Study and Report on the Effects of Flooding River Kelvin – Kilsyth

Case Study

Report on the Effects of Flooding River Kelvin – Kirkintilloch

1. The Task

Assess the vulnerability of the town of Kirkintilloch to flooding from the River Kelvin and its tributaries at return periods of 50, 100 and 200 years and determine the maximum level of flood defence embankments to protect the town from further flooding.

2. Requirements

Calibrate the HEC-RAS model provided using the historical information provided in Table 2 from the December 1994 flood.

Use the calibrated model to estimate flood levels for the 50, 100 and 200 year flood events and hence determine the maximum defence levels for a flood prevention scheme for Kirkintilloch.

3. Reporting

The report should include:

• 
  A map showing the location liable to flooding at a return period of 1 in 200 years if no flood defences are built.
  

• 
  Details of the required flood defence levels in the location of Kirkintilloch.
  

4. 
   Calibration data
   

There are four flow gauges operated by SEPA in the River Kelvin catchment of relevance to this study. Theses are on the Glazert Water (Milton), Luggie Water (Oxgang) and River Kelvin (Bridge End and Dryfield). The Dryfield guage is at the downstream end of the study site. Measured peak flows from these for the 10^th to 11^th December 1994 and given in the table below. In addition, another small ungauged tributary, the Park Burn joins the River Kelvin within the study area. An estimated value for this flow is also provided.

Table 1

Location	Cross-section number (from upstream end)	Peak flow (m^3/s)
River Kelvin @ Bridge End	23	40
Glazert Water @ Milton	12	69
Luggie Water @ Oxgang	9	59
Park Burn (ungauged)	4	6 (estimated)
River Kelvin @ Dryfield	1	174

After the December 1994 flood the following data was collected for the purpose of computer model calibration.

Table 2

Section No.	Observed Water Level (m OD)
14	38.90
12	38.50
11	38.10
10	38.00
8	37.70
6	37.10
4	36.80
2	36.72
1	36.65	Downstream end

5. Flood assessment
The design flows in the table below were obtained from the Flood Estimation Handbook for the River Kelvin and its tributaries. These flows should be used as model boundary conditions to determine future flood risk and the height of the flood defences. For downstream boundary conditions assume a constant water level of 36.65 m OD.

Table 3

Return Period (years)	Kelvin @ Dryfield (m^3/s)	Kelvin @ Bridgend (m^3/s)	Glazert @ Milton (m^3/s)	Luggie @ Oxgang (m^3/s)	Park Burn (m^3/s)
50	104	18	43	39	4
100	117	22	47	44	4
200	125	25	49	47	4