Efficacy of natural wetlands to retain nutrient, sediment and microbial pollutants

A. K. Knox, R. A. Dahlgren, K. W. Tate, Edward R Atwill

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

Wetlands can improve water quality through natural processes including sedimentation, nutrient transformations, and microbial and plant uptake. Tailwater from irrigated pastures may contribute to nonpoint source water pollution in the form of sediments, nutrients, and pathogens that degrade downstream water quality. We examined benefits to water quality provided by a natural, flow-through wetland and a degraded, channelized wetland situated within the flood-irrigation agricultural landscape of the Sierra Nevada foothills of Northern California. The non-degraded, reference wetland significantly improved water quality by reducing loads of total suspended sediments, nitrate, and Escherichia coli on average by 77, 60, and 68%, respectively. Retention of total N, total P, and soluble reactive P (SRP) was between 35 and 42% of loads entering the reference wetland. Retention of pollutant loads by the channelized wetland was significantly lower than by the reference wetland for all pollutants except SRE A net export of sediment and nitrate was observed from the channelized wetland. Decreased irrigation inflow rates significantly improved retention efficiencies for nitrate, E. coli, and sediments in the reference wetland. We suggest that maintenance of these natural wedands and regulation of inflow rates can be important aspects of a best management plan to improve water quality as water runs off of irrigated pastures.

Original languageEnglish (US)
Pages (from-to)1837-1846
Number of pages10
JournalJournal of Environmental Quality
Volume37
Issue number5
DOIs
StatePublished - Sep 2008

Fingerprint

Wetlands
Nutrients
Sediments
wetland
pollutant
nutrient
Water quality
sediment
water quality
Nitrates
nitrate
Irrigation
Escherichia coli
pasture
inflow
irrigation
Suspended sediments
Water pollution
nonpoint source pollution
Pathogens

ASJC Scopus subject areas

  • Environmental Science(all)
  • Environmental Chemistry

Cite this

Efficacy of natural wetlands to retain nutrient, sediment and microbial pollutants. / Knox, A. K.; Dahlgren, R. A.; Tate, K. W.; Atwill, Edward R.

In: Journal of Environmental Quality, Vol. 37, No. 5, 09.2008, p. 1837-1846.

Research output: Contribution to journalArticle

Knox, A. K. ; Dahlgren, R. A. ; Tate, K. W. ; Atwill, Edward R. / Efficacy of natural wetlands to retain nutrient, sediment and microbial pollutants. In: Journal of Environmental Quality. 2008 ; Vol. 37, No. 5. pp. 1837-1846.
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