QCM : River Hydrology and Flood Management — 12 questions

Explication

A river drainage basin is the land area where all precipitation and groundwater drain into a main river, bounded by watersheds, as described in the source content.

Explication

Watershed boundaries are often formed by geographical features such as mountain ranges or elevations that serve as natural boundaries separating adjacent drainage basins, as explicitly mentioned in the content.

Explication

The main river system's primary role is to drain water from the drainage basin, including all tributaries, into the sea, forming the complete network that channels water from the land to the ocean.

Explication

The classification of river course sections into upper, middle, and lower courses was first established in the early 20th century, notably by geographer William Morris Davis and later refined by others such as Hack. This framework has been fundamental in geomorphology for understanding river development and morphology.

Explication

Glacier rivers are primarily fed by glacier meltwater, which causes their flow to vary seasonally with melting patterns, whereas rain rivers are mainly influenced by precipitation, leading to more seasonal variability. The other options incorrectly describe the sources and flow regimes of these river types.

Explication

Horton is credited with developing the classification of rivers and their flow regimes, including the concept of flow regime types. The other scientists contributed significantly to river morphology and classification but are not specifically credited with formulating flow regime types.

Explication

Urbanization and soil sealing reduce infiltration capacity, leading to a shorter flow delay time. This causes water to reach the river more quickly after rainfall, increasing peak discharges and flood risks.

Explication

Understanding river gradient and drop helps estimate the river's flow velocity and erosion potential, which are critical for designing effective flood defenses and erosion control measures.

Explication

Flow rate, also known as discharge, refers to the volume of water passing a specific point in the river per second. It is a measure of how much water is flowing through the river at any given time, which is essential for understanding river dynamics and flood risks.

Explication

Precipitation distribution refers to the pattern or spread of rainfall over a specific period, which influences the flow regime of rivers and the timing of peak discharges.

Explication

The Rhine is classified as a mixed river because it receives water from both glacier meltwater and precipitation, resulting in a more uniform flow regime throughout the year, as explicitly stated in the content.

Explication

Understanding tide variations helps in managing flood risks by informing when to heighten or lower dikes, especially during spring tides (vloed) and neap tides (eb), to protect floodplains and inland areas from flooding.