Hydroclimatology of Sariz Creek Watershed, Located In Seyhan Basin, And Simulation Of The Snowmelt...
-
Upload
university-of-the-highlands-and-islands -
Category
Education
-
view
487 -
download
4
Transcript of Hydroclimatology of Sariz Creek Watershed, Located In Seyhan Basin, And Simulation Of The Snowmelt...
International conference: ‘Global Change and the World's Mountains’
Perth, Scotland,
26-30 September 2010
Hydro-climatology Of Sarız Creek Watershed, and Simulation of the
Snowmelt Runoff Using Remote Sensing and Geographic
Information Systems
İbrahim Gürer, [email protected]
İbrahim Ucar, [email protected]
Gökhan Tasdemir,[email protected]
Faculty of Engineering, Gazi University, Ankara, Turkey
Introduction
The significant part of annual runoff volume of central
Taurus mountain basins in Turkey, which are at
altitudes above 1200m, and have a great snow
potential, is constituted by melting of the accumulated
snow in spring months. Modeling of accumulation and
melting of snow is important in view of operating
integrated water resources of such high altitude basins
which are recharged by snow melting as efficient and
sustainable as possible.
Case Study Area
In this study, Sarız basin is chosen as case study area. At
the outlet of Sariz creek, Sarız town is located. The
history of Sariz town goes back to 7000 B.C., and
located at 123km to the east of Kayseri city, the river
basin covers a surface area of 1410km2, and the mean
elevation is 1560m, surrounded by mountains. The main
economy is animal husbandry and agriculture. The
population is about 12700 people according to 2007
census, 8000 live in downtown, but 4610 live in rural area.
There is a strong immigration from Sariz town to big
towns and EU.
Location of Sariz Basin Sarız town
Ankara
İstanbul
Black Sea
Mediterranean Sea
Agean Sea
Kayseri
As in many high plato settlements, the local economy had to be
improved by providing necessary infrastructure by the public sector,
e. i. Turkish State. In this case, Turkish State Hydraulics Works DSI
constructed a weir at about 300m upstream in 1983, to raise the
water level in Sariz creek; of which the annual inflow was basicly
from snowmelt floods, and provided the possibility of gravitational
irrigation of 1080 ha. The Sariz town and the villages around use the
Sariz water during irrigation season starting from the beginning of
May.
To convert dry farming into irrigated farming increases the grains
production tenfold. The state also expects to stop immigration and
keep the people in their original land by providing work in local
industry and decreasing the unemployment.
09.12.2010 6
Irrigation From Sarız Creek
Diversion is 300m u/s from
18-17 stream gauging
station
Size of the area planned to
be irrigate d is 1080 ha.
Operated by local farmers.
The start of the irrigation
season is mid-April and/or
the 1 st of May.
Sariz basin has continental climate, with maximum of 33 oC and the
minimum of -24 oC. The land is covered by low bushes and small
tress of oak and too much erosion at barren surfaces.
Sarız Creek watershed is a sub-basin of Seyhan Basin, with the
coordinates of 3827’ - 3841’ N, and 3627’ - 3640’ E. The flow is
planned to be forecasted by simulation of hydrographs of Sarız
Creek watershed, for the special winters’ of 2004 and 2005 snow
melting seasons (March-April).
Hydro-meteorological Observations
The Sariz creek is equipped with discharge measuring station,
located at 1550m elevation, labelled DSI 18-17 and operated by
Turkish State Hydraulics Works (DSI). In this study the total
hydrographs of spring snowmelt flood, which comes during March-
April periods of 2004 and 2005 are simulated.
Weir, Discharge measuring; 18-17 and Sarız MGİ precipitation stations.
The watershed is covered by snow up to 70% of the winter season
which usually extends from the beginning of January through April.
Perennial snow cover area starts to decrease in March and melts
away completely before the end of April. The main reason to select
the 2004 and 2005 snow melting periods is the more snowfall during
these two years.
The meteorological data is from the station of Turkish Meteorological
Office (DMI) in Sariz located at 1591m elevation. The snow data from
two snow courses of Electric Survey Administration (EIEI), labelled as
18-K10 located at 1670m and 18-K11 located at 1760m.
Simulation Model Used
In this research, snowmelt runoff model (SRM) is used to compute the
runoff produced by melting of the snow accumulated during winter
season. The rate of melting is computed by using the temperature
index. Remote Sensing (RS) and Geographic Information System (GIS)
tools are also utilized to obtain more reliable results in a shorter period
of time. The part of the watershed covered by snow can be defined by
MODIS sensors put in TERRA and AQUA satellites.
SRM model computes the runoff components from the daily snowmelt
and rainfall contributions on the watershed, and superimpose them on
flow recession curve and convert it to watershed outflow by using the
following equation.
n n n n n nn+1 Rn n+1 n+1Sn
A.10000Q =[c .a (T +ΔT ).S +c .P ]. .(1-k )+Q .k
86400
Where
Q= Daily mean discharge (m3/s)
c= Ratio expressing the losses,runoff coefficients(runoff/precipitation) Cs for snow, Cr for
rain
a= Degree day factor(cm/ C.day)
T= Number of degree days (C.day)
T= temperature variation due to elevation difference (C)
S= Snow covered area / Total area
P= Precipitation contributing flow (cm)
A= Basin or area of specific elevation zone(km2)
k= Flow recession coefficient
n= Order of the days
It is necessary to measure T, S, and P and also determine the
parameters of Cr, Cs, T, critical temperature Tkr, k and lag time L,
which are characteristic parameters for a basin and even for climate.
Model Inputs
SRM model uses the spatial variation of snow covered area as input
in model improvement. The images obtained by MODIS sensors of
Terra and Aqua satellites are utilized to determine the variation of
snow borders. For SRM analysis two 500m elevation bands were
selected. In forming the recession curve of snow cover, basicly
images from Terra satellite was used. The Runoff coefficients ; Cs
and Cr were computed from flow data of flow measuring station AGI
18-17.
Flow recession coefficient are derived from consecutive daily flow
data of dry-no precipitation periods.
To compute the daily snowmelt water (M expressed as cm), degree-
day factor (a expressed as cm/0C/day), and daily degree days (T
expressed as oC), are used. Temperature gradient T value is
assumed to be 0.65 oC/100m.
The critical temperature value is assumed as 0.01 oC. Rain
contribution area; RCA was assumed 1 for both 2004 and 2005. In
assessing the lag time, the World Meteorological Organization Study
done by comparative estimates of lag times was utilized.
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
2500
2600
2700
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210
Altitu
de
(m
)
Area (km2)
The area-elevation curve of the Sariz Basin
-12
-8
-4
0
4
8
12
16
1 M
art
04
3 M
art
04
5 M
art
04
7 M
art
04
9 M
art
04
11
Ma
rt 0
4
13
Ma
rt 0
4
15
Ma
rt 0
4
17
Ma
rt 0
4
19
Ma
rt 0
4
21
Ma
rt 0
4
23
Ma
rt 0
4
25
Ma
rt 0
4
27
Ma
rt 0
4
29
Ma
rt 0
4
31
Ma
rt 0
4
2 N
isan
04
4 N
isan
04
6 N
isan
04
8 N
isan
04
10
Nis
an 0
4
12
Nis
an 0
4
Sıc
aklık (
C)
Günler
Ortalama Sıcaklık 2004 Zon A Zon B
Temperature variation during Melting Season
R² = 0.9431
R² = 0.9369
R² = 0.9725
R² = 0.9741
0
100
200
300
400
500
600
1350 1400 1450 1500 1550 1600
Mean P
recip
itation,
Port
(m
m)
Altitude, h (m)
Annual Winter February March-April
Linear (Annual) Linear (Winter) Linear (February) Linear (March-April)
Tomarza Pınarbaşı
Sarız
Variation of Mean precipitation with altitude in Sarız Basin
0
10
20
30
40
50
60
70
80
90
100
1-M
ar
3-M
ar
5-M
ar
7-M
ar
9-M
ar
11
-Mar
13
-Mar
15
-Mar
17
-Mar
19
-Mar
21
-Mar
23
-Mar
25
-Mar
27
-Mar
29
-Mar
31
-Mar
2-A
pr
4-A
pr
6-A
pr
8-A
pr
10
-Apr
12
-Apr
14
-Apr
16
-Apr
Sn
ow
Co
ve
red
Are
a (
%)
Days
Zone A Zone B
Depletion of the snow covered area in the Sarız Basin
Samples from Satellite data of snow covered,
no snow and cloudy parts of the Sarız Basin.
Model Outputs
SRM was run for two different cases for the snow melt seasons of
the years 2004 and 2005. The variables computed and parameters
estimated before the simulation were directly included in analysis.
Hydrograph simulations for March and April of 2004 and 2005 for case 1.
Hydrograph simulations for March and April of 2004 ve 2005 for case 2.
Conclusions
With the available data of limited representation of the basin
characteristics, the simulations of the snowmelt runoff hydrographs
were resulted quite satisfactorily. Especially in Case 2, the average
values of Cs, Cr and flow recession coefficients helped to improve the
hydrograph simulation. If the coefficients and model parameters which
are natural inputs of the SRM simulation are computed from direct field
data, more successful model simulations can be obtained
Acknowledgment
This research was supported by SCR of Gazi University, by Project
Contract No 2006 -02
THANK YOU FOR YOUR PATIENCE