FIELD: agricultural and forestry. SUBSTANCE: according to proposed method, section with meeting drainage channels is formed. Then said section is divided into zones with different intensity of draining, observation gates are formed equipped with outlet grounds, water flow rates are recorded, samples of water are taken, concentration of contaminants in samples is measured and compared with tolerable values. Water flow in channels is cut off in turn starting from border of source water zone by means of partitions and then water flow rates are recorded and samples of water are taken from neighbor border of zone located down along bed of channel. Measurements of water flow rate and taking of water samples are started when depth of water after partition is reduced to 3-5 cm. Water outlet with thin wall or flow rate metering head is used as flow rate meter. Accuracy of measurements is improved owing to the fact that cutting off of flow eliminates influence of transit water flow onto taken measurements. EFFECT: improved accuracy of measurements. 34 cl, 2 tbl, 2 dwg
