Inflows

Inflows are resources that enter a system from outside its boundaries. The term is used in several disciplines with related but distinct meanings. In hydrology and water resource management, inflows refer to water entering a lake, reservoir, or watershed from external sources such as rivers, rainfall, snowmelt, and groundwater discharge. In economics and finance, inflows denote funds received by an organization, a sector, or a country from operating activities, financing arrangements, or external sources.

In a hydrological context, inflows are balanced against outflows, evaporation, seepage, and storage changes. They are estimated with stream gauges, rainfall-runoff models, and forecasting methods, and their variability affects water supply reliability, flood risk, and environmental flow requirements. Reservoir operation and drought planning rely on accurate inflow projections to manage storage and releases.

In finance and accounting, cash inflows include sales receipts, interest, dividends, capital gains from asset sales, and loans or equity injections. For a country, capital inflows comprise foreign direct investment, portfolio investments, official development assistance, loans, and reserve asset movements. These inflows influence liquidity, debt sustainability, exchange rates, and monetary and fiscal policy.

Net inflows represent inflows minus outflows. In hydrology, net inflow informs changes in storage and water balance. In finance, net cash flow affects liquidity and funding needs. The composition and reliability of inflows shape risk exposure and resilience to shocks, guiding planning and policy decisions.

See also: cash flow, balance of payments, water balance.