Civil Insight: A Technical Magazine Volume 3 | Page 69

Tandon S.S. et al.
Civil Insight (2019) 64-70
Discharge
FDC of Roshi and Ghyalku Rivers Combined
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
0.00
20.00
40.00
60.00
80.00
100.00
120.00
% Exceedance
Fig. 4. Flow Duration Curve (FDC) of Roshi and Ghyalku Rivers combined
5) Results
The analyses from Tables 2, 3, and 4 demonstrate that other conditions remaining constant (e.g. location of
water mill, efficiency, energy rate), under varied heads and discharges, the energy generated from the
merged condition is less than that of former condition.
Roshi River has higher head but less discharge in comparison to Roshi and Ghyalku Rivers combined.
Further, it is observed that the gross head decreases by about 2 meters, whereas discharge increases by
0.18m 3 /s in merged condition, as presented in Table 4. The theoretical energy (both dry and wet) generated
from the merged or combined condition is about 10% less than the energy generated from Roshi River only.
Moreover, the comparison in terms of monetary value shows that annual revenue generated on combined
condition of Roshi and Ghyalku Rivers is about 8% less than revenue generated from the Roshi River only.
6) Conclusions
Water mills like that of Kushadevi can be used both for both agro-processing and generation of electricity.
Electricity can be generated in non-operating hours of water mill. However, some technical improvements
are necessary in terms of installation of generators, turbines, transmission systems, and improvement of
flow mechanisms.
The following conclusions can be outlined from the research:
x Since the head in unmerged condition (Roshi River only) is greater by 2m and discharge not
significantly less than (Roshi and Ghyalku merged), the energy generated is 10% more than the merged
condition and this concludes revenue generation is almost greater by 8% in the former condition.
x More than 27,000 water mills are present in Nepal; their identification and upgradation can play an
important role in improving rural electrification and reduction in consumption of carbon fuels. The
problem of rural electrification can be surmounted with the development of such micro-hydropower
stations.
Further Recommendations
As the research is limited to prefeasibility stage only, the detailed topographical and hydrological survey
can be carried out for further studies. Geological study can be conducted to better understand the hydraulic
characteristics of the rivers.
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