4l 2004
ributes
hereas,
whole
neated
adakola
Total
4,10
14,00
region,
itershed
ersheds.
dient of
ediment
survey
ts from
h points
S. Thus,
T order
ediment
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
First Second Third Fourth
Order Order Order Order
Numbers 101,0 17,0 2.0 1,0
Stream orders
Average stream
453,0 1899,5 | 24019,9 | 65505,3
length (m)
Average area
T (
(km!) ),1 0,3 4,6 14,1
Average altitude
€ € 3
difference (m) 87,9 113.5 260,0 360,0
Average drainage
density (km/km^) TS 6,8 4,7
Stream que 14.1 2,9 0.2 0.1
(nos. stream/km")
Bifurcation ratio 5.9 8,5 2,0 -
Table 2. Statistical Data on Geomorphometric Parameters of
Thadokhola Watershed
3.2 Landuse/landcover Classification
The landuse/landcover change from 1988 to 2003 within the
study area is shown in Figures 5 to 8. In general, areas under
floodplains/eroded lands have increased whereas those under
rain-fed cultivation land and sparse forest have decreased
within the study area. The expansion of floodplains/eroded
lands and dense forest from 1988 to 2003 were 0.8 and 0.9 km”,
respectively (Figure 5). The increase in dense forest area mostly
due to implementation of hill community forestry, integrated
soil conservation and watershed management programme and
an operational forest management plans after the government
intervention for integrated landuse and natural resources
management.
DO Cultivation Ends D Srarse forest B Aood plans © Dense forest
Whole watershed
Perea (Km)
1998 1999 2000
S
=
e
Figure 5. Changes in Landuse/landcover in Whole Watershed
Landuse/landcover has undergone significant alteration. and
transformation in 2000. Specifically increase in
floodplains/eroded lands observed between 1999 and 2000.
There is a 143 days difference between the dates of the images
taken 1999 and 2000 (November 4, 1999 and February 16,
2000). This is highly significant in compare to the changes
occurred between 1988 and 1999. It is assumed that an intense
rainfall might have occurred during September, 1999 to March,
567
2000, and depleted cultivation lands and sparse forest floors
resulting increase in class 3 areas (rainfall data is unavailable).
This period accords with post harvest and plant dormancy time,
thus might have enhanced erosions.
OCiitiattn Bek OBE: brest MW Flood plas B Legge Toe
m
Thfdorer
en
2
Area
hà
Figure 6. Changes in Landuse/landcover at Third Order
Watershed
DC ricrtior Eds D 5
Secoidorkr
e
cC
„Ara HZ
2
2003
war
Figure 7. Changes in Landuse/landcover at Second Order
Watershed
in Cul luiloniionids D Spase Toesi 8 Acod piis Bl Deree Tesi]
Fir | cider
uh
Figure 8. Changes in landuse/landcover at first order watershed
In the year 2003, cover classes 2 and 3 were decreased and
cover class 4 was increased. Cover class 1, in whole watershed
remain unchanged, whereas, it was observed decreasing in all
sub-watersheds. This reflects the occurrence of abandonment of