Explosive ordnance surveying in Düsseldorf

The historical aerial photograph analysis must be read with its guidance and the application area. For a follow-up discussion, it should be clear which task has already been processed officially and which decision remains outstanding. A street name or proximity to the Rhine does not replace site-specific assessment.

For the investigation working map, the Düsseldorf guideline specifies a scale of 1:500 to a maximum of 1:1000. The investigation area is marked in colour, its area stated and adjacent roads labelled. Information in the application, working map and on-site setting out must match. If the excavation changes, therefore do more than pass on the new drawing: also identify the old boundary it replaces. Existing communications and their appendices remain the reference for comparison. Specific execution is prepared using applicable local requirements.

For a proposed survey, the specific interventions and existing installations must be considered. Specialist foundation engineering may involve questions different from an area investigation. Whether supplementary privately commissioned activities are permissible and suitable must be clarified using state-specific legal requirements and the investigation task.

The guideline distinguishes preparation of a specific suspected unexploded bomb point from preparation of an area investigation. Permissible and necessary works are determined for each case. Post-war fill is recorded by origin and thickness. If its date of origin remains unclear despite research, this is stated in the application with the underlying information used. Where different investigation levels are needed, their positions, sizes and elevation references are agreed before implementation. Building records, historical photographs, aerial photographs or existing geological investigations help distinguish today’s surface from earlier ground levels.

A specialist supervision service during construction is not an option solely because of time pressure. State-specific legal conditions and necessary coordination must be observed. It does not replace a prior investigation that remains possible. Merely watching excavation is not sufficient for proper explosive ordnance clearance during construction.

The current guideline requires dated photographs showing the prepared condition, area markings and, where applicable, marked utilities. Completed works are related to the date the photographs were taken. If rain, a new storage area or additional machinery use changes the area, compare the current condition with the agreed requirements again. Following measurement data acquisition, the investigated area remains untouched until the results report in accordance with local requirements. Measurement, assessment and any further checking of anomalous locations are different work steps; only the results status handed over is compared with the proposed execution.

For retained infrastructure, describe actual utility alignments and accessible working areas. Operational closures, ownership boundaries and necessary access to neighbouring property require organisational clarification. The measurement areas needed and permissible preparatory works are compared with existing buildings and utilities. Remaining obstacles are explicitly identified in plans and coordination. Necessary structural support for neighbouring buildings may influence the investigation sequence; any change required is clarified with the KBD through the fire service and justified using the corresponding plans and necessary clearance concept.