Contaminated site investigation and remediation of former shooting ranges in the Lower Engadine, Grisons

Following the merger of the former municipalities of Ardez, Ftan, Guarda, Scuol, Sent and Tarasp in 2015, there are now numerous shooting ranges in the municipality of Scuol (the largest municipality in Switzerland in terms of area) that need to be investigated and, sooner or later, remediated. In the meantime, shooting only takes place at one location (Urezzas, Ftan).

The following shooting ranges in the municipality of Scuol have been investigated since 2008, and some have already been remediated:

The aim of the work is to comprehensively record the contamination resulting from previous shooting activities (XRF mapping) and to assess the risk to protected resources, such as soil, surface water, and groundwater, in accordance with contaminated site legislation. The technical investigation provides the basis for the subsequent remediation project, which will be supervised on site by the contaminated site specialist.

The investigation of contaminated sites (e.g. shooting ranges, landfills, petrol stations, industrial areas) is part of GEOTEST’s interdisciplinary field of activity and is based on many years of experience dealing with numerous comparable sites throughout Switzerland.
 

During the investigations in the Engadine, evidence emerged of additional bullet traps that were not yet listed in the register of contaminated sites (KbS) or were listed in the wrong location. Based on these findings, GEOTEST was commissioned to carry out additional investigations.
 

GEOTEST took on the overall project management for the investigations and the remediation work and supported the client throughout all phases of the project.

Some of the affected sites are located in agricultural areas and show heavy metal contamination in the bullet trap areas, with concentrations that exceed several times the values specified in the Contaminated Sites Ordinance (AltlV). This means that the former shooting ranges are considered contaminated sites in need of remediation.

The preliminary investigation of contaminated sites is divided into a historical investigation (HI) and a technical investigation (TI). As part of the HI, activities relevant to contaminated sites are documented based on historical records (e.g. archive documents, old aerial photographs and maps, and interviews with contemporary witnesses). In the case of shooting ranges, the TI includes XRF mapping of lead contamination and an assessment of protected resources, in accordance with contaminated site legislation.

The results of the TI enable a well-founded assessment of the need for remediation and provide a reliable basis for planning further measures.

— Reto Barbüda, Head of Real Estate, Municipality of Scuol

Shooting ranges in need of remediation require contaminated site remediation through excavation of the contaminated material. The excavated material is continually classified according to the contamination classes of the Ordinance on the Avoidance and Disposal of Waste (Waste Ordinance, VVEA). The sorting process is supervised on site by GEOTEST’s contaminated site specialist (specialist construction management). The disposal classes are determined using a hand-held XRF device, and precise instructions are given to the machine operator. In this way, the transport and disposal costs, which account for the majority of the remediation costs, can be kept to a minimum.

As the project coordinator for the remediation projects, GEOTEST AG supports the client with the construction permit application (usually a BAB procedure), with the selection of the construction contractor (tendering process), and during the execution, all within the scope of specialist construction management. If necessary, additional services (e.g. environmental construction supervision) are provided in close cooperation with local partner offices.

Shooting ranges are often located in beautiful scenic surroundings a short distance from villages, but they are often difficult to access, especially in alpine regions. In many places, accessibility for construction machinery is severely restricted by narrow roads through small villages, weight restrictions on access roads, and/or steep terrain. This requires customised transport solutions for each remediation project.
 

It is also important to protect habitats such as dry meadows, wetlands and floodplains from construction work. Ecologically valuable structures, for example hedgerows and dry stone walls, are also common on the dry slopes of the Lower Engadine. Here, it is important to work with environmental construction supervisors (UBB) to find the most environmentally friendly solution. The right timing of construction work during the already short growing season is crucial. Moreover, wet summers with daily thunderstorms require interruptions to excavation work and short-term schedule changes for the construction company.
 

Due to the long transport distances to the soil washing plant or landfill site, it is important to coordinate the required transport with the responsible company so that sufficient, but not too many, vehicles are available on the right day. The availability of suitable soil material is essential for the professional recultivation of the remediated areas. Finally, the right seeds, temperature and soil moisture are crucial for the successful sowing of the areas.

The specialist construction management team is therefore the first point of contact for the client, construction company, land owner, lease-holder/manager, and UBB. The specialist construction management team is also responsible for checking measurements and preparing the remediation and disposal report for the Cantonal Office for the Environment (ANU GR), which ultimately applies to the Federal Office for the Environment (FOEN) for federal subsidies for the remediation work.

The carefully planned remediation of former shooting ranges makes an important contribution to environmental protection. Harmful or worrisome effects on protected resources, such as soil, groundwater and surface water, caused by the high pollutant content in bullet traps are eliminated through targeted removal. Professional recultivation of the remediated areas ensures the long-term use of the land – for agriculture or local recreation, for example – for future generations as well.