Technical map view of the Kassel administrative district with Kassel marked for explosive ordnance assessment and surveying by FONTANA-EOD

Explosive ordnance surveying for your Kassel construction project

For new groundworks in Kassel, project owners, design practices and site managers need a traceable comparison of existing reports with the current intervention. FONTANA-EOD supports review of the records and the agreed supplementary explosive ordnance investigation. Send us maps, official statements, complete survey reports and the current site plan so that areas, depths and outstanding tasks can be defined.

Existing records

Collect the complete maps, evaluations and survey reports.

New groundworks

Show new structures and groundworks depths on the plan.

Supplementary work needed

Identify missing information and unresolved areas.

Review existing records for your projectExplosive ordnance assessment in Hesse
Assess the construction project

Read existing reports for their actual purpose

For your Kassel project, we check which question an existing report answers and which area it covers. Ground-penetrating radar, historical maps and technical explosive ordnance investigations are assessed according to their respective purposes. This establishes which information is still needed for the planned groundworks.

Project references

Selected project examples

Project site

Connect the site with the specific construction task

Schematic map with a coat of arms and state colours, alongside a tablet, safety helmet, pen and notebook.

Identify Kassel and the specific project location

The explanatory statement for Weserstraße 2B describes the ground-penetrating radar investigation in the context of archaeological questions. Its separate explosive ordnance section addresses a different investigation need. Reports in your project file are likewise assessed according to their actual purpose. A technical method name alone does not replace comparison of the commission, area investigated and conclusion needed for your construction project.

Kassel is an independent city in the Kassel administrative district in Hesse, Germany. For the enquiry, state the actual project address and proposed intervention. For projects in Innenstadt, Vorderer Westen, Bad Wilhelmshöhe, Wehlheiden, Bettenhausen, Waldau, Harleshausen, Nord-Holland or Oberzwehren, the respective previous records and local working conditions are considered. Enquiries from Vellmar, Lohfelden, Baunatal, Kaufungen, Fuldatal or other municipalities in North Hesse identify the actual municipality. Responsible authorities are determined from the project location and respective technical task.

Hesse
Local context

Distinguish a ground-penetrating radar report from an explosive ordnance assessment

Read the Weserstraße example for its investigation tasks

For the planned new building at Weserstraße 2B, ground-penetrating radar was used to investigate possible historical structural remains. The explanatory statement for Development Plan I/22 dated 21 February 2025 describes this investigation in the context of heritage protection. In its separate “Explosive ordnance” section, it identifies a suspected point from aerial photograph evaluation and requires its investigation before work disturbing the ground. The investigation of structural remains and required explosive ordnance assessment serve different purposes here. These statements concern the plan area described there. For an existing ground-penetrating radar report for your own project, therefore, first check whether the investigation commission included the explosive ordnance question at all and which area and depth the report covers.

The explanatory statement also requires systematic investigation of the groundworks areas described there before demolition, construction and ground investigation activities. This requirement applies to that plan area. For another project, its own underlying information and the intervention actually proposed are assessed. An earlier report is accompanied by its complete commission and plans so that its conclusions can be technically assessed for the new task.

Keep official information and technical findings distinct

For official explosive ordnance matters, the explosive ordnance clearance service at Darmstadt Regional Council is responsible throughout Hesse. It describes research using Allied wartime aerial photographs followed by an official statement. In the project file, distinguish the official statement, other historical material and reports of technical investigations actually carried out.

The City of Kassel recalls the air raid of 22 October 1943 and severe destruction across the city. It also describes Kassel’s importance as an armaments production centre and subsequent reconstruction. For a current construction task, available historical indications are assigned to the specific property. Known changes caused by rubble clearance, filling, new construction or infrastructure work are considered. Information about industrial, storage and railway sites, bridges or underpasses remains connected to its respective area and history of use; the actual technical clarification needed follows from this.

Working together

Allocate tasks within the construction project

Client and operator

The client describes the project and provides the available project documents. The operator adds requirements relating to use, access and scheduling. The participants agree their respective tasks and decision-making responsibilities. A coordinating contact person brings the project information together. Before an appointment, it is recorded clearly which information is missing, who will obtain it and which decision the result is intended to support.

Planning and construction management

The specialist designers describe areas, depths, construction methods and changes. Site management coordinates the planned sequence with the construction contractors and agreed specialist works. Results are assigned to the respective intervention. A technical plan change is communicated early enough for its effect on the survey task to be assessed before construction. Organisational construction stage boundaries remain distinguishable from technical survey boundaries.

Specialist company and competent bodies

The private explosive ordnance specialist carries out the agreed investigation and documentation. Official requirements and decisions are clarified with the competent bodies. Documents needed for a specific procedure depend on the site and project. The technical report describes the specialist work completed with its spatial extent and limits. Its applicability to further groundworks is checked against the specific ground disturbance. The competent bodies make official decisions.

The KMRD based at Darmstadt Regional Council is responsible for all of Hesse. Suitable specialist contractors are commissioned for technical investigation or clearance within the respective permit and competence framework. Under Hesse's General Provisions, defusing, blasting and removal are reserved exclusively to the KMRD or a person commissioned by it. Assign the competent authorities and responsible specialists clearly before the task concerned.

Investigation task

Which specialist task comes next?

Define the investigation objective before choosing equipment

The suitable method follows from the conclusion needed and the conditions of the specific area. An existing ground-penetrating radar report may contain relevant preliminary information. Whether it addresses explosive ordnance, however, must be clear from its commission and interpretation. Suitability, interference and possible limits of conclusions are considered explicitly for the new service.

Compare suitable investigation methods

Account for the limits of the earlier investigation

An uncovered boundary area or a different groundworks depth is described as a separate unresolved question. Supplementary work is technically directed at this need. Changes to surface conditions may also matter. An old results label alone does not permit transfer to additional areas or a different investigation purpose.

Compare investigation methods
Project types

Use existing records for the correct purpose

Illustration: two people with a tablet beside a drawing table and a survey trolley on a construction site.

Establish the original investigation commission

Alongside the results, read the agreed question and description of the work carried out. A method can be used for different tasks. What was actually investigated and interpreted is therefore decisive. An equipment name alone does not establish that a report answers the explosive ordnance question for your planned groundworks.

State which subsurface question an earlier commission was intended to answer and the work area for which the interpretation was prepared. A report on structural remains, utilities or other subsurface structures may provide useful preliminary information. For the explosive ordnance task, this is compared with the appropriate historical information and technical conclusions required. The supplementary work identifies which findings can be reused and which question remains unresolved for the proposed groundworks.

Compare specialist services
Illustration: two people review plans and documents at a table beside a construction vehicle.

Bring together complete site plans and appendices

A report can be meaningfully related to the new plans only with its spatial reference. Missing appendices are identified and obtained where possible. The original plan revision and later changes remain clear. A current site plan may help presentation, but does not extend the scope of the investigation previously carried out.

Retain the original report and associated drawings as a coherent record. Identify an overview added later as such. Coordinates, the elevation reference used and the ground surface at that time remain traceable. Where later filling or excavation is known, compare this information with the current plans. Request missing or conflicting appendices specifically before using the results as the basis for a new commission.

Document findings and their limitations
Illustration: two people with a tablet beside a drawing table and a survey trolley on a construction site.

Define a supplementary service clearly

The new task builds on traceable earlier findings and identifies the remaining question. It is connected to the proposed groundworks and site conditions. Supplementary work can then be planned specifically. Using an old report means neither adopting it wholesale nor starting again from scratch.

For tendering, describe the unresolved question, spatial scope needed and available previous work together. Include accessible investigation areas, known obstacles and preparation required. The specialist service offered identifies the reports and plans expected. When a change occurs, state which specific task is added or removed. Specialist work already carried out remains available for further planning with its actual documented progress.

Compare specialist services
Preparation

Prepare the scope and commission together

Establish what needs to be known before commissioning the work

Submit existing reports with their commission, date and complete appendices. For the enquiry, clarify whether their relevance to explosive ordnance must first be assessed or whether supplementary field investigation is already needed. Include the status of any assessed finding. The current construction plans identify the area, depth and newly affected ground volumes. A quotation can then describe the specific technical task and results documents needed, rather than treating an older report’s title as sufficient evidence.

Define the specialist task

Coordinate preparatory work with the investigation

Describe the present condition of the investigation area alongside the older reports. Access, utilities, existing structures and work by other trades may have changed since a preliminary investigation. Technical planning compares actual surveying conditions with the suitable method and agrees preparation required with those responsible. New access, demolition or changes to the surface are prepared separately for this purpose; independent ground disturbance to create a survey area is not part of this coordination.

Clarify preparatory work in the programme

Agree a clear scope and schedule

The scope of private specialist work is agreed using the project documents, actual execution conditions and permissible activity. Necessary preparatory works, investigation, evaluation and documentation are described transparently. Costs and dates are related to these prerequisites and the required coordination. Changes to the construction plans are checked against the agreed contract before work is extended.

Discuss the scope and schedule
Tasks at the site

Compare old reports with the proposed groundworks

01

Check the report’s question and limits

Distinguish a general map, historical evaluation, official statement and survey report. Read the associated appendices too; the title alone does not fully describe the scope of conclusions. The question addressed, spatial reference and limits explicitly stated in each document are decisive.

02

Show earlier investigation areas on the current plan

If buildings, property boundaries or landscaping have changed, the relationship between the earlier report and current plans must be traceable. Mark the documented investigation areas on a suitable current plan. Clarify whether the same area is meant. Similar labels on old and new plans are not sufficient.

03

Additional foundations, connections and access roads

A possible site extension may add new foundations, utility connections or an additional access road. Describe this work separately from the existing use. A report for the existing building does not automatically answer the explosive ordnance question for structures outside it or extending to different depths.

For urban civil engineering and utility construction, mark crossings of existing networks, sewer and supply works, and additional working volumes. For excavations and underground car parks, also describe shoring, foundations and the ground volumes they affect. A new access road or municipal road project may lie outside the area previously considered. Necessary investigations and protective measures are also agreed for preparatory groundworks before they begin.

04

Missing appendices and unclear area information

If appendices to an old report or details of the part of the site investigated are missing, for example, this is initially a gap in the underlying information. Such a gap proves neither absence of risk nor suspected explosive ordnance contamination. Obtain technical clarification of the information missing and further services required to address it.

Project documents

Documents that establish the next step

Identify preliminary information used in the results

The documentation shows which earlier records informed the work and which additional conclusions the new investigation provides. Both levels remain traceable. Site management receives the shared spatial reference and respective limits. A summary must not turn preliminary information from another discipline into additional explosive ordnance evidence.

The agreed recipients receive reports and plans with the areas actually covered and remaining restrictions. In a staged handover, uninvestigated areas and unresolved questions remain identifiable. A later contractor can then check the position reached and requirements for its task. Supplementary results are assigned to the relevant section and kept available with the earlier findings still in use. After clearance work has been carried out, the clearance record stating clearance scope, results and remaining limits is assigned to the section actually covered and associated site plan.

Explain changes between plan revisions

Compare the old investigation area with the new groundworks. Identify different boundaries, depths or additional ancillary work explicitly. The existing report retains its original content. The new technical assessment describes which parts can be used for the current project and which questions remain unresolved.

Construction sequence

Coordinate investigation and construction sections

Organise records by task before the enquiry

Compile official statements, technical reports and other planning information with their appendices. Note missing documents. Show the current groundworks on the site plan. The review can then build on existing findings and determine the technical needs actually outstanding for your project.

Coordinate the construction phase with us

Hand over the combined records after supplementary work

The new report is connected to the older records used and current groundworks plan. Identify the questions answered and restrictions remaining. Later participants can then trace the development. Shared filing supports access while each technical conclusion remains unambiguously assigned.

Coordinate the construction phase with us
Method selection

Select methods according to the task and survey conditions

Historical records and aerial photographs

Historical aerial photograph evaluation and other older records help locate the basis for suspected contamination. For the current question, image dates, area considered and limits of conclusions are compared with the construction plans. A historical map may explain a former use without describing the status of a technical explosive ordnance investigation. Other findings are added with their respective purposes. Historical assessment supports investigation planning, but is not a survey of the present-day subsurface or general confirmation for later interventions.

Understand aerial photograph assessment

Magnetometric survey

Magnetic surveying methods detect magnetic anomalies. Their suitability is determined for the explosive ordnance question and ground volume actually needed, independently of the title of an existing report from another discipline. Expected objects, subsurface conditions, fences, utilities and existing structures affect interpretation. Technical assessment interprets signals and identifies any further clarification needed. The strength of an anomaly alone does not establish explosive ordnance. Magnetometry measures the magnetic field passively. Detection depends on the magnetic effect of the object sought; electrical conductivity alone does not establish that this method can detect it.

Understand the scope of magnetometry

Electromagnetic methods

Electromagnetic investigations may be suitable for certain metallic target objects and site conditions. Existing survey reports are checked for their investigation purpose, actual coverage and documented interference. Supplementary work depends on the technical question still unresolved and accessible work areas. New results include spatial references and information on surveying conditions. An equipment name or its availability alone determines neither the conclusion needed nor the choice of supplementary methods. Transient electromagnetic methods, or TDEM, evaluate the time-dependent electromagnetic response of conductive objects. The method is selected according to the investigation objective and actual surveying conditions.

Understand electromagnetic surveying

Ground-penetrating radar

Under suitable conditions, ground-penetrating radar can provide information about subsurface structures and reflections. An older report must make clear whether it investigated structural remains, for example, or whether explosive ordnance was part of the commission. Ground conditions, moisture and installations affect possible interpretation. An anomaly does not automatically identify explosive ordnance; data without anomalies do not establish findings to arbitrary depths. Technical review therefore determines which conclusions can be used, and their limits, for the current groundworks.

GPR and limitations

Deep-ground and downhole surveys

For deeper groundworks, the areas previously documented are compared with the planned excavation or foundation. The assessment checks whether the conclusion needed can be reached from the surface or whether deep surveying or borehole surveying is required. Position, depth, arrangement and relationship to utilities belong in technical planning, as does suitable investigation access. A general depth figure or standard grid does not replace this comparison of tasks. The results apply to the ground volumes actually covered and method used.

Prepare deep interventions

Survey during construction

If necessary investigations remain incomplete before a construction phase, the technical suitability of an approach alongside construction is assessed for the unresolved areas. Investigation, interpretation and reporting of new findings are described within the specific workflow. Visual observation during excavation alone does not replace a survey needed. After every work step, site management needs the findings actually reached and outstanding tasks. An existing report addressing another technical question does not automatically include these unresolved areas.

Agree the approach during construction
Technical assessment

Aerial photograph evaluation, survey reports and further investigations

What historical and current aerial photographs show

The Historical aerial photograph analysis must be read in terms of the material used and question addressed. Current aerial photographs may show existing structures, but do not replace the evaluation needed for a historical explosive ordnance question. Conversely, a historical image does not automatically describe all later changes to the subsurface.

Conclusions and limits of an earlier survey

For a completed Surface survey it must remain clear which area was covered and which conclusions were possible. Also account for the areas identified in the report as uninterpretable or inaccessible. Whether existing results match the new groundworks is assessed against the documented information. Magnetometry detects magnetic anomalies; active electromagnetic methods and ground-penetrating radar have different conditions of use. For ground-penetrating radar, propagation conditions in the ground are decisive. Ground composition, existing utilities and interfering objects are assessed against the investigation objective and groundworks depth. For deeper interventions, any necessary deep surveying or borehole surveying is technically planned. Borehole clearance or technical evidence remains assigned to the ground volume actually investigated and its documented limits.

Which additional investigation is needed

Supplementary Surveying should answer a specific unresolved question. The commission therefore follows from existing findings, the new plans and actual conditions. Only this technical comparison establishes which earlier results are usable for the new project and what must be investigated again.

Next steps

Review records and plan further investigations

01

Organise the documents

Collect evaluations, official statements and survey reports with their appendices. The initial contact identifies the project location, construction task and conclusion needed. Existing records are checked for currency, spatial reference, completeness and gaps.

02

Assign the investigated areas

Assign earlier investigation areas to the current plans. Where historical questions remain unresolved, the necessary research and aerial photograph evaluations are carried out under a technically agreed commission. The KMRD statement is considered; supplementary findings are connected to the current interventions.

03

Assess changes

Technically compare new structures, depths and gaps in the underlying information. The investigation method is selected from the information required, groundworks depth, ground composition, existing utilities, interfering objects and actual surveying conditions.

04

Define the commission

Agree necessary supplementary work and a traceable handover of results. The technical commission, access, preparatory work and necessary protective measures are clarified with the relevant responsible parties before the groundworks concerned.

05

Perform the agreed investigation

The agreed surveying or proper investigation during construction is carried out within the permitted specialist commission on the areas and points agreed. Measurement data and observations receive clear position and elevation references. Uninvestigated areas, restricted access and relevant interference are recorded.

06

Assess survey data and findings

The collected data and findings are evaluated against the investigation objective. The technical assessment considers interference, the areas reached and remaining limits of the conclusions. It establishes which further investigation or work is needed for the planned groundworks.

07

Document the assessment and scope

The report and plans document the specialist work performed, technical assessment, areas covered and respective limits of conclusions. Location, elevation and depth references are stated transparently. The records show which task is complete and which areas or further questions remain unresolved. The relevant responsible parties use these records to decide on necessary additions or changes for the next specific groundworks.

Documentation

Earlier findings and new results in the report

Findings and their scope

A supplementary investigation should identify the earlier findings used, new question addressed and resulting conclusions. Attached site plans connect the documentation to the actual area. Later design participants can use these records to check whether the information also applies to their groundworks or requires another comparison.

Project responsibilities

Under the General Provisions for Hesse, investigated or cleared areas are documented with a site plan and the results submitted to the explosive ordnance clearance service. The responsible authorities make official decisions on the relevant technical basis. The BFR KMR explain planning and evidence for construction and operation of federal properties; outside their direct scope, their technical principles provide guidance alongside local requirements.

Hesse’s provisions specify site plans at a scale of 1:1,000. The spatial reference of investigated or cleared areas and agreed service scope remain traceable in the documents handed over.

Working approach

How FONTANA-EOD works

Document the agreed specialist service clearly

FONTANA-EOD reviews existing information against its actual commission and coordinates the agreed supplementary investigation with the new groundworks. The results distinguish reused findings from areas newly covered. The report documents execution, relevant conditions and limits of conclusions. If plans or site conditions change, additional needs are assessed before the work concerned. Construction planning can therefore trace which technical evidence answers the specific task and which question remains unresolved.

Discuss the investigation task

The task before the equipment

The results needed determine method selection. The term ground-penetrating radar or an old report’s equipment name does not establish a conclusion for a new explosive ordnance question. Technical selection connects the investigation objective, proposed ground volume and actual surveying conditions.

Keep limitations visible

Reports and plans show which areas and depths were actually covered and which conclusions remain restricted. Inaccessible areas or those investigated differently retain their own identification. Further planning can then use existing evidence specifically and prepare missing investigations for the structures affected.

Clarify changes before intervening in the ground

For a relocated excavation, new structure or additional depth, compare the current geometry with existing results before the intervention. Changed ground surfaces are also considered with their elevation reference. The technical review determines which earlier conclusion remains applicable and which supplementary investigation is needed.

Hand over the report and plan together

The handover includes the respective investigation commission, complete results report and its location and depth appendices. A summary identifies the position reached for the construction task and outstanding questions without replacing the records. New site management or a specialist contractor also needs this relationship between the report’s purpose, area actually covered and subsequent work.

Understand the results

Use technical statements for the next decision

Record maps with their date and purpose

The City of Kassel offers historical plans and aerial photographs as well as current map products. These documents can illustrate changes or present-day spatial relationships. Each is assessed according to its origin. An image extract alone is not a technical result; the evaluation must match the question asked and area concerned.

Understand investigation reports and their limitations

An older report may remain useful

Its content and relationship to the current task are decisive. Check whether complete appendices are available and which changes have occurred since the investigation. Technical assessment determines which conclusions can be reused. Age alone makes a report neither unusable nor sufficient evidence for new groundworks.

Understand the service scope
Design and findings

Documents for the next construction decision

Illustration: aerial photographs and maps on two screens and printed on a desk.

Historical evidence and the current design

Aerial photograph interpretation is related to the actual groundworks. Its purpose and geographical scope remain distinct from a technical investigation of the ground as it is today.

Understand aerial photograph assessment
Illustration: two people review plans and documents at a table beside a construction vehicle.

Specialist reports for site management

The findings, their locations and limitations are handed over together. This makes clear to those carrying out the work which area has been investigated and which task remains outstanding.

Assess investigation reports
Four people in orange high-visibility vests in front of two excavators on a construction site.
Person with a yellow survey cart on a footpath in front of a hedge.
Questions from planning

Questions about existing records and new construction in Kassel

Is an older report unusable merely because of its age?

Not merely because of its age. Its content, investigation area, scope of conclusions and changes up to the new project are decisive. The report is technically compared with the current task; its date alone does not replace this assessment.

Can I use a current aerial photograph as explosive ordnance evidence?

A current photograph can illustrate existing above-ground structures. On its own, it is not the result of a historical explosive ordnance evaluation or technical investigation. The material, evaluation and question investigated must match.

What does a missing investigation report appendix mean?

Initially, information that may be essential to understanding the results is missing. Have it clarified whether the appendix can be obtained and which conclusion remains traceable without it. Missing information must not be replaced by an unproven statement that there is no risk.

Do results for the existing building also apply to a new extension?

Only where the documented conclusions actually cover the new groundworks. Position, areas affected and proposed depths must be compared. Additional utilities or ancillary work may raise their own questions even if they form part of the same project organisationally.

What should I do if I find possible ordnance?

Stop the work concerned and keep your distance. Do not touch, move or further expose the object. Notify the police immediately on 110 and follow the authorities’ instructions. Do not attempt recovery yourself or transport it to a police station or other official premises. Leave the danger area and keep others away. A routine project enquiry is not the correct reporting procedure for an immediate find.

Why is the term ground-penetrating radar in a report title not sufficient?

It identifies a method, but not the question investigated. The commission, interpretation and spatial scope must show whether explosive ordnance was addressed.

How is an additional investigation connected to the earlier report?

The new documentation identifies the preliminary information used, supplementary question addressed and new results with their limits.

Which cost factors matter for supplementary investigations in Kassel?

The work involved depends on usable previous records and the KMRD statement, preparation and access required, area size or number and depth of investigation points, suitable method, surveying conditions, interpretation and documentation. Unresolved areas and supplementary tasks are quoted with their actual prerequisites. Private specialist services, official duties and other preparatory services remain distinguishable within the service scope.

Project enquiry

Review records for your Kassel construction project

Provide reports with their appendices

Include the original commission and available site plans. State the project address, parcel numbers, existing file reference and current construction progress. Identify missing records as outstanding points. Name a coordinating contact and the bodies involved. FONTANA-EOD discusses the specialist service needed and its prerequisites with you. For several locations, each intervention receives its own records; for a project in Frankfurt am Main they are compared separately with the construction task there.

Identify the new question

Show which groundworks the previous records have not yet clarified. Add the construction area, route or borehole list with positions, depths and relevant elevation reference. Include information about existing utilities, installations, conditions and known ground alterations. Identify access, construction dates and work stages needed first. State which earthworks should begin first and which areas are not yet accessible. The subsequent decision required is linked to the specific unresolved question.

GPR on a construction site
Project enquiry

Have your project assessed

Whether historical aerial photograph analysis, explosive ordnance surveying, surface surveying using GPR, magnetometry or TDEM, deep-ground surveys, downhole surveys, excavation supervision, area clearance or ordnance recovery is needed depends on the location, ground disturbance, depth, ground and existing documents. An early ordnance assessment provides clarity for tendering, programming, occupational safety and construction.

FONTANA-EOD combines its Section 7 SprengG licence, specialists holding Section 20 SprengG certificates of competence, suitable survey and clearance methods, and traceable documentation. Send the site plan, depth of ground disturbance, construction phase and existing documents for an initial technical assessment.

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