So a lag time changes depending on the characteristics of the river basin
What kinds of things might cause rainfall to enter the river more slowly or more quickly? (Tip – think about factors that slow down infiltration or increase surface run-off)
Short lag times = are caused by steep slopes , impermeable rock, sparse vegetation and a small drainage basin. These mean surface run-off is high so water enters the river quickly following precipitation.
Long lag times = are caused by gentle slopes, permeable rock, dense vegetation and a large drainage basin. These mean surface run-off is lower, there is more interception and infiltration so water takes longer to get to the river channel.
Lag times This could be for an urban location, quick surface runoff and less infiltration This could be for a rural location, slow surface runoff and more infiltration
Lag times are short if water cannot infiltrate or is not intercepted, it means water from precipitation is getting in to the river flow very quickly + there is more surface runoff Could be an urban drainage basin
Lag times are longer if water can infiltrate or gets intercepted, it means water is taking longer to enter the river channel + there is less surface runoff Could be a rural drainage basin