*Assessment of the Impact of Reclaimed Lands for Rice Fields and Water Conservation Zones on Water Budget and Quality for Sustainable Agriculture in Northeast ChinaPANG Z YUAN L KONG Y LUO L XU Bz.pang@mail.iggcas.ac.cn Institute of Geology & Geophysics (IGG), Chinese Academy of Sciences (CAS) BeijingIAEA CN191/56, 24 July 12, Vienna

*OutlineIntroductionMethods and materialsHydrological regimeWater quality Conclusions

*Sanjiang wetland observatory

*400mm1200mmAnnual Precipitation: 500 mm300mmSanjiang Catchments

*Long-term mean monthly precipitation

*Wetlands in Sanjiang Plain1950S2000

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

*OutlineIntroductionMethods and materialsHydrological regimeWater quality Conclusions

*Wetland Monitoring

* 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 groundwater and other water bodies have been sampled for stable isotopes and tritium measurements. aCross SectionbSchematic Hydrogeology

*Horizontal seepage from the paddy field Sampling soil water

*Sampling soil water

*DIONEX ICICP-OESICP-MSliquid-water stable isotope instrumentLab measurements & QA

IAEA TRIC2008 Interlab comparison on Tritium measurements

Tritium measurement

IAEATUTUTU1T141.541.540.000.40AT154.073.960.110.45AT167.747.880.140.53AT1714.4614.890.430.53AT180.670.380.290.36A

WICO2011 Interlab on stable isotopes

IAEA WICO2011Sample18O2H18O2H18O2Hvalue1s uncvalue1s uncvalue1s uncvalue1s uncOH-13-0.960.04-2.30.9-0.860.06-2.1 0.33-0.10 -0.2 OH-14-5.590.05-37.70.8-5.510.05-37.3 0.32-0.08-0.4 OH-15-9.370.04-78.0 0.8-9.340.06-77.5 0.31-0.03-0.5 OH-16-15.410.04-113.80.9-15.330.08-114.2 0.42-0.080.4

*Rice field plot test

*Lab tests of constructed wetlands

*OutlineIntroductionMethods and materialsHydrological regimeWater quality Conclusions

* Groundwater monitoring in Honghe, Qianfeng and Qianshao farmsDecline of groundwater levelWell 1Well 2Well 3

*Hydrological setting of Honghe wetlandETPInflowOutflow

*Before 1950s

*Present

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*Mechanism of transport: Hydrogeology

Tritium in groundwater*

*OutlineIntroductionMethods and materialsHydrological regimeWater quality Conclusions

*Groundwater quality

Groundwater nitrate

*YalvheNongjiangRaoliheWater quality of smaller rivers in the area has not been affected to a large extent by agricultural activities.River water quality

*Soil water quality

*Water in the rice fields

* SonghuajiangRiver water quality WusulijiangSource: Environmental Ministry

*OutlineIntroductionMethods and materialsHydrological regimeWater quality Conclusions

*ConclusionsConversion 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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