Cyngor Bro Morgannwg
Vale of Glamorgan Council

1. Primary request: delete Site 2299 from the RLDP and remove it from Policy HG4.
2. Settlement boundary: do not redraw the Aberthin settlement boundary to include this field parcel; if already redrawn, reinstate the defensible boundary aligned to existing built form unless a published boundary review justifies change.
Evidence disclosure requests (minimum):
a. Robust evidence qualifying necessity under HG4, aligned to national policies
b. Full Site 2299 proforma (BP18A indicates proformas exist and are available on request), including all scoring and override rationale.
c. Full FCA including modelling outputs, assumptions, and climate change allowances for both fluvial and pluvial events, surface runoff from surrounding slopes, high groundwater susceptibility, principal aquifer conditions, cumulative testing, implications on the nearby SSSI wetland habitat, ecology assessment and no worsening test.
d. Surface water modelling demonstrates intermediate risk treatment, exceedance routing and no worsening.
e. The advised 12-month Groundwater monitoring and data
f. SuDS feasibility and design, including implications on the nearby SSSI and ecology.
g. Drainage strategy demonstrating foul connection feasibility, capacity, and any required off-site reinforcement.
h. Dry access/egress assessment for residents and emergency vehicles during flood events.
i. Highways feasibility: access location, visibility, swept-path tracking and road safety audit.
j. Active travel and public transport assessment with deliverable mitigation package and funding mechanism.
k. Landscape/visual assessment for SLA impacts.
l. Ecology and heritage appraisals including SSSI proximity and Conservation Area setting.
m. Site-specific viability appraisal (including all abnormal costs) demonstrating affordable housing deliverability.
3. Confirmation regarding protection of hedgerow
4. Confirmation regarding PRoW

This representation objects to the allocation of Site HG4(2) – Land West of Maendy Road,
Aberthin (Site 2299) within the Vale of Glamorgan Replacement Local Development Plan (RLDP).
The allocation proposes approximately 25 dwellings as an affordable housing-led development
on greenfield agricultural land forming part of the countryside immediately west of Aberthin.
The allocation is unsound for several independent reasons.
First, the proposal conflicts with the Plan’s spatial strategy.
Aberthin is identified as a Minor Rural Settlement, where development is expected to be limited
in scale and primarily related to local needs. A development of approximately 25 dwellings
would represent around a 14% expansion of the settlement in a single phase, introducing
estate-scale growth into a small rural village with very limited services. This represents a
material step-change inconsistent with the role of such settlements within the hierarchy.
Second, the site is not necessary for delivery of the Plan’s housing strategy.
The RLDP identifies a housing requirement of 7,890 dwellings and housing provision of 8,660
dwellings, creating a surplus of 770 dwellings above the requirement. Removal of HG4(2)
Aberthin would still leave a surplus of 745 dwellings, and even removal of all HG4 rural
affordable-led sites would leave a surplus of 648 dwellings. The allocation is therefore not
required for the Plan to deliver its housing requirement.
Third, the RLDP evidence identifies affordable housing need at a ward level (Cowbridge) rather
than within Aberthin itself, and no evidence has been presented demonstrating a specific locally
arising need within the settlement.
Forth, the site makes only a negligible contribution to affordable housing delivery. The site is
expected to deliver approximately 13 affordable homes, representing only 0.42% of the Plan’s
projected affordable housing delivery of 3,070 homes. The Plan is therefore not materially
dependent on the site to deliver its affordable housing strategy.
Fifth, the site is heavily constrained by flood risk and drainage uncertainty.
Part of the site lies within Flood Zone 3, where highly vulnerable development on greenfield
land is not permitted under Technical Advice Note 15 (TAN15) unless the development is
essential to the Local Development Plan. Given the Plan’s housing surplus, and no identified
local need, the site cannot reasonably be considered essential. In addition:
• no detailed hydraulic model exists for the Nant Aberthin watercourse,
• no Flood Consequence Assessment has been undertaken at allocation stage,
• groundwater susceptibility is classified as “Red – high – groundwater likely to be at or
near the surface”, with a recommendation for 12 months monitoring which has not
been undertaken,
• surface water mapping indicates intermediate flood risk across part of the site, and
historical flood data indicates flooding
• the proposed SuDS detention basin location appears to fall within Flood Zone 3
according to Council constraint mapping, raising questions regarding compliance with
SuDS design guidance,
• the viability and performance of the proposed drainage strategy has not been
demonstrated, including potential effects on the hydrology of the nearby Cors Aberthin
SSSI wetland system, and
• no modelling has been provided to demonstrate that development would not worsen
flood risk to neighbouring properties, including those at Maes Lloi.
Taken together, these factors create substantial uncertainty regarding whether a compliant
drainage strategy could be delivered and whether flood risk could be safely managed.
Sixth, the site presents infrastructure and accessibility constraints.
Aberthin has very limited services and infrastructure. The settlement contains no shops and
limited community facilities, with most services located in nearby Cowbridge. Public transport
provision is limited to infrequent bus services which cease in the early evening and do not
operate on Sundays, and there are no designated active travel routes connecting the settlement
to surrounding towns. The road network through the village, particularly along the A4222
corridor, already experiences traffic pressures and safety concerns. The Council’s education
evidence also confirms that secondary school capacity serving the area is already under
pressure, with additional places required to accommodate projected growth.
Seventh, the allocation introduces development into a sensitive landscape and environmental
setting.
The site lies entirely within a Special Landscape Area, contributes to the countryside setting of
the Aberthin Conservation Area, lies close to Cors Aberthin SSSI, and contains established
hedgerow boundaries forming part of the historic field pattern of the Vale landscape.
Finally, the allocation represents a clear departure from the Council’s published site assessment
methodology.
Background Paper BP16 indicates that sites affected by flood risk should normally be discounted
from further consideration. Despite multiple constraints — including Flood Zone 3, groundwater
susceptibility and surface water risk — Site 2299 was not discounted. The site was previously
rejected during preparation of the adopted LDP on the basis that it was unrelated to the
settlement and constituted sporadic development in the countryside, and no material change in
circumstances has been demonstrated to justify a different conclusion. Additionally, audit trail
concerns are evident, e.g. N/A values in justification columns.
Taken together, the evidence demonstrates that the allocation:
• is not necessary to deliver the Plan’s housing requirement or affordable housing
outcomes, and no need has been established
• conflicts with national flood policy (TAN15),
• is inconsistent with Council’s own site assessment methodology, and
• introduces development into a sensitive rural landscape with infrastructure constraints
unnecessarily.
In conclusion, these matters demonstrate that the allocation fails the key tests of soundness: it
is not justified by the evidence, is not effective or deliverable due to unresolved environmental
and infrastructure constraints, and is not consistent with national policy, including Planning
Policy Wales (sustainable spatial strategy and protection of landscape) and Technical Advice
Note 15 (flood risk)
For these reasons, Site HG4(2) – Land West of Maendy Road, Aberthin should be removed from
the RLDP.

3.1 Settlement size and character
Aberthin is classified as a minor rural settlement. It is a historic agricultural village built around
the Nant Aberthin (Aberthin Brook), a tributary that flows into the River Thaw. The settlement is
surrounded by agricultural land parcels and a large common land called Stalling Down.
It is estimated to contain approximately 176 dwellings.
There is a close-knit community feel, with many residents taking parts in community events
organised by the village hall committee, such as a duck race (where plastic yellow ducks are
raced down the stream), a free bonfire and fireworks display held on the downs, quiz nights,
amateur dramatics and an annual Village Day, which has a barbeque, music and a dog show.
Aberthin has already been recently extended, under the last LDP. In around 2017, 20 properties
were built in Court close, 6 of those affordable. The settlement boundary was redrawn to
accommodate the site, as can be seen in the map below, marked in red. (REFER TO ATTACHED PDF FOR IMAGES)
3.1.1 Settlement boundary

3.2 Landscape and Environmental Context of Aberthin
The settlement is characterised by its historic village form, traditional buildings and strong
relationship with the surrounding countryside. Much of the landscape surrounding the village is
designated as a Special Landscape Area by Vale of Glamorgan Council, reflecting the recognised
scenic quality and rural character of the Nant Aberthin valley and the wider Vale landscape. The
historic character of the settlement is also recognised through the designation of the Aberthin
Conservation Area, which protects the architectural and historic character of the village and its
relationship with the surrounding rural landscape.
The surrounding countryside comprises a network of agricultural fields defined by historic
hedgerow boundaries, forming part of the traditional field pattern typical of the Vale of
Glamorgan. The area is also notable for its historic environment, with several Scheduled Ancient
Monuments and other archaeological features recorded in the surrounding landscape, reflecting
long-standing human activity in the Nant Aberthin valley. The landscape also supports important
ecological features associated with the Nant Aberthin watercourse and valley system, including
the nearby Cors Aberthin SSSI, a designated wetland site protected under the Wildlife and
Countryside Act 1981. Public rights of way cross the surrounding farmland, providing access to
the countryside and contributing to the rural character and recreational value of the area.
3.2.1 Landscape features
SSSI: shown in red, Conservation Area – maroon boundary, monuments in blue, ancient
woodland in green crosshatch, and SINC in green horizontal lines

3.3 Services and facilities
Aberthin has very limited services and infrastructure.
Known facilities include:
• a small community centre (a charity created to support itself, run by volunteers)
• two public houses, one of which has been operated and staffed primarily by the same
family for approximately 20 years.
The pubs are both well attended.
There are no shops.
The nearest Medical Centre is in central Cowbridge.
Cowbridge primary and secondary schools are within walking distance. The schools have had
significant oversubscription issues for at least a decade, despite recent expansion. There are no
other easily commutable secondary schools in the area.
3.4 Transport accessibility
Public transport provision is also extremely limited:
• The nearest train station is in Pontyclun, 4.7 miles way
• There is only one bus stop, located on one side of the road, for buses headed North.
Although buses do stop in the opposite direction, taking residents towards Cowbridge,
there is no designated bus stop, street furniture or pavements, for safety purposes. The
stop is also on a 90-degree bend with multiple side roads and opposite a pub car park
which all together pose a risk to personal safety.
• Buses operate approximately hourly
Services run only until around 7:30 pm
• No Sunday or bank holiday services exists.
• Buses are not busy
There are no designated cycle paths (Active Travel). A scheme went through consultation but
met with multiple objections. Some of these are relevant to LDP planning elements, such as:
o The high volume and speed of traffic on the existing highways, predominantly the A4222
that runs directly through Aberthin
o A lack of segregated infrastructure in the area, which would force cyclists to share space
with cars in narrow sections.
o The lack of street lighting in the area, which made the route unappealing for use at night
or during winter.
o Concerns regarding installing lighting due to wildlife disruption
The project has been on hold for 3 years.
The settlement is not (for many) realistically walkable to any nearby towns, including
Cowbridge, the nearest town, the centre of which is 2km away. There is a reliance on Cowbridge
for most needs. In some places pavements do not exist or are not continuous through either
side of the village. Most residents rely on car travel.
3.5 Flood risks and geology
Aberthin is in a flood risk area, with most of the heart of the village in flood zone 3 and further
parts in flood zone 2:
• Fluvial Risk (Rivers): The area immediately surrounding the Nant Aberthin is subject to
flood risk. Nant Aberthin joins the River Thaw,
• Surface Water: Due to its position at the base of the steep Pen y Lan Road and Stalling
Down, the village and the adjacent field of the proposed site 2299 are susceptible to
local flood risk caused by surface runoff during intense rainfall. Groundwater also
naturally flows downhill towards valley bottoms, where it can emerge as springs or
cause the water table to reach the surface.
• Groundwater: Much of the village and the surrounding valley floor is classified by the
British Geological Society as having a High Susceptibility to groundwater flooding. This
means geological conditions (specifically the permeable limestone bedrock and
overlying river gravels) could enable groundwater to emerge at the surface or remain
very shallow.
• Aquifer Designation: The underlying Carboniferous Limestone is classified as a Principal
Aquifer. These are layers of rock with high permeability that provide significant water storage. In Aberthin, this leads to a "flashy" groundwater table that rises rapidly in
response to rainfall.
• Alluvial Deposits: The valley floor contains permeable layers of alluvium and gravel.
When the nearby River Thaw or Nant Aberthin rises, it can "push" groundwater up
through these deposits into low-lying areas, a process known as groundwater-surface
water interaction.
• Under the Water Framework Directive (WFD), the groundwater body in this part of the
Vale of Glamorgan is generally monitored for "Good" or "Poor" quantitative status.
Additionally, much of the centre and the surrounding agricultural land to the immediate North
and West has experienced historical flooding and is in Development Advice Map Zone B

4 Site identification and baseline facts
4.1 Site 2299 or HG4(2)
Site 2299 is described as ‘Land West of Maendy Road, Aberthin’, promoted for 25 dwellings.
Its’ status is undeveloped greenfield land (agricultural field). Current lawful use and any
covenants/easements must be confirmed via Land Registry title and planning history searches.
The site is one of 4 proposed through policy HG4 – rural affordable housing-led site.

4.2 Scale and proportionality
Aberthin is understood to have 176 dwellings. 25 dwellings = 14.2% increase in a single phase.
This also follows a development in 2017 which already saw a 13% increase, so the new
development constitutes urban sprawl.

4.2.1 Site map for HG4 (2) in relationship to existing Aberthin settlement
4.3 Development proposal context diagram

4.4 Key mapped constraints/sensitivities
• Wholly within Special Landscape Area (SLA).
• Partial Flood Zone 3 (southern end) and broader fluvial sensitivity in the Nant Aberthin
corridor.
• Intermediate surface water risk across approximately half the site (per Vale planning
constraints mapping), with additional low surface water risk elsewhere.
• Groundwater susceptibility identified as ‘red – highest to ground’ and recommendations for 12
months groundwater monitoring and FCA
• History of flooding (DEVELOPMENT ADVICE MAP Zone B) across middle of the site
• Current (known) southern access wholly within Flood Zone 3; width constraints for emergency
vehicles.
• No existing sewerage or drainage infrastructure on site.
• Public right of way interacts with the southern access area and proposed drainage features
and run along western end from bottom to top of site
• Proximity to designated assets (SSSI nearby, SINC 165, Conservation Area setting) and mineral
safeguarding (limestone safeguarding area).
• Historic hedgerow running down western side of site

5 Principle, spatial strategy and previous rejection
5.1 Conflict with the Plan’s Spatial Strategy
The core objection is one of principle. The proposed allocation would release open countryside
for estate-scale residential development in a Minor Rural Settlement, contrary to the spatial
strategy of the RLDP.
The RLDP directs the majority of housing growth to sustainable locations — higher-order
settlements and service centres — where employment, services, public transport and
infrastructure are available. Minor Rural Settlements are not intended to accommodate estate
scale development; growth in such locations is expected to be very limited and typically
confined to local need or small-scale infill. Aberthin is not identified as a strategic growth
location and no specific local affordable housing need within the settlement has been
demonstrated.
This strategic approach is reflected in the housing distribution set out in BP9A. Figure 2 shows
that only 4.5% of total housing growth is directed to Minor Rural Settlements and Primary
Settlements outside the Strategic Growth Area. Applied to the Plan’s total housing provision of
8,660 dwellings, this equates to approximately 390 dwellings across all minor rural settlements
over the 15-year plan period. By contrast, the overwhelming majority of growth is directed to
larger settlements:
Settlement Category
Share of Housing
Primary settlements in Strategic Growth Area 40.5%
Service centres
26.4%
Key settlements
24.9%
This distribution demonstrates that minor rural settlements are not intended to play a
significant role in housing delivery, with growth instead concentrated in locations with stronger
services, infrastructure and sustainable transport connections.
Within this context, allocating HG4(2) Aberthin for approximately 25 dwellings would represent
a 14.2% expansion of the settlement in a single phase, introducing suburban-scale development
into a small rural village with very limited services and infrastructure. Although described as
“small-scale”, the assessment fails to consider proportionality: a 14% expansion of a minor rural
settlement cannot reasonably be regarded as small-scale development.
The allocation therefore represents a departure from the Plan’s spatial distribution strategy
rather than an implementation of it.

5.2 Consistency with Previous Plan Evidence
The site was previously assessed during preparation of the Vale of Glamorgan LDP 2011-2026
and rejected. The reason for rejection was clear: the site was considered unrelated to the
settlement and would represent unacceptable sporadic development in the countryside. This
reasoning remains valid.
The physical relationship between the site and the settlement has not changed. The field
remains a separate agricultural parcel outside the established built form of Aberthin. No new
infrastructure, services, or settlement expansion has occurred that would alter this relationship.
Allocating the same site in the absence of any material change in context raises serious
questions about the consistency and robustness of the site selection process.
5.3 Internal Inconsistency in the Council’s Own Assessment
The Council’s Candidate Site Assessment contains a clear internal inconsistency regarding the
status of Site 2299. At Stage 1 the site is described as “adjacent to a minor rural settlement”
(BP18A, p.14), which indicates that the land lies outside the settlement and forms part of the
open countryside. However, at Stage 2 the site is assessed on the basis that “a small-scale
affordable housing led development in a minor rural settlement would accord in principle with
the strategy” (BP18A, p.20).
These statements are incompatible. A site that is adjacent to a settlement is not within it. The
assessment therefore appears to assume that the settlement boundary will be extended to
incorporate the site, yet no explanation or evidence is provided to justify such a boundary
change. This raises serious concerns regarding the transparency and robustness of the site
selection process and suggests that the allocation may be site-led rather than plan-led.
5.4 Scale Does Not Resolve the Principal Conflict
The number of dwellings proposed does not resolve the fundamental policy conflict.
Even if the development were reduced in scale, the underlying issue would remain: the site
constitutes development in the countryside beyond a defensible settlement boundary and
represents estate-style expansion rather than small-scale infill.
5.5 Reliance Solely on Affordable Housing Justification
The Council’s own assessment makes clear that the only substantive justification for the site is
the potential delivery of affordable housing. No other strategic justification is provided.
Indeed, the assessment acknowledges that:
• Aberthin has limited services and facilities, and
• public transport provision is relatively infrequent.
The reliance solely on affordable housing as justification is problematic in principle. Affordable
housing provision cannot justify development in locations that conflict with the spatial strategy,
particularly where the overall housing requirement is already exceeded, the plan target for
affordable housing doubles the historic attainment and need for the LDP to contribute, and
alternative sustainable sites are available.
The detailed assessment of affordable housing need and delivery is addressed separately in
Section [6] of this representation.

6 Affordable Housing, Spatial Strategy, and Necessity: Why HG4(2) Is
Not Required
6.1 The RLDP Already Exceeds the Housing Requirement (and Explicitly Builds
in Flexibility)
A key test in allocating additional housing sites is whether they are necessary for the Plan to
deliver its housing requirement and strategy.
BP9A confirms a housing requirement of 7,890 dwellings and total housing provision of 8,660
dwellings, explicitly described as a 10% flexibility allowance:
• “The housing provision of 8,660 dwellings rounds to a 10% flexibility allowance…”
• “…it is considered that a 10% flexibility should be considered a maximum…”
This creates a surplus of 770 dwellings above the requirement (8,660 – 7,890), meaning the Plan
is not operating at the margin but already includes a substantial buffer.
Removal of HG4(2) Aberthin (25 dwellings) would leave provision at 8,635 dwellings, still
exceeding the requirement by 745 dwellings. Even removal of all HG4 rural affordable-led sites
(122 dwellings) would leave provision at 8,538 dwellings, still exceeding the requirement by 648
dwellings.
The Plan therefore retains a substantial flexibility margin without reliance on the HG4 rural sites.
These allocations are consequently discretionary additions rather than necessary components of
the housing strategy.
6.2 HG4 Rural Affordable-Led Sites Represent a Very Small Component of
Supply and are not Numerically Essential
BP9A identifies “Affordable housing led sites” (HG4) as a limited element of supply totalling 122
dwellings across four settlements (Colwinston 25, Aberthin 25, Wick 50, Fferm Goch 22).
This is 1.4% of total Plan provision.
HG4 rural affordable-led sites therefore represent a very small and numerically non-essential
component of supply. Numerically, the Plan is not dependent on these sites. As set out above,
even removing all HG4 sites, the Plan retains a surplus of 648 dwellings above the requirement.
This confirms that these allocations are not structurally required for housing delivery.
6.3 The 3,070 Affordable Homes Figure Represents Expected Delivery — Not
Demonstrated Need and HG4(2) is immaterial to delivery
A key point in interpreting the Plan’s affordable housing evidence is the meaning of the 3,070
figure referenced throughout the RLDP evidence base.
BP9A confirms that:
“the various sources of housing will contribute 3,070 affordable homes.”
This figure represents expected affordable housing delivery arising from the housing supply
identified in the Plan, including sites with planning permission, sites under construction, housing
allocations, windfalls and affordable-led sites. It is therefore derived from the overall housing
supply and assumed policy performance, rather than representing a quantified level of housing
need that must be met in full. In other words, 3,070 is a projection of delivery, not a measure of
need.
The actual level of demonstrated need is identified through the Local Housing Market
Assessment (LHMA). BP9A confirms that the LHMA identifies:
• 461 affordable homes per year, equating to
• 6,918 affordable homes over the 15-year plan period.
This distinction is critical.
Measure
Demonstrated affordable housing need (LHMA)
Number
6,918 homes
Affordable housing expected to be delivered by the RLDP 3,070 homes
The Plan therefore anticipates delivering less than half of the identified affordable housing need
through the planning system. This is not unusual, as delivery through planning mechanisms is
constrained by factors such as development viability, housing delivery rates, reliance on market
schemes to generate affordable units, and the availability of subsidy and Registered Social
Landlord funding.
However, this distinction is fundamental when considering the necessity of individual
allocations. Because the 3,070 figure represents expected delivery arising from the overall
housing supply, it is not a target that must be achieved through allocating specific individual
sites. The inclusion or exclusion of a small site therefore does not materially affect the Plan’s
affordable housing strategy.
This is particularly clear in the case of HG4(2) Aberthin. BP9A indicates that affordable housing
led sites are expected to deliver at least 50% affordable housing, meaning HG4(2) would provide
approximately:
• 13 affordable homes from 25 dwellings,
with 62 affordable homes across all HG4 rural affordable-led sites combined.
The numerical impact of removing the Aberthin site is therefore extremely small:
• Removing HG4(2) Aberthin reduces affordable delivery from 3,070 to approximately
3,057 homes (0.42% reduction).
• Removing all HG4 rural affordable-led sites reduces delivery from 3,070 to
approximately 3,008 homes (2.02% reduction).
BP18A states that “the 2023 LHMA indicated that the ward of Cowbridge has a need for 230
additional affordable units over the next 15 years and this site could make an important
contribution in meeting that.” However, a contribution of 0.42% from the Aberthin site cannot
reasonably be described as important and is numerically negligible.
Accordingly, the Plan is not materially dependent on HG4(2) Aberthin to meet its affordable
housing delivery expectations. The loss of the site would not undermine the Plan’s affordable
housing strategy or prevent the RLDP from delivering the level of affordable housing the Council
expects to arise from the housing supply.
The evidence therefore demonstrates that HG4(2) Aberthin is not necessary for the Plan to
achieve its projected affordable housing delivery.
6.4 Affordable Housing Delivery Framework
Affordable housing delivery in Wales is not solely dependent on allocations or planning
obligations secured through the Local Development Plan (LDP). Welsh Government statistics
show that affordable housing is delivered through a range of mechanisms, including Welsh
Government capital grant programmes, housing association development and direct local
authority provision.
In 2024–2025, 3,643 additional affordable homes were delivered across Wales. Of these, 882
homes (approximately 24%) were delivered through planning obligations linked to market
housing developments, while around 76% were delivered through other routes, primarily grant
funded programmes and delivery by Registered Social Landlords and local authorities. This
demonstrates that the planning system represents one component of the wider affordable
housing delivery framework, rather than the principal delivery mechanism.
Within the Vale of Glamorgan, monitoring reports indicate that 2,398 affordable homes were
delivered between 2011 and 2025 under the current LDP period. Recent statistics also show 147
local authority homes delivered in 2024–2025, demonstrating that council-led delivery
programmes continue to contribute alongside housing association development.
The RLDP evidence suggests that approximately half of identified affordable housing need may
be delivered through planning mechanisms associated with housing allocations. When
compared with national delivery patterns — where planning obligations account for around 24%
of affordable housing provision — this represents approximately double the typical contribution
delivered through planning mechanisms.
The available evidence therefore indicates that the RLDP is already expected to make an
unusually high contribution to affordable housing delivery through planning mechanisms alone.
Given national delivery patterns and the Vale’s historic delivery record, it is reasonable to expect
that a proportion of affordable housing supply during the plan period will continue to arise
through other established mechanisms operating alongside the LDP, including Welsh
Government grant programmes, housing association development and local authority housing
delivery.
The evidence therefore indicates that the Local Development Plan should be understood as one
delivery mechanism within a wider system, rather than the principal mechanism through which
affordable housing need is expected to be met.
6.4.1 Implications for Site Allocation
In this context, the justification for allocating additional sites primarily to support affordable
housing delivery becomes less clear. If the RLDP already assumes a level of provision through
planning mechanisms that doubles typical national delivery patterns, further allocations risk
over-provision relative to what is required to support the plan strategy, raising a potential
question of plan soundness.
This is particularly relevant where proposed sites are rural or environmentally sensitive
locations, or where development may introduce landscape, infrastructure or environmental
impacts affecting the rural character that defines much of the Vale of Glamorgan.
The evidence therefore suggests that the necessity for additional site allocations should be
clearly demonstrated, particularly where affordable housing delivery may reasonably be
expected to arise through the wider delivery framework operating alongside the planning
system.
6.5 The Evidence Base Identifies the Greatest Affordable Need in Larger
Settlements
The LHMA evidence summarised in the RLDP identifies that the greatest affordable housing
need is in:
• Barry
• Penarth / Llandough
• Llantwit Major
• Dinas Powys
• Rhoose
The Plan’s spatial strategy directs the overwhelming majority of growth to these areas and
settlement categories: Key Settlements, Service Centres and Primary Settlements in the
Strategic Growth area. This alignment between identified housing need and the spatial
distribution of growth is a central principle of the Plan’s strategy.
By contrast, Minor Rural Settlements such as Aberthin are not identified as primary locations for
addressing affordable housing need, and the evidence base does not demonstrate a specific
local need within the settlement itself. In this context, allocating a greenfield affordable housing
site in Aberthin appears inconsistent with the evidence base.
6.6 The Council’s “Local Need and Support for Services” Justification Requires
Evidence
The Plan suggests that rural affordable housing allocations are intended to:
• respond to local affordable housing needs, and
• support local services and facilities.
However, the evidence presented within BP9A does not demonstrate:
• there is any affordable housing need locally within Aberthin,
• What services exist that can be supported by extra residents
The justification for HG4 rural affordable housing sites relies on two related propositions: that
they respond to locally arising affordable housing need and that they support the sustainability
of rural communities by helping to maintain local services and facilities. However, the evidence
base does not demonstrate a specific affordable housing need within Aberthin itself (only the
ward of Cowbridge). Nor does the settlement contain a range of services that would realistically
be sustained by a development of this scale. In these circumstances, the policy rationale
underpinning the allocation appears weak. PPW and TAN 6 expects rural affordable housing to
be genuinely locally justified.
6.7 Development Within the Wider Corridor
Housing development has taken place across the Cowbridge–Aberthin–Ystradowen corridor in
recent years. Within Aberthin itself, approximately 20 dwellings were completed around 2017
2018, including affordable homes. The redevelopment of the former Cowbridge school site
between Aberthin and Cowbridge is currently under construction and will deliver approximately
34 affordable homes.
Further housing has been delivered in nearby settlements, including Maple Walk in Ystradowen
(46 homes), with expansion in the RLDP, the former police station site in Cowbridge (14), and
Clare Garden Village (475), with further expansion. Collectively, these developments
demonstrate that housing supply, including significant levels of affordable housing, is already
being delivered within the surrounding area and the corridor may already be at saturation point.
6.8 Overall Conclusion
The evidence demonstrates that the allocation of HG4(2) Aberthin is not necessary for the RLDP
to deliver either its housing requirement or its projected affordable housing outcomes.
Even if HG4(2) Aberthin were removed, the Plan would still exceed its housing requirement by
745 dwellings, and even if all HG4 rural affordable-led sites were removed the surplus would
remain 648 dwellings. These allocations are therefore not required to maintain an appropriate
housing supply or flexibility allowance.
HG4(2) Aberthin itself is expected to deliver approximately 13 affordable homes, reducing
projected affordable housing delivery by only 0.42% if removed. Even removing all HG4 rural
affordable-led sites would reduce projected delivery by only 2.02%. The Plan is therefore not
materially dependent on these sites to achieve its affordable housing outcomes.
National evidence also demonstrates that affordable housing delivery in Wales arises through
multiple mechanisms operating alongside the planning system. The RLDP assumption that
around 50% of affordable housing need will be delivered through planning mechanisms
represents a doubling of the typical contribution made through the planning system.
Extensive corridor development of housing supply and affordable is already taking place and
may have already saturated this corridor.
No clear evidence has been presented demonstrating a specific local affordable housing need
within the settlement.

7 Flood risk, surface water, ground water, drainage, and methodological
concerns
7.1 TAN 15 Section 10.22 – Highly Vulnerable Development on Greenfield
Land in Flood Zone 3
BP21A (p.15) states:
“For a proposed development site within Flood Zones 3 of the Flood Map for Planning for Rivers,
Section 10.22 of TAN-15 states that highly vulnerable development on greenfield land is not
permitted. Section 10.23 of TAN-15 states that other development proposals are acceptable if
they are essential to the LDP.”
This is the primary policy test.
• Residential development = highly vulnerable development.
• The site is greenfield land.
• The southern part of the site lies within Flood Zone 3.
• TAN 15 states highly vulnerable development on greenfield land in Flood Zone 3 is not
permitted.
The only potential exception pathway is if the development is “essential to the LDP.”
This site is not essential:
• The housing trajectory demonstrates over delivery.
• Strategic sites are already allocated and viability tested.
• Minor rural settlements are not required to meet housing numbers.
• Affordable housing delivery is already occurring in service centres along this corridor
and through other delivery vehicles
• No need established in Aberthin
Accordingly, the allocation conflicts directly with TAN 15 Section 10.22.
7.2 Welsh Government Notification Direction – Escalation to Ministers
BP21A (p.15) states:
“It is recognised that the Welsh Government notification direction requires applications for
Highly Vulnerable Development where the whole or part of the site is within Flood Zone 3 on a
Greenfield site to be referred to the Welsh Ministers. Any development proposals for this site
which include residential use are therefore likely to be required to be notified to the Welsh
Government.”
This confirms:
• The seriousness of the constraint.
• That residential development here triggers Ministerial scrutiny.
• That the proposal is not routine.
It is unclear whether this allocation has been formally notified to Welsh Government at plan
stage. Allocation without clarity on Ministerial position introduces further procedural and
soundness risk.
7.3 SuDS Basin – Location Discrepancy and Flood Zone 3 Conflict
BP21A (p.16) states:
“Residential units located entirely within Flood Zone 1. A proposed SuDS detention basin is
located to the south of the site and is within Flood Zone 2.
As per the advice of the CIRIA SuDS Manual, SuDS should not be located within an area at a
greater than 1% AEP chance of flooding, which aligns to Flood Zone 3.”
However:
• Vale of Glamorgan planning constraints mapping indicates the basin location falls wholly
within Flood Zone 3.
If the basin is within Flood Zone 3:
• This conflicts with CIRIA guidance.
• Basin storage may be compromised during fluvial events.
• Coincident pluvial + fluvial events reduce attenuation capacity.
• Exceedance flows could affect:
o Site access (within Flood Zone 3),
o The public right of way,
o Existing properties at Maes Lloi.
No combined-event modelling outputs have been published.
7.3.1 Mapping overlay showing SUDs basin entirely in Flood Zone 3
Flood Zone
3
Flood Zone
3
7.4 Drainage, SuDS Feasibility and Groundwater Constraints
The hydrogeological and flood characteristics of the area raise significant doubt as to whether
an effective Sustainable Drainage System (SuDS) could be implemented on the site without
creating additional flood or environmental risk.
Aberthin lies within a valley setting where several interacting flood mechanisms operate. Much
of the village lies within Flood Zone 3, with surrounding areas within Flood Zone 2, reflecting
fluvial flood risk associated with the Nant Aberthin, which ultimately joins the River Thaw. In
addition to fluvial flooding, the area is susceptible to surface water runoff due to the steep
topography of surrounding higher ground, including Pen-y-Lan Road and the Stalling Down
plateau, which generate rapid runoff during intense rainfall events that drain towards the valley
floor where the village and the proposed site are located.
Groundwater conditions present a further constraint. The valley floor surrounding Aberthin is
identified by the British Geological Survey as having high susceptibility to groundwater flooding.
The site lies above Carboniferous Limestone classified as a Principal Aquifer, overlain by
permeable gravels and alluvial deposits associated with the Nant Aberthin valley. These
geological conditions can produce a rapidly responding (“flashy”) groundwater table in which
groundwater levels rise quickly following rainfall and may emerge at the surface or remain very
shallow. Interaction between river levels and groundwater within the alluvial deposits can
further exacerbate this effect, with elevated river levels capable of forcing groundwater upward
into adjacent low-lying land.
These conditions create a challenging environment for SuDS design. Welsh SuDS standards
require infiltration to be demonstrated as suitable for local ground conditions and to assess its
effects on groundwater levels. Where groundwater is shallow or highly responsive to rainfall,
infiltration techniques such as soakaways or infiltration basins may become ineffective or may
worsen groundwater emergence and flooding. Introducing additional infiltration in a valley floor
already prone to groundwater rise could therefore increase the risk of groundwater flooding in
surrounding parts of the village.
Even if infiltration techniques were unsuitable and an attenuation-based system were proposed,
significant uncertainty would remain. Such systems require sufficient space for attenuation
features, exceedance routing and safe discharge to a receiving watercourse. In this case, the site
is constrained by landscape sensitivity, established hedgerows, a public right of way, and its
position at the base of surrounding slopes where runoff naturally accumulates, raising doubt as
to whether a compliant SuDS solution could be delivered without substantial engineering
intervention.
There are also potential implications for Cors Aberthin SSSI, which lies within the same
hydrological valley system. Wetland habitats are typically highly sensitive to changes in
hydrology, groundwater levels and water quality, and development that alters surface water
pathways, increases runoff or modifies groundwater recharge patterns could affect the
hydrological conditions supporting the wetland ecosystem.
Together this creates significant uncertainty regarding whether a SuDS solution could be both
effective and environmentally acceptable. In the absence of detailed hydrogeological
investigation, seasonal groundwater monitoring and robust drainage modelling demonstrating
no increase in flood risk or ecological harm, the assumption that drainage issues can be
satisfactorily resolved remains unproven. This uncertainty raises further concerns regarding the
deliverability and environmental suitability of the allocation.
7.5 Absence of a Detailed Hydraulic Model – Nant Aberthin
BP21A (p.12) states:
“The southern extent of the Site is partially located within Flood Zones 2 and 3… No detailed
model is available of the Nant Aberthin.”
This is critical.
• There is no detailed hydraulic model of the Nant Aberthin.
• Flood extents are therefore based on national-scale modelling.
• No localised calibration or site-specific modelling has been published.
• Flood depth, velocity and hazard classification are not robustly evidenced.
Allocation of highly vulnerable development without a detailed fluvial model is precautionary
risk deficient.
7.6 Absence of Allocation-Stage FCA
The assessment documented in BP21a for site 2299 was undertaken by JBA Consulting. They
note the assessment was purely desk-based, taking information provided by others with no
verification.
BP21A (p.17) states:
“Any planning application for the Site should be accompanied by an FCA which demonstrates
how the proposals meet the requirements of TAN-15.”
This confirms:
• An FCA is required.
• It has not yet been undertaken.
• It is deferred to application stage.
However, TAN 15 requires flood consequences to be demonstrated as acceptable.
Allocation of highly vulnerable development in Flood Zone 3 without an FCA at plan stage
means:
• Flood consequences have not been demonstrated.
• Mitigation feasibility has not been proven.
• Deliverability is uncertain.
7.7 TAN 15 Section 10.18 – Flood Zone 2 Justification Pathway Not Engaged
BP21A (p.15) states:
“Section 10.18 of TAN-15 states that it is possible to allocate sites within Flood Zone 2 where the
proposals assist the implementation of the strategy of the LDP to regenerate or revitalise
existing settlements or to achieve key economic or environmental objectives.”
However:
• The site is not within the established settlement form.
• It was previously rejected as unrelated countryside.
• It does not regenerate the settlement.
• It does not achieve a key economic objective.
• It does not achieve a key environmental objective.
The Section 10.18 justification pathway does not apply.
7.8 Surface Water Risk – “Minimal” Assertion vs Mapping Evidence
BP21A states:
“Surface water and small watercourse flood risk is minimal across the site…”
However:
• Vale planning constraints mapping identifies intermediate surface water risk across
approximately half of the site.
• The site slopes from north to south toward Maes Lloi.
• Proposed dwellings fall within areas of intermediate surface water flood risk.
• Proposed dwellings are in an area of historical flooding (DEVELOPMENT ADVICE MAP
Zone B)
• No surface water modelling outputs are published.
• No velocity modelling.
• No exceedance routing plan.
• No no-worsening assessment.
Surface water risk has not been robustly evidenced at allocation stage.
7.9 Mapping shows majority of proposed houses located in risk areas
The following mapping overlays show that 16 of the 25 houses are in areas of either surface
water risk or have experienced historical flooding
7.9.1 Map overlay showing houses in risk areas for surface water
Surface risk
intermediate
Surface risk
intermediate
Surface risk
less
Surface risk
less
7.9.2 Map overlay showing houses in historical flooding area (DEVELOPMENT ADVICE MAP
Zone B)
Historical
flooding
Historical
flooding
7.10 Groundwater – “Red – High” and 12-Month Monitoring Requirement
The site is classified “Red – Hhigh – groundwater likely to be at or near the surface” meaning:
Groundwater levels are either at or very near (within 0.025m of) the ground surface.
BP21A recommends groundwater monitoring over a 12-month period to capture seasonal
variation.
There is no evidence that:
• 12 months monitoring has been undertaken.
• Basin performance takes account of high groundwater.
• Infiltration feasibility has been proven.
• Climate change allowances have been applied to groundwater conditions.
Allocation prior to completion of recommended monitoring is evidentially premature.
7.11 Topography and Potential Runoff Toward Existing At-Risk Properties
The site slopes from north to south toward Maes Lloi.
• Existing properties at Maes Lloi are largely within Flood Zone 3.
• Residents have noted drainage overload during wet periods.
• There is no evidence published that assesses whether the proposed development would
not worsen existing flood risks to surrounding properties
• No quantified runoff comparison between greenfield and developed sites is provided.
• No exceedance flow mapping is published.
Downstream impact risk has not been robustly assessed.
7.12 Failure to Apply Council Methodology
BP21A (p.13) states:
“the approach adopted by the Council within its assessment methodology was for flood risk to
be given the strongest possible weighting… sites identified to fall within areas of flood risk were
discounted from further consideration.”
This is unequivocal.
However, this site:
• Lies partially within Flood Zone 3.
• Has mapped intermediate surface water risk.
• Has groundwater classified “Red – High.”
• Has access within Flood Zone 3.
• Has a history of flooding (DEVELOPMENT ADVICE MAP Zone B)
• Requires Ministerial notification.
• Requires FCA and groundwater monitoring.
• Requires SUDs viability assessment
• Requires SSSI/ecology assessment
This represents a clear departure from the Council’s own stated methodology.
BP16 (p.20) states:
“Sites located within Zone 2 will only be considered where: It will assist, or be part of, a strategy
supported by the Development Plan to regenerate an existing settlement or achieve key
economic or environmental objectives or address national security or energy needs; AND • Its
location meets the definition of a brownfield site, And • Is supported by a FCA that indicates
that the potential consequences of a flooding event for the development proposed is found to
be acceptable in accordance with the criteria contained in section 11 of TAN 15 (2021).
Sites located within Zone 3 will only be considered where: • The development is required under
exceptional circumstances, as defined in TAN e.g. addressing national security or energy security
needs, reasons of public health or to mitigate the impacts of climate change, AND • Its location
meets the definition of a brownfield site, And • Is supported by a FCA that indicates that the
potential consequences of a flooding event for the development proposed is found to be
acceptable in accordance with the criteria contained in section 11 of TAN 15 (2021).”
This site is within Flood zones 2 and 3, is not brownfield, has no FCA, meets none of the
conditions in section 11, TAN 15 and is not required for exceptional circumstances.
The council do not appear to have followed any of these elements of methodology with regard
to flood risk.
7.13 Soundness Consequences
The allocation:
• Conflicts with TAN 15 Section 10.22.
• Does not meet Section 10.18 justification.
• Requires Welsh Government notification.
• Proceeds without any hydraulic model.
• Proceeds without FCA.
• Proceeds without groundwater monitoring.
• No-worsening test absent
• No SUDs viability assessment
• Contains mapping discrepancies.
• Defers critical evidence to application stage.
Accordingly, the allocation fails the soundness tests because it is:
• Not Justified – not based on robust, proportionate evidence.
• Not Effective – deliverability dependent on unresolved flood constraints.
• Not Consistent with national policy – specifically TAN 15 restrictions.

8 Infrastructure Constraints
8.1 Access Considerations
Indicative plans suggest that access to the proposed development may be provided from the
A4222 on the northern side of Aberthin. This would introduce an additional junction onto a
section of road that already contains numerous access points and turning movements. Given the
existing road layout and traffic conditions, the introduction of a further access point warrants
careful consideration in relation to highway safety.
The existing southern access route also presents constraints. It lies within Flood Zone 3, is
restricted in width, and cannot accommodate emergency vehicles safely. Flood events could
potentially affect access and egress, which may have implications for both existing and future
residents.
8.2 Existing Road Environment
The A4222 Maendy Road, which connects Cowbridge and Ystradowen through Aberthin, already
carries significant traffic volumes, including heavy goods vehicles. The road environment
includes several features that influence traffic movement and safety, including:
• a 90-degree bend over a bridge
• multiple side road junctions
• pub car park exits and private driveways accessing the road
• limited footpath provision and crossing points
• areas of reduced street lighting
These characteristics mean that drivers already navigate a relatively complex road environment
through the village.
Historic planning decisions also indicate sensitivity around access to this road. In 1978, South
Glamorgan County Council required the closure of the access from Skaife House onto the A4222
(Directly opposite the proposed new entrance), as part of planning consent for development at
The Spinney, Downs View Close, reflecting previous concerns regarding additional junctions
along this section of road (at a time with far less traffic).
8.3 8.3 Strategic Transport Policy Context
The RLDP is supported by BP14 – Strategic Transport Assessment Stage 1, which emphasises the
importance of locating development where sustainable travel options are available and where
the need to travel can be reduced. The assessment highlights the role of planning policy in
encouraging modal shift toward walking, cycling and public transport.
The Strategic Transport Assessment Stage 2 (BP14a) identifies capacity pressures within parts of
the local network. In particular, the Aberthin Road / Cardiff Road / St Athan Road / Eastgate
junction is recorded as operating beyond theoretical capacity during the AM peak period. This
indicates that parts of the local highway network already experience congestion during peak
travel times.
8.4 Car Dependency and Sustainable Transport
The Strategic Transport Assessment highlights that the Vale of Glamorgan has relatively high
levels of car ownership, with 83.4% of households owning one or more vehicles. In smaller rural
settlements such as Aberthin, limited public transport and no active travel infrastructure mean
that residents are likely to rely heavily on private vehicles.
The Vale’s active travel network is described within the transport evidence as limited and
fragmented in certain areas. Aberthin currently has:
• no designated Active Travel routes
• no proposed routes within the Active Travel Network Maps
• limited safe walking or cycling connections to nearby settlements such as Cowbridge
and Ystradowen, with narrow or missing footpaths and poorly lit sections.
An Active Travel scheme went through consultation but met with multiple objections. Some of
these are relevant to LDP planning elements, such as:
o The high volume and speed of traffic on the existing highways, predominantly the A4222
that runs directly through Aberthin
o A lack of segregated infrastructure in the area, which would force cyclists to share space
with cars in narrow sections.
o The lack of street lighting in the area, which made the route unappealing for use at night
or during winter.
o Concerns regarding installing lighting due to wildlife disruption
The project has been on hold for 3 years.
Public transport provision is also limited, with bus services operating approximately hourly,
ending in the early evening at 7.30, with no Sunday services. These factors may influence travel
patterns and increase reliance on private vehicles.
8.5 Cumulative Transport Considerations
As discussed earlier, extensive development has occurred and is still ongoing in the Cowbridge
Aberthin–Ystradowen corridor. These settlements are largely connected by the A4222 corridor,
which functions as the principal route linking the surrounding communities. The route already
accommodates traffic associated with existing settlements and recent development.
In this context, the cumulative impact of additional development along the corridor raises
considerations regarding traffic growth, junction capacity, road safety and infrastructure
demand. These factors may warrant careful evaluation when assessing additional rural
allocations, particularly where the transport evidence indicates existing pressures within parts of
the network.
8.6 Policy Considerations
Based on the transport evidence and local context outlined above, several policy considerations
arise.
8.6.1 Conflict with sustainable transport objectives
The Strategic Transport Assessment supporting the RLDP (BP14 and BP14a) emphasises the
importance of locating development where sustainable transport options are available and
where reliance on private vehicles can be reduced.
8.6.2 Infrastructure capacity and network pressures
Transport evidence identifies existing pressures within parts of the local highway network,
including peak-period congestion at key junctions serving the area. When considered alongside
recent and ongoing development within the Cowbridge–Aberthin corridor, the potential
cumulative effect of additional traffic generation may require further assessment to ensure that
local infrastructure can accommodate additional demand.
8.6.3 Consistency with the RLDP spatial strategy
Planning Policy Wales and the RLDP strategy emphasises directing development toward
locations with stronger accessibility to services, facilities and sustainable transport networks. As
a small rural settlement with limited transport connectivity, the role of Aberthin within this
spatial strategy may require careful consideration when assessing the suitability of additional
housing allocations.
8.7 Education capacity
The Council’s education evidence (BP43 Education) confirms that secondary education provision
serving the Cowbridge area is already under pressure.
Appendix F of BP43 identifies that Cowbridge Comprehensive School will require an additional
177 places to accommodate projected demand generated by RLDP growth.
BP43 uses the following pupil yield formula:
• Primary: Dwellings × 0.278
• Secondary: Dwellings × 0.208
Applying this to a development of 20–30 dwellings at Aberthin would generate approximately:
• 6–8 primary pupils
• 5–6 secondary pupils
• approximately 1 Additional Learning Needs (ALN) pupil
BP43 also confirms that ALN provision across the authority is already under pressure.
The Aberthin allocation therefore adds additional pupil demand to an already constrained
education system.
Given that the RLDP already provides 8,660 dwellings against a requirement of 7,890 (a surplus
of 770 dwellings) and affordable housing delivery is already secured through larger strategic
allocations, the additional education demand created by HG4(2) Aberthin is unnecessary for the
delivery of the Plan’s housing strategy.
9 Landscape, Settlement Edge, Hedgerow Protection, Public Right of
Way, Conservation Area and Nearby SSSI
9.1 Landscape and heritage setting sensitivity
The proposed allocation HG4(2) – Land West of Maendy Road, Aberthin lies wholly within a
Special Landscape Area (SLA) designated by Vale of Glamorgan Council. Special Landscape Areas
identify landscapes of locally significant character and visual quality, and planning policy
requires development within such areas to conserve and enhance landscape character and
avoid unnecessary harm to valued landscapes.
The site comprises open agricultural land immediately west of Aberthin, forming part of the
rural valley landscape associated with the Nant Aberthin corridor and contributing to the wider
countryside setting of the village and surrounding landscape extending toward Cowbridge.
Key landscape characteristics include:
• open pastoral farmland typical of the Vale of Glamorgan landscape
• strong hedgerow field boundaries reflecting historic field patterns
• visual connection with the Nant Aberthin valley landscape
• a continuous mature hedgerow along the western boundary running north–south
This hedgerow forms a defining landscape feature, contributing both to the historic field
structure of the landscape and to ecological connectivity.
The existing development along Maendy Road forms a clear and well-defined rural settlement
edge to Aberthin. The proposed site lies beyond this edge and currently reads as open
countryside rather than part of the village. Development of approximately 25 dwellings would
extend the built form westwards into open farmland, resulting in:
• encroachment of residential development into countryside
• erosion of the clear distinction between settlement and rural landscape
• urbanisation of the existing rural settlement edge.
These changes would be particularly sensitive given the site’s location within a Special
Landscape Area.
The site also forms part of the wider setting of the Aberthin Conservation Area, which protects
the historic character and appearance of the village under the Planning (Listed Buildings and
Conservation Areas) Act 1990. Aberthin is characterised by traditional stone cottages, a compact
historic form and a strong relationship with the surrounding countryside. The open farmland
west of the village contributes to this rural setting and historic landscape context. Development
of the site would extend the built form into land that currently forms part of that setting,
potentially altering the way the historic settlement is experienced within the surrounding
landscape.
The site is also located close to Cors Aberthin SSSI, a designated Site of Special Scientific Interest
recognised for its wetland habitats and ecological importance within the Nant Aberthin valley
system. SSSIs are protected under the Wildlife and Countryside Act 1981, and planning policy
requires that development should avoid Development Advice Mapage to their special scientific
interest and associated ecological systems.
The proximity of the allocation to Cors Aberthin SSSI reinforces the environmental sensitivity of
the wider landscape, particularly in relation to:
• hydrology and water movement within the valley
• ecological connectivity through the Nant Aberthin corridor
• protection of surrounding habitats that contribute to the ecological functioning of the
SSSI.
9.2 Significance and protection of the boundary hedgerow
The continuous hedgerow running along the western boundary of the site is likely to be of
considerable ecological, historic and landscape value.
Hedgerows of this type in the Vale countryside commonly:
• form part of historic field boundaries
• provide habitat corridors for birds, bats and small mammals
• contribute significantly to the traditional landscape character of the Vale of Glamorgan
Such hedgerows may qualify as “Important Hedgerows” under the Hedgerows Regulations 1997.
Where a hedgerow meets the criteria set out in these Regulations:
• removal requires formal consent from the local authority, and
• if the hedgerow is classified as important, consent for removal must normally be
refused.
Removal of an important hedgerow without permission constitutes a criminal offence.
Given the continuous north–south structure of the boundary hedgerow and its role in the
historic field pattern, there is a realistic possibility that the hedgerow would meet the criteria for
protection.

9.3 Public Right of Way and proposed realignment
A Public Right of Way (PRoW) currently crosses the site through open agricultural land, forming
part of the rural footpath network around Aberthin. In its current form the route is experienced
as a traditional countryside path, crossing open farmland with clear visibility and an open rural
character.
However, the indicative layout associated with the allocation appears to show the path diverted
along the western boundary of the site, coinciding with the existing hedgerow. The proposed
layout indicates:
• rear residential gardens backing onto the path
• tree planting along the boundary
• the route positioned between housing plots and boundary vegetation.
9.3.1 Loss of rural character and safety concerns
This realignment would fundamentally alter the character of the route. Instead of crossing open
countryside, the diverted path would form a long, narrow corridor along the edge of the
development. The path would therefore be experienced as a confined passage rather than an
open countryside route, raising concerns regarding:
• loss of the rural character of the right of way
• reduced visibility and openness
• personal safety for walkers.
The arrangement would effectively create a long-enclosed route resembling an alleyway,
particularly where gardens back directly onto the path. These concerns are amplified by the
likelihood that the route would remain unlit, as public rights of way across rural land are rarely
provided with lighting, particularly within Special Landscape Areas where lighting may conflict
with policies protecting rural character and dark skies.
The resulting route would therefore be a long, narrow and potentially unlit corridor, raising
further safety and amenity concerns.
Length of enclosed
alleyway
9.3.2 Legal implications of diversion
Any diversion of a Public Right of Way requires a legal order under the Highways Act 1980.
To be confirmed, such an order must demonstrate that:
• the diversion is necessary to enable the development, and
• the alternative route is not substantially less convenient or less enjoyable for the public.
Replacing a path that currently crosses open countryside with a route running along the edge of
housing development may therefore attract objections from users, residents or rights-of-way
groups, potentially preventing confirmation of the diversion order.
9.4 Interaction between the path diversion and hedgerow removal
The proposed diversion appears to coincide directly with the existing boundary hedgerow,
suggesting that the development may require removal or substantial alteration of this hedgerow
in order to accommodate the path and housing layout.
If the hedgerow qualifies as an Important Hedgerow under the Hedgerows Regulations 1997, its
removal may be legally restricted or refused, creating uncertainty regarding whether the layout
assumed by the allocation could be implemented.
9.5 Implications for site deliverability
The allocation therefore appears to depend upon:
• diversion of an existing Public Right of Way,
• possible removal or alteration of a potentially protected hedgerow, and
• development within an SLA and sensitive landscape setting closely associated with the
Cors Aberthin SSSI and Nant Aberthin ecological corridor.
Each of these matters involves separate legal and environmental considerations, none of which
can be assumed to be achievable at the plan allocation stage.
If the diversion were refused, or if removal of the hedgerow were not permitted, the layout
assumed by the allocation may not be achievable in practice.
9.6 Conclusion
The allocation of HG4(2) would introduce residential development into open countryside within
a designated Special Landscape Area, extending the settlement edge of Aberthin into land that
currently contributes to the village’s rural setting and the wider setting of the Aberthin
Conservation Area.
The site contains a continuous boundary hedgerow likely to be of significant landscape and
ecological value, which may qualify for protection under the Hedgerows Regulations 1997.
The indicative layout also proposes diverting an existing Public Right of Way from its current
route across open farmland to a narrow boundary corridor running between residential gardens
and boundary planting, fundamentally altering the character of the route and raising safety and
amenity concerns, particularly as the path would likely remain unlit.
The site also lies close to Cors Aberthin SSSI, further highlighting the environmental sensitivity of
the surrounding landscape.
Taken together, these factors raise serious concerns regarding landscape impact, heritage
setting, environmental sensitivity, legal constraints and the practical deliverability of the
allocation, particularly given that the Plan already provides sufficient housing supply without
reliance on development of this sensitive site.

10 Plan Soundness and potential Misapplication of Policy HG4
10.1 Affordable Housing Exception Policy Must Operate Within National Policy
Policy HG4 allows for small-scale affordable housing-led development in Minor Rural
Settlements, reflecting the Welsh Government policy approach to rural exception sites.
However, such policies are intended to operate within the framework of the Plan’s spatial
strategy, not to override it.
Affordable housing exception mechanisms are designed to allow limited, carefully justified
departures from the normal settlement boundary approach where local need is demonstrated
and cannot otherwise be met. They are not intended to provide a general mechanism for
allocating greenfield housing sites in rural settlements.
The allocation of Site 2299 appears to rely on HG4 as the primary justification for development,
rather than demonstrating that the site aligns with the broader spatial strategy and site
selection methodology of the Plan.
PPW (12) allows rural affordable housing through exception mechanisms, but only where
certain conditions are met.
• small-scale
• genuinely local need (not demonstrated in Aberthin)
• proportionate to settlement size (2299 is disproportionate estate scale development)
• does not undermine settlement strategy (outside strategic growth and sustainable
areas)
Development Plans Manual (Edition 3) states that site allocations should:
• flow from the spatial strategy
• follow the site search sequence
• be supported by a transparent assessment process
In other words:
Strategy → site selection → allocation
In the case of site 2299 the order appears reversed:
Site promoted → affordable housing justification → boundary expanded → allocation.
That is the type of site-led planning the manual warns against.
10.2 HG4 Overrides the Plan-Led Site Selection Process
The evidence in the Candidate Site Assessment indicates that the site has been taken forward
solely on the basis that it could deliver affordable housing and there is no indication that the
assessment methodology has been carried out
This approach effectively allows HG4 to override the wider plan-making framework, including:
• the settlement hierarchy,
• the spatial distribution of housing growth,
• the requirement to prioritise sustainable locations, and
• the established methodology for identifying appropriate development sites.
This creates a policy loophole whereby any countryside site adjacent to a minor rural settlement
could potentially be justified simply by proposing affordable housing. This risk appears to have
been realised. HG1, 3 and 4 were all rejected according to the assessment methodology but
resubmitted as affordable led upon guidance: “but the site could be reconsidered as a small
scale affordable housing led development”.
HG4(2) Aberthin was previously rejected in the 2011-2026 LDP then crucially did not go through
the normal assessment process but went straight to allocation as affordable-led. This creates a
precedent for any candidate site, including those previously rejected to be submitted as
affordable-led and potentially be allocated without robust assessment.
Such an approach undermines the plan-led system and the spatial strategy on which the RLDP is
based.
10.3 Lack of Evidence That the Site Is Necessary to Deliver Affordable Housing
The justification for the site relies on reference to the Local Housing Market Assessment
(LHMA), which identifies a need for additional affordable housing within the relevant ward of
Cowbridge.
However, the existence of an identified need does not in itself justify the allocation of specific
countryside sites.
The RLDP must demonstrate that:
1. the affordable housing requirement cannot be met within the overall housing supply,
and
2. the proposed site represents the most appropriate and sustainable location to
contribute to meeting that need.
Neither has been demonstrated.
As previously discussed, the RLDP already provides a significant surplus of housing provision
over the housing requirement, including substantial capacity within more sustainable
settlements.
In these circumstances, the allocation of a countryside site solely on the basis of affordable
housing provision i.e. HG4 exception, is not justified.
10.4 Soundness Implications
For a Local Development Plan to be sound it must be:
• Justified – based on a robust and credible evidence base and the most appropriate
strategy.
• Consistent with national policy.
• Effective and deliverable.
The reliance on Policy HG4 as the primary justification for Site 2299 raises concerns in respect of
all three tests.
In particular:
• Justified: The evidence base does not demonstrate that the site is necessary to deliver
the Plan’s housing or affordable housing objectives, or that there is any evidenced need
in Aberthin
• Consistent with National policy: The allocation does not appear to arise from a
consistent application of the spatial strategy or site selection methodology and does not
take account of flood risks in accordance with policy. The approach risks undermining
the plan-led system by allowing countryside sites to be allocated solely on the basis of
affordable housing provision.
• Effective and Deliverable: The number of constraints lack mitigation evidence, e.g. no
FCA, SUDs assessment, overall site viability assessment and other missing assessments,
the limited infrastructure of the area is not mitigated, and only summary financial
viability is provided, and this has discrepancies
For these reasons, the allocation of Site 2299 using HG4 cannot be considered justified or sound.

11 Conflicts with methodology, shifts, audit trail concerns and gaps
11.1 Candidate Site Assessment Methodology (BP16)
11.1.1 Site Assessment Criteria Outcomes
Site 2299 has been assessed against 35 criteria within the candidate site assessment framework.
Of these, 12 criteria are recorded as green (no identified constraints to development). Four
criteria are marked as red, which represent the most significant level of concern, typically
indicating a major constraint to development, potential conflict with national policy, or
insufficient information to support the assessment.
A review of the scoring suggests that some classifications may warrant further consideration, as
below, and may increase red scores to 6. A site could be rejected on the basis of a single red
score (p10).
11.1.2 Potential Issues in the Scoring
11.1.2.1 Environment and Physical Constraints
The site is recorded as Amber under the category of Environmental and Physical Constraints.
However, part of the site lies within Flood Zone 3 and therefore appears to engage the
requirements of Technical Advice Note 15 (TAN15), specifically the Justification Test and
Acceptability of Consequences tests set out in Sections 10 and 11.
Guidance provided in Background Paper BP16 (page 20) states that sites located within Flood
Zone 3 will only be considered where specific criteria are met. These include:
• The development is required under exceptional circumstances, such as those relating to
national security, energy security, public health, or climate change mitigation.
• The site meets the definition of previously developed (brownfield) land.
• The proposal is supported by a Flood Consequences Assessment (FCA) demonstrating
that the potential consequences of flooding are acceptable in accordance with the
criteria contained within Section 11 of TAN15 (2021).
In the case of Site 2299:
• No exceptional circumstances have been identified.
• The site is greenfield rather than previously developed land.
• No evidence has been presented demonstrating compliance with the acceptability of
consequences test.
Further, on page 7 of the guidance:
“Flood risk – sites located within either a TAN 15 Defended Area, or Flood Zone 2 or 3 area which
do not meet the justification test and acceptability of consequences section 10 and11 out in TAN
15 will not pass the initial sifting.”
In light of these factors, the classification of Amber within this category is surprising, as it
appears the site should have not have even passed initial sifting.
11.1.2.2 Landscape Considerations
The site is also scored Amber under the Special Landscape Area criterion. However, the scoring
guidance indicates that a site should be classified as Red where it is predominantly greenfield
and wholly located within a Special Landscape Area or a Registered Landscape of Outstanding or
Special Historic Interest.
Site 2299 is identified as greenfield land and lies entirely within a designated Special Landscape
Area. Based on the stated scoring methodology, this suggests that a Red classification could be
more consistent with the guidance provided.
11.1.3 FCA requirement
On page 22 the FCA requirement and discounting rule is clear:
“Sites which are not accompanied by a FCA or do not meet the tests shall be automatically
discounted from further consideration.”
Site 2299 does not have an FCA, so should have been discounted.
11.2 Deposit assessment audit-trail concerns (BP18A) and unexplained shifts
Inconsistencies in the deposit candidate site assessment narrative are noted:
• BP18A p.14 describes the site 2299 as conforming with strategy/initial filter and uses
language indicating it is ‘adjacent’ to the settlement; later narrative suggests it is ‘in’ the
settlement without a published boundary justification.
• BP18A p.20 notes ‘suitable for further consideration’ while listing constraints without
explaining why those constraints did not prevent progression under BP16.
• BP18A p.34 significantly downplays flood risk (references only a part in Flood Zone 3) and
does not reflect mapped intermediate surface water risk covering around half the site,
historical flood data and ground water risk.
• BP18A p.77 contains a ‘Acceptable at PS stage’ recorded as “N/A” for site 2299 and a
‘Justification’ field recorded as “N/A” for site 2299, which undermines transparency.
• BP18A also indicates that detailed site proformas exist and are available on request. The
Council should disclose the full Site 2299 proforma used for decision-making, including RAG
scoring rationale and any override decisions.
• BP18A p.34 – indicates a viability assessment has been submitted for site 2299 which
demonstrates that the site is deliverable as an affordable housing led site. Only a summary
table has been published, which appears to under cost, and may need validating in light of
flood risks, SUDs viability, no sewerage on site, and contributions to education and
infrastructure costs cited elsewhere.
11.3 Independent viability evidence gap and deliverability risk (BP42A)
• BP42A (December 2025) provides Independent Financial Viability Assessments of five
strategic/key sites. Site 2299 is not included. Planning Policy Wales (PPW 12) directs
that: “as part of demonstrating the deliverability of housing sites, financial viability must
be assessed prior to their inclusion as allocations in a development plan. At the
‘Candidate Site’ stage of development plan preparation, land owners/developers must
carry out an initial site viability assessment and provide evidence to demonstrate the
financial deliverability of their sites.”
• BP42A states it is concerned with financial viability only and not broader constraints.
• Site 2299 is not a low-risk site; it is flood constrained, and requires a robust
management plan, SUDs viability needs testing (extending to SSSI implication), requires
full new sewage/drainage infrastructure, has access uncertainties and SLA landscape
constraints. These drive abnormal costs. Without site-specific viability testing,
deliverability and affordable housing delivery cannot be assumed.
• Site 2299 has viability tension: as abnormal costs rise (flood mitigation, SuDS,
groundwater management, highway works, sewage/drainage installation and potential
off-site reinforcement), affordable housing delivery is typically the first pressure point.
The RLDP must evidence deliverability for this site, not assume it.

12 Tests of soundness
For the RLDP to be sound it must be Justified, Effective and Consistent with National Policy.
12.1 Not Justified
The allocation is not supported by proportionate evidence:
• the RLDP already provides 770 dwellings above the housing requirement
• the site contributes only 0.42% of projected affordable housing delivery
• no specific local affordable housing need has been demonstrated within Aberthin
• the site conflicts with the spatial strategy which limits growth in Minor Rural
Settlements
• the allocation represents a departure from the Council’s own site assessment
methodology
• the allocation lacks a transparent audit trail
• does not demonstrate why this constrained countryside site is the most appropriate
option, particularly given delivery elsewhere in the corridor and strategic sites
12.2 Not Effective
The site cannot be shown to be deliverable because:
• significant flood risk constraints remain unresolved
• no Flood Consequence Assessment has been undertaken
• groundwater monitoring recommended in the evidence has not been completed
• the SuDS strategy has not been demonstrated to be viable
• potential impacts on Cors Aberthin SSSI hydrology have not been assessed
• no-worsening test absent
• access, drainage and infrastructure constraints remain uncertain
• viability is not independently tested or fully costed
12.3 Not Consistent with National Policy
The allocation conflicts with Technical Advice Note 15 (Flood Risk) because:
• the site partly lies within Flood Zone 3
• residential development is highly vulnerable development
• TAN15 states such development should not occur on greenfield land in Flood Zone 3
unless essential to the LDP
• the RLDP already contains a substantial housing surplus, meaning the site cannot be
considered essential
12.4 Conclusion
For these reasons the allocation of HG4(2) – Land West of Maendy Road, Aberthin cannot be
considered sound.
The site should therefore be removed from the RLDP.
10.3 Not consistent with national policy: the allocation conflicts with national objectives for
sustainable location and robust flood risk management (including safe access/egress and no
worsening).

13 Formal request and proposed modifications
1. Primary request: delete Site 2299 from the RLDP and remove it from Policy HG4.
2. Settlement boundary: do not redraw the Aberthin settlement boundary to include this
field parcel; if already redrawn, reinstate the defensible boundary aligned to existing
built form unless a published boundary review justifies change.
Evidence disclosure requests (minimum):
a. Robust evidence qualifying necessity under HG4, aligned to national policies
b. Full Site 2299 proforma (BP18A indicates proformas exist and are available on
request), including all scoring and override rationale.
c. Full FCA including modelling outputs, assumptions, and climate change
allowances for both fluvial and pluvial events, surface runoff from surrounding
slopes, high groundwater susceptibility, principal aquifer conditions, cumulative
testing, implications on the nearby SSSI wetland habitat, ecology assessment
and no worsening test.
d. Surface water modelling demonstrates intermediate risk treatment, exceedance
routing and no worsening.
e. The advised 12-month Groundwater monitoring and data
f.
SuDS feasibility and design, including implications on the nearby SSSI and
ecology.
g. Drainage strategy demonstrating foul connection feasibility, capacity, and any
required off-site reinforcement.
h. Dry access/egress assessment for residents and emergency vehicles during flood
events.
i.
j.
Highways feasibility: access location, visibility, swept-path tracking and road
safety audit.
Active travel and public transport assessment with deliverable mitigation
package and funding mechanism.
k. Landscape/visual assessment for SLA impacts.
l.
Ecology and heritage appraisals including SSSI proximity and Conservation Area
setting.
m. Site-specific viability appraisal (including all abnormal costs) demonstrating
affordable housing deliverability.
3. Confirmation regarding protection of hedgerow
4. Confirmation regarding PRoW

Changes to plan
1. Primary request: delete Site 2299 from the RLDP and remove it from Policy HG4.
2. Settlement boundary: do not redraw the Aberthin settlement boundary to include this
field parcel; if already redrawn, reinstate the defensible boundary aligned to existing
built form unless a published boundary review justifies change.
Evidence disclosure requests (minimum):
a. Robust evidence qualifying necessity under HG4, aligned to national policies
b. Full Site 2299 proforma (BP18A indicates proformas exist and are available on
request), including all scoring and override rationale.
c. Full FCA including modelling outputs, assumptions, and climate change
allowances for both fluvial and pluvial events, surface runoff from surrounding
slopes, high groundwater susceptibility, principal aquifer conditions, cumulative
testing, implications on the nearby SSSI wetland habitat, ecology assessment
and no worsening test.
d. Surface water modelling demonstrates intermediate risk treatment, exceedance
routing and no worsening.
e. The advised 12-month Groundwater monitoring and data
f.
SuDS feasibility and design, including implications on the nearby SSSI and
ecology.
g. Drainage strategy demonstrating foul connection feasibility, capacity, and any
required off-site reinforcement.
h. Dry access/egress assessment for residents and emergency vehicles during flood
events.
i.
j.
Highways feasibility: access location, visibility, swept-path tracking and road
safety audit.
Active travel and public transport assessment with deliverable mitigation
package and funding mechanism.
k. Landscape/visual assessment for SLA impacts.
l.
Ecology and heritage appraisals including SSSI proximity and Conservation Area
setting.
m. Site-specific viability appraisal (including all abnormal costs) demonstrating
affordable housing deliverability.
3. Confirmation regarding protection of hedgerow
4. Confirmation regarding PRoW