Aerial Archaeology in Ireland - The Heritage Council

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Pipelines
The general principles that apply to roads were developed and continue, in principle, to apply to pipelines. The provisions of the
archaeological code of practice for new pipelines, drawn up in recognition of the need for major new pipelines between Mayo,
Galway, Limerick and Dublin, are almost identical to those for roads (Bord Gáis undated). However, respondents comment that
because the scale and impact of pipelines are less than other major linear developments like roads, and the scope for minor
diversions greater, there tends to be less emphasis on the use of aerial photographic reconnaissance as a standard procedure, at
least on the smaller schemes.
Minerals
There are now similar guidelines for archaeological reconnaissance for minerals, issued with the Irish Concrete Federation in
relation to aggregates (Irish Concrete Federation and DAHGI 2002). The purpose of this code is to provide a consistent framework
within existing legislation and regulations to enable ICF members to maintain the supply of development materials while having
appropriate regard for archaeology (Figures 48, 49).
The code also provides for the appointment of a Project Archaeologist to manage archaeology within the industry, and like
others mentioned above, it refers to the value of aerial photography. In effect, the code represents the industry’s recognition
that it is in the interest of both the public and the industry to minimise the risks and unexpected costs that can arise from
archaeology. Dr Charles Mount, the ICF archaeological officer, explains this as follows:
‘Proposals for new quarries and new land acquisitions are vetted by the ICF for their members on a
confidential basis, pre-purchase, to assess the likelihood of encountering archaeology. Members are
encouraged to avoid acquisitions with known sites and monuments, and the attendant risks, planning
difficulties and costs are outlined. Indicative surveys would be useful, but the ICF does not have a
mechanism for funding work that is industry based, only member-based.’
Section 261 of the 2000 Planning Act established a Register of quarries, bringing all quarries into the planning process for the
first time. In relation to quarries predating 1 October 1964, the local authorities have the option to require them to apply for
planning consent with an Environmental Impact Assessment if they are over 5ha, are likely to have a significant environmental
effect, or if they are located in an area subject to a European designation. Quarries in operation for less than seven years which
have not received planning permission should be subject to the full planning process, including the preparation of an EIA. For
quarries with planning permissions more than five years old, local authorities have the option to restate, modify or impose
conditions. The GSI carries out geologically based Mineral Potential Mapping which assists industry and local authorities alike to
plan for future quarrying of commercially valuable aggregates and other minerals.
As with other large-scale developments, EIAs for individual mineral extraction schemes may occasionally incorporate purposive
archaeological aerial photography as part of the site assessment process, but this is by no means always the case. In any event,
success may depend heavily on seasonality and weather conditions, especially in relation to soil- and cropmarks in arable areas
subject to exploitation for aggregates (e.g. Figures 33, 34, 35, 49).
The archaeological potential of mineral-rich areas (whether for aggregates, hardrock or specialist minerals) is well established, as
is the value of both low-level oblique photography and low/medium-level vertical photography for recording previously unknown
earthworks and soil- or cropmarks (see above). Cropmark evidence is especially important for locating buried archaeological sites
on river gravels and limestones that are both well-drained and fertile, and which have long attracted agricultural settlement.
This can raise specific research opportunities. For example, Dr Mount notes that
‘One promising area [involves] twelfth and thirteenth century manors which have been ploughed for arable
for up to 800 years, especially in Leinster, so that practically all earlier archaeology has been removed
by deep ploughing. With the changes in land ownership which accompanied the Act of Settlement (1653)
and the Williamite confiscations (1690-1703), the medieval remains have been ploughed up as well. Often
these are sited on exactly the aggregate deposits that the industry requires.’