The flow of a river at the start of a baseflow recession, on june 7, 2018, was 4,790 t3/s. after 59 days of continuous recession, on august s, 2018, the flow had declined to 1,631 t/s. (a) what is the value of the recession constant? (b) what will the flow be on september 12, 2018, if the recession continues?

recession constant = 0.9819

Q(97) =  815.6910 m³/s

Explanation:

given data

on June 7, 2018

flow = 4790 m³/s

august flow declined = 1,631 m/s

time = 59 day from June 7, 2018 i.e on August 5, 2018

time = 97 days from June 7, 2018 i.e on September 12, 2018

solution

we know here equation that is

Q(t) = Q(o)  

here Q(t) is flow at any time t and Q(o) is initial flow and

K is recession constant i.e

so first we find recession constant

Q(t) = Q(o)  

put here value

1631 = 4790  

take ln both side

-1.07733 = - 59 a

a = 0.01825

so

recession constant =

recession constant =

recession constant =

recession constant = 0.9819

and

flow after 97 day that is on 12 September

Q(97) = 4790  

Q(97) =  815.6910 m³/s