Wednesday 1 September 2004 12.04pm
It sounds more like the sort of maths problem I could never get to grips with -
Presumably you would first need to estimate the surface area of the Thames between Teddington Weir and the Thames Barrier. I think geograpgers have some rough and ready calculus for this if you know the river's width at both points and the distance in a straight line on the map.
You then need the volume of water entering per unit of time,
The only useful infomation I can provide is from
>"The freshwater flow over Teddington Weir is normally maintained at about 800 million litres/day (178 million gallons/day) but it can be as low as 200 million litres/day (44 million gallons/day) in times of drought. Conversely, it may exceed 30,000 million litres/day (6600 million gallons/day) during the winter. The mean flow (taken over 25 years) is about 5200 million litres/day (1145 million gallons/day)."
So you would need to make some assumptions on likely weather...
Also, are you allowed to assume that the slope of the banks doesn't need to be taken into account.