Final answer:
Constructing a bridge over a stream can lead to higher flood water levels upstream due to obstruction and reduced flow area. Stream gauge data is important for predicting floods and making flood control decisions. Thoughtful construction is needed to avoid worsening potential flooding.
Step-by-step explanation:
When a bridge is constructed over a stream, it can have significant impacts on the flood water level of the stream. The presence of the bridge structure can act as an obstruction, reducing the effective cross-sectional area through which the water can flow.
This constriction can cause water to back up upstream of the bridge, leading to higher water levels and potentially increased flooding, especially during high-flow events such as heavy rainfall or snowmelt.
Floodplains are often developed due to their attractive views, but the construction on them can exacerbate the flooding issue. During periods of intense rainfall, stream gauge data can help predict flood frequency and severity, guiding construction and flood control decisions.
It's important to consider the potential for obstruction and the alterations to natural water habitat when constructing bridges to avoid exacerbating flood risks, especially in areas prone to high rainfall or significant snowmelt.