Monitoring systems

Because of the intervention in the original status of the environment, the effect of interventions should be monitored in the period preceding metro construction, during construction and in the period following construction.

Monitoring of the existing status (condition) of underground waters

The system of ground waters should be determined by systematic surveys, which could be form the base document in case of possible changes. Consequently, technical condition of monitoring wells and the state of operation of well heads should be checked.

In the renewed monitoring wells water level readings taken minimum every three days should be introduced instead of the non-systematic and rare observation as earlier. These wells should be equipped with water level recording devices in order to establish the initial status of ground waters with sufficient accuracy and safety.

Ground water quality should be surveyed every month and water samples should be collected following pumping under relevant regulations in order to establish water quality. Water samples should be used to establish specifications.

In order to monitor water quality, monitoring wells should be installed on each of the sections 29-31 and 39-45 km at the location with the highest expected SO4 content. In such wells, in addition to the water level reading every three days, a detailed water quality test should be made every month.

Two ground water monitoring wells around each of the stations should be implemented to record any change in ground water level. Surface connections of these stations and the station buildings that may be modified from the surface could sometimes diagonally traverse the ground water storing layer. Local dimension of such crossings can also influence ground water flow and in a restricted area it could result in an increase of ground water level.

Monitoring the condition of underground water in the period of construction

• Ground water monitoring should be continued in the period of construction using the system described above.
• The monitoring of confined waters in the period of construction should mainly focus on water quality. With this in mind, water samples should be taken every 50 meters in case of an open face tunnelling, then analysed for the components specified for ground water.

Monitoring ground waters following the start of operation

• All kinds of monitoring should be continued following construction in compliance with the instructions in force for the construction period.
• Ground water and karst water monitoring in further periods of operation is not in the interest of the metro service but could ensure protection of those parties concerned. Accordingly, on the basis of earlier monitoring results those parties concerned should decide whether monitoring is reasonable to be continued (specifically, the number of monitoring points or the frequency of observations).

Minimum monitoring required:

• In case of the ground water a water level measurement should be performed every two weeks in the first year (then less frequently), and water quality should be analysed in the wells four times a year.
• In the system of monitoring karst waters the operation water level and temperature of production units should be checked in a continuous manner, however, at least every day. In non-operating units water level and temperature measurement every two weeks should be maintained. Test of the water quality can be reduced to once every quarter of year. Notwithstanding, whenever a more frequent monitoring or measurement is required by the operator BGYF Rt. in his own interest, then - following consultation - one should proceed accordingly.

Elements of the monitoring system, monitoring means, methods and frequency

• The facilities necessary for monitoring should be designed and depicted in special plans, which do not form part of the construction plan, since monitoring should be started as early as prior to construction.
• For the monitoring of underground waters (standard) monitoring wells are to be implemented that enable (pumped) water sampling in addition to the measurement of water levels. The design of such monitoring wells includes their instrumentation and the comprehensive instructions of the monitoring network.

Comprehensive plans of a monitoring system should cover:

• Plans of the monitoring points periodically checking air quality (plans of measuring components, frequency, instrumentation etc.)
• Installation of the sensor points detecting transport and construction borne noises and vibrations, operating instructions related to observations etc.

It is reasonable to check road traffic (traffic count) from time to time to enable traffic assessment and related comparisons.

A driven or vibrated sheet-pile working pit is associated with higher noise level than a pit with diaphragm wall or bored pile wall. One should intend to minimise the construction time. Only such works are permitted at night that do not cause any significant environmental noise emission.

Individual construction phases, with their admissible noise and vibration load limit values should be specified in the invitation for tenders, and these values shall be periodically checked by independent experts in order to prevent any conflict between the population concerned and the contractors.

Following implementation and in the period of operation vibration checking measurements should be carried out and assessed for the whole metro line.

The base condition should be established by measurements and modelling, which should be re-assessed prior to actual construction commencement. In addition to the "natural" change in motor vehicle traffic, the impact of the vehicle traffic involved in construction works will also occur. Dust-proof solutions should be applied in transports, construction and loading, which should be checked from time to time. Vehicle condition should be checked by environment protection tests.

In the period of operation it is mainly the air pollution effect of ventilation systems with a surface exit should be checked, although no such complaints are known so far.

On the basis of the assessment and results obtained by the experts and measuring instruments of various disciplines, it is considered necessary to investigate the possible joint and mutual effects of the influencing factors in the period of base site condition, construction and operation.

Consequently, on the basis of the investigations carried out within the present impact study it can be established that the construction of Metro 4 shall positively influence Budapest's environmental quality, causing no damage, and any possible damage to the environment can be prevented and eliminated by proper technical measures.