Storage and drainage characteristics of the Dokriani Glacier (9.66 km2) located in the Garhwal Himalayas have been studied. In order to understand these characteristics, clear weather (non-rainy) days data for three ablation seasons (1996–1998) are used because discharge is melt-driven on such days. Moreover, diurnal variations in the discharge on clear days represent the true picture of glacier response to streamflow. Results indicate that meltwater storage characteristics of the glacier lead to high discharges in the stream during the night. Consequently, night-time discharges are comparable with those observed during daytime throughout the melt season. Meltwater storage characteristics of the glacier are much stronger in the early part of the melt season and they weaken as the melt season progresses.
Diurnal variations in the discharge are observed to be clearer with advancement of the melt season providing variations in the timing of peak flow. Maximum discharge for different years was observed between 1700 and 1900 hours, showing a lag of 2 hours in the timing of maximum flow over the ablation period. The time to peak flow varied from 8.5 to 11 hours. For all the years, a strong seasonal trend towards increasing diurnal amplitude in discharge until August and thereafter a decreasing trend, was observed. The time lag between Qmax and Tmax varied from 3–6 hours over the ablation season and recession of melt water became faster with time. The time lag is higher at the beginning of the melt season and reduces as the melt season progresses. Recession trends of the hydrographs with time suggested a similar hydrological response of the glacier in June and September. The basin behaved like a single conceptual linear reservoir for these two months, while for July and August it behaved like two conceptual linear reservoirs, namely, accumulation and ablation reservoirs.
