Mountains stretch vertically from north to south in the center of the Japanese archipelago. The forests which cover these mountains absorb rainwater through pores in the sponge-like soil, therefore purifying and retaining rainwater. Also, when water permeates through the soil, it passes through rocks and stones which enrich it with minerals, producing good-tasting water. Water originates in the mountains and flows through river and groundwater systems out to the ocean, providing drinking water and water for agricultural and industrial use along the way, as well as supplying the minerals that ocean organisms need for their development. It is important for man that forests, rivers and groundwater veins maintain these functions.

In Japan, communities along many river systems have sought ways to involve downstream beneficiaries using the river water in activities upstream to maintain and manage forests. Such efforts date back to the end of the 18th century, when waterworks and electric power companies offered grants to upstream forestry workers for their afforestation and silviculture activities (Kumazaki, 1984). Today, a diversity of undertakings is seen in different river systems.

This section will introduce two transborder water conservation efforts in which downstream beneficiaries of the water source recharging services and water purification service, provided by forests, have assumed the costs required to maintain and manage forests upstream. It will also introduce the groundwater conservation efforts of a private company that uses pumped up groundwater to return the same amount of water into groundwater veins.