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Historic Gardens 2010
BCD Special Report
It is important to remember that too
much pond vegetation can have a detrimental
impact and can cause undesirable chemical
changes such as daily oxygen depletion.
Ideally, a pond with approximately 35 per
cent open water and 65 per cent vegetation
cover during late summer is recommended,
as some species require areas that are
relatively plant-free. Newts for example
need areas of open water to mate.
Broadleaved trees and shrubs on the
margins of ponds can be both desirable and
detrimental. Many aquatic invertebrates
feed on decaying organic matter and the
input of small amounts of deadwood and
leaves from bank-side trees is desirable. In
addition, trees on the north side of a pond
can be beneficial because they shelter the
pond surface and keep areas ice-free, allowing
wildfowl such as diving ducks to forage.
However, too many bank-side trees will
shade the surface of the pond and restrict
aquatic plant growth and excessive input
of dead leaves can rapidly increase water
acidity and accelerate the rate of infill.
ponds in historic landscapes
In historic landscapes, estate managers will
often be expected to manage ponds primarily
for their ornamental appeal, but this does not
need to conflict with ecological management.
For example, many of the techniques
employed to maintain the aesthetic appeal
of ponds, such as clearance of emergent
vegetation, can also benefit wildlife.
In a short article it is not possible to
cover all aspects of pond management
techniques, but the Brackenhurst case study
which follows covers many of the generic
issues and solutions for restoring and
managing a pond of significant ecological,
historical and cultural importance.
Discussions with English Heritage during
the late 1990s identified the dew pond and
its associated features as a high priority for
restoration and work began in March 2001.
By this time the dew pond was usually dry
in summer, choked with tall reeds and partly
infilled at the east end, which had isolated
the boathouse from the pond. However, the
restoration was not straightforward because,
a year before the work was due to start,
biological surveys identified the presence
of great crested newts in the gardens.
The presence of the newts required the
restoration work to be carried out under a
conservation licence from English Nature
(now Natural England). In order to obtain a
licence it was necessary to demonstrate that
the work would be of benefit to the newts.
Clearly the provision of a restored 150m
2
breeding pond would be a conservation
gain for newts, but horticultural staff raised
concerns about the constraints of managing
the gardens, given the presence of a
protected species. Concerns were addressed
by the preparation of an action plan which
minimised the risk of harming newts and
enabled the gardens to be managed without
undue constraints. Although many ponds
will not contain newts or protected species,
this example confirms the importance of
carrying out biological surveys and historical
research before restoring a pond or resuming
pond management in historical landscapes.
The restoration work required tracked
excavators to remove vegetation and soils,
and to restore the original profile. The
The drawing shows a cross-section of a typical dew pond.
The straw and lime layers are flexible and protect the
impermeable layer of puddled clay from damage by grazing
livestock. (Source unknown)
Brackenhurst Hall and dew pond in the early 1930s
(Photo: Nottingham Trent University Archives)
The rose-garden pond at Brackenhurst Hall in the 1930s
(Photo: Nottingham Trent University Archives)
The dew pond at Brackenhurst Hall, which was constructed in 1928, is a fine example of a pond with significant ecological
and historical value in a formal garden setting. (Photo: Neville Davey)
Brackenhurst Hall Dew Pond
The 200ha Brackenhurst Estate is
approximately 1.5 miles to the south of
Southwell in Nottinghamshire. The estate
includes the 18th century, Grade II-listed
Brackenhurst Hall, gardens and parkland.
The hall and its grounds have been used
as an agricultural college for over 60 years
and in 1999 merged with Nottingham
Trent University. The hall is now home
to the university’s School of Animal,
Rural and Environmental Sciences, and its
gardens are managed by the university’s
estates department and horticulture
staff at the Brackenhurst campus.
In 1928 the gardens were landscaped in
the style of Sir Edwin Lutyens, including an
Italianate courtyard, a sunken Dutch garden,
rose garden, Japanese rock garden and a
teardrop-shaped dew pond that was partly set
in ornamental woodland, with a boathouse
and ‘willow pattern’ bridge. Water collected
from the roof of the hall was fed through a
drainage system to supply water to the dew
pond and small stone-lined ponds located in
the formal garden areas. Excess water drained
out of the system via outflow pipes into the
ha-ha that still surrounds the gardens.
The dew pond was of particular historical
interest because of its traditional design
and construction, a feature not commonly
found in Nottinghamshire. Although the dew
pond was primarily designed as an attractive
feature, its close proximity to the hall ensured
a useful source of water in event of a fire.
Prior to its merger with Nottingham Trent
University, a lack of resources during the latter
half of the 20th century led to some of the
garden features falling into a state of neglect.
Fortunately, the development of horticultural
courses on the campus provided the expertise
and labour to start to restore the gardens.
Natural
ground level
Top water level
Average depth 3–6
6 layer of straw
2 layer of lime
Top layer of selected
material
Impervious layer of
puddled clay