The equipment for the measurements at the experimental basin was purchased in 1998 and 1999. The items purchased were: a sediment sampler; a lysimeter; a tahimeter; compact compound probes for the measurement of temperature, conductivity, oxygen and pH; an ultrasonic Doppler instrument for the measurement of water velocity; a datalog current meter and a water level recorder.

We used three instruments to measure the velocity: Valeport Self Recording current meter; Starflow ultrasonic velocity meter and ISCO 6700 compatible Area-Velocity Module. For measurement of the suspended solids concentration we used the following instruments: Hach SS6 turbidimeter; Partech IR40 infrared sensor and ISCO 3700 sampler. The last two were installed on 29-30 March 2000 only.
 

We measured temperature, pH, conductivity (SEC) and dissolved oxygen (DO) of the Reka River at different hydrological conditions with a Sound YSI 600 compatible to the portable ISCO 6700 auto-sampler. Before the installation of the Sound in the field, for in-situ measurements, we performed a calibration of conductivity, pH (two-point calibration) and dissolved oxygen. Occasionally, we checked the Sound operation in the field with portable WTW instruments: temperature and conductivity with an LF 597 profiLab instrument; pH with a Multiline P4 instrument and dissolved oxygen with Oxy 196.
 

The aim of selecting three microbiotests was to find out if there were any differences in their sensitivity. Namely, the conventional Daphnia toxicity test is legally adopted for testing the toxicity of samples from rivers during the regular annual biomonitoring of surface water quality.
 

We selected Daphnotoxkit F^TM with the test organism Daphnia magna, Thamnotoxkit F^TM with the test organism Thamnocephalus platyurus and Protoxkit F^TM with the test organism Tetrahymena thermophila. Toxkits available on the market contain test organisms in inactive form and standard material needed to perform the tests. This assures very high reliability of the test results.
 

The experimental measurements were done for flood waves from:

21-24 May 1999,
16-21 November 1999,
28 March to 5 April 2000,
11-17 April 2000 and
22-24 November 2001.

The measurement of velocity and discharge took place at the Cerkvenikov mlin state gauge station. Power supply was necessary for some of the other measurements, and these were moved 1.200 m upstream to the abandoned water supply station with an electrical power supply immediate to the riverbank. Water samples for ecotoxical investigation were taken from a creek near an abandoned sewage disposal site and near the Cerkvenikov mlin gauge.