{
    "title": "Salt Water Irrigation",
    "inventor_name": "Mark Tonkin",
    "publication_year": 2009,
    "device_name": "dRHS irrigation system",
    "goal": "Enable crop production using saline, brackish, or polluted water by delivering water directly to plant roots with minimal waste.",
    "problem_addressed": "Fresh-water scarcity for agriculture, soil salinization, and water loss from conventional irrigation methods.",
    "concept_summary": "A gravity-fed network of sub-surface porous plastic pipes made of a hydrophilic polymer membrane. Water diffuses through the pipe walls to the root zone while contaminants are retained inside the pipe. The system requires no pressure, emitters, or active control; plants draw water on demand, preventing over-watering and reducing evaporation and runoff.",
    "detailed_description": "The dRHS system consists of corrugated tubular hydrophilic membranes (polyether-based polymer) buried in the growing medium. The pipes are filled with any water source-fresh, brackish, salty, or industrial waste. Water moves by diffusion through the porous walls, while virtually all dissolved contaminants are held inside the pipe. The network is fed by gravity from an elevated storage tank, eliminating the need for pumps or pressure regulators. Plants take up water as the soil dries, and the system automatically reduces flow when the soil is wet, thus avoiding over-irrigation. Maintenance consists mainly of occasional flushing to remove accumulated salt crystals. Trials have demonstrated successful growth of tomatoes, radishes, peppers, lettuce, strawberries, beans, and several tree species using water up to seawater salinity.",
    "category": "Mechanical Engineering",
    "principles": [
        "Diffusion through porous hydrophilic membrane",
        "Gravity-fed water delivery",
        "Selective permeability (contaminant retention)",
        "Demand-driven water uptake by plants"
    ],
    "scientific_domains": [
        "Agriculture",
        "Hydrology",
        "Materials Science",
        "Civil Engineering"
    ],
    "mechanisms_of_action": [
        "Water diffusion across porous pipe walls",
        "Capillary action in the root zone",
        "Physical filtration of contaminants"
    ],
    "materials": [
        "Hydrophilic polymer (polyether) membrane",
        "Plastic pipe (likely polyethylene or similar)",
        "Corrugated tubular structure"
    ],
    "energy_sources": [],
    "inputs": [
        "Water of any quality (fresh, brackish, saline, polluted)",
        "Gravity head from elevated supply tank"
    ],
    "outputs": [
        "Clean water delivered to plant roots",
        "Supported plant growth"
    ],
    "claimed_performance": "Can grow a wide variety of crops using salt water or industrial waste water with virtually no evaporation loss, no over-watering, and minimal maintenance.",
    "experimental_evidence": "The system was trialled in the UK with tomato plants and later in the US with multiple crops. Over 20,000 m of pipe have been shipped for testing in the Middle East with water more saline than seawater. Trials are planned in Chile, Libya, Tanzania, Mauritius, and Spain.",
    "replication_status": "Tested in the UK and US; further field trials scheduled in several countries.",
    "keywords": [
        "salt water irrigation",
        "porous pipe",
        "gravity-fed irrigation",
        "hydrophilic membrane",
        "water-efficient agriculture",
        "waste-water reuse"
    ],
    "related_technologies": [
        "Drip irrigation",
        "Subsurface irrigation",
        "Desalination",
        "Hydroponics"
    ],
    "controversy_level": "low",
    "confidence_score": 0.9,
    "practicability_score": 0.8,
    "fringe_score": 0.2,
    "evidence_strength": 0.6,
    "risk_score": 0.1,
    "trl_estimate": 6,
    "source_urls": [
        "http://www.wired.co.uk/news/archive/2009-05/01/irrigation-system-can-grow-crops-with-salt-water.aspx",
        "http://www.dti-r.co.uk",
        "http://web.mac.com/marktonkin/Site/dRHS.html"
    ],
    "organizations": [
        "Dsign Technology and Irrigation",
        "Global Water Intelligence",
        "International Desalination Association"
    ],
    "applications": [
        "Agricultural production in arid or saline regions",
        "Reuse of industrial or municipal waste water for irrigation",
        "Low-maintenance large-scale irrigation"
    ],
    "limitations": [
        "Requires an elevated water tank for gravity feed",
        "Periodic flushing needed to remove salt crystals",
        "Long-term durability of the membrane under harsh water chemistry not fully documented"
    ],
    "open_questions": [
        "How does the membrane performance degrade over years of exposure to highly saline or polluted water?",
        "What are the lifecycle costs compared with conventional drip or sprinkler systems?",
        "Can the system be scaled to thousands of hectares without loss of efficiency?",
        "What is the maximum contaminant load the pipe can retain before performance drops?"
    ],
    "red_flags": [
        "Claims of \"no over-watering\" are idealised and may depend on soil conditions",
        "Limited quantitative data on water use efficiency and crop yields"
    ],
    "evidence_quotes": [
        "The dRHS irrigation system ... can grow crops using salt water.",
        "Water diffuses through the pipe walls, there are no holes or emitters to become clogged or blocked, virtually all contaminants are retained within the pipes.",
        "Since the water is delivered directly to the plant roots, there is much less wastage through evaporation and run-off than with traditional irrigation systems.",
        "The system has so far supported the growth of tomatoes, radishes, courgettes, peppers, lettuce, strawberries and beans as well as three different types of tree - cherry, olive and prosopis.",
        "20,000 metres of pipe are on their way to the Middle East, where it will be tested with water that's more saline than sea water."
    ]
}