River Kelvin Case Study Steady Flow Analysis Theory

1D Steady Flow Modelling Geometrical data River cross-sections + distance between them. x Q h Hydraulic structures

1D Steady Flow Modelling Equation Solution Standard step method. Q 1 2 x Z + y

1D Steady Flow Modelling Boundary Conditions Upstream – constant inflow. Downstream – known water level. Q T Q h h Q T

1D Steady Flow Modelling Prediction Water level at each cross-section. x Q h Advantages Easy to predict maximum water level.

River Kelvin Case Study Steady Flow Analysis Case Study

River Kelvin Case Study The December 1994 Flood Rainfall event with a return period between 1 in 300 and 1 in 1000 years. Flood return periods Lower River Kelvin 1 in 200 years. Main tributaries - Luggie Water and Glazert Water 1 in 50 years. Flood outline 9 to 11th December 1994

River Kelvin Case Study Consequences Catastrophic flood which caused: Damage estimated at £10 million. Extensive damage to over 300 business and residential properties. The loss of two lives. Inundation in Kirkintilloch Flooding of McNair’s Factory Overtopping of flood defences at Balmore

River Kelvin Case Study Solution Options considered: Flood storage – discounted due to timing of flood peaks. Channel dredging – discounted due to environmental damage and increased flood peaks downstream in Glasgow. Solution adopted was a system of direct defences using earth embankments and retaining walls, the location of which was chosen to preserve as much of the existing flood plain as practical.

River Kelvin Case Study Solution Examples of the direct defences used of the River Kelvin flood defence scheme.

River Kelvin Case Study Steady Flow Analysis The Task

River Kelvin Case Study Model Calibration The HEC-RAS model provided has been set up with: Gauged inflows for the River Kelvin and its tributaries for the December 1994 flood, Table 1. A rating curve downstream boundary based on uniform flow. Manning’s ‘n’ values of 0.02 and 0.01 on the flood plain and main channel respectively. Calibrate the model by altering the Manning’s ‘n’ values to obtain a reasonable agreement ± between the observed results provided in Table 2 and the computed values.

River Kelvin Case Study Flood modelling Use the calibrated model to estimate flood levels for the 50, 100 and 200 year flood events, inflow data is provided in Table 3. Determine the maximum defence levels for a flood prevention scheme for Kirkintilloch.

River Kelvin Case Study Reporting The case study report should include: A map showing the location liable to flooding for a return period of 1 in 200 years. Details of required flood defence levels in the location of Kirkintilloch.