Conference presentation

1. Spatial distribution of halobity
in floodplain related to OM
accumulation
Gabriella Tóth, Amadé Halász, József Dezső,
Jakub Miřijovský, Dénes Lóczy
Hungarian Scientific Research Fund

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Old-Drava Rehabilitation Programme (ODP)
”ecologically sustainable and cost-effective water supply”
Research area of Univ Pécs (2013-14)
Cún-Szaporca oxbow
„check the ODP plans”
planned pipe or channels
for water recharge and
regulation
lakes, oxbows under
revitalization
settlements
planned reservoirs
forests with
planned irrigation
arable with
planned irrigation
sluices

3. THE CÚN – SZAPORCA OXBOW

5. The planners* set the following criteria for the regulation of water level:
• Water level fluctuation should not exceed 0.5 m within a year;
• Water recharge should take place step by step, in divisions;
• In a year water recharge should be implemented by not more than two
fillings;
• The length of the filling period should remain within two weeks.
*In the planning document Old Drava Project

6. Problematic planning
concept and calculations
• Success of water recharge is questionable:
hydraulic connection not clear
• Quality of inflow water is different from that in
the oxbow
• water quality parameters of Lake Kisinc are not
pecisely known

7. Study area
• Area: 20 ha
• Length: 2 km
• Average latitude: 100
m
• Average depth: 1 m
•Lake Kisinc, one of the remains of the late Old-
Drava bed
•The bank is significantly covered with tangle

8. Problems
• Lack of water, water quality,
• Exploitation of the lake, aims (by
planners):
• Protection of ecologycal/natural values,
restitution of wetlands;
• ‘Establishment of sustainable water-
management in the region’
• ‘Development of tourism and recreation’

9. Water supplement (plans)
90, 70 mBf 158 000 m3 A= 318525 m2 >>> 91,5 mBf (645 000 m3) A=635 000 m2

11. Water quality of Fekete-víz stream
EC: 937 μS; DO: 5.72 mg/l; O2: 68.8%, KOI: 8.7 mg/l
Feeder canal
(under construction)
Water quality of Drava river (earlier natural water supplier, until 1976)
EC: 283 μS; DO: 8.99 mg/l; O2: 101.1%, KOI: 4.1 mg/l

12. The aim
• Measure Lake Kisinc (oxbow), waterchemistry,
the daily dynamism of the parameters (halobity)
• Is the condition suitable after a cool and rainy
summer, by the measured parameters?
Mesotrophic condition Eutrophic condition
Phosphorous
µg/l
10-30
Phosphorous
µg/l
30-100
Total
nitrogen µg/l 400-600
Total
nitrogen µg/l 600-1500

13. Sampling
• water sampling for every
hour in 24 hours from two
different depth:
30 cm
210 cm

14. Measurements
In field:
Rapidly varying parameters:
WTW 390i
pH
C°
Redoxpotential
Soluted O (mg/l, (%)
In laboratory:
Nanocolor 500D VIS
NH4
+, NO3- -- PO4
PO4-T
KOI

15. 2 4 6 8 10 12 14 16 18 20 22 24
18
19
20
21
22
237,0
7,2
7,4
7,6
600
650
700
750
1
2
3
4
10
20
30
40
50
20
30
40
0,06
0,08
0,10
0,12
0,14
0,10
0,15
0,20
0,0
0,1
0,2
0,3
0,40
1
2
3
2 4 6 8 10 12 14 16 18 20 22 24
16
18
20
22
hours (210cm)
T(water) (°C)
pH
EC (µS)
O2 (mg/l)
O2 (%)
KOI (mg/l)
Orto-P (mg/l)
Total-P (mg/l)
nitrate (mg/l)
ammonium (mg/l)
T (air) (°C)
2 4 6 8 10 12 14 16 18 20 22 24
20
21
22
7,6
7,8
8,0
540
545
550
555
560
565
2
3
4
5
10
20
30
40
50
60
24
26
28
30
0,00
0,04
0,08
0,06
0,08
0,10
0,12
0,02
0,04
0,06
0,080,0
0,1
0,2
0,3
0,4
2 4 6 8 10 12 14 16 18 20 22 24
16
18
20
22
hours (30cm)
30cm
30
EC (µS)
O2 (mg/l)
O2 (%)
KOI (mg/l)
Orto-P (mg/l)
Total-P (mg/l)
nitrate (mg/l)
ammonium (mg/l)
T (air) (°C)

16. Classification

18. Results
• No thermo-stratification
Oxygen:
ORP: -210 cm (kb – 30 mV)
O2: low (mg/l) also in saturation %
C circulation:
KOI: high
Phosphorous forms:
Orto- and total phosphate grate – adequate
Nitrogen forms:
nitrate, ammonium: great - tolerable

19. Conclusion
1. Bad water quality remains
2. Shallow depth: deeper layers (-210cm) heat up,
low soluted O2 capacity
3. ORP: deeper layers are reductive (average: -
30mV), high KOI: high organic matter content
4. Moderated transport of nutrients
5. The bigger water surface won’t owe adequate
depth
6. Periodically refilling from Dráva river (I. class
water quality): inland inundation

20. • Earlier investigations
show similar results,
most of the oxbows
are at the same
condition.

21. Thank you for your
attention!
Hungarian Scientific Research Fund