HomeMy WebLinkAbout2560432 - Other Assessments - Storm / Foul Sewer DesignRECEIVED: 29/10/2025
RECEIVED: 29/10/2025
RECEIVED: 29/10/2025
RECEIVED: 29/10/2025
M5(60) mm Logue fig. 6 16 Routing Coeff. Cr 1.3 C =1.001
Job:Tully M5(2d) mm Logue fig. 2 50 Volumetric Runoff Coeff. Cv 0.77 Cv between 0.6 and 0.9
Program Design by Marcus Dancey.Return Period years 1-100 1 Ks Automatic or Manual m Met Office 1k or Min of Health mrm or Modified Rational Method (MRM)
PVC Exit #######Conc Ks 1.5 Slime? Normal/Poor (N/P)n
Conc.Invert PVC Ks 0.6 Time of entry (mins)5 Min of 4 for MRM
MH Pipe Ground Entry Pipe Sewer If Exit Water Volume Pipe Unity Spare Velocity Cover Cover GradientPipe Imperm Imperm Cum Ks
No.Run Level Invert Size Type Drop Invert or Capacity Factor Capacity Inlet Outlet Length Area Area Ex Area Actual
MOD MOD mm P/C MH MOD Runoof flow lts/s lts/s Check lts/s m/s m m 1:m m²Tributary m²mm
10 80.120 78.685 78.685 1.20 542.8
11 10 to 11 77.600 76.150 232.0 p 76.150 10.7 151.7 0.21 141.08 3.59 1.22 13.9 35.3 542.8 0 867.8 0.6
12 11 to 12 77.350 75.915 232.0 p 75.915 18.6 82.7 0.38 1.96 1.20 46.5 10.93 325 1520.8 0.6
13 12 to 13 74.670 73.235 232.0 p 73.235 19.3 130.5 0.24 3.09 1.20 18.8 50.358 653 1617.1 0.6
5 13 to 5 74.850 72.760 232.0 p 72.992 19.2 109.7 0.29 2.60 1.86 26.5 12.6 96.27 1617.1 0.6
15/08/2024 RECEIVED: 29/10/2025
M5(60) mm Logue fig. 6 16 Routing Coeff. Cr 1.3 C =1.001
Job:Tully M5(2d) mm Logue fig. 2 50 Volumetric Runoff Coeff. Cv 0.77 Cv between 0.6 and 0.9
Program Design by Marcus Dancey.Return Period years 1-100 1 Ks Automatic or Manual m Met Office 1k or Min of Health mrm or Modified Rational Method (MRM)
PVC Exit Conc Ks 1.5 Slime? Normal/Poor (N/P)n
Conc.Invert PVC Ks 0.6 Time of entry (mins)5 Min of 4 for MRM
MH Pipe Ground Entry Pipe Sewer If Exit Water Volume Pipe Unity Spare Velocity Cover Cover GradientPipe Imperm Imperm Cum Ks
No.Run Level Invert Size Type Drop Invert or CapacityFactor Capacity Inlet Outlet Length Area Area Ex Area Actual
MOD MOD mm P/C MH MOD Runoof flow lts/s lts/s Check lts/s m/s m m 1:m m²Tributary m²mm
14 76.860 75.430 75.430 1.20 612.16
3 14 to 3 77.196 74.917 232.0 p 74.916 11.2 79.9 0.40 68.75 1.89 2.05 49.8 25.532 612.16 0 912.16 0.6
29/10/2025 RECEIVED: 29/10/2025
M5(60) mm Logue fig. 6 16 Routing Coeff. Cr 1.3 C =1.001
Job:Tully M5(2d) mm Logue fig. 2 50 Volumetric Runoff Coeff. Cv 0.77 Cv between 0.6 and 0.9
Program Design by Marcus Dancey.Return Period years 1-100 1 Ks Automatic or Manual m Met Office 1k or Min of Health mrm or Modified Rational Method (MRM)
PVC Exit Conc Ks 1.5 Slime? Normal/Poor (N/P)n
Conc.Invert PVC Ks 0.6 Time of entry (mins)5 Min of 4 for MRM
MH Pipe Ground Entry Pipe Sewer If Exit Water Volume Pipe Unity Spare Velocity Cover Cover GradientPipe Imperm Imperm Cum Ks
No.Run Level Invert Size Type Drop Invert or CapacityFactor Capacity Inlet Outlet Length Area Area Ex Area Actual
MOD MOD mm P/C MH MOD Runoof flow lts/s lts/s Check lts/s m/s m m 1:m m²Tributary m²mm
1 82.000 80.565 80.565 1.20 579
2 1 to 2 79.628 78.000 232.0 p 78.000 12.3 127.2 0.25 114.94 3.01 1.40 19.8 50.74 579 1006.5 0.6
3 2 to 3 77.600 74.304 232.0 p 74.304 0.0 112.0 0.28 111.95 2.65 3.06 25.5 94.22 396 778 1930.2 0.6
4 2 to 4 76.215 74.000 232.0 p 74.000 13.8 69.2 0.46 55.42 1.64 1.98 66.1 20.1 427.45 1152.2 0.6
5 4 to 5 74.975 72.760 232.0 p 72.760 15.9 147.5 0.22 131.54 3.49 1.98 14.7 18.28 145.7 1336.7 0.6
6 5 to 6 74.100 72.200 232.0 p 72.200 56.9 95.8 0.59 38.97 2.27 1.67 34.7 19.444 184.53 1617.1 4824.8 0.6
7 6 to 7 69.520 68.000 232.0 p 68.000 59.0 114.8 0.51 55.82 2.72 1.29 24.3 101.87 1871 5225.8 0.6
8 7 to 8 67.370 65.800 232.0 p 64.800 64.800 61.5 123.8 0.50 62.34 2.93 1.34 2.34 20.9 45.9 401 5540.8 0.6
INT 8 to INT 65.250 63.750 232.0 p 63.682 61.0 125.0 0.49 64.00 2.96 1.27 20.5 21.49 315 5540.8 0.6
9 INT to 9 65.150 63.650 300.0 p 63.650 61.0 162.4 0.38 101.38 2.30 1.20 46.9 1.5 5540.8 0.6
OF 9 to OF 65.000 63.500 300.0 p 63.800 59.3 76.8 0.77 17.55 1.09 1.20 205.9 30.88 5540.8 0.6
29/10/2025 RECEIVED: 29/10/2025
RECEIVED: 29/10/2025
Job:Geda Construction - Tully Date:
Foul Sewer - F01 to F03 Traditional/Irish Water T/I T
Program Design by Marcus Dancey.Unity Unity Slime? Normal/Poor (N/P)n
PVC Exit Check Check No of people per house 2.75
Conc.Invert Max flowSelf cleansing Lts per person/day 165 Pumped
MH Pipe Ground Entry Pipe Sewer If Exit Runoff Pipe Check Check Velocity Cover GradientPipe No of Houses Other Cum Cum Cum Cum 6 x
No.Run Level Invert Size Type Drop Invert Flow Capacityif OK if OK LengthHouses From SourcesHouses Lts/day Lts/s Other Total DWF
MOD MOD mm P/C MH MOD lts/s lts/s m/s m 1:m Tributary Lts/s Cum Houses HsesSources
1 82.533 79.780 79.780 2.60 0 0 0 0 0 0 0
2 1 to 2 78.800 77.450 152.0 p 76.8 76.800 0.3 45.4 0.01 0.32 2.50 1.20 23.1 53.85 8 0 0 8 3630 0.04 0 0.042 0.25
3 2 to 3 77.610 75.250 152.0 p 75.250 0.4 42.7 0.01 0.34 2.35 2.21 26.0 40.36 5 0 0 13 5899 0.07 0 0.068 0.41
15/08/2024
RECEIVED: 29/10/2025
Job:Geda Construction- Tully Date:
Foul Sewer - F01-F02 Traditional/Irish Water T/I T
Program Design by Marcus Dancey.Unity Unity Slime? Normal/Poor (N/P)n
PVC Exit Check Check No of people per house 2.75
Conc.Invert Max flowSelf cleansing Lts per person/day 165 Pumped
MH Pipe Ground Entry Pipe Sewer If Exit Runoff Pipe Check Check Velocity Cover GradientPipe No of Houses Other Cum Cum Cum Cum 6 x
No.Run Level Invert Size Type Drop Invert Flow Capacityif OK if OK LengthHouses From SourcesHouses Lts/day Lts/s Other Total DWF
MOD MOD mm P/C MH MOD lts/s lts/s m/s m 1:m Tributary Lts/s Cum Houses HsesSources
5 76.950 75.520 75.520 1.20 0 0 0 0 0 0 0
4 5 to 4 77.610 75.402 232.0 p 75.402 0.1 43.9 0.00 0.77 1.04 1.98 187.1 22.08 7 0 0 4 1815 0.02 0 0.021 0.13
3 4 to 3 77.610 75.210 232.0 p 75.442 0.1 53.1 0.00 0.64 1.26 2.17 147.9 28.39 4 1815 0.02 0 0.021 0.13
29/10/2025
RECEIVED: 29/10/2025
Job:Geda Construction- Tully Date:
Foul Sewer - F09- F06 Traditional/Irish Water T/I T
Program Design by Marcus Dancey.Unity Unity Slime? Normal/Poor (N/P)n
PVC Exit Check Check No of people per house 2.75
Conc.Invert Max flowSelf cleansing Lts per person/day 165 Pumped
MH Pipe Ground Entry Pipe Sewer If Exit Pipe Check Check Velocity Cover GradientPipe No of Houses Other Cum Cum Cum Cum 6 x
No.Run Level Invert Size Type Drop Invert Flow Capacityif OK if OK LengthHouses From SourcesHouses Lts/day Lts/s Other Total DWF
MOD MOD mm P/C MH MOD lts/s lts/s m/s m 1:m Tributary Lts/s Cum Houses HsesSources
14 80.165 77.550 77.550 2.46 0 0 0 0 0 0 0
15 14 to 15 77.400 76.050 152.0 p 75.755 75.755 0.2 45.2 0.00 0.32 2.5 1.20 23.3 34.94 5 5 2269 0.03 0 0.026 0.16
16 15 to 16 76.550 75.190 152.0 p 75.190 0.3 45.3 0.01 0.32 2.5 1.21 23.2 13.09 4 9 4084 0.05 0 0.047 0.28
17 16 to 17 74.620 73.260 152.0 p 73.260 0.4 42.2 0.01 0.34 2.3 1.21 26.6 51.31 4 13 5899 0.07 0 0.068 0.41
6 17 to 6 74.903 72.895 152.0 p 73.047 0.4 35.4 0.01 0.41 2.0 1.86 37.4 13.64 1 14 6353 0.07 0 0.074 0.44
15/08/2024
RECEIVED: 29/10/2025
Job:Geda Construction- Tully Date:
Foul Sewer - F02-OF Traditional/Irish Water T/I T
Program Design by Marcus Dancey.Unity Unity Slime? Normal/Poor (N/P)n
PVC Exit Check Check No of people per house 2.75
Conc. Invert Max flowSelf cleansing Lts per person/day 165 Pumped
MH Pipe Ground Entry Pipe Sewer If Exit Runoff Pipe Check Check Velocity Cover GradientPipe No of Houses Other Cum Cum Cum Cum 6 x
No. Run Level Invert Size Type Drop Invert Flow Capacityif OK if OK LengthHouses From SourcesHouses Lts/day Lts/s Other Total DWF
MOD MOD mm P/C MH MOD lts/s lts/s m/s m 1:m Tributary Lts/s Cum Houses HsesSources
3 77.610 75.210 75.210 2.17 0 0 0 0 0 0 0
5 3 to 5 76.166 74.700 232.0 p 74 74.000 0.7 100.9 0.01 0.34 2.4 1.23 42.7 21.77 2 20 0 22 9983 0.12 0 0.116 0.69
6 5 to 6 74.903 73.450 232.0 p 72.895 72.895 1.1 107.8 0.01 0.31 2.5 1.22 37.5 20.64 1 13 36 16335 0.19 0 0.189 1.13
7 6 to 7 74.050 72.420 232.0 p 72.1 72.100 1.2 105.4 0.01 0.32 2.5 1.40 39.2 18.64 1 37 16789 0.19 0 0.194 1.17
8 7 to 8 72.930 71.420 232.0 p 70.15 70.150 1.3 106.5 0.01 0.32 2.5 1.28 38.4 26.1 4 41 18604 0.22 0 0.215 1.29
9 8 to 9 71.650 69.500 232.0 p 69.500 1.4 103.9 0.01 0.33 2.5 1.92 40.3 26.2 3 44 19965 0.23 0 0.231 1.39
10 9 to 10 70.440 68.900 232.0 p 68.900 1.5 101.4 0.01 0.33 2.4 1.31 42.3 25.39 4 48 21780 0.25 0 0.252 1.51
11 10 to 11 69.460 68.000 232.0 p 66.74 66.740 1.5 87.4 0.02 0.39 2.1 1.23 56.4 50.78 1 49 22234 0.26 0 0.257 1.54
12 11 to 12 67.000 65.570 232.0 p 64.18 64.180 1.5 105.9 0.01 0.32 2.5 1.20 38.8 45.44 0 49 22234 0.26 0 0.257 1.54
13 12 to 13 65.200 64.000 232.0 p 64.000 1.5 56.7 0.03 0.60 1.3 0.97 130.6 23.51 0 49 22234 0.26 0 0.257 1.54
of 13 to of 65.060 63.770 232.0 p 63.770 1.5 106.8 0.01 0.32 2.5 1.06 38.2 8.78 0 49 22234 0.26 0 0.257 1.54
28/10/2025
RECEIVED: 29/10/2025
RECEIVED: 29/10/2025
Tully Attenuation No 3 Lowest area Summary of information for Tank 1 Primary
Notes on design Orifice size mm 29
Greenfield area that would have drained in area now attenuated 0.890 HA. Hard surface is 855m².Depth of water in storage at 1 year m 0.370
IH124 equation used with WRAP value of 3 and SAAR of 1000mm.1 year flow out max lts/s 1.09
Site specific Depth Duration Frequency Tables are used for the site (256000 324000) multiplied by 1.2 to account for climate change. Permissible 1 year flow lts/s 2.0
Minimum flow through orifice is taken to be 2lts/s. Orifice size is 29mm. This may be replicated by a vortex flow controller.Unity on 1 year flow 0.545
Maximum flow is limited to Qbar because there is no long term storage provided for River Flood Protection (Per Criterion 4 GDSDS)Depth of water in storage area at 100 year m 1.300
The 1 year flood volume can be accommodated within the storage at 0.37m while the 100 year storage is accommodated at a depth of 1.3m 100 year flow out max lts/s 1.9
The critical storm duration for the 1 year event is 1.5 hours and for the 100 year event is 3 hours.Permissible 100 year flow lts/s 2.0
The centreline of the orifice is 86mm below the level of the base of storage and invert of Vortex flow controller 100mm below the base Unity on 100 year flow 0.971
The maximum flow from the orifice should not exceed 1.94lts/s when the level of water in the tank is 1.3m above the base of storage. Volume of storage required m³ for 1 year event 4.6
The average flow is 1.39lts/s which is approximately 72% of the maximum flow Vol of storage provided at 1 year level m³5.8
Unity on 1 year volume 0.798
Volume of storage required m³ for 100 year event 25.0
Storm tech (Y/N)Y Vol storage provided at 100 year level m³28.2
No of units in length 9 Unity on 100 year volume 0.887
No of units width wise 1
Volume of Storage by dimensions Treatment 1 year 100 year Surface level upper 66.100
Slope of sides 1:? (0 for vertical)0 0 0 Surface level lower 65.3
Length of attenuation storage 11.75 11.75 11.75 Lowest Gulley level 65 COVER
Width of base level of storage 3.34 3.34 3.34 Level of top of storage 65 1.248
Area of base 39.2 39.2 39.2 Level of top of arches 64.85 PASS
Depth of storage taken 0.520 0.370 1.300 Level of bottom of arches 64.09
Length of storage level 11.75 11.75 11.75 Level of base of storage 63.70
Width of top of storage level 3.34 3.34 3.34 Level of CL of orifice 63.61 86
Area of top of storage 39.2 39.2 39.2 Level of invert of vortex flow controller 63.6 100
Volume of of storage beteween levels 20.4 14.5 51.0 Level of base of treatment 63.18
Porosity (1.0 if air, 0.4 for stone, 0.635 for standard Stormtech) 0.400 0.400 0.552 Average depth of dig 2.52
Volume of water stored 8.2 5.8 28.2 Average depth to top of storage 0.70
Required water storage 7.7604 4.6 25.0 Volume of excavation to base of treatment 78
Unity on water storage 0.951 0.798 0.887 Volume of hardcore in storage 38
Volume in arches 13
Volume of storage 28
Volume of hardcore in treatment 20
Site 1 year storm Site 100 year storm
Greenfield runoff Greenfield runoff
Greenfield area applicable for total site Ha 0.0890 Greenfield area applicable for total site Ha 0.089
SAAR mm 1000 SAAR mm 1000
WRAP value 3 WRAP value 3
Soil Value 0.4 Soil Value 0.4
IH 124 Qbar for area under 50 hectares lts/s 0.46 IH 124 Qbar for area under 50 hectares lts/s 0.46
IH124 Qbar for area lts/s 0.92 IH124 Qbar for area lts/s 0.92
Qbar applicable lts/s 0.46 Qbar applicable lts/s 0.46
Return period year for flow controller (2.35 =Qbar)1 Return period year for flow controller (2.35 =Qbar)100
Growth Curve (Dublin - Bruin or Ireland - FSR) D/I I Growth Curve (Dublin - Bruin or Ireland - FSR) D/I I
Growth multiplier from Qbar 0.85 Growth multiplier from Qbar 1.96
Climate change factor 1.20 Climate change factor 1.20
Permissible outflow from site based on IH124 lts/s 0.47 Permissible outflow from site based on IH124 lts/s 1.08
Limit outflow to Qbar (Y/N)y Limit outflow to Qbar (Y/N)y
Max outflow allowed 0.46 Max outflow allowed 0.46
Minimum outflow through a throttle 2.00 Minimum outflow through a throttle 2.00
Permissible Outflow taken lts/s 2.0 2.0 2.0 2.0 2.0 2.0 Permissible Outflow taken lts/s 2.0 2.0 2.0 2.0 2.0 2.0
Duration increment 1 Duration increment 2
Duration of storm hrs 0.5 1.5 2.5 3.5 4.5 5.5 Duration of storm hrs 0.5 2.5 4.5 6.5 8.5 10.5
Depth of water in storage for return period m 0.370 0.370 0.370 0.370 0.370 0.370 Depth of water in storage for return period m 1.300 1.300 1.300 1.300 1.300 1.300
Average flow through throttle lts/s 0.84 0.84 0.84 0.84 0.84 0.84 Average flow through throttle lts/s 1.40 1.40 1.40 1.40 1.40 1.40
Max flow through throttle at max depth lts/s 1.09 1.09 1.09 1.09 1.09 1.09 Max flow through Throttle at max depth lts/s 1.94 1.94 1.94 1.94 1.94 1.94
Unity on maximum flow 0.545 0.545 0.545 0.545 0.545 0.545 Unity on maximum flow 0.971 0.971 0.971 0.971 0.971 0.971
Area of impermeable catchment taken m²647 647 647 647 647 647 Area of impermeable catchment taken m²647 647 647 647 647 647
Site specific or MRM ss ss ss ss ss ss Site specific or MRM ss ss ss ss ss ss
Rainfall return period 1:? Years 1 1 1 1 1 1 Rainfall return period 1:? Years 100 100 100 100 100 100
Rainfall depth mm 7.8 11.8 14.3 16.3 18.0 19.5 Rainfall depth mm 29.7 48.4 57.9 64.9 70.5 75.2
Climate change factor 1.2 1.2 1.2 1.2 1.2 1.2 Climate change factor 1.2 1.2 1.2 1.2 1.2 1.2
Rainfall depth taken mm 9.4 14.2 17.2 19.6 21.6 23.3 Rainfall depth taken mm 35.6 58.1 69.5 77.9 84.6 90.2
Amount in m³6.1 9.2 11.1 12.7 14.0 15.1 Amount in m³23.0 37.5 45.0 50.4 54.7 58.4
Average flow rate in lts/s 3.37 1.69 1.24 1.01 0.86 0.76 Average flow rate in lts/s 12.79 4.17 2.78 2.15 1.79 1.54
Amount out m³1.5 4.5 7.5 10.5 13.6 16.6 Amount out m³2.5 12.6 22.6 32.7 42.8 52.8
Net amount of water in m³4.6 4.6 3.6 2.1 0.4 0.0 Net amount of water in m³20.5 25.0 22.3 17.7 11.9 5.5
Porosity if storing in hardcore 1.0 otherwise 1.00 1.00 1.00 1.00 1.00 1.00 Porosity if storing in hardcore 1.0 otherwise 1 1.00 1.00 1.00 1.00 1.00
Volume of space required for strorage m³4.6 4.6 3.6 2.1 0.4 0.0 Volume of space required for strorage m³20.5 25.0 22.3 17.7 11.9 5.5
Inflow rate applicable lts/s 1.69 Inflow rate applicable lts/s 4.17
Outflow rate applicable lts/s 0.84 Outflow rate applicable lts/s 1.40
Volume in for duration m³9.2 Volume in for duration m³37.5
Volume out in duration m³4.5 Volume out in duration m³12.6
Max volume of storage required m³4.6 Max volume of storage required m³25.0
Storm duration to give max storage requirement hrs 1.5 Storm duration to give max storage requirement hrs 2.5
Time to empty half volume when rain stops
Average flow for emptying half volume lts/s 1.6 1.6 1.6 1.6 1.6 1.6
Volume out per hour m³5.8 5.8 5.8 5.8 5.8 5.8
Half volume to be emptied m³10.3 12.5 11.2 8.8 6.0 2.8
Time to empty half the volume hours 1.75 2.14 1.91 1.51 1.02 0.47
No of hours permitted 24 24 24 24 24 24
Unity on emptying criteria 0.073 0.089 0.080 0.063 0.042 0.020
Site specific rainfall depth for duration and return period for Tully Monaghan Site specific rainfall depth for duration and return period for Tully Monaghan
RP Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
RP Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
0.5 0.5
1 7.8 11.8 14.3 16.3 18.0 19.5 1 7.8 14.3 18.0 20.8 23.0 25.0
2 2
3 3
4 4
5 5
10 10
20 20
30 21.6 30.7 36.2 40.4 43.8 46.8 30 21.6 36.2 43.8 49.4 54.0 57.8
50 50
75 75
100 29.7 41.4 48.4 53.6 57.9 61.6 100 29.7 48.4 57.9 64.9 70.5 75.2
150 150
0.5 1.5 2.5 3.5 4.5 5.5 Duration hrs 0.5 2.5 4.5 6.5 8.5 10.5
Return period years 1 1 1 1 1 1 Return period years 100 100 100 100 100 100
Trial answer 7.8 11.8 14.3 16.3 18.0 19.5 Trial answer N/A N/A N/A N/A N/A N/A
Rainfall amount mm 7.8 11.8 14.3 16.3 18.0 19.5 Rainfall amount mm 29.7 48.4 57.9 64.9 70.5 75.2
Rainfall intensity unfactored for climate change 15.66 7.86 5.73 4.66 4.00 3.54 Rainfall intensity unfactored for climate change 59.34 19.35 12.88 9.98 8.29 7.16
Rain fall prediction. (Modified Rational Method.)Rain fall prediction. (Modified Rational Method.)
M5 60 for location 16.5 16.5 16.5 16.5 16.5 16.5 M5 60 for location 16 16 16 16 16 16
M5 2d mm ditto 55 55 55 55 55 55 M5 2d mm ditto 50 50 50 50 50 50
Return period years 1 1 1 1 1 1 Return period years 100 100 100 100 100 100
Required duration minutes 30 90 150 210 270 330 Required duration minutes 30 150 270 390 510 630
r 0.3 0.3 0.3 0.3 0.3 0.3 r 0.32 0.32 0.32 0.32 0.32 0.32
Z1 trial (4 to 120)0.78 1.13 Not applicableNot applicableNot applicableNot applicable Z1 trial (4 to 120)0.79 Not applicableNot applicableNot applicableNot applicableNot applicable
Z1 trial (120 to 600)Not applicableNot applicable 1.34 1.52 1.65 1.75 Z1 trial (120 to 600)Not applicable 1.30 1.60 1.78 1.98 Not applicable
Z1 trial (600 to 2880)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Z1 trial (600 to 2880)Not applicableNot applicableNot applicableNot applicableNot applicable 2.14
Z1 taken 0.78 1.13 1.34 1.52 1.65 1.75 Z1 taken 0.79 1.30 1.60 1.78 1.98 2.14
M5 (T) mm 12.85 18.66 22.11 25.05 27.24 28.86 M5 (T) mm 12.67 20.86 25.67 28.44 31.75 34.31
Ratio Z2 Trial (5 to 20)0.69 0.69 Not applicableNot applicableNot applicableNot applicable Ratio Z2 Trial (5 to 20)2.00 Not applicableNot applicableNot applicableNot applicableNot applicable
Ratio Z2 Trial (20 to 40)Not applicableNot applicable 0.69 0.69 0.69 0.69 Ratio Z2 Trial (20 to 40)Not applicable 1.95 2.02 2.02 2.05 2.05
Ratio Z2 Trial (40 to 100)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Ratio Z2 Trial (40 to 100)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable
Ratio Z2 Trial (100 to 200)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Ratio Z2 Trial (100 to 200)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable
Ratio Z2 taken 0.69 0.69 0.69 0.69 0.69 0.69 Ratio Z2 taken 2.00 1.95 2.02 2.02 2.05 2.05
Actual rainfall for Return period MRM mm 8.91 12.96 15.36 17.24 18.74 19.86 Actual rainfall for Return period MRM mm 25.30 40.60 51.85 57.44 65.22 70.47
Actual rainfall for Return period Site specific mm 7.83 11.79 14.33 16.32 17.99 19.45 Actual rainfall for Return period Site specific mm 29.67 48.38 57.94 64.89 70.47 75.20
Rainfall depth taken mm 7.83 11.79 14.33 16.32 17.99 19.45 Rainffall depth taken mm 29.67 48.38 57.94 64.89 70.47 75.20
Rainfall intensity MRM 17.83 8.64 6.14 4.93 4.17 3.61 Rainfall intensity MRM 50.60 16.24 11.52 8.84 7.67 6.71
Rainfall intensity Site Specific 15.66 7.86 5.73 4.66 4.00 3.54 Rainfall intensity Site Specific 59.34 19.35 12.88 9.98 8.29 7.16
Rainfall intensity taken 15.66 7.86 5.73 4.66 4.00 3.54 Rainfall intensity taken 59.34 19.35 12.88 9.98 8.29 7.16
DDF for Tully Monaghan
0.0
1.0
2.0
3.0
4.0
5.0
0 1 2 3 4 5 6Volume m³Duration hrs
Volume of space required for strorage m³
0.0
5.0
10.0
15.0
20.0
25.0
30.0
0 1 2 3 4 5 6 7 8 9 10 11 12Volume m³Duration hrs
Volume of space required for strorage m³RECEIVED: 29/10/2025
Tully Attenuation No 1 Summary of information for Tank 1 Primary
Notes on design Orifice size mm 59
Greenfield area that would have drained in area now attenuated 1.4076 HA. Hard surface is 9498m².Depth of water in storage at 1 year m 0.290
IH124 equation used with WRAP value of 3 and SAAR of 1000mm.1 year flow out max lts/s 3.79
Site specific Depth Duration Frequency Tables are used for the site (256000 324000) multiplied by 1.2 to account for climate change. Permissible 1 year flow lts/s 7.3
Minimum flow through orifice is taken to be 2lts/s. Orifice size is 59mm. This may be replicated by a vortex flow controller.Unity on 1 year flow 0.521
Maximum flow is limited to Qbar because there is no long term storage provided for River Flood Protection (Per Criterion 4 GDSDS)Depth of water in storage area at 100 year m 1.170
The 1 year flood volume can be accommodated within the storage at 0.29m while the 100 year storage is accommodated at a depth of 1.17m 100 year flow out max lts/s 7.3
The critical storm duration for the 1 year event is 6 hours and for the 100 year event is 9 hours.Permissible 100 year flow lts/s 7.3
The centreline of the orifice is 70mm below the level of the base of storage and invert of Vortex flow controller 100mm below the base Unity on 100 year flow 0.998
The maximum flow from the orifice should not exceed 7.25lts/s when the level of water in the tank is 1.170m above the base of storage. Volume of storage required m³ for 1 year event 90.9
The average flow is 5.1lts/s which is approximately 70% of the maximum flow Vol of storage provided at 1 year level m³98.5
Unity on 1 year volume 0.923
Volume of storage required m³ for 100 year event 370.3
Storm tech (Y/N)Y Vol storage provided at 100 year level m³434.1
No of units in length 17 Unity on 100 year volume 0.853
No of units width wise 11
Volume of Storage by dimensions Treatment 1 year 100 year Surface level upper 76.600
Slope of sides 1:? (0 for vertical)0 0 0 Surface level lower 75
Length of attenuation storage 37.79 37.79 37.79 Lowest Gulley level 74.47
Width of base level of storage 16.35 16.35 16.35 Level of top of storage 74.45 Cover
Area of base 617.7 617.7 617.7 Level of top of arches 74.23 2.37
Depth of storage taken 0.320 0.290 1.170 Level of bottom of arches 73.47 PASS
Length of storage level 37.79 37.79 37.79 Level of base of storage 73.28
Width of top of storage level 16.35 16.35 16.35 Level of CL of orifice 73.21
Area of top of storage 617.7 617.7 617.7 Level of invert of vortex flow controller 73.18
Volume of of storage beteween levels 197.7 179.1 722.7 Level of base of treatment 72.96
Porosity (1.0 if air, 0.4 for stone, 0.635 for standard Stormtech) 0.400 0.550 0.601 Average depth of dig 2.84
Volume of water stored 79.1 98.5 434.1 Average depth to top of storage 1.35
Required water storage 74.712 90.9 370.3 Volume of excavation to base of treatment 1557 0.07
Unity on water storage 0.945 0.923 0.853 Volume of hardcore in storage 481
Volume in arches 242
Volume of storage 434
Volume of hardcore in treatment 198
Site 1 year storm Site 100 year storm
Greenfield runoff Greenfield runoff
Greenfield area applicable for total site Ha 1.4076 Greenfield area applicable for total site Ha 1.4076
SAAR mm 1000 SAAR mm 1000
WRAP value 3 WRAP value 3
Soil Value 0.4 Soil Value 0.4
IH 124 Qbar for area under 50 hectares lts/s 7.27 IH 124 Qbar for area under 50 hectares lts/s 7.27
IH124 Qbar for area lts/s 10.77 IH124 Qbar for area lts/s 10.77
Qbar applicable lts/s 7.27 Qbar applicable lts/s 7.27
Return period year for flow controller (2.35 =Qbar)1 Return period year for flow controller (2.35 =Qbar)100
Growth Curve (Dublin - Bruin or Ireland - FSR) D/I I Growth Curve (Dublin - Bruin or Ireland - FSR) D/I I
Growth multiplier from Qbar 0.85 Growth multiplier from Qbar 1.96
Climate change factor 1.20 Climate change factor 1.20
Permissible outflow from site based on IH124 lts/s 7.41 Permissible outflow from site based on IH124 lts/s 17.05
Limit outflow to Qbar (Y/N)y Limit outflow to Qbar (Y/N)y
Max outflow allowed 7.27 Max outflow allowed 7.27
Minimum outflow through a throttle 2.00 Minimum outflow through a throttle 2.00
Permissible Outflow taken lts/s 7.3 7.3 7.3 7.3 7.3 7.3 Permissible Outflow taken lts/s 7.3 7.3 7.3 7.3 7.3 7.3
Duration increment 1 Duration increment 1
Duration of storm hrs 4 5 6 7 8 9 Duration of storm hrs 6 7 8 9 10 11
Depth of water in storage for return period m 0.290 0.290 0.290 0.290 0.290 0.290 Depth of water in storage for return period m 1.170 1.170 1.170 1.170 1.170 1.170
Average flow through throttle lts/s 2.75 2.75 2.75 2.75 2.75 2.75 Average flow through throttle lts/s 5.11 5.11 5.11 5.11 5.11 5.11
Max flow through throttle at max depth lts/s 3.79 3.79 3.79 3.79 3.79 3.79 Max flow through Throttle at max depth lts/s 7.25 7.25 7.25 7.25 7.25 7.25
Unity on maximum flow 0.521 0.521 0.521 0.521 0.521 0.521 Unity on maximum flow 0.998 0.998 0.998 0.998 0.998 0.998
Area of impermeable catchment taken m²6226 6226 6226 6226 6226 6226 Area of impermeable catchment taken m²6226 6226 6226 6226 6226 6226
Site specific or MRM ss ss ss ss ss ss Site specific or MRM ss ss ss ss ss ss
Rainfall return period 1:? Years 1 1 1 1 1 1 Rainfall return period 1:? Years 100 100 100 100 100 100
Rainfall depth mm 17.2 18.7 20.1 21.4 22.5 23.5 Rainfall depth mm 63.3 66.4 69.2 71.7 74.1 76.3
Climate change factor 1.2 1.2 1.2 1.2 1.2 1.2 Climate change factor 1.2 1.2 1.2 1.2 1.2 1.2
Rainfall depth taken mm 20.6 22.5 24.1 25.6 27.0 28.3 Rainfall depth taken mm 76.0 79.7 83.0 86.1 88.9 91.5
Amount in m³128.4 140.0 150.3 159.6 168.1 175.9 Amount in m³473.0 496.0 516.8 535.9 553.5 569.9
Average flow rate in lts/s 8.92 7.78 6.96 6.33 5.84 5.43 Average flow rate in lts/s 21.90 19.68 17.94 16.54 15.37 14.39
Amount out m³39.6 49.5 59.4 69.3 79.2 89.2 Amount out m³110.4 128.8 147.2 165.5 183.9 202.3
Net amount of water in m³88.8 90.5 90.9 90.2 88.8 86.7 Net amount of water in m³362.6 367.2 369.6 370.3 369.6 367.6
Porosity if storing in hardcore 1.0 otherwise 1.00 1.00 1.00 1.00 1.00 1.00 Porosity if storing in hardcore 1.0 otherwise 1 1.00 1.00 1.00 1.00 1.00
Volume of space required for strorage m³88.8 90.5 90.9 90.2 88.8 86.7 Volume of space required for strorage m³362.6 367.2 369.6 370.3 369.6 367.6
Inflow rate applicable lts/s 6.96 Inflow rate applicable lts/s 16.54
Outflow rate applicable lts/s 2.75 Outflow rate applicable lts/s 5.11
Volume in for duration m³150.3 Volume in for duration m³535.9
Volume out in duration m³59.4 Volume out in duration m³165.5
Max volume of storage required m³90.9 Max volume of storage required m³370.3
Storm duration to give max storage requirement hrs 6 Storm duration to give max storage requirement hrs 9
Time to empty half volume when rain stops
Average flow for emptying half volume lts/s 6.2 6.2 6.2 6.2 6.2 6.2
Volume out per hour m³22.2 22.2 22.2 22.2 22.2 22.2
Half volume to be emptied m³181.3 183.6 184.8 185.2 184.8 183.8
Time to empty half the volume hours 8.17 8.28 8.33 8.35 8.33 8.28
No of hours permitted 24 24 24 24 24 24
Unity on emptying criteria 0.341 0.345 0.347 0.348 0.347 0.345
Site specific rainfall depth for duration and return period for Tully Monaghan Site specific rainfall depth for duration and return period for Tully Monaghan
RP Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
RP Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
0.5 0.5
1 17.2 18.7 20.1 21.4 22.5 23.5 1 20.1 21.4 22.5 23.5 24.5 25.4
2 2
3 3
4 4
5 5
10 10
20 20
30 42.2 45.4 48.2 50.7 52.9 55.0 30 48.2 50.7 52.9 55.0 56.9 58.7
50 50
75 75
100 55.9 59.9 63.3 66.4 69.2 71.7 100 63.3 66.4 69.2 71.7 74.1 76.3
150 150
4 5 6 7 8 9 Duration hrs 6 7 8 9 10 11
Return period years 1 1 1 1 1 1 Return period years 100 100 100 100 100 100
Trial answer 17.2 18.7 20.1 21.4 22.5 23.5 Trial answer N/A N/A N/A N/A N/A N/A
Rainfall amount mm 17.2 18.7 20.1 21.4 22.5 23.5 Rainfall amount mm 63.3 66.4 69.2 71.7 74.1 76.3
Rainfall intensity unfactored for climate change 4.30 3.75 3.35 3.05 2.81 2.62 Rainfall intensity unfactored for climate change 10.55 9.48 8.65 7.97 7.41 6.93
Rain fall prediction. (Modified Rational Method.)Rain fall prediction. (Modified Rational Method.)
M5 60 for location 16.5 16.5 16.5 16.5 16.5 16.5 M5 60 for location 16 16 16 16 16 16
M5 2d mm ditto 55 55 55 55 55 55 M5 2d mm ditto 50 50 50 50 50 50
Return period years 1 1 1 1 1 1 Return period years 100 100 100 100 100 100
Required duration minutes 240 300 360 420 480 540 Required duration minutes 360 420 480 540 600 660
r 0.3 0.3 0.3 0.3 0.3 0.3 r 0.32 0.32 0.32 0.32 0.32 0.32
Z1 trial (4 to 120)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Z1 trial (4 to 120)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable
Z1 trial (120 to 600)1.60 1.70 1.79 1.90 2.00 2.09 Z1 trial (120 to 600)1.72 1.83 1.94 2.03 2.12 Not applicable
Z1 trial (600 to 2880)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Z1 trial (600 to 2880)Not applicableNot applicableNot applicableNot applicable 2.12 2.17
Z1 taken 1.60 1.70 1.79 1.90 2.00 2.09 Z1 taken 1.72 1.83 1.94 2.03 2.12 2.17
M5 (T) mm 26.33 28.08 29.60 31.37 32.98 34.47 M5 (T) mm 27.51 29.32 30.97 32.51 33.95 34.65
Ratio Z2 Trial (5 to 20)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Ratio Z2 Trial (5 to 20)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable
Ratio Z2 Trial (20 to 40)0.69 0.69 0.69 0.68 0.68 0.68 Ratio Z2 Trial (20 to 40)2.02 2.02 2.05 2.05 2.05 2.05
Ratio Z2 Trial (40 to 100)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Ratio Z2 Trial (40 to 100)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable
Ratio Z2 Trial (100 to 200)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Ratio Z2 Trial (100 to 200)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable
Ratio Z2 taken 0.69 0.69 0.69 0.68 0.68 0.68 Ratio Z2 taken 2.02 2.02 2.05 2.05 2.05 2.05
Actual rainfall for Return period MRM mm 18.12 19.32 20.37 21.39 22.49 23.50 Actual rainfall for Return period MRM mm 55.58 59.21 63.61 66.77 69.73 71.18
Actual rainfall for Return period Site specific mm 17.19 18.74 20.12 21.36 22.49 23.54 Actual rainfall for Return period Site specific mm 63.31 66.39 69.17 71.72 74.08 76.28
Rainfall depth taken mm 17.19 18.74 20.12 21.36 22.49 23.54 Rainffall depth taken mm 63.31 66.39 69.17 71.72 74.08 76.28
Rainfall intensity MRM 4.53 3.86 3.39 3.06 2.81 2.61 Rainfall intensity MRM 9.26 8.46 7.95 7.42 6.97 6.47
Rainfall intensity Site Specific 4.30 3.75 3.35 3.05 2.81 2.62 Rainfall intensity Site Specific 10.55 9.48 8.65 7.97 7.41 6.93
Rainfall intensity taken 4.30 3.75 3.35 3.05 2.81 2.62 Rainfall intensity taken 10.55 9.48 8.65 7.97 7.41 6.93
DDF for Tully Monaghan
86.0
87.0
88.0
89.0
90.0
91.0
92.0
0 1 2 3 4 5 6 7 8 9 10Volume m³Duration hrs
Volume of space required for strorage m³
362.0
364.0
366.0
368.0
370.0
372.0
0 1 2 3 4 5 6 7 8 9 10 11 12Volume m³Duration hrs
Volume of space required for strorage m³RECEIVED: 29/10/2025
Tully Attenuation No 2 Summary of information for Tank 1 Primary
Notes on design Orifice size mm 29
Greenfield area that would have drained in area now attenuated 0.4328 HA. Hard surface is 2071m².Depth of water in storage at 1 year m 0.430
IH124 equation used with WRAP value of 3 and SAAR of 1000mm.1 year flow out max lts/s 1.23
Site specific Depth Duration Frequency Tables are used for the site (256000 324000) multiplied by 1.2 to account for climate change. Permissible 1 year flow lts/s 2.2
Minimum flow through orifice is taken to be 2lts/s. Orifice size is 29mm. This may be replicated by a vortex flow controller.Unity on 1 year flow 0.552
Maximum flow is limited to Qbar because there is no long term storage provided for River Flood Protection (Per Criterion 4 GDSDS)Depth of water in storage area at 100 year m 1.600
The 1 year flood volume can be accommodated within the storage at 0.42m while the 100 year storage is accommodated at a depth of 1.6m 100 year flow out max lts/s 2.2
The critical storm duration for the 1 year event is 3 hours and for the 100 year event is 8 hours.Permissible 100 year flow lts/s 2.2
The centreline of the orifice is 145mm below the level of the base of storage and invert of Vortex flow controller 160mm below the base Unity on 100 year flow 0.978
The maximum flow from the orifice should not exceed 2.18lts/s when the level of water in the tank is 1.6m above the base of storage. Volume of storage required m³ for 1 year event 29.3
The average flow is 1.59lts/s which is approximately 73% of the maximum flow Vol of storage provided at 1 year level m³29.3
Unity on 1 year volume 0.999
Volume of storage required m³ for 100 year event 127.1
Storm tech (Y/N)Y Vol storage provided at 100 year level m³146.3
No of units in length 16 Unity on 100 year volume 0.868
No of units width wise 3
Volume of Storage by dimensions Treatment 1 year 100 year Surface level upper 71.500
Slope of sides 1:? (0 for vertical)0 0 0 Surface level lower 70.5
Length of attenuation storage 35.62 35.62 35.62 Lowest Gulley level 69.6
Width of base level of storage 4.79 4.79 4.79 Level of top of storage 69.6 COVER
Area of base 170.4 170.4 170.4 Level of top of arches 69.26 2.238
Depth of storage taken 0.375 0.430 1.600 Level of bottom of arches 68.5 PASS
Length of storage level 35.62 35.62 35.62 Level of base of storage 68.00
Width of top of storage level 4.79 4.79 4.79 Level of CL of orifice 67.85 0.145
Area of top of storage 170.4 170.4 170.4 Level of invert of vortex flow controller 67.84 0.160
Volume of of storage beteween levels 63.9 73.3 272.7 Level of base of treatment 67.63
Porosity (1.0 if air, 0.4 for stone, 0.635 for standard Stormtech) 0.400 0.400 0.537 Average depth of dig 3.38
Volume of water stored 25.6 29.3 146.3 Average depth to top of storage 1.40
Required water storage 24.864 29.3 127.1 Volume of excavation to base of treatment 511
Unity on water storage 0.973 0.999 0.868 Volume of hardcore in storage 211
Volume in arches 62
Volume of storage 146
Volume of hardcore in treatment 64
Site 1 year storm Site 100 year storm
Greenfield runoff Greenfield runoff
Greenfield area applicable for total site Ha 0.4328 Greenfield area applicable for total site Ha 0.4328
SAAR mm 1000 SAAR mm 1000
WRAP value 3 WRAP value 3
Soil Value 0.4 Soil Value 0.4
IH 124 Qbar for area under 50 hectares lts/s 2.24 IH 124 Qbar for area under 50 hectares lts/s 2.24
IH124 Qbar for area lts/s 3.77 IH124 Qbar for area lts/s 3.77
Qbar applicable lts/s 2.24 Qbar applicable lts/s 2.24
Return period year for flow controller (2.35 =Qbar)1 Return period year for flow controller (2.35 =Qbar)100
Growth Curve (Dublin - Bruin or Ireland - FSR) D/I I Growth Curve (Dublin - Bruin or Ireland - FSR) D/I I
Growth multiplier from Qbar 0.85 Growth multiplier from Qbar 1.96
Climate change factor 1.20 Climate change factor 1.20
Permissible outflow from site based on IH124 lts/s 2.28 Permissible outflow from site based on IH124 lts/s 5.24
Limit outflow to Qbar (Y/N)y Limit outflow to Qbar (Y/N)y
Max outflow allowed 2.24 Max outflow allowed 2.24
Minimum outflow through a throttle 2.00 Minimum outflow through a throttle 2.00
Permissible Outflow taken lts/s 2.2 2.2 2.2 2.2 2.2 2.2 Permissible Outflow taken lts/s 2.2 2.2 2.2 2.2 2.2 2.2
Duration increment 1 Duration increment 1
Duration of storm hrs 3 4 5 6 7 8 Duration of storm hrs 8 9 10 11 12 13
Depth of water in storage for return period m 0.430 0.430 0.430 0.430 0.430 0.430 Depth of water in storage for return period m 1.600 1.600 1.600 1.600 1.600 1.600
Average flow through throttle lts/s 0.96 0.96 0.96 0.96 0.96 0.96 Average flow through throttle lts/s 1.59 1.59 1.59 1.59 1.59 1.59
Max flow through throttle at max depth lts/s 1.23 1.23 1.23 1.23 1.23 1.23 Max flow through Throttle at max depth lts/s 2.18 2.18 2.18 2.18 2.18 2.18
Unity on maximum flow 0.552 0.552 0.552 0.552 0.552 0.552 Unity on maximum flow 0.978 0.978 0.978 0.978 0.978 0.978
Area of impermeable catchment taken m²2072 2072 2072 2072 2072 2072 Area of impermeable catchment taken m²2072 2072 2072 2072 2072 2072
Site specific or MRM ss ss ss ss ss ss Site specific or MRM ss ss ss ss ss ss
Rainfall return period 1:? Years 1 1 1 1 1 1 Rainfall return period 1:? Years 100 100 100 100 100 100
Rainfall depth mm 15.4 17.2 18.7 20.1 21.4 22.5 Rainfall depth mm 69.2 71.7 74.1 76.3 78.3 80.3
Climate change factor 1.2 1.2 1.2 1.2 1.2 1.2 Climate change factor 1.2 1.2 1.2 1.2 1.2 1.2
Rainfall depth taken mm 18.4 20.6 22.5 24.1 25.6 27.0 Rainfall depth taken mm 83.0 86.1 88.9 91.5 94.0 96.4
Amount in m³38.2 42.7 46.6 50.0 53.1 55.9 Amount in m³172.0 178.3 184.2 189.7 194.8 199.6
Average flow rate in lts/s 3.54 2.97 2.59 2.32 2.11 1.94 Average flow rate in lts/s 5.97 5.50 5.12 4.79 4.51 4.27
Amount out m³10.4 13.9 17.3 20.8 24.3 27.7 Amount out m³45.7 51.4 57.1 62.9 68.6 74.3
Net amount of water in m³27.8 28.9 29.3 29.2 28.8 28.2 Net amount of water in m³126.3 126.9 127.1 126.8 126.2 125.3
Porosity if storing in hardcore 1.0 otherwise 1.00 1.00 1.00 1.00 1.00 1.00 Porosity if storing in hardcore 1.0 otherwise 1 1.00 1.00 1.00 1.00 1.00
Volume of space required for strorage m³27.8 28.9 29.3 29.2 28.8 28.2 Volume of space required for strorage m³126.3 126.9 127.1 126.8 126.2 125.3
Inflow rate applicable lts/s 2.59 Inflow rate applicable lts/s 5.12
Outflow rate applicable lts/s 0.96 Outflow rate applicable lts/s 1.59
Volume in for duration m³46.6 Volume in for duration m³184.2
Volume out in duration m³17.3 Volume out in duration m³57.1
Max volume of storage required m³29.3 Max volume of storage required m³127.1
Storm duration to give max storage requirement hrs 5 Storm duration to give max storage requirement hrs 10
Time to empty half volume when rain stops
Average flow for emptying half volume lts/s 1.8 1.8 1.8 1.8 1.8 1.8
Volume out per hour m³6.5 6.5 6.5 6.5 6.5 6.5
Half volume to be emptied m³63.1 63.5 63.5 63.4 63.1 62.7
Time to empty half the volume hours 9.73 9.78 9.79 9.78 9.73 9.66
No of hours permitted 24 24 24 24 24 24
Unity on emptying criteria 0.406 0.408 0.408 0.407 0.405 0.403
Site specific rainfall depth for duration and return period for Tully Monaghan Site specific rainfall depth for duration and return period for Tully Monaghan
RP Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
RP Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
Rainfall
amount
0.5 0.5
1 15.4 17.2 18.7 20.1 21.4 22.5 1 22.5 23.5 24.5 25.4 26.3 27.1
2 2
3 3
4 4
5 5
10 10
20 20
30 38.4 42.2 45.4 48.2 50.7 52.9 30 52.9 55.0 56.9 58.7 60.4 62.0
50 50
75 75
100 51.2 55.9 59.9 63.3 66.4 69.2 100 69.2 71.7 74.1 76.3 78.3 80.3
150 150
3 4 5 6 7 8 Duration hrs 8 9 10 11 12 13
Return period years 1 1 1 1 1 1 Return period years 100 100 100 100 100 100
Trial answer 15.4 17.2 18.7 20.1 21.4 22.5 Trial answer N/A N/A N/A N/A N/A N/A
Rainfall amount mm 15.4 17.2 18.7 20.1 21.4 22.5 Rainfall amount mm 69.2 71.7 74.1 76.3 78.3 80.3
Rainfall intensity unfactored for climate change 5.12 4.30 3.75 3.35 3.05 2.81 Rainfall intensity unfactored for climate change 8.65 7.97 7.41 6.93 6.53 6.18
Rain fall prediction. (Modified Rational Method.)Rain fall prediction. (Modified Rational Method.)
M5 60 for location 16.5 16.5 16.5 16.5 16.5 16.5 M5 60 for location 16 16 16 16 16 16
M5 2d mm ditto 55 55 55 55 55 55 M5 2d mm ditto 50 50 50 50 50 50
Return period years 1 1 1 1 1 1 Return period years 100 100 100 100 100 100
Required duration minutes 180 240 300 360 420 480 Required duration minutes 480 540 600 660 720 780
r 0.3 0.3 0.3 0.3 0.3 0.3 r 0.32 0.32 0.32 0.32 0.32 0.32
Z1 trial (4 to 120)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Z1 trial (4 to 120)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable
Z1 trial (120 to 600)1.43 1.60 1.70 1.79 1.90 2.00 Z1 trial (120 to 600)1.94 2.03 2.12 Not applicableNot applicableNot applicable
Z1 trial (600 to 2880)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Z1 trial (600 to 2880)Not applicableNot applicable 2.12 2.17 2.21 2.25
Z1 taken 1.43 1.60 1.70 1.79 1.90 2.00 Z1 taken 1.94 2.03 2.12 2.17 2.21 2.25
M5 (T) mm 23.66 26.33 28.08 29.60 31.37 32.98 M5 (T) mm 30.97 32.51 33.95 34.65 35.31 35.93
Ratio Z2 Trial (5 to 20)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Ratio Z2 Trial (5 to 20)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable
Ratio Z2 Trial (20 to 40)0.69 0.69 0.69 0.69 0.68 0.68 Ratio Z2 Trial (20 to 40)2.05 2.05 2.05 2.05 2.05 2.05
Ratio Z2 Trial (40 to 100)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Ratio Z2 Trial (40 to 100)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable
Ratio Z2 Trial (100 to 200)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable Ratio Z2 Trial (100 to 200)Not applicableNot applicableNot applicableNot applicableNot applicableNot applicable
Ratio Z2 taken 0.69 0.69 0.69 0.69 0.68 0.68 Ratio Z2 taken 2.05 2.05 2.05 2.05 2.05 2.05
Actual rainfall for Return period MRM mm 16.44 18.12 19.32 20.37 21.39 22.49 Actual rainfall for Return period MRM mm 63.61 66.77 69.73 71.18 72.53 73.80
Actual rainfall for Return period Site specific mm 15.37 17.19 18.74 20.12 21.36 22.49 Actual rainfall for Return period Site specific mm 69.17 71.72 74.08 76.28 78.35 80.29
Rainfall depth taken mm 15.37 17.19 18.74 20.12 21.36 22.49 Rainffall depth taken mm 69.17 71.72 74.08 76.28 78.35 80.29
Rainfall intensity MRM 5.48 4.53 3.86 3.39 3.06 2.81 Rainfall intensity MRM 7.95 7.42 6.97 6.47 6.04 5.68
Rainfall intensity Site Specific 5.12 4.30 3.75 3.35 3.05 2.81 Rainfall intensity Site Specific 8.65 7.97 7.41 6.93 6.53 6.18
Rainfall intensity taken 5.12 4.30 3.75 3.35 3.05 2.81 Rainfall intensity taken 8.65 7.97 7.41 6.93 6.53 6.18
DDF for Tully Monaghan
27.5
28.0
28.5
29.0
29.5
0 1 2 3 4 5 6 7 8 9Volume m³Duration hrs
Volume of space required for strorage m³
125.0
125.5
126.0
126.5
127.0
127.5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14Volume m³Duration hrs
Volume of space required for strorage m³RECEIVED: 29/10/2025
RECEIVED: 29/10/2025
CONSULTING ENGINEERS BUILDING SURVEYORS ARCHITECTS
Tel: 042-9746492
Fax: 042-9746511
Email: info@cspringle.com
Website: www.cspringle.com
Registered Office:
Monaghan Road,
Castleblayney,
Co. Monaghan.
Incorporated in Ireland:
Reg No 640491
MNK Engineering Ltd trading as C S Pringle
Page 1 of 7
2nd July 2024.
Re: Design of compensatory flow by removing Surface Water flow along Glen Road into a
combined sewer so as to free up capacity in the mains sewer for foul sewage coming from the
site.
To whom it concerns,
I have assessed what area of impermeable surface should be removed in order to produce such a
net benefit to the public sewer system as to accommodate the foul water flow from this proposed
housing development in Tully.
At present a combined sewer exists going down the road. This is done in a manner where two
pipes are run parallel to each other with the smaller taking the flow from the surface water gullies
and the large taking the flow from the foul together with what flows from the surface water in
times of high flow. It is presumed that the two-pipe system continues to the treatment works with
the SW pipe given lesser treatment than the other pipe. Alternatively, it is combined further down
the line.
Thus, in times of rainfall the treatment works has to cope with SW runoff from the catchment area
and in times of heavy rainfall the size of the pipe is inadequate to carry the flow causing the
combined sewer to surcharge and flood out on to the road. This has caused considerable problems
in the past for the houses located south of the Lewis Convent school.
For this reason, Uisce Eireann and the Local Authorities are rightly concerned about the addition
of any extra load on the system.
When there are only small intensities of rainfall the treatment system can cope with the combined
flow. It is only when the rainfall intensities get significant that it causes problems at the treatment
works and for significant events causes surcharging and overflow of the network at least down to
the traffic lights.
RECEIVED: 29/10/2025
MNK Engineering Ltd trading as C S Pringle
Page 2 of 7
Registered Office:
Monaghan Road, Castleblayney,
Co. Monaghan.
Incorporated in Ireland:
Reg No 640491
Consulting Engineers
Building Surveyors
Design Certifiers
Assigned Certifiers
It is proposed that the surface water runoff from the proposed Tully housing estate would be
attenuated to greenfield flow levels and the throttled flow put into the culvert running past the site
on the east side.
What is requested is that we be allowed to connect the proposed foul flow into the main combined
sewer. A new independent storm sewer would be installed along Glen road picking up all existing
surface water gullies in the selected catchment area before being discharge to nearby watercourse.
The average flow rate per day amounts to 0.25lts per second or less than 22m² per day. The peak
flow is estimated to be six times this flow rate figure at 1.5lts/s.
We propose to divert approximately 8000m² of site from the sewer. An indicative area is shown
below together with an indicative length of surface water sewer conveying the flow from the road
gulleys to the stream.
RECEIVED: 29/10/2025
MNK Engineering Ltd trading as C S Pringle
Page 3 of 7
Registered Office:
Monaghan Road, Castleblayney,
Co. Monaghan.
Incorporated in Ireland:
Reg No 640491
Consulting Engineers
Building Surveyors
Design Certifiers
Assigned Certifiers
Map shows the area of impermeable surface contributing to the combined sewer at present
together with an indication of the run of new SW pipe to service same.
We have taken the depth duration frequency of the location in Drumbear, and this has been shown
in the table at the bottom. We created formulae to reproduce the table on spreadsheet including
interpolation of figures.
We must remember that for any given return period that shorter durations produce more intense
rainfall figures in mm of water depth per hour. When this is multiplied by the impermeable
catchment area it gives the runoff in litres per hour which when divided by 3600 (60x60) gives the
runoff rate in litres per second.
We choose a return period for the rainfall and modify the duration such that the average runoff
from the diverted catchment is at or greater than the desired 6DWF for the foul sewer i.e. 1.5lts/s.
The following table gives the duration in days and hours of the rainfall event that will give a runoff
of 1.5lts/s. If the duration is less than this value, the runoff rate is greater than 1.5 otherwise it is
less.
Table gives duration of rainfall event in days and hours below which the runoff from the
diverted catchment will exceed 1.5lts/s and thus its removal will make an overall
improvement on the downstream conveyance infrastructure and on what reaches the
treatment works. RECEIVED: 29/10/2025
MNK Engineering Ltd trading as C S Pringle
Page 4 of 7
Registered Office:
Monaghan Road, Castleblayney,
Co. Monaghan.
Incorporated in Ireland:
Reg No 640491
Consulting Engineers
Building Surveyors
Design Certifiers
Assigned Certifiers
Spreadsheet screenshot shows the calculation of the 1.5lts/s value of the peak foul discharge
from the proposed development and shows also the duration of the storm in days and hours
that gives this value of runoff for various return periods.
RECEIVED: 29/10/2025
MNK Engineering Ltd trading as C S Pringle
Page 5 of 7
Registered Office:
Monaghan Road, Castleblayney,
Co. Monaghan.
Incorporated in Ireland:
Reg No 640491
Consulting Engineers
Building Surveyors
Design Certifiers
Assigned Certifiers
Assessment of the risk of the extra flow that is diverted to the stream at Beechgrove Lawns
entrance.
The 100-year return period flow in the culvert under the road at the entrance to Beechgrove is
between 6.5 and 8.5m³/s.
The time of concentration of the stream is estimated to be in the order of 2.5 hours which gives a
rainfall runoff from the catchment being diverted of 43.5lts/s or 0.0435m³/s for a 100-year storm.
Thus, the increase in flow relative to the original is somewhere between 100.5% and 100.7%
which is very low. Given that the road floods in time of high rainfall as a result of the surcharging
of the combined sewer the stream ends up taking the flow further down the line in any case. It
then boils down to the greater good of separating combined flow from going to the treatment
works and having a conveyance system that is more capable of taking the flow than previously and
having a marginally greater flow in the stream in times of rainfall.
If the rainfall has a duration that is longer than 2.5 hours, then the rainfall intensity is less for the
same area of catchment contributing. If the rainfall has a duration of less than 2.5 hours, then
while the rainfall intensity is slightly greater the catchment area has not been fully mobilised
resulting in a lower flow. Thus, combining the flows at what is considered to be the time of
concentration of the catchment for this location produces the most onerous conditions for
consideration. RECEIVED: 29/10/2025
MNK Engineering Ltd trading as C S Pringle
Page 6 of 7
Registered Office:
Monaghan Road, Castleblayney,
Co. Monaghan.
Incorporated in Ireland:
Reg No 640491
Consulting Engineers
Building Surveyors
Design Certifiers
Assigned Certifiers
Screenshot of spreadsheet showing characteristics of the catchment.
Screenshot gives the flow from the subject area for a 2.5-hour storm duration for various
return periods.
RECEIVED: 29/10/2025
MNK Engineering Ltd trading as C S Pringle
Page 7 of 7
Registered Office:
Monaghan Road, Castleblayney,
Co. Monaghan.
Incorporated in Ireland:
Reg No 640491
Consulting Engineers
Building Surveyors
Design Certifiers
Assigned Certifiers
Screenshot of spreadsheet shows the runoff from the catchment using IH124 formula.
Depth duration frequency table from Met Eireann
I trust that this is of assistance.
Regards
Marcus Dancey BSc (Eng), Dip Eng, CEng MIEI, FConsEI
Chartered Engineer RECEIVED: 29/10/2025