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Appendix B: - Data Analysis
B.1 Data Analysis
B.1.1 Flow Analysis
Table B-1: Indicative Design Peak
Flows
Return period | River Don | River Tweed |
|---|
Bridge of Alford Peak Flow
m3/s | Parkhill Peak Flow m3/s | Lyne Station Peak Flow
m3/s | Norham Peak Flow m3/s |
|---|
Single | Pooled | Single | Pooled | Single | Pooled | Single | Pooled |
|---|
2 | 99 | 100 | 136 | 144 | 33 | 35 | 667 | 648 |
5 | 137 | 133 | 178 | 216 | 46 | 50 | 886 | 883 |
10 | 161 | 157 | 206 | 275 | 57 | 62 | 1036 | 1033 |
25 | 189 | 189 | 244 | 369 | 72 | 83 | 1243 | 1229 |
50 | 210 | 217 | 275 | 458 | 86 | 102 | 1412 | 1383 |
75 | 221 | 235 | 294 | 518 | 95 | 116 | 1518 | 1476 |
100 | 229 | 248 | 308 | 566 | 102 | 127 | 1597 | 1544 |
150 | 239 | 268 | 329 | 641 | 112 | 145 | 1714 | 1641 |
200 | 247 | 283 | 345 | 700 | 121 | 158 | 1800 | 1712 |
Table Notes:
1. Single Site Flood Frequency Analysis carried out
using data from target site, using Generalised Logistic (
GL) distribution fitted using the method
of L-Moments. Does not always provide robust estimates as
only reliable up to return periods matching the length of
record of the target site (shown in red text above).
2. Pooled distribution is derived by pooling data
from the target site along with data from other similar
sites.
B.1.2 Rainfall Analysis
Table B-2: Don Catchment Daily Rainfall Totals
and Indicative Return Periods August 2004
Duration (days) | Cushnie (
OSNGR 352800
807200) | Insch (
OSNGR 363000
828200) | Tullinessle (
OSNGR 356100
818400) |
|---|
Total rainfall Depth (mm) | Return Period (Years) | Total rainfall Depth (mm) | Return Period (Years) | Total rainfall Depth (mm) | Return Period (Years) |
|---|
0.252 | 66.0 | 590 | 47.7 | 140 | 39.9 | 60 |
0.52 | 66.0 | 163 | 47.7 | 37 | 39.9 | 14.1 |
1 | 66.0 | 38 | 47.7 | 8.3 | 39.9 | 3.4 |
2 | 68.2 | 8.5 | 57.6 | 4.1 | 50.3 | 2.14 |
3 | 74.2 | 5.6 | 61.8 | 2.8 | 54.6 | 1.59 |
4 | 76.4 | 3.6 | 78.9 | 5.5 | 80.1 | 5.1 |
5 | 76.8 | 2.37 | 83.1 | 4.7 | 84.4 | 4.4 |
6 | 82.3 | 2.32 | 85.2 | 3.9 | 86.1 | 3.4 |
7 | 93.2 | 3.1 | 85.2 | 3 | 86.4 | 2.7 |
14 | 121.3 | 3.3 | 112.0 | 3.9 | 117.7 | 3.9 |
15 | 124.4 | 3.3 | 118.7 | 4.8 | 123.0 | 4.4 |
Notes:
1. N Day Rainfall Totals calculated from Daily
rainfall data on a fixed duration. Return periods
calculated using 1km point
FEHDDF model.
2. Return periods calculated hypothetically for 0.5
and 0.25 day as exact duration of rainfall over the 24
hours between readings is unknown.
Table B-3: Tweed Catchment Daily Rainfall
Totals and Indicative Return Periods August
2004
Duration (days) | Hallmanor (
OSNGR 321000
635100) | Hawick (
OSNGR 351200
615600) | Cappercleuch (
OSNGR 323900
623200) |
|---|
Total rainfall Depth (mm) | Return Period (Years) | Total rainfall Depth (mm) | Return Period (Years) | Total rainfall Depth (mm) | Return Period (Years) |
|---|
0.252 | 37.6 | 34 | 40.7 | 51 | 48.9 | 57 |
0.52 | 37.6 | 10.8 | 40.7 | 18.9 | 48.9 | 16.4 |
1 | 37.6 | 2.7 | 40.7 | 4.6 | 48.9 | 3.4 |
2 | 61.7 | 4.8 | 57.4 | 4.3 | 72.3 | 3.3 |
3 | 78.1 | 7 | 72.5 | 6.9 | 97.6 | 6.3 |
4 | 115.5 | 32 | 102.9 | 28 | 135.1 | 20.2 |
5 | 125.9 | 34 | 107.9 | 25 | 144.1 | 18.9 |
6 | 126.0 | 24.3 | 107.9 | 18.7 | 144.1 | 13.4 |
7 | 126.2 | 18.5 | 107.9 | 14.5 | 144.3 | 10.1 |
14 | 181.8 | 50 | 153.8 | 48 | 211.8 | 29 |
15 | 182.5 | 45 | 159.9 | 57 | 215.8 | 29 |
Notes:
1. N Day Rainfall Totals calculated from Daily
rainfall data on a fixed duration. Return periods
calculated using 1km point
FEHDDF model.
2. Return periods calculated hypothetically for 0.5
and 0.25 day as exact duration of rainfall over the 24
hours between readings is unknown.
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