Summary:

In order to define basic parameters of a water stream, it is necessary to de-termine the location of characteristic field points that influence local hydrological conditions. The papers presents the methodology for performing geodesical mea-surements that are necessary to obtain data about water state in rivers and river bed profiles. The comprehensive process includes the following stages: field mea-surements, which include highly-accurate and stabilized minor control points; de-tailed measurements of selected relief points and water mirror level; finally, calcu-lations and indispensable analysis performed outside the field. Accuracy parameters should be in line with requirements defined in relevant regulations, norms and geodesical instructions.Data obtained from measurements are used in the preliminary stage of hydrological analysis preparation. The paper presents the procedure of field data collection applied in hydrological works, which includes selection of measurement point, methods of exact determination of river bed profile and density of measurements along profile cross-sections. These tasks are less frequent in geodesical practice, yet they may be significant for the group performing the measurements and may help to develop own methodology for high-accuracy tasks.