stress period

[manish manjul]

sir,

pl. tell me about stress period for any study.

On what basis we decide the stress period for any study.????

Thanks in advance

Regards
Manish Manjul

[An Ho Antonio Taylor]

the stress period depends at grosso modo of the pump schedule and the observation heads in days or per month, therefore facilitate representation of the cyclical nature of irrigation, urban water use, and aquifer-system storage. if you want learn more i recommend  Chapter C. Numerical Model of the Hydrologic Landscape and Groundwater Flow in California’s Central Valley by (Faunt, Hanton et. al.) this is a report (Paper 1766) by USGS, is very practical.

Best Regards

2012/5/7 manish manjul <manju...@gmail.com>

Manish Manjul

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[Sajal Adhikary]

Dear Manjul,

It depends on the seasonal behavior you are going to consider. For example, you can divide the whole year (water year) into two periods such as dry and wet period. In that case, you will take recharge in wet period and assume no recharge in dry period. So, you will take two stress periods. If you simulation period is 30 years, then  your stress periods will be 60. all this thing is true for groundwater flow modelling. each stress can be divided into smaller time periods such one month, 15 days, 1 day etc. depending on your work and choice.

But if you further want to do transport modelling, then you have to take smaller stress periods than flow modelling (plz refer to  MODFLOW manual and MT3DMS manual). In that case, you need to divide the previous time step into smaller smaller part, such 1 min, in that case a flow model time step of 1 day will be further divided into 60 time steps. This will be done because you need to establish the numerical convergence criteria and courant no. etc.

thanks

Manish Manjul

[Richard B. Winston]

Stress periods are defined based on when a stress on the system changes.
For example, if a well is turned on or off, that would be a reason for
starting a new stress period. Seasonal changes in recharge and
evaoptranspiration would be other common reasons for defining new stress
periods.

Within each stress period, you need to define a sufficient number of
time steps to get a solution that is accurate enough for the purposes of
the model.