Online Drought Indicators and Indices

Standardized Water-Level Index (SWI) 


Index name: Standardized Water-Level Index (SWI).

Ease of use: Yellow.

Origins: Developed by Bhuiyan at the Indian Institute of Technology, India, as a way to assess groundwater recharge deficits.

Characteristics: As a hydrology-based drought indicator, it uses data from wells to investigate the impact of drought on groundwater recharge. Results can be interpolated between points.

Input parameters: Groundwater well levels.

Applications: For areas with frequent seasonal low flows on main rivers and streams.

Strengths: The impact of drought on groundwater is a key component in agricultural and municipal water supplies.

Weaknesses: Only takes groundwater into account, and interpolation between points may not be representative of the region or climate regime.

References: Bhuiyan, C., 2004: Various Drought Indices for Monitoring Drought Condition in Aravalli Terrain of India. ISPRS Archives – Volume XXXV Part B7, 2004, XXth ISPRS Congress, Technical Commission VII, July 12-23, 2004, Istanbul, Turkey (O. Altan, ed.). International Society for Photogrammetry and Remote Sensing, 1283-1288.

  1. Aarthi
    August 10, 2018 Reply

    Hello sir, this is Aarthi and i am a student of anna university,chennai , doing BE(geo-informatics). your reference article is very much helpful for my final year project idea. But , I have one doubt that ” How to calculate SWI? and which software is used to calculate SWI index?….. please , i request you to clarify my doubts. It’ll be very much helpful for me. please concern my request.

    1. Robert Stefanski
      August 10, 2018 Reply

      Dear Aarti,

      Please see the extract below from the article on the SWI index website:
      SWI has been developed to scale the ground water recharge deficit. The SWI expression stands as
      SWI = (Wij −Wim)/σ

      where Wij is the seasonal water level for the ith well and jth observation, Wim its seasonal mean, and σ is its standard deviation.

      The SWI index webpage is

      And the Article can be found at:

      IDMP Team

  2. Mehran
    November 28, 2018 Reply

    Thank you, sir.

  3. Parimita Saikia
    January 4, 2019 Reply

    I am a beginner in Hydrology. Can you please let me know the steps to use my groundwater level data to calculate SWI. Please explain SWI in basic level

    1. vijay kumar somu
      February 28, 2019 Reply

      mail me i will help you …

    2. Robert Stefanski
      August 12, 2019 Reply

      Dear Parimita Saikia,

      Please refer to the SWI page:

      I would also recommend that you read the following reference:

      Best regards,
      IDMP Team

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