Investigation of the water conditions is necessary in all these cases, when the stability and durability of a historic object depends on the influence of hydrological phenomena prevailing in a given area.
Research into water conditions usually comes down to:
a) przeprowadzenia obserwacji stanu wód podskórnych i gruntowych dla ustalenia wahań poziomu ich zwierciadła,
b) carrying out measurements of the direction of water flow and determining the slope of the mirror,
c) ustalenia wpływu opadów atmosferycznych na ruchy wody gruntowej,
d) ustalenia wpływu sieci dróg wodnych, so streams, rivers, channels etc., on the condition of groundwater and the direction of its flow,
e) opracowania wniosków odnośnie do wpływu wyżej przytoczonych zjawisk na warunki posadowienia, stability and durability of the structure.
You know, that the groundwater level depends on the existing land configuration, as well as nearby rivers, streams etc.. The movement of groundwater in the saturated zone is in this direction, in which the mirror is inclined. In order to study the fluctuations of the water table and the direction of its flow, observation holes are installed. The number of holes must not be less than three, they should be so situated in relation to the historic building, that it would be inside the figure outlined by their arrangement.
The holes are assumed at a distance from 100 do 500 m apart, and coordinates their location with the contour plan and the network of benchmarks.
Observation of the groundwater level in the test wells, as well as in neighboring streams, rivers etc.. carried out at a specific time interval (e.g. twice a month), as well as after heavy rains and long-lasting showers.
The observation results are presented graphically.
It is important to determine the impact of the terrain slope on the movement of rainwater in relation to the historic building, namely: whether water flows towards the structure, whether they are missing it; whether the waters run off completely from the surface to the nearby streams, rivers, sewerage pipes or others, or only partially, and some seeps into the ground. When studying water conditions, it is important to establish, possibly carrying out an inventory of the existing condition of melioration and sewage systems, e.g. drains, drainage ditches etc..
The study of water conditions is usually preceded by a thorough diagnosis of the existing ground conditions, because the water level in the tested boreholes depends to a large extent on the structural properties of the soil, through which the water flows, namely, cohesive soil obstructs its flow, non-cohesive soils, loose, they facilitate the flow and favor the raising of the water table.
When examining hydrological relations, as a rule, the results of observations carried out by the relevant Regions of Waterways and research stations of the Hydrological and Meteorological Institute should be used.. These institutions can provide the results of observations from several dozen years back, so more reliable than the results, which can be obtained during the observations carried out at a given object, especially in emergencies.