1 Assessment of the Impact of Reclaimed Lands for Rice Fields and Water Conservation Zones on Water Budget and Quality for Sustainable Agriculture in Northeast China PANG Z YUAN L KONG Y LUO L XU B Institute of Geology & Geophysics (IGG), Chinese Academy of Sciences (CAS) Beijing IAEA CN191/56, 24 July 12, Vienna

2 Outline Introduction Methods and materials Hydrological regime Water quality Conclusions

3 Sanjiang wetland observatory

4 400mm 1000mm 900mm 500mm 1200mm Annual Precipitation: 500 mm 300mm Sanjiang Catchments

5 Long-term mean monthly precipitation

6 Wetlands in Sanjiang Plain 1950S 2000

7

8 Past Present

9 Significant drop in the water table has been observed: 4-8 meters in 5 years

10 Outline Introduction Methods and materials Hydrological regime Water quality Conclusions

11 Wetland Monitoring Water lever monitoring well Evapo-transpiration data collection

12 Sampling groundwater

Sampling campaign in August 2011, along a 250km cross section. Monitoring of precipition has been continued in the mean time.

Sampling groundwater W-E cross section in the southern part of the region, where groundwat er and other water bodies have been sampled for stable isotopes and t ritium measurements. a Cross Section b Schematic Hydrogeology

15 Horizontal seepage from the paddy field Description of the contents Horizontal seepage Pipe Horizontal seepage pond Horizontal seepage channel Sampling soil water

16 Sampling soil water

17 DIONEX IC ICP-OESICP-MS liquid-water stable isotope instrument Lab measurements & QA

IAEA TRIC2008 Interlab comparison on Tritium measurements

Tritium measurement IAEA TU TU 1σ T A T A T A T A T A

IAEA WICO2011 Sample δ 18 Oδ2Hδ2H δ2Hδ2H Δδ 18 OΔδ 2 H value1s uncvalue1s uncvalue1s uncvalue1s unc OH OH OH OH WICO2011 Interlab on stable isotopes

21 Rice field plot test A test plot in a paddy field

22 Lab tests of constructed wetlands

23 Outline Introduction Methods and materials Hydrological regime Water quality Conclusions

24 Groundwater monitoring in Honghe, Qianfeng and Qianshao farms Decline of groundwater level Well 1 Well 2 Well 3

25 Hydrological setting of Honghe wetland ET P Inflow Outflow

26 Before 1950s

27 Present

28 Hydrogeology profile of natural wetland

29 Mechanism of transport: Hydrogeology

Tritium in groundwater 30

31 Outline Introduction Methods and materials Hydrological regime Water quality Conclusions

32 Groundwater quality

Groundwater nitrate

34 YalvheNongjiang Raolihe Water quality of smaller rivers in the area has not been affected to a large extent by agricultural activities. River water quality

35 Soil water quality

36 Water in the rice fields

37 Songhuajiang River water quality Wusulijiang Source: Environmental Ministry

38 Outline Introduction Methods and materials Hydrological regime Water quality Conclusions

39 Conclusions Conversion of natural wetlands into paddy rice fields has changed the hydrological regime of wetlands systems to different extents, depending on their hydrogeological settings. Deterioration of surface water quality has been observed, though insignificant. There is a clear correlation to agriclutural activites. Groundwater quality has not been affected on the whole, likely attributing to the slow infiltration into the aquifers. In places where groundwater doesn't receive adequate recharge, river water needs to be used to ensure sustainability.

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