Large catchments in estimating peak runoff, Civil Engineering

Assignment Help:

Question

Is it true that rational process has to not be used for large catchments in estimating peak runoff?


Answer

Rational process is appropriate for small catchments only as time of absorption of small catchments is small. In Rational system peak runoff is calculated based on assumption that time of concentration is equal to rainfall duration. For small catchments, this assumption might hold true in mainly circumstances. One of assumptions of rational process is that rainfall intensity over entire catchment remains constant all through storm period. Though, in case of a large catchment it stands a high possibility that rainfall intensity varies in a variety of part of large catchment. In adding, for long period of rainfall, it is rare that rainfall intensity remains constant over total rainstorm and a shorter period but an additional intense rainfall might create a higher peak runoff. Furthermore, a decrease of peak runoff is also brought about by temporary storage of storm water similar to channels within catchment.

In genuine condition, runoff rate within catchment differs from place to place since of different soil properties and past conditions. Sometimes peak free occurs before all of drainage area is contributing. For example, when a significant portion of drainage area within catchment has very little time of concentration so that a higher rainfall strength be able to be used for this portion, runoff coming solely from this portion is higher than that of whole catchment in which a lower rainfall strength is adopted since remaining part of catchment has comparatively large occasion of concentration. Therefore, this results in wrong estimation of peak runoff of large catchments if rational process is adopted.

 

 


Related Discussions:- Large catchments in estimating peak runoff

Gas welding be erected in upright position, Question Explain some reaso...

Question Explain some reasons why should acetylene gas cylinders used for gas welding be erected in upright position? Answer Acetylene gas is usually used for gas wel

Construction of parabolic shapes, construct parabolic shapes using the enve...

construct parabolic shapes using the envelop method and the offset method with dimensions 80 by 120

Project management, planking and strutting for shallow excavation

planking and strutting for shallow excavation

Torsion, assumptions made in the simple torsion theory

assumptions made in the simple torsion theory

Determine the ground elevation, The trigonometric levelling from the survey...

The trigonometric levelling from the surveyor's notes is shown below. The ground elevation of T (ft) is most nearly: Solution:  The elevation of point P can be found from: E

Design of the aeration basin based on solids retention time, Design of the ...

Design of the Aeration Basin Based on Solids Retention Time - sewer construction: You are provided the following information about a municipal wastewater treatment plant. That

Sampling distribution and approximations of distributions, Sampling Distrib...

Sampling Distribution And Approximations Of Distributions: 1) Learnt three approaches for deriving the probability distributions of functions of one or more random variables v

Earth dam, earth dam design and its force

earth dam design and its force

Torsion, what is torsional moment of resistance

what is torsional moment of resistance

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd