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Irrigation Method · Irrigation method

Rainwater Harvesting

Also known as: Rainwater catchment, Water harvesting

Rainwater harvesting captures and stores rainfall or runoff — from field surfaces, catchment areas, or rooftops — in ponds, tanks, or soil-based structures for later use in irrigation, supplementing or extending other water sources.

Dated referenceLast reviewed: 2026-07-12Updated: 2026-07-12
Illustrative diagram · AgricultureID (original)

Rainwater harvesting spans a range of techniques, from simple in-field structures such as contour bunds and small check dams that capture runoff, to farm ponds and reservoirs, to rooftop or surface catchment systems feeding storage tanks. The shared purpose is capturing water during wet periods for use during dry spells or to supplement other irrigation sources.

It is particularly valued in regions with pronounced wet and dry seasonality, such as monsoon climates, or where access to groundwater or canal irrigation is limited. Storage capacity, evaporation losses, and construction or maintenance costs constrain how much water can practically be captured and held.

Common techniques

  • Farm ponds and small reservoirs that collect and store runoff
  • Check dams and percolation tanks that slow runoff and encourage groundwater recharge
  • Contour bunds and trenches that slow and capture surface runoff on sloped land
  • Rooftop or surface catchment systems feeding storage tanks

The appropriate technique depends on the catchment available, terrain, and the scale of storage needed for the intended use.

Why it is used

Rainwater harvesting can bridge short dry spells within a wet season, extend water availability into the dry season, reduce dependence on groundwater pumping, and buffer some of the variability in seasonal rainfall.

Design and storage considerations

FactorWhy it matters
Catchment area and rainfall patternDetermines the potential volume of water that can be captured
Storage capacityLimits how much water can be held between rain events
Evaporation and seepageReduce the effective stored volume over time
Water qualityAffects suitability of stored water for irrigation versus other uses
Key factors affecting rainwater harvesting performance

Benefits and trade-offs

  • Can extend water availability into dry periods within or after the rainy season
  • Reduces reliance on groundwater pumping or external water supplies
  • Can be implemented at a range of scales, from small farm structures to community reservoirs
  • Does not create new water; it redistributes captured rainfall in time
  • Construction and maintenance require investment and ongoing upkeep
  • Storage volume is limited by catchment area, structure size, and evaporation or seepage losses

Where rainwater harvesting is used

Rainwater harvesting is practiced across smallholder and larger farming systems in seasonal-rainfall and water-scarce regions worldwide, often alongside other irrigation methods rather than as the sole water source.

Relationships

Evidence-backed connections in the knowledge graph.

Irrigates

Related topics

Scope & limitations

Geographic scope: Practiced worldwide, especially in regions with strongly seasonal rainfall or limited groundwater or canal access; specific techniques and storage scale depend on local rainfall and terrain.

Climate context: Most valuable in climates with pronounced wet and dry seasons, such as monsoon regions, where captured wet-season water can extend availability into drier months.

  • Rainwater harvesting redistributes captured rainfall rather than adding new water to a region.
  • Storage capacity, evaporation, and seepage limit how much can practically be held; no universal capacity or yield figures are given.

Sources

This article draws on the following authoritative sources. See our sources & methodology for how they are selected.

  1. [1]FAO — Land and Water (opens in a new tab)

    FAO Land and Water Division

    Authoritative

    Cited for: Rainwater harvesting techniques and water-management context

    Type:
    Intergovernmental organization
    Jurisdiction:
    Global
    Accessed:
    2026-07-12
  2. [2]FAO — Food and Agriculture Organization (opens in a new tab)

    Food and Agriculture Organization of the United Nations (FAO)

    Authoritative

    Cited for: Water harvesting in smallholder and rainfed farming systems

    Type:
    Intergovernmental organization
    Jurisdiction:
    Global
    Accessed:
    2026-07-12
  3. [3]USDA NRCS — Natural Resources Conservation Service (opens in a new tab)

    USDA Natural Resources Conservation Service (NRCS)

    Authoritative

    Cited for: Farm pond and water-storage structure guidance

    Type:
    Government agency
    Jurisdiction:
    United States
    Accessed:
    2026-07-12
  4. [4]AHDB — Agriculture and Horticulture Development Board (opens in a new tab)

    Agriculture and Horticulture Development Board (AHDB)

    High

    Cited for: On-farm water storage and irrigation supply context

    Type:
    Government agency
    Jurisdiction:
    United Kingdom
    Accessed:
    2026-07-12

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