Discharge measurement at the river "Große Roeder" in Saxony - Germany
Due to the seasonally strong weed growth and low flow during low water periods the relation level/flow at the measurement site "„Kleinraschuetz“ was rather distorted and had to be corrected by putting in additional manpower for manual measurements. Therefore it was decided to modernize the station completely and to install a stationary discharge measuring system. The challenge of the measurent situation was to find a solution that measures reliably at all water levels from low level 29 cm to high level at flood events with 310 cm.
OTT SLD
Sistema Doppler para la medición estacionaria del caudal
El OTT SLD es un sistema de medición Doppler independiente para el registro continuo de la velocidad de fluidez y el nivel en aguas que fluyen naturalmente y seminaturalmente.
- Instalación fija
- Ultrasónico
- Flujo, nivel de agua (opcional)
- Filtro de barco integrado, interfaz Modbus para sistemas de control de proceso, cálculo de cantidades de extracción y vertido por intervalo de tiempo (máx. 1 día). Alcance hasta 80 m, según la frecuencia.
- ±10 m/s
- ±1 % del vaor medido ±0.5 cm/s
The river Große Roeder is a tributary of the river Schwarze Elster. It has a length of 105 km, rises northeastern from Dresden and is flowing into the river Schwarze Elster near the town Elsterwerda. At the measuring station „Kleinraschuetz“ the Große Roeder is a typical man-induced lowland river.
This measure was ordered by the BfUL (Staatliche Betriebsgesellschaft für Umwelt und Landwirtschaft) who is also the operator of the Saxonian water measurement network.
The measurement task was: online measurement of velocity of flow and subsequent calculation of discharge per velocity – index method in water levels from 29 cm to 310 cm
Storage and management of all data for the Saxonian authority for environment, agriculture and geology (LfULG) with remote data transfer and remote maintenance of the measuring systems
This was realized by:
- OTT SonicFlow travel time system (one-level cross path)
- OTT SLD 2.0 MHz Side-Looking-Doppler-Sensor for measurement of local velocity of flow (index velocity)
- OTT SE 200 shaft encoder water level sensor
- Datalogger OTT LogoSens2 for monitoring and storing measured data, for discharge calculation and for remote data transfer
The measurement profile was designed as double-trapeze and paved with armour stone. Two independently installed empty conduits DN 50 which are protected by a galvanized steel tube at the river bed (mainly during the pavement works) are crossing the water body. For easier access to the cables a cable duct has been installed.