Descriptions
The V-notch weir uses the principle of flow of water over a triangular or rectangular notched weir plate. For a given profile size and shape, discharge is a function of the head of water at the weir.
Standard experimentally determined formulae (e.g. Kindsvater-Carter) are available which calculate the head of water to the rate of discharge.
A V-notch weir system comprises a stainless steel plate with a chosen notch profile to suit expected flow rates and a means of measuring the head on the weir plate.
The weir plate is mounted at the exit of a channel, tank or stilling basin through which the flow to be measured is channelled. The measuring point for the head of water is located upstream of the weir plate within the channel or basin.
Measurement can be carried out using a stainless steel scale or staff gauge fixed to the basin wall, from where manual readings for head above the vortex of the notch may be read.
Case Studies
Tishreen Dam
Completed in 1991 and situated within the Tigris-Euphrates basin, the 630MW hydro-electric Tishreen Dam has a storage capacity of 1.9 km3 and generates 1.6 billion kWh of electricity every year.
The dam is constructed with a chalk impervious core and seepage beneath it controlled by a Bentonite/cement cut-off wall. The complex comprises the main dam, a powerhouse constructed as a gravity dam and a small fuse plug.
The original instrumentation equipment was installed during construction and was entirely manually read.
Due to a serious dam failure in Syria the General Organisation for Euphrates Dam (GOED) decided to upgrade the instrumentation to a modern automatic system including full data logging of all instruments together with alarm trigger levels.
After consultation with the GOED Engineers, Geosense designed a new system installing new instruments side by side with the existing instrumentation and upgrading several areas to provide a fully integrated and automatic dam safety monitoring system.
All the new instruments were connected into a data logging system and provided real time visualisation within the dam control room.
Tishreen Dam Case Study
Baish Dam
The Baish Dam is a gravity dam on Wadi Baish about 35km northeast of Baish in the Jizan Region of south-western Saudi Arabia.
The dam has many purposes including flood control, irrigation and groundwater recharge. The total reservoir capacity of the dam is 192 million m3.
The dam was constructed between 2003 and 2009 and at 106m high on completion, it was the tallest dam in Saudi Arabia. It is owned and operated by the Ministry of Water and Electricity.
Baish dam is one of six dams currently undergoing the change from a manual to a fully-automated monitoring system.
The original instrumentation equipment was installed during construction and was entirely manually-read. The Ministry made the decision to upgrade the instrumentation to a modern automatic system including full data logging of all instruments together with alarm trigger levels and data access via the Internet.
Baish Dam Case Study
