Precipitation

"In meteorology, precipitation (also known as hydrometeor) is any product of the condensation of atmospheric water vapor that is deposited on the earth's surface. It occurs when the atmosphere (being a large gaseous solution) becomes saturated with water vapors and the water condenses and falls out of solution (i.e., precipitates) Air becomes saturated via two processes, Cooling and Adding Moisture. Precipitation that reaches the surface of the earth can occur in many different forms, including rain, freezing rain, snow, sleet, and hail." (European Environmental Agency, 2019)

Sources

European Environmental Agency. "Water glossary". Accessed March 2, 2019. Available at: https://www.eea.europa.eu/themes/water/glossary

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Capacity Building and Training Material

ARSET - Water Resource Management Using NASA Earth Science Data

Overview:

This online course covers precipitation (rainfall and snow fraction), soil moisture, evapotranspiration, runoff and streamflow, groundwater, and lake level heights. Participants are introduced to a number of NASA data products.

Objective:

Participants will be able to use NASA remote sensing observations and land-atmosphere models to: 

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Overview:

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Local Perspectives Case Studies

Project / Mission / Initiative / Community Portal

GPM/DPR : Global Precipitation Measurement/Dual-frequency Precipitation Radar

The 21st century is often called "the century of water." Water is an essential element of the Earth's environment and is indispensable for our life and economic activities. Many places in the world now face water problems, such as water shortages and floods, which can cause food shortages, epidemic diseases, and so on. In addition to these problems, global warming and climate change affect the global water cycle and result in abnormal weather, such as frequent heavy rains and droughts.

Person

Space-based Solution

Collaborating actors (stakeholders, professionals, young professionals or Indigenous voices)
Suggested solution

Why is the approach suggested

Rainwater harvesting is a crucial solution for water scarcity in semi-arid countries like Kenya. Kenya’s arid and semi-arid lands (ASALs) cover 80% of its territory, making rainwater harvesting essential. There are various reasons why this approach can be beneficial in Samburu County.  

  • Water Scarcity Mitigation: Semi-arid regions face unpredictable rainfall and frequent droughts, exacerbated by climate change. Rainwater harvesting captures the little rainfall received, providing a reliable water source. 
  • Sustainable Water Supply: Rainwater harvesting techniques include small planting basins, trenches, stone bunds, and grass strips. These structures redirect runoff towards crops and pastures. By capturing rainwater, communities can sustain livestock, crop production, and domestic needs. 
  • Environmental Resilience: Droughts in Kenya are becoming more frequent due to environmental degradation and climate change. Rainwater harvesting helps mitigate the impact of these droughts.  
  • Cost-Effective and Low-Tech: Rainwater harvesting doesn’t require complex infrastructure. It utilizes existing resources effectively. 

Requirements

  • Site Selection: Identify suitable locations for rainwater harvesting. Consider factors such as rainfall patterns, topography, and proximity to communities. Choose areas with consistent rainfall during specific seasons. 
  • Catchment Area: Determine the catchment area where rainwater will be collected. Common catchment surfaces include rooftops, roads, or open fields. Ensure that the catchment area is clean and free from contaminants. 
  • Conveyance System: Design an efficient system to channel rainwater from the catchment area to storage facilities. Components include gutters, downspouts, pipes, and first-flush diverters. Proper sizing and maintenance are crucial. 
  • Storage Tanks or Reservoirs: Select appropriate storage options based on community needs. Common choices include: 
  • Roof catchment tanks: Placed near buildings to store rainwater from rooftops. 
  • Ground-level tanks: Buried or partially buried to store larger volumes. 
  • Rock catchments: Natural depressions or excavated pits lined with impermeable materials. 
  • Consider tank capacity, material durability, and accessibility for maintenance. 
  • Water Quality and Treatment: Rainwater may contain impurities. Implement filtration systems to improve water quality. Use first-flush diverters to discard initial runoff (which may contain debris). 
  • Climate Resilience: Adapt the project to changing climate conditions. Monitor rainfall patterns and adjust storage capacity accordingly. 

Data requirements 

  • Rainy season identification 
    Decadal Precipitation in Kenya
    Figure 1: Decadal Precipitation in Kenya. Precipitation information during 21-31 December 2023. (Source: Dekadal Rainfall (meteo.go.ke))

     

    • Precipitation data from at least the last three years: CHRIPS  
    Decadal rainfall data
    Figure 2: Decadal rainfall in mm from July 2020 to July 2023. (Source: Dekadal Rainfall (meteo.go.ke))

     

    • Digital elevation Model (DEM)
    DEM in the Samburu County
    Figure 3: Elevation Map (DEM) made with QGIS. Version 3.32.3 / Version 3.28.11 LTR 

    Future steps

    • Map available rainfall with CHIRPS with Kenya Space Agency data ​
    • Determine if enough water can be stored during the rainy season to last the dry season
    • Combine with meteorological data (SPI values)
    • NDVI and DEM to get seasonality of the water cycle
    Relevant publications
    Related space-based solutions
    Keywords (for the solution)
    Climate Zone (addressed by the solution)
    Dry
    Habitat (addressed by the solution)
    Region/Country (the solution was designed for, if any)
    Relevant SDGs