Hydrological monitoring: survey of the bog surface on the hydrometric station
On the 10th of September, Polistovsky Reserve specialists conducted a third survey of the bog surface at the hydrometric station, designed to measure the level of bog waters during the growing season. This is an important part of hydrological monitoring, designed to monitor water level in the raised bog system.
The hydrometric station is a linear gauge in the bog with a length of about 1.5 km with 5 wells for measuring bog water level. Wells are located in various micro-landscapes, with different vegetation and micro-relief. In each of the wells there is an automatic logger, which measures and record the pressure. This pressure data and manual measurements three times during the growing season allow us to determine water level.
For a more complete description of the state of bog waters, it is also necessary to monitor changes of the bog micro-relief near the wells, and the depth of water relative to the surface of the bog. Survey of the bog surface is carried out exactly for this purpose three times a year.
In the course of works on specialists determine the distance from the water surface to the surface of the bog (up to the heads of sphagnum moss). Near each well, a 30-meter line is selected. Then the rope is stretched along this line above the bog parallel to the water level at a height of 60 cm from water. Then the distance from the rope to the moss is determined with the ruler. The measurements are carried out every 10 cm, about 300 measurements near each well. Subtraction of the obtained values from 60 determines the distance from the water to the moss heads - this allows to accurately describe the micro-relief.
After this survey, specialists of the scientific department compare the obtained data on the surface of the bog with the data on the water level from the loggers. As a result, they receive a complete description of both changes in the water level during the summer and the depth of water relative to the surface of the bog. It is also possible to correlate these data with meteorological observations and trace the influence of precipitation, atmosphere pressure and air temperatures on the level of bog water.
Hydrological monitoring is tracking changes in the state of the raised bog system as a water body. In winter, the snow cover and the depth of freezing of the bog are monitored, in the summer - monitoring of water level in the bog and in the rivers of the raised bog system is carried out. Now in Polistovsky Reserve, the water level is regularly monitored at 6 hydrometric stations on the rivers and at 1 station in the bog.
In the long term, it is planned to create a denser network of hydrological monitoring and get the most complete picture of the water turnover in the raised bog system: how much water comes to the bog and where from (with precipitation, groundwater and surface water), how much water leaves the bog (by evaporation and outflow) and how the volume of "stored" water in the raised bog varies with time. Installation of many hydrometric stations in addition to the existing ones will require considerable resources and will take many years, but as a result a complete picture of the life of Polistovsky bog as a hydrological object will be obtained.