RUNOFF AND SEDIMENT LOSSES FROM TALL FESCUE UNDER SIMULATED RAINFALL

A study was initiated to examine runoff volume and sediment loss from various density tall fescue (Festuca arundinacea Schreb.) turf stands. Plots were established with seeding rates of 0, 98, 244, 390 and 488 kg ha-1 and allowed to mature for 9 months. Three different rainfall intensities (76, 94, and 120 mm h-1) were applied to the plots using a variable intensity rainfall simulator. Results indicate that there were significant differences in runoff volume and sediment load as affected by rainfall intensity. The runoff initiation time for the 0 kg ha-1 seeding rate was the only seeding rate that was significantly different from all others. Mean runoff rates over time were significantly different for the first 5-min time interval of the 30-min storm for all three intensities. There was a significant difference in total sediment load for all three rainfall intensities. At the high (120 mm h-1) rainfall intensity, there was over a sixfold reduction in sediment loss when comparing the 0 kg ha-1 seeding rate to the 98 kg ha-1 seeding rate. Greater sediment loss reductions were observed at the lower rainfall intensities when comparing the same seeding rates. Sediment loss rates did not differ for the 98, 244, 390, and 488 kg ha-1 seeding rates at the low (76 mm h-1) and medium (94 mm h-1) rainfall intensities. At the high (120 mm h-1) rainfall intensity, significant differences were detected between the 0 kg ha-1 and the 488 kg ha-1 seeding rate. The 98, 244, and 390 kg ha-1 seeding rates were not statistically different at this intensity. These results indicate that even low density turfgrass stands significantly reduce sediment loss.