Nitrate transport and reduction measures in coastal aquifer of an agricultural watershed, southern Japan

Mitsuyo Saito, Shin Ichi Onodera

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

The authors conducted the study to demonstrate the nitrate (NO3-) transport and reduction process in the coastal groundwater of Seto Inland Sea, southern Japan. The results are summarized as follows: 1) NO3--N concentrations in the shallow groundwater were about 30mgL-1 in the midstream area of the catchment, whereas it decreased less than 2.0mgL-1 in the downstream area toward the groundwater flow direction. The inverse relationship between HCO3--C and NO3--N concentrations suggests biochemical denitrification process in the shallow groundwater. This is also supported by the low ratio of seawater contribution (<1.0%), and relatively low ORP in the groundwater of the downstream area; 2) The NO3--N concentrations in the downstream area were relatively higher in the High-flow season than that in the Low-flow season. This result indicates that the NO3--N discharge by shallow groundwater in the High-flow is larger than that in the Low-flow season; 3) NO3--N concentrations in deep groundwater were higher than that in shallow groundwater at the downstream area. This result suggests that leaching of organic matters from the upper sedimentary layer and groundwater recharge by the river water leads to supply of DOC to the shallow groundwater, and as a result it significantly increase denitrification process in shallow aquifer; 4) Based on these results, NO3--N discharge by groundwater from the study catchment is estimated to be about 5.0% of the annual nitrogen input from fertilizer application at orange groves.

Original languageEnglish
Title of host publication31st IAHR Congress 2005
Subtitle of host publicationWater Engineering for the Future, Choices and Challenges
EditorsJun Byong-Ho, Il Lee Sang, Seo Il Won, Choi Gye-Woon
PublisherKorea Water Resources Association
Pages5381-5388
Number of pages8
ISBN (Electronic)8987898245, 9788987898247
Publication statusPublished - Jan 1 2005
Event31st IAHR Congress 2005: Water Engineering for the Future, Choices and Challenges - Seoul, Korea, Republic of
Duration: Sep 11 2005Sep 16 2005

Publication series

Name31st IAHR Congress 2005: Water Engineering for the Future, Choices and Challenges

Conference

Conference31st IAHR Congress 2005: Water Engineering for the Future, Choices and Challenges
CountryKorea, Republic of
CitySeoul
Period9/11/059/16/05

Keywords

  • Agricultural watershed
  • Coastal aquifer
  • Nitrate
  • Reduction
  • Transport

ASJC Scopus subject areas

  • Engineering (miscellaneous)
  • Environmental Science (miscellaneous)
  • Water Science and Technology

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  • Cite this

    Saito, M., & Onodera, S. I. (2005). Nitrate transport and reduction measures in coastal aquifer of an agricultural watershed, southern Japan. In J. Byong-Ho, I. L. Sang, S. I. Won, & C. Gye-Woon (Eds.), 31st IAHR Congress 2005: Water Engineering for the Future, Choices and Challenges (pp. 5381-5388). (31st IAHR Congress 2005: Water Engineering for the Future, Choices and Challenges). Korea Water Resources Association.