Environmental Statement 6.2
Brechfa Forest Connection Development Consent Order Application - Reference EN020016
Environmental Statement Appendix 13.1 Hydrology, flood risk and drainage data tables
May 2015
Regulation reference: The Infrastructure Planning (Applications: Prescribed Forms and Procedure) Regulations 2009 Regulation 5(2)(a)
Environmental Statement – Appendix 13.1 – Volume 6.4
Contents
Tables
Table 1 Watercourses along Proposed Development
Table 2 Nant Pibwr recorded water quality
Table 3 River Towy recorded water quality
Table 4 Nant Crychiau recorded water quality
Table 5 River Gwili (near Abergwili) recorded water quality
Table 6 River Gwili (near Llanllawddog) recorded water quality
Table 7 River Pib recorded water quality
Table 8 Hydrological features along Proposed Development
Table 9 Surrounding watercourses near Burry Port Substation
Table 10 Barnaby Pil recorded water quality
Table 11 Hydrological features near New Lodge Substation, Burry Port
Table 12 Surrounding watercourses near main construction compound
Table 13 Tawelon recorded water quality
Table 14 Surrounding watercourses near satellite construction compound
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 1 – Watercourses along Proposed Development
Watercourse Name Approximate Profile (observed from site visit/ Crossing Location aerial mapping)
Nant Morlais 240452, 211290 Small stream, approx 1m wide flowing south easterly towards Gwendraeth Fach.
Tributary of Nant 241427, 212975 Very small field boundary ditch, Morlais heavily overgrown, flows in south westerly direction.
Tributary of Nant 242160, 214522 Very small field boundary ditch, Trhydw heavily overgrown.
Tributary of Nant 243666, 215927 Very small field drain, flows in north Cwmffrwd westerly direction towards Nant Cwmffrwd.
Nant Cwmffrwd 244099, 216417 Small watercourse, 1-2m wide, meandering and overgrown near crossing location, flows in a westerly direction.
Tributary of Nant Pibwr 244686, 217437 Very small ditch, heavily overgrown.
Tributary of Nant Pibwr 244708, 218203 Very small ditch, heavily overgrown, flowing north towards Nant Pibwr.
Nant Pibwr 243965, 218424 Main River, approximately 2-3m wide, meandering (straight at crossing point), vegetation lined banks, flows in a westerly direction towards the River Towy.
Tributary of Nant Pibwr 243916, 218682 Very small field boundary ditch, heavily overgrown.
Tributary of River Towy 243583, 219321 Very small field boundary ditch, tree lined.
River Towy 243441, 220147 Main River, 30m wide, meandering, associated flood plain (GB110060029590).
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Environmental Statement – Appendix 13.1 – Volume 6.4
River Gwili Nr 243364, 220909 Main River, approximately 15m wide, straight channel, sparse vegetation on banks, flows southerly towards confluence with Towy (GB110060029080).
Bwlch Stream 243518, 220647 Main River, small watercourse approx 1-2m wide, flows from Bishop’s Pond to Afon Gwili.
Tributary of Bwlch 243468, 220703 Small watercourse, approx <1m wide Stream flows from Abergwili to Bwlch Stream.
Abergwili Mill Leat 243352, 220730 Main River small watercourse approx 1m wide, flows from north of Abergwili Road to confluence with Bwlch Stream, vegetated banks. The Abergwili Mill Leat is approximately 0.8km in length. The watercourse was dry when site visit was undertaken on 19/9/2014 by RSK hydrologist.
Nant Crychiau 243333, 221551 Small, straight watercourse, approx 4- 5m wide, tree lined banks, flows south westerly towards Gwili (GB11006029070).
Tributary of River Gwili 243329, 222099 Small ditch, approx 1m wide flows in southerly direction towards Gwili.
Nant Felys 242781, 224121 Small, shallow watercourse, 1m wide, meandering and overgrown near crossing location, flows in a south westerly direction.
Tributary of Nant 243505, 225344 Small ditch, approx 1m wide flows in Brechfa northerly direction towards Nant Brechfa.
Nant Brechfa 243505, 226192 Small watercourse, approx 2m wide, tree lined banks, flows westerly towards Gwili.
Tributary of Nant 243508, 227164 Small ditches, approx 1m wide flows Brechfa in southerly direction towards Nant Brechfa.
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Tributary of Nant 243806, 227943 Small ditch, approx 1m wide flows in Corrwg northerly direction towards Nant Corrwg.
Nant Corrwg 243722, 228437 Small, watercourse, approx 2m wide, tree lined banks, flows north towards Gwili.
River Gwili 243942, 228327 Main River, approx 5m wide, meandering, sparse/intermittent vegetation on banks, flows westerly (GB110060029080).
Nant y Boncath 243994, 229001 Small, shallow watercourse, 1m wide, straight and overgrown near to proposed route, flows in a southerly direction.
Tributary of Nant y 244261, 229547 Small ditch, approx 1m wide, Boncath overgrown, flows in westerly direction towards Nant y Boncath.
Nant y Boncath 244156, 229895 Small, shallow watercourse, 1m wide, straight and overgrown near to proposed route, flows in a southerly direction.
Nant Alltwalis Nr 3243777, 230721 Small watercourse, heavily wooded banks, flows south westerly towards Gwili.
Tributary of Nant 243976, 230562 Small ditch, tree lined and vegetated Alltwalis banks, flows westerly towards Nant Alltwalis
Tributary of Nant 244755, 230888 Small ditch, tree lined and vegetated Alltwalis banks, flows north westerly towards Nant Alltwalis.
Tributary of Nant 245374, 231471 Small ditch, heavily wooded banks, Alltwalis flows north westerly towards Nant Alltwalis.
Nant Aerau 246825, 231573 Small watercourse, heavily wooded banks, flows south westerly, source close to proposed route.
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Environmental Statement – Appendix 13.1 – Volume 6.4
Nant Cwm Dafydd 247062, 231469 Small watercourse, heavily wooded banks, flows south westerly, source close to proposed route.
Tributary of River Pib 248092, 231665 Small ditch, heavily wooded banks, flows north easterly towards River Pib, source close to proposed route.
Tributary of River Pib 248490, 231278 Small ditch, heavily wooded banks, flows north easterly towards River Pib, source close to proposed route.
Tributary of River Pib 248777, 231201 Small ditch, heavily wooded banks, flows north easterly towards River Pib, source close to proposed route.
Tributary of River Pib 249054, 230643 Small ditch, heavily wooded banks, flows north easterly towards River Pib, source close to proposed route.
Tributary of River Pib 250029, 230394 Small ditch, heavily wooded banks, flows easterly towards River Pib.
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 2 – Nant Pibwr recorded water quality
Waterbody Name Nant Pibwr
Grid Reference of intersect point 243965, 218424
WFD Waterbody ID GB110060029260
WFD Status Objective 2027 overall, 2027 ecological (2015/2021/2027)
Hydromorphological Designation Not designated A/HMWB
Designations Freshwater Fish Directive, Natura 2000 (Habitats and/or Birds Directive)
WFD Element Current Status
Ecological Status Poor
Biological Status Poor
Chemical Status High
Hydrology Not High
Morphology High
Fish Poor
Macro-invertebrates High
Ammonia High
Dissolved Oxygen High pH High
Phosphate High
Temperature High
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 3 – River Towy recorded water quality
Waterbody Name Towy
Grid Reference of intersect point 243441, 220147
WFD Waterbody ID GB110060029590
WFD Status Objective 2027 overall, 2015 chemical (2015/2021/2027)
Hydromorphological Designation Heavily Modified
Designations Freshwater Fish Directive, Natura 2000 (Habitats and/or Birds Directive)
WFD Element Current Status
Ecological Status Moderate
Biological Status High
Chemical Status High
Macro-invertebrates High
Ammonia High
Dissolved Oxygen High pH High
Phosphate High
Temperature High
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 4 – Nant Crychiau recorded water quality
Waterbody Name Crychiau
Grid Reference of intersect point 243333, 221551
WFD Waterbody ID GB110060029070
WFD Status Objective 2015 overall, 2015 ecological (2015/2021/2027)
Hydromorphological Designation Not Designated A/HMWB
Designations Not Designated
WFD Element Current Status
Ecological Status Moderate
Biological Status Moderate
Chemical Status Moderate
Hydrology High
Morphology Good
Fish Good
Macro-invertebrates Moderate
Ammonia High
Dissolved Oxygen High pH High
Phosphate Moderate
Temperature High
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 5 – River Gwili (near Abergwili) recorded water quality
Waterbody Name Gwili
Grid Reference of intersect point N/A
WFD Waterbody ID GB110060029080
WFD Status Objective 2015 overall, 2015 ecological (2015/2021/2027)
Hydromorphological Designation Not Designated A/HMWB
Designations Freshwater Fish Directive
WFD Element Current Status
Ecological Status Moderate
Biological Status Good
Chemical Status Good
Hydrology High
Morphology Good
Fish Good
Ammonia High
Dissolved Oxygen High pH High
Phosphate Moderate
Temperature High
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 6 – River Gwili (near Llanllawddog) recorded water quality
Waterbody Name Gwili
Grid Reference of intersect point 243942, 228327
WFD Waterbody ID GB110060036100
WFD Status Objective 2015 overall, 2015 ecological (2015/2021/2027)
Hydromorphological Designation Not Designated A/HMWB
Designations Freshwater Fish Directive
WFD Element Current Status
Ecological Status Good
Biological Status High
Hydrology High
Morphology Good
Invertebrates High
Ammonia High
Dissolved Oxygen High pH High
Phosphate High
Temperature High
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 7 – River Pib recorded water quality
Waterbody Name Pib
Grid Reference of intersect point N/A
WFD Waterbody ID GB110060035990
WFD Status Objective 2015 overall, 2015 ecological (2015/2021/2027)
Hydromorphological Designation Not Designated A/HMWB
Designations Freshwater Fish Directive
WFD Element Current Status
Ecological Status Moderate
Biological Status Moderate
Hydrology High
Morphology Good
Fish Moderate
Ammonia High
Dissolved Oxygen High
Phosphate High
Temperature High
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 8 – Hydrological features along Proposed Development
Hydrological Feature Grid Reference Distance (approx to centreline (m))
Spring 239693, 211370 325
Spring 239880, 211485 300
Issues 240094, 211521 250
Issues 240261, 211456 125
Spring 240539, 211246 100
Well 240373, 211640 225
Well 240784, 211535 200
Small pond associated with Farm / Spring 241062, 211854 275
Well / Small pond associated with Farm 241731, 212414 500
Well 241185, 212667 100
Well 241140, 212924 300
Issues 241448, 212985 0
Well 241818, 212865 400
Small pond associated with Farm 241117, 213349 400
Issues 241349, 213551 250
Well 242377, 213573 500
Issues 241468, 213829 450
Issues 241523, 214045 350
Small pond associated with Farm/Well/Issues 242214, 214183 300
Small pond associated with Farm 241538, 214208 300
Small pond associated with Farm/Issues/Well 241563, 214490 350
Small pond associated with Farm 242280, 214522 100
Small pond associated with Farm 242458, 214475 300
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Environmental Statement – Appendix 13.1 – Volume 6.4
Issues 242734, 214886 300
Well/Issues 242941, 215040 300
Well/Small pond within a field 241905, 215239 1000
Small pond within a field 242586, 215441 200
Spring 242900, 215723 225
Well 242832, 215772 300
Issues 243080, 215769 200
Well 244772, 216549 425
Small pond associated with Farm 245263, 217194 500
Spring 244895, 217329 175
Spring 244940, 217247 100
Small pond associated with Farm 244799, 217420 100
Issues 244743, 217569 100
Well 244724, 218050 350
Issues 243663, 219067 150
Small pond associated with Farm (dry) 243646, 219158 225
Small pond associated with Farm (dry) 243573, 219242 125
Small pond associated with Farm (dry) 243163, 219597 300
Well 243683, 219650 200
Spring 243151, 221744 50
Well 243041, 222179 100
Well 243357, 222257 225
Well 243878, 222166 750
Spring 243895, 222310 750
Spring 243590, 222448 500
Well 243673, 222498 550
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Environmental Statement – Appendix 13.1 – Volume 6.4
Issues 242800, 222408 300
Small pond associated with Farm/Spring 242861, 222451 250
Spring 242805, 222699 275
Spring 242613, 222752 450
Spring 242890, 222860 150
Spring 243389, 222860 350
Spring 242613, 222949 425
Springs/Well/Small pond associated with 242481, 223417 500 Farm
Well 243420, 223390 425
Small pond associated with Farm 243513, 223526 500
Issues 243517, 223563 500
Issues 242555, 223587 425
Spring 242749, 223620 225
Issues 243087, 223638 100
Concealed pond 242608, 223664 350
Spring 242705, 223762 200
Spring 242723, 223951 100
Spring 243228, 224127 450
Issues 243362, 224277 625
Issues 243066, 224540 200
Small pond associated with Farm 242460, 224683 400
Spring 242338, 224712 550
Issues 242559, 224858 425
Spring 243342, 224938 175
Small pond associated with Farm 243450, 226093 75
Village pond 244142, 227000 600
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Environmental Statement – Appendix 13.1 – Volume 6.4
Spring/Issues 244050, 227669 350
Danfforddgaer Farm Fishing lake (1.5 acre 243996, 228289 200 lake)
Danfforddgaer Farm Fishing lake (1.5 acre 243917, 228396 150 lake)
Spring 244205, 229656 0
Small pond associated with Farm 244083, 229587 150
Small pond within field 243439, 229949 375
Fishing lake 243256, 230137 500
Pond within field 243766, 230419 100
Small pond within field 244251, 231044 150
Small pond associated with farm 245133, 231464 225
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 9 – Surrounding watercourses near Burry Port Substation
Watercourse Name Approximate Profile (observed from site visit/ Location (nearest aerial mapping) point to site)
Barnaby Pil 246136, 201214 Small watercourse extending from the substation around the Ashpits Pond and Pwll Lagoon Nature Reserve before discharging to the River Loughor.
Railway drains 246105, 200849 Small drainage running adjacent to the railway line to the south of the substation.
River Loughor 246348, 200655 Estuary of River Loughor into Carmarthen Bay.
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 10 – Barnaby Pil recorded water quality
Waterbody Name Barnaby Pil
Grid Reference of intersect point N/A
WFD Waterbody ID GB110059025490
WFD Status Objective 2015 overall, 2015 ecological (2015/2021/2027)
Hydromorphological Designation Not designated A/HMWB
Designations Shellfish Water Directive
WFD Element Current Status
Ecological Status Good
Biological Status N/A
Chemical Status N/A
Hydrology High
Morphology Good
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 11 – Hydrological features near New Lodge Substation, Burry Port
Hydrological Feature Grid Reference Distance (approx to substation (m))
Ashpits Pond 246159, 201119 50
Pwll Lagoon 246717, 201160 575
Coastal Pond 246172, 200719 425
Coastal Pond 245811, 200667 500
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 12 – Surrounding watercourses near main construction compound
Watercourse Name Approximate Profile (observed from site visit/ Location (nearest aerial mapping) point to site)
Drains/Ditches 236988, 219119 Small watercourse flowing adjacent to the western boundary of the proposed construction compound, with further small drains and ditches to the south west of the compound. Drains and ditches eventually discharge to Tawelon Brook.
Tawelon 237631, 219060 Small Brook running adjacent to the eastern boundary of the County Fairground, 375m to the east of the site locations.
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 13 – Tawelon recorded water quality
Waterbody Name Tawelon
Grid Reference of intersect point N/A
WFD Waterbody ID GB110060029320
WFD Status Objective 2015 overall, 2015 ecological (2015/2021/2027)
Hydromorphological Designation Not designated A/HMWB
Designations Freshwater Fish Directive
WFD Element Current Status
Ecological Status Good
Biological Status Good
Chemical Status High
Hydrology High
Morphology Good
Macro-invertebrates High
Ammonia High
Dissolved Oxygen High pH High
Phosphate High
Temperature High
Copper High
Zinc High
Ammonia (annex 8) High
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Environmental Statement – Appendix 13.1 – Volume 6.4
Table 14 – Surrounding watercourses near satellite construction compound (Brechfa Forest)
Watercourse Name Approximate Profile (observed from site visit/ Location (nearest aerial mapping) point to site)
Unknown – tributary of 242160, 214522 Small watercourse flowing Nant Hafren approximately 100m to the south east of the proposed development in a southerly direction. Watercourse joins Nant Hafren and eventually the River Gwili near Llanllawddog.
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