Calculation of Large and Medium-Size Bridge Design Discharge under Unascertained Information

Hydrological system is an unascertained system. When calculate the large and medium-size bridge design discharge with hydrological data, with different method and series different results may be gained. As the design discharge has the unascertained character, applying unascertained mathematics theory to calculate can get the bridge design discharge with more confidence and more conforming to the actual situation. It also provides theoretical basis for experts to optimally select results.