The potential for offsite movement of nutrients and pesticides in surf
ace runoff from golf courses has generated a need to better understand
the movement of water from intensely maintained turfgrass. This study
assessed the influence that creeping bentgrass [Agrostis stolonifera
L. var. palustris (Huds.) Farw.; syn. Agrostis palustris Huds.] and pe
rennial ryegrass (Lolium perenne L.) had on the surface movement of wa
ter when maintained similarly to golf fairways. On eight dates, 123.5-
m(2) sloped plots of bentgrass and ryegrass were irrigated at 152 mm h
(-1) to force runoff for the generation of hydrographs. As the grasses
matured, runoff from ryegrass occurred earlier and at greater volumes
than from bentgrass. Four additional experiments were conducted to pr
ovide some explanation of these runoff differences. Tn one experiment,
average infiltration rates for the bentgrass (64 mm h(-1)) and ryegra
ss (35 mm h(-1)) plots were not significantly different, because of hi
gh sampling variation. In an experiment that used 0.25-m(2) sloped tra
ys of turf, bentgrass retarded the Bow of surface runoff through its v
egetation significantly longer than ryegrass. It was also found that b
entgrass (1410 tillers dm(-2)) intercepted 113% more water than ryegra
ss (260 tillers dm(-2)), and that bentgrass thatch slowed runoff initi
ation because of its high water-holding capacity and increased hydraul
ic resistance. The high-density, thatch-forming bentgrass provided a m
ore tortuous pathway for water movement, which increased resistance an
d in turn increased residence time and allowed for greater infiltratio
n. For golf courses that have potential runoff concerns, the selection
of creeping bentgrass rather than perennial ryegrass could reduce sur
face runoff from golf fairways.