The system involves a direct collection of rainwater into storage tanks. Implementing such a system has several challenges that a space-based GIS system can address comprehensively. The developed Rain4Drinking portal will be an opensource tool.
The model will be implemented in Google Earth Engine (GEE) and made available to communities through GEE App where they can just provide the shapefile of their rooftop or draw it on the interactive interface to get:
- Size of tank they need
- Type of tank they need
- Best time of the year to store water for drinking
- Filtration requirements
- Indigenised filter available
- Feasibility of the rooftop rainwater collection system
- Cost benefit analysis of the rooftop rainwater collection system
Requirements
Data
- Daily precipitation data: https://www.chc.ucsb.edu/data/chirps3
- Environmental quality assessment:
- https://giovanni.gsfc.nasa.gov/giovanni/
- Local availability of materials for potential required filtration
Software
Open-source cloud computing platform, Google Earth Engine (GEE) will be used for the development of this solution and the code will be public in form of GEE app.
Physical
Storage tank for collecting and storing water is a variable that needs to be constructed physically based on the output from space-based solutions. The important parameters for the tanks are their size and type.
- Size of the tank:
The size of storage tank depends on the amount of rainwater received (varies locally) and size of collection area (rooftop). This requires a temporary track of precipitation in a region.
The rainfall data is also important for quantifying the purity of rainwater, as the month with a little rainfall gives more polluted water than the month with extensive rainfall.
- Type of the tank:
Type of the tank usually comes with economic suitability. Plastic tanks are a ready-made solution but transportation to remote areas is very expensive, so their suitability zone is urban areas and its outskirts. The other option includes ferrocement tanks that can be built on the spot (with a low cost of material transportation) with huge sizes to store even thousands of gallons of water. The two famous types are Kalabashi Tank and Pumpkin Tank
Steps to a solution
The solution will be implemented in following three stages:
- Data access: There are global repositories of air quality and precipitation, developed using both space and ground-based measurements.
- Global rainfall repositories provide rainfall patterns, average precipitation, months of maximum rainfall in a specific region that can help communities to estimate the suitable tank size and time of the year with the best quality of rainwater as well as to meet the water demand during both wet and dry seasons.
- Global air quality repositories provide details of particulate matter, volatile organic compounds and other contaminants in the atmosphere.
- Processing / modelling
- All the online available global repositories can be combined through multi-criteria analysis, helping communities determine their requirements, to estimate cost benefit analysis, and to conduct sustainability as well as risk assessment of their investment in harvesting rain for drinking purposes.
- Implementation of Rain4Drinking: This requires the development of portal allowing governments, organizations and communities to determine their feasibility plans and help them understand the benefits they can have from such investments.
