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Potential Efficiency of Riparian Vegetated Buffer Strips in Intercepting Soluble Compounds in the Presence of Subsurface Preferential Flows.

Allaire SE, Sylvain C, Lange SF, Thériault G, Lafrance P - PLoS ONE (2015)

Bottom Line: However, such strips do not intercept all contaminants, particularly soluble ones.Our results demonstrate that the risk of water contamination by soluble contaminants is high in such systems, even when a well-vegetated buffer strip is used.The design of buffer strips should be modified to account for underground bypass, either by using plants that have deep, fine roots that do not favour PF or by adding a filter extending deep underground that can be regularly changed.

View Article: PubMed Central - PubMed

Affiliation: Département des sols et de génie agroalimentaire, Université Laval, Québec City, Quebec, Canada.

ABSTRACT
Buffer strips have been widely recognized as to promote infiltration, deposition and sorption of contaminants for protecting surface water against agricultural contamination. However, such strips do not intercept all contaminants, particularly soluble ones. Although preferential flow (PF) has been suggested as one factor among several decreasing the efficiency of buffer strips, the mechanisms involved are not well understood. This project examines buffer strip efficiency at intercepting solutes when subsurface PF occurs. Two soluble sorbed tracers, FD&C Blue #1 and rhodamine WT, were applied on an agricultural sandy loam soil to evaluate the ability of a naturally vegetated buffer strip to intercept soluble contaminants. Rhodamine was applied about 15 m from the creek, while the Blue was applied 15 m to 165 m from the creek. Tracer concentration was measured over a two-year period in both the creek and the buffer strip through soil and water samples. Although the tracers traveled via different pathways, they both quickly moved toward the creek, passing beneath the buffer strip through the soil matrix. Our results demonstrate that the risk of water contamination by soluble contaminants is high in such systems, even when a well-vegetated buffer strip is used. The design of buffer strips should be modified to account for underground bypass, either by using plants that have deep, fine roots that do not favour PF or by adding a filter extending deep underground that can be regularly changed.

No MeSH data available.


Related in: MedlinePlus

Precipitation and creek flow during 2011 and 2012.
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pone.0131840.g003: Precipitation and creek flow during 2011 and 2012.

Mentions: The temperature (data not shown) and precipitation of winter 2011 were representative of the 30-year average. The month of May received one large (83 mm) rain event over a short period (Fig 3), representing about half of the 164 mm total for the month. Surface runoff and erosion were observed during this large rain event, and gullies developed throughout the field (Fig 1D). These gullies did not follow wheel tracks but were parallel to the slope. Some of the gullies reached more than 1 m wide. No gullies were observed in the measured area of the buffer strip. During this event, a portion of the sediment was trapped by the grass in the buffer strip, while another portion passed through the strip. This phenomenon seems to have occurred only during this extreme weather event and the prior one in fall 2010, although other intense rainfalls did occur during the summer (Fig 3). The mass of sediments that bypassed the buffer strip was not measured.


Potential Efficiency of Riparian Vegetated Buffer Strips in Intercepting Soluble Compounds in the Presence of Subsurface Preferential Flows.

Allaire SE, Sylvain C, Lange SF, Thériault G, Lafrance P - PLoS ONE (2015)

Precipitation and creek flow during 2011 and 2012.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492607&req=5

pone.0131840.g003: Precipitation and creek flow during 2011 and 2012.
Mentions: The temperature (data not shown) and precipitation of winter 2011 were representative of the 30-year average. The month of May received one large (83 mm) rain event over a short period (Fig 3), representing about half of the 164 mm total for the month. Surface runoff and erosion were observed during this large rain event, and gullies developed throughout the field (Fig 1D). These gullies did not follow wheel tracks but were parallel to the slope. Some of the gullies reached more than 1 m wide. No gullies were observed in the measured area of the buffer strip. During this event, a portion of the sediment was trapped by the grass in the buffer strip, while another portion passed through the strip. This phenomenon seems to have occurred only during this extreme weather event and the prior one in fall 2010, although other intense rainfalls did occur during the summer (Fig 3). The mass of sediments that bypassed the buffer strip was not measured.

Bottom Line: However, such strips do not intercept all contaminants, particularly soluble ones.Our results demonstrate that the risk of water contamination by soluble contaminants is high in such systems, even when a well-vegetated buffer strip is used.The design of buffer strips should be modified to account for underground bypass, either by using plants that have deep, fine roots that do not favour PF or by adding a filter extending deep underground that can be regularly changed.

View Article: PubMed Central - PubMed

Affiliation: Département des sols et de génie agroalimentaire, Université Laval, Québec City, Quebec, Canada.

ABSTRACT
Buffer strips have been widely recognized as to promote infiltration, deposition and sorption of contaminants for protecting surface water against agricultural contamination. However, such strips do not intercept all contaminants, particularly soluble ones. Although preferential flow (PF) has been suggested as one factor among several decreasing the efficiency of buffer strips, the mechanisms involved are not well understood. This project examines buffer strip efficiency at intercepting solutes when subsurface PF occurs. Two soluble sorbed tracers, FD&C Blue #1 and rhodamine WT, were applied on an agricultural sandy loam soil to evaluate the ability of a naturally vegetated buffer strip to intercept soluble contaminants. Rhodamine was applied about 15 m from the creek, while the Blue was applied 15 m to 165 m from the creek. Tracer concentration was measured over a two-year period in both the creek and the buffer strip through soil and water samples. Although the tracers traveled via different pathways, they both quickly moved toward the creek, passing beneath the buffer strip through the soil matrix. Our results demonstrate that the risk of water contamination by soluble contaminants is high in such systems, even when a well-vegetated buffer strip is used. The design of buffer strips should be modified to account for underground bypass, either by using plants that have deep, fine roots that do not favour PF or by adding a filter extending deep underground that can be regularly changed.

No MeSH data available.


Related in: MedlinePlus