wAbstract
@Surface water contamination can often be reduced by passing runoff
water through perennial grass filters. Research was conducted
in 2006 to 2008 to evaluate the size of cool season grass filters
consisting primarily of tall fescue (Festuca arundinacea
Schreb) with some orchard grass (Dactylis glomerata L.)
relative to drainage area size in reducing runoff sediment and
phosphorus (P). The soil was Pohocco silt loam Typic Eutrochrepts
with a median slope of 5.5. The grass filters occupying 1.1 and
4.3 of the plot area were compared with no filter with four replications.
The filters were planted in the V-shaped plot outlets which were
3.7~11.0 m in size. The filter effect on sediment and P concentration
was determined from four natural runoff events when nearly all
plots had runoff. Filter effect on runoff volume and contaminant
load was determined using total runoff and composites of samples
collected from 12 runoff events. Sediment concentration was reduced
by 25 with filters compared with no filter (from 1.10 to 1.47
gL-1), but P concentration was not affected. The 1.1
and 4.3 filters, respectively, compared with having no grass
filter, reduced: runoff volume by 54 and 79; sediment load by
67 and 84 (357 to 58 kgha-1); total P load by 68 and
76 (0.58 to 0.14 kgha-1); particulate P (PP) load
by 66 and 82 (0.39 to 0.07 kgha-1); and dissolved
reactive P (DRP) load by 73 and 66 (0.2 to 0.07 kgha-1),
respectfully. A snowmelt runoff event had 56 greater SDP concentration
compared with rainfall-induced runoff events. Grass filters reduced
sediment and P load largely by reducing runoff volume rather than
reducing concentration. Well-designed and well-placed grass filters
that occupy 1.0 to 1.5 of the drainage area and intercept a uniform
flow of runoff from a drainage area can reduce sediment and nutrient
loss in runoff by greater than 50.
Keywords: Sediment; Grass filter; Tall fescue; Water qualityx
1. Introduction
2. Materials and methods
@2.1. Study site and experimental design
@2.2. Runoff sample collection and analysis
@2.3. Statistical analysis
3. Results and discussion
@3.1. Three rainfall and one snowmelt runoff events
@3.2. All runoff events
4. Summary and conclusion
Acknowledgments
References