(1) Meteorological/Climate factor: -Rainfall intensity -Rainfall amount -Rainfall duration -Distribution of rainfall over the drainage basin. (2) Phsyiographic factors (e.g. watershed) - watershed size -Watershed shape -watershed slope (3) Vegetation - Dense vegetation leads to less run-off while sparse vegetation leads to more run-off. (4) Urban development. - Roads and buildings have do not allow infiltration into the soil. Water will therefore run off directly into the stream, at a very fast rate and in significant volume.