q4 Measuring instrumentTemperature sensor 1239551_PM171_upstr (T 350m up), Maisbich LUXTemperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of stream water just upstream of lateral inflow at 350 m downstream of V-notch weir Q4 Measuring instrumentTemperature sensor 1239553_M11_downstr (T 178m down), Maisbich LUXTemperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of stream water just downstream of lateral inflow at 178 m downstream of V-notch weir Q4 Measuring instrumentTemperature sensor 1239554_M171_downstr (T 350m down), Maisbich LUXTemperature sensor,TidbiT v2 temp logger: Hobo USA.Temperature of stream water just downstream of lateral inflow at 350 m downstream of V-notch weir Q4 Measuring instrumentFibre optic Distributed Temperature Sensor DTS, Maisbich, LuxemburgThe fibre optic Distributed Temperature Sensing (DTS) system measures the water temperature along the entire stream. It consists of a dedicated desktop computer with built-in data-acquisition and processing software, to which a fibre optic cable is attached. Short laser pulses (in the order of a few nanoseconds) are sent through the fibre optic cable. When light strikes matter a small portion of the light may be reflected. By measuring the time between the moment the laser pulse is sent through the cable and the moment a reflected photon comes back, the location of reflectance can be determined, since the speed of light in glass is known.The system is from Halo, Sensornet, UK, and has a spatial resolution of 2 m and a temporal resolution of 3 min. This configuration results in a precision of ∼0.1◦C. Measuring instrumentMaisbich basin: V-notch discharge meter Q3 (Qdown)Type: Pressure Sensor Keller DCX-4.0, SN 1467This instrument is based on differential pressure measurement of twoabsolute sensors. The sensors measure pressure and temperature.Height of V-notch above sensor: -0.0015m.Datasets with correction contain the corrected discharge observed at the Vnotch.The discharge is calculated as Q=Cd*h^2.5After correcting the logger measurements with hand measured depths we interpolated the difference (dH)Then we determined the factor Cd with discharge measurements which we also interpolatedThe timing of hand measurements can be corrected to better represent the logged valuesThe last corrections (variable "clean_corr") were made for blocking of the V-notch weir as folows:z1 represents the last good discharge value after which sedimentation slowly starts blocking the weirz2 represents the moment when the blocking is maxz3 represents the moment just before cleaning of the weirz4 represents the moment after cleaning of the weirThe max difference in discharge is Q(z3)-Q(z4) Measuring instrumentMaisbich basin: V-notch discharge meter Q4 (Qup)Type: Van Essen TD-Driver, SN 19613This instrument measures pressure with one absolute sensor. It also measures temperature.Height V-notch above sensor: 0.0018m.Datasets with correction contain the corrected discharge observed at the Vnotch.The discharge is calculated as Q=Cd*h^2.5After correcting the logger measurements with hand measured depths we interpolated the difference (dH)Then we determined the factor Cd with discharge measurements which we also interpolatedThe timing of hand measurements can be corrected to better represent the logged valuesThe last corrections (variable "clean_corr") were made for blocking of the V-notch weir as folows:z1 represents the last good discharge value after which sedimentation slowly starts blocking the weirz2 represents the moment when the blocking is maxz3 represents the moment just before cleaning of the weirz4 represents the moment after cleaning of the weirThe max difference in discharge is Q(z3)-Q(z4) Measuring instrumentMaisbich basin: Tipping bucket rainfall meterType: Casella Tipping Bucket 100000 EThis instrument measures rainfall by counting the times a bucket tips overdue to filling with rainfall.Aperture 400 cm3 (?)Bucket size 0.2mm (?) Measuring instrumentMaisbich basin: Weather stationType HOBO Weather Station. Measures: rain, wind, gust speed, wind direction, temperature, relative humidity, solar radiation.