TITLE:
Hydro-Chemical Characterization of Glacial Melt Waters Draining from Langtang Valley, Nepal
AUTHORS:
Anisha Tuladhar, Rijan Bhakta Kayastha, Smriti Gurung, Ahuti Shrestha
KEYWORDS:
Hydro-Chemistry, Langtang River, Weathering Process, Glacier Melt Water
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.7 No.8,
June
11,
2015
ABSTRACT: A
detailed analytical study of the physico-chemical parameters of melt water
draining from glaciers of Langtang Valley with an elevation ranging from 1395 m
a s l to 4200 m a s l in Rasuwa district, Nepal was carried out in order to
study the seasonal and altitudinal variation in hydro-chemistry along the
Langtang River and glacial melts from the Lirung and the Khimsung Glaciers. The
study was carried out during 6 - 10 April and 30 June-3 July, 2014 at 11 sites.
A total of 22 composite samples were collected. The concentration of cations
and anions of the Langtang Valley were found in the order Ca2+ > K+ > Na+ > Mg2+ and , respectively.
Significant seasonal variation in electrical conductivity (EC), turbidity,
dissolved oxygen (DO), calcium (Ca), sodium (Na), magnesium (Mg), chloride
(Cl), sulphate (SO4) and total phosphorus (TP-PO4) and
altitudinal variation in EC, total dissolved solids (TDS), DO and Na was found
out. The concentrations of the heavy metals (As, Al, Mn, Zn, Cd, Cr) were below
the detection limit except Fe (0.5 to 18.1 mg/l), which was highly variable.
Calcium carbonate weathering was found out to be the major source of dissolved
ions in the region. The elemental ratios (Ca/Si and K/Na) were typical of
glacial melt water and the low Na/Cl and K/Cl ratios indicated major
contribution from atmospheric precipitation to the observed dissolved ions of
melt waters. The study showed an increase in the concentration of cations as
compared to previous studies, which could be attributed to increasing
weathering rates due to temperature increase. Elevated concentration of NO3 and TP-PO4 compared to previous studies show the effect of human
impact in the region. Differences in the melt water composition between the
debris covered and clean type glacier was found out.