**Tributary**
A tributary is a stream or river that flows into a larger stream, river, or lake. It does not flow directly into an ocean or sea but contributes its water to another watercourse, increasing its volume.
## Overview
Tributaries play a crucial role in the hydrological system by collecting and channeling water from smaller drainage basins into larger rivers or lakes. They help distribute water, sediments, and nutrients throughout a watershed, influencing the ecology and geography of the region.
## Types of Tributaries
Tributaries can vary in size from small streams to large rivers. They are often classified based on their order in the river system, with first-order tributaries being the smallest streams that have no tributaries of their own. Higher-order tributaries form as smaller streams merge.
## Importance
Tributaries contribute to the overall flow and health of river systems. They provide habitats for diverse aquatic species and support surrounding ecosystems. Additionally, tributaries can affect flood dynamics and sediment transport, impacting human settlements and land use.
## Examples
Famous tributaries include the Missouri River, which is a major tributary of the Mississippi River, and the Blue Nile, which joins the White Nile to form the Nile River.
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**Meta Description:**
A tributary is a stream or river that flows into a larger watercourse, playing a vital role in the hydrological and ecological systems of a watershed.