Chengeability of suspended sediment concentration during snowmelt floods in lowland catchment A.HEJDUK, L. HEJDUK, K.BANASIK. Warsaw University of Life Sciences-SGGW. Dept. of Water Engineering. Warsaw. Poland; e-mail:
[email protected]
Introduction The particles of suspended sediment are usually the major part of sediment transported by the cross-section (Banasik 1994). Suspended sediment is the indicator of water quality and erosion processes in the catchment. Increase of suspended sediment transport has a negative impact for the biological life, economic use of water and recreation conditions. Particles of suspended sediment mediate in transport of nutrients and contaminates like phosphorus or heavy metals (Martinez-Carreras et al. 2010). More often effective sediment control strategies are requirement in catchments management plans.
Results The data from Zagożdżonka river demonstrated the individuality of snowmelt floods. The most common type of snowmelt floods recorded in Zagożdżonka catchment is mixed one (snowmelt-rainfall) (Hejduk 2009). Snowmelt floods in Zagożdżonka catchment are not so rapid as in the mountains, but the amount of transported sediment is notable.
Warsaw University of Life Sciences-SGGW, Department of Water Engineering and Environmental Restoration conducts research on suspended sediment transport in small, lowland catchment in central Poland. The aim of this investigation is to recognize the water runoff and suspended sediment transport processes during recorded floods. The results presented on this paper concerns snowmelt floods.
Suspended sediment concentration and it’s relation with the water discharge have been analyzed for 15 snowmelt floods, which occurred between 2001 and 2007.The general information about each flood are given in table 1. Snowmelt floods on Zagożdżonka River tend to be the biggest in hydrological year. The maximum water discharge fluctuated between 0.144-3.444 m3/s. For instance, the two-year -flood discharge WQ50% = 1.04 m3/s for Zagożdżonka River. The recorded value of mean suspended sediment concentration (SSC) during snowmelt floods contained in a range 16.29-25.21 [mg/l], with the average value of 19.5 [mg/l]. Suspended sediment concentration during snowmelt floods is lower then during rainfall one recorded in this same catchment (Hejduk ,2009) According to historical data, the biggest amount of sediment in Zagożdżonka River is transported during winter and spring time. Total mass of transported suspended sediment during snowmelt events fluctuated between 0.48-9.75 Mg., with the average value of 2.2 Mg. The average weight of sediment transported on Zagożdżonka during the hydrological year is about 60 tons. (Hejduk et al., 2006)
Catchment and data collection Warsaw University of Life Sciences-SGGW, Department of Water Engineering and Environmental Restoration developed and manages the monitoring station at Zagożdżonka River. The area of Zagożdżonka catchment till Czarna gauge station is 23.4 km2. Mean annual precipitation is 610 mm, mean annual runoff is 109 mm, the snow cover appear between 25-30 of November and disappear between 20-25 of March. 70% of the catchment area is under cultivation. The investigation has been carried out science 1962, when the first equipment has been installed. The equipment and scope of researches has been modificated during passed years. The gauging station now is equipped with electronic system of data collection connected to Internet. The temperature of: air, water and soil, water level, rainfall and sediment concentration data are collected with 10 minutes time step. The time integrated bathometers, self–acting bathometers, refrigerated samplers and settling tanks collect samples for suspended sediment concentration and grain size analyses as well. Science 2003 also the deep of snow and water content of snow during the winter time are measured every day.
Table 1. General information about recorded snowmelt floods in Zagożdżonka catchment.
Number of The beginning Snowmelt period the flood of the flood
1
2
3
1
5.01.2001
5-02-2001
The end of the flood
Maximum water discharge Q max[m3/s]
Average water discharge Q śr[m3/s]
Land drainage Vgr[103 m3]
Surface runoff
Mean event SSC Vp[103 m3] C[mg/l]
Sediment yield M[Mg]
4
5
6
7
8
9
10
9-02-2001
0.265
0.114
23.6
13.0
18.79
0.69
24-01-2002 0.241
28.9
82.3
3
3.01.2003
3-01-2000
8-01-2000
0.164
0.093
24.8
14.7
10.7
0.42
4
2
20-21.01.2002 1.02.2004
20-01-2002 1-02-2004
3-02-2004
0.156
0.636
0.090
6.9
7.1
22.95
16.29
0.32
1.81
5
10-13.03.2004
10-03-2004
15-3-2004 0.627
0.157
15.3
8.8
19.83
0.48
0.231
0.144
55.9
32.2
21.15
1.86
1-03-2005 6
22-24.02.2005
23-02-2005
7
14-17.03.2005
16-03-2005
20-03-2005 3.444
1.268
43.3
316.3
25.21
9.07
0.219
0.091
24.2
17.9
22.26
0.94
2.781
0.792
118.4
295.7
23.54
9.75
0.184
0.104
20.0
13.4
17.80
0.59
0.144
0.118
21.4
5.0
19.70
0.52
2-02-2007
1.105
0.448
25.8
70.9
22.01
2. 13
6-02-2007
0.799
0.301
77.6
39.5
18.69
2.19
0.307
0.184
42.3
20.5
16.72
1.05
0.427
0.190
42.8
25.4
17.04
1.16
Minimum
0.144
0.090
6.9
5.0
10.7
0.32
Maximum
3.444
1.268
118.4
316.3
25.21
9.75
Average
0.766
0.289
38.1
64.2
19.5
2.2
28-12-2005 8
23-24.12.2005
23-12-2005
9
20-29.03.2006
25-03-2006
10
5.11.2006
5-11-2006
11
28.01.2007
28-01-2007
12
31.01.2007
31-01-2007
13
2-4.02.2007
2-02-2007
14
9.02.2007
9-02-2007
15
13.02.2007
13-02-2007
31-03-2006 10-11-2006 30-01-2007 Figure 1. The location and of Zagożdżonka catchment
12-02-2007 15-02-2007 .
There is a relation between SSC and the water discharge for snowmelt events in Zagożdżonka River. For most of the analyzed floods , the relation between SSC and water discharge shows the clockwise hysteresis, but for two cases (event 2 and 15) this relation shows anticlockwise hysteresis. In two more cases (event 4 and 8) hysteresis of a shape of number „8” have been noticed. In each of recorded snowmelt flood the pick of sediment flood occurred before the pick of runoff flood. The examples of SSC/discharge relation are shown on figure 3. Literature:
Figure 2. Czarna gauge schema, installed equipment and upstream view (Hejduk et.al 1999)
Banasik K., 1994. Model sedymentogramu wezbrania opadowego w małej zlewni rolniczej. Wydawnictwo SGGW. Hejduk A., 2009. Transport rumowiska unoszonego podczas wezbrań roztopowych w małej zlewni rolniczej. Unpublished PhD, SGGW. Hejduk L., Hejduk A., Banasik K., 2006. Suspended sediment transport Turing rainfall and snowmelt floods in a small lowland catchment(central Poland). Rozdział 9 w monografii CABI pod redakcją P.N. Owens i A.J.Collins. Hejduk L., Banasik K., Górski D., 1999.System monitoringu jakości wody i rumowiska dla małej zlewni rolniczej. Konferencja: Postepy w Inżynierii Środowiska, Polańczyk, Martinez-Carreras n., Krein A., Undelhoven T., Gallart F., Iffly J.F., Hoffmann L., Pfister L., Walling D.E., 2010. A rapid spectralreflectance-based fingerprinting approach for documenting suspended sediment sources during storm runoff events. Journal of Soil Sediments 10, 400-413.
European Geosciences Union General Assembly,Vienna, Austria 2-7 May 2010.
Figure 3. Examples of the recorded snowmelt floods and the SSC/discharge relation.
