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Statistical evaluation of effects of riparian buffers on nitrate and ground water quality

Journal of Environmental Quality

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Abstract

A study was conducted to statistically evaluate the effectiveness of riparian buffers for decreasing nitrate concentrations in ground water and for affecting other chemical constituents. Values for pH, specific conductance, alkalinity, dissolved organic carbon (DOC), silica, ammonium, phosphorus, iron, and manganese at 28 sites in the Contentnea Creek Basin were significantly higher (p < 0.10) in old (>20 yr) discharging ground water draining areas with riparian buffers compared with areas without riparian buffers. No differences in chloride, nitrate nitrogen, calcium, sodium, and dssolved oxygen concentrations in old ground water between buffer and nonbuffer areas were detected. Comparison of samples of young (<20 yr) discharging ground water samples from buffer and nonbuffer areas indicated significantly higher specific conductance, calcium, chloride, and nitrate nitrogen in nonbuffer areas. Riparian buffers along streams can affect the composition of the hyporheic zone by providing a source of organic carbon to the streambed, which creates reducing geochemical conditions that consequently can affect the chemical quality of old ground water discharging through it. Buffer zones between agricultural fields and streams facilitate dilution of conservative chemical constituents in young ground water that originate from fertilizer applications and also allow denitrification in ground water by providing an adequate source of organic carbon generated by vegetation in the buffer zone. Based on the median chloride and nitrate values for young ground water in the Contentnea Creek Basin, nitrate was 95% lower in buffer areas compared with nonbuffer areas, with a 30 to 35% reducton estimated to be due to dilution and 65 to 70% due to reduction and/or denitrification.A study was conducted to statistically evaluate the effectiveness of riparian buffers for decreasing nitrate concentrations in ground water and for affecting other chemical constituents. Values for pH, specific conductance, alkalinity, dissolved organic carbon (DOC), silica, ammonium, phosphorus, iron, and manganese at 28 sites in the Contentnea Creek Basin were significantly higher (p<0.10) in old (>20 yr) discharging ground water draining areas with riparian buffers compared with areas without riparian buffers. No differences in chloride, nitrate nitrogen, calcium, sodium, and dissolved oxygen concentrations in old ground water between buffer and nonbuffer areas were detected. Comparison of samples of young (<20 yr) discharging ground water samples from buffer and nonbuffer areas indicated significantly higher specific conductance, calcium, chloride, and nitrate nitrogen in nonbuffer areas. Riparian buffers along streams can affect the composition of the hyporheic zone by providing a source of organic carbon to the streambed, which creates reducing geochemical conditions that consequently can affect the chemical quality of old ground water discharging through it. Buffer zones between agricultural fields and streams facilitate dilution of conservative chemical constituents in young ground water that originate from fertilizer applications and also allow denitrification in ground water by providing an adequate source of organic carbon generated by vegetation in the buffer zone. Based on the median chloride and nitrate values for young ground water in the Contentnea Creek Basin, nitrate was 95% lower in buffer areas compared with nonbuffer areas, with a 30 to 35% reduction estimated to be due to dilution and 65 to 70% due to reduction and/or denitrification.Using data derived from a study area located in the Contentnea Creek Drainage Basin in North Carolina, the presence of riparian buffers 30-m wide or more and composed of lowland hardwood vegetation was assessed statistically in terms of nitrate-nitrogen concentrations in discharging groundwater passing beneath the buffers. The groundwater and surface-water sampling sites were selected by overlaying a digital coverage of a ma

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Statistical evaluation of effects of riparian buffers on nitrate and ground water quality
Series title:
Journal of Environmental Quality
Volume
29
Issue:
5
Year Published:
2000
Language:
English
Publisher:
American Soc of Agronomy Inc
Publisher location:
Madison, WI, United States
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Environmental Quality
First page:
1523
Last page:
1538
Number of Pages:
16