Ratio between maximum and minimum discharge (Qmax/Qmin) as the anticipated indicator of river disaster in 30 watersheds of Indonesian

This paper intended to analyze the initial indicator of a river by comparing maximum and minimum discharge. Ratio between maximum and minimum discharge (Qmax/Qmin) is known as coefficient of river regime. This study conducted in 30 mini-hydros electrical power of Indonesia. The methodology consisted of analysis on Qmax/Qmin (Qid, coefficient of river regime) in each site of mini-hydro and than there were classified as good, good enough, bad enough, bad or very bad river quality due to the indicators as follow: if Qid < 5 indicated good quality; if 5 < Qid < 15 indicated enough to good quality; if 15 < Qid < 25 indicated enough to bad quality; if 25 < Qid < 50 indicated bad quality; and if Qid > 50 indicated very bad quality. Results showed that as the discharge supplier of mini-hydro, 2 watersheds were in good condition, 17 watersheds in enough to good condition, 3 watersheds in enough to bad condition, 3 watersheds in bad condition and 5 watersheds in very bad condition. This results can give the authority of local or center government for making firm steps to save the available rivers.