Effect of weir´s theoretical discharge coefficient on discharge measurements in small Andean streams

Andean ecosystems provide important hydrological services for downstream communities. Due to this importance, several studies have been carried out in recent years, with emphasis on processes identification and land use change impacts. In studies, but also the operation of small-scale irrigation drinking water projects, small streams equipped compound, sharp-crested weirs discharge estimation. To transform level (stage) into a (water rate), weir equations theoretical coefficients, which do not necessarily apply under actual field conditions, mainly site fluviomorphology construction aspects, introducing uncertainty their measurements. Therefore, study analyzes effect using coefficients instead adjusted field. The was conducted 9 micro-catchments (0.2 – 7.53 km2) located Zhurucay Ecohydrological Observatory páramo southern Ecuador. calibrate curves were generated by mechanical salt-dilution gauging methods. Results revealed that differed from value up 15% triangular (V-notch) section (DCvn) 41% rectangular (DCr). DCvn affects 4 times more low medium discharges estimation than high discharges. On other hand, method is precise discharges, at very it overestimates 10%. Overall, results suggest essential avoid errors studies.