Answers to Questions on Jaltol
From the Q&A session during the Jaltol launch event
The Jaltol digital tool launch on November 30, was attended by around 130 water experts, entrepreneurs and enthusiasts. Though we fielded their questions during the session, we found that the questions they raised were so pertinent that they deserved to be collated and shared. We have clubbed all the audience questions by theme and rephrased them for brevity.
- Is a copy of this presentation available?
Yes, the presentation is available here and on our website.
2. The demo showed data for a past year. For future years, does the tool make forecasts?
We have not provided forecast values for water balance calculation in the Jaltol version 1. This will require adding a hydrological model to estimate the water balance. We hope to incorporate this request in the future versions of the tool. Currently, we are using a numerical method to estimate the water balance. In the upcoming version, we plan to add trend analysis for individual data layers as well as for water balance in the tool. To get updates on the next version of the Jaltol tool, sign up here.
3. As of now, for what time period is data available?
Most datasets are available for a 20-year period (2000–2020) with some gaps. For example, evapotranspiration data is available from 2003, soil moisture from 2015 and groundwater from 1996–2015. More recent data is available but hasn’t yet been input into the tool. We plan to incorporate the latest data in Jaltol version 2. In the next phase we’re also planning to provide alternate data sources for each of these water budget layers. But we expect the time period to cover the most recent decade.
4. What is the source for crop water requirement values i.e., potential evapotranspiration (PET)?
The crop water requirement (CWR) is based on ET from Modis. The next version of the tool will have PET and CWR requirements. This is why we included the LULC maps even in the current version. We’re currently using the SSEBOP dataset (https://earlywarning.usgs.gov/docs/SSEBopETreadme.pdf) and not estimating ET by ourselves.
5. The base LULC layer for Maharashtra is missing. Will it be incorporated later?
Yes, we plan to add Land Use/Land Cover (LULC)for Maharashtra in version 2. We plan to cover the whole of India in a phased manner focusing first on the 7 states included in Atal Jal.
6. What was the validation strategy used for Jaltol model results?
We have not created our own datasets. Jaltol uses previously validated datasets and simple mass balance equation to estimate the water balance. So if any errors exist in the water balance estimates they’re likely to be in the datasets themselves. One easy way to validate the results is to check if the water balance for a particular water year is closing. That is, whether the LHS of the water balance equation is approximately equal to the RHS.
7. Is the tool prepared for managing the loss of rural status and land use of villages due to urbanisation. Also, is it prepared for ponds and lakes losing their purpose as a water ecosystem and attracting real estate.
Jaltol is not well set up for urbanised areas because wastewater return flows become very important in these. But we are hoping to include this in future.
8. The data set is based on secondary data, and the data varies based on the spatial resolution of source data. Will that influence water balance estimates?
The water budget components simply take the mean of all pixels intersecting with the area of interest (village, watershed etc). For example, the resolution of rainfall data is low, approximately 25 km. This means, for a chosen village the rainfall is the mean of one or two pixels. But the resolution of evapotranspiration data is high, about 1 km. This means, for a chosen village the ET is often the mean of several pixels.
9. Is the district irrigation plan referred to as a water security plan?
A water security plan can include a drinking water plan and an irrigation plan for the concerned region. District irrigation plan is part of the Pradhan Mantri Kisan Sinchayee Yojana while the water security plan is part of schemes like Atal Bhujal Yojana and Jal Jeevan Mission. The important thing to note here is that a water balance is the core element of both district irrigation plans and water security plans. We can start intervention planning for drinking water or irrigation requirements on the basis of an accurate water balance.
10. In case of water deficit, is there a possibility to design interventions and simulate the impact of interventions using Jaltol?
Linking intervention planning with the water balance is a challenge faced by many CSOs as we discovered during the first phase of this project. We are currently working on developing indicators like water equity, sustainability, etc. as a part of our typologies work which will be released soon. These indicators will also be incorporated in the Jaltol plugin. This can guide CSOs in intervention planning. We are also developing frameworks for hydrologic impact evaluation of supply and demand side interventions.
11. Will the result of this tool match with groundwater development (GWD) status of safe/critical/overexploited?
That could be a good test case, thanks for the suggestion!
12. Is it possible to calculate the water budget for a lake of a huge watershed area using Jaltol?
Yes. If you have a boundary file you can compute the water budget for any area. Feel free to reach out to us at jaltol@atree.org if you try this and face any challenges.
All information about Jaltol digital tool is available on our website at www.csei.org/jaltol.
To stay updated on Jaltol v2 development, sign up here.
