Why sand dams Our theory of change Our theory of change See below the Sand Dams Worldwide (formerly Excellent Development) theory of change, which outlines our methodology and plan towards our long-term goals - a key part of Our Strategy to 2025. Please donate what you can and help more dryland communities to transform their own lives and land with sand dams Please select a donation amount (required) £25 could provide a farmer with drought-resistant seeds, so they can feed and support their family. £50 could provide a roll of barbed wire to reinforce a sand dam, anchoring it to the bedrock. £85 could provide 500 seedlings and a spray pump, to protect the trees from insects Other Set up a regular payment Donate Manage Cookie Preferences