河流洪災及其影響：練習題

Which of the following landforms is a depositional feature consisting of an embankment of sediment found along the banks of a river, often formed during flood events?

Compare two drainage basins. Basin A has high drainage density and steep slopes, while Basin B has low drainage density and gentle slopes. How would the storm hydrograph for Basin A differ from Basin B?

A drainage basin has a total stream length of \(150\text{ km}\) and a total area of \(50\text{ km}^2\). Calculate the drainage density and determine its likely impact on the storm hydrograph lag time compared to a basin with a density of \(1.0\text{ km/km}^2\).

In the context of underground water, what is the specific term for the process where water is added back to the groundwater store from the surface?

Which pattern of river flow is characterized by water moving in parallel layers with no vertical or horizontal mixing, usually occurring in smooth channels at low velocities?

In the context of the drainage basin system, describe the process of throughflow.

Explain why a drainage basin with a high drainage density is likely to produce a storm hydrograph with a short lag time.

Analyze the relationship between channel roughness and the hydraulic radius in a river, and explain how these variables influence the efficiency of turbulent flow within a meander.

(a) Briefly explain the difference between porosity and permeability of soils.
(b) Identify two physical factors that can lead to surface water storage in a drainage basin.
(c) Define the term recharge in the context of underground water.

Using your knowledge of discharge relationships:
(a) Explain how urbanisation typically modifies the shape of a storm hydrograph.
(b) Discuss why antecedent moisture is a critical factor in determining whether a river will flood during a high-intensity rainfall event.
(c) Describe how a straightening project (hard engineering) aims to reduce flood risk in a specific river reach.