The word "灌溉" is formed by combining two characters, both meaning "to irrigate". 灌 consists of the water radical (氵) and the component "雚", which historically indicates pronunciation, while 溉 similarly uses the water radical (氵) with "既" for pronunciation. Together, they create a compound word where each character contributes the same semantic idea of watering, reinforced by their shared water-related radicals.