Comparing the significance of the studied environmental factors in individual canal types, the greatest variability in the irrigation-drainage canals and the canals with a specific function is explained by morphometrical variables (water width and depth), while in the group of drainage canals the impact of land-use type, sediment type and bank structure was decisive. Only in the case of the anthropogenically affected Hurbanovsk´ y canal the last two factors were insignificant, while the inflow of sewage water to the canal was decisive (Table 5).