Purpose of Flood Control: Manage river flow to prevent flooding in downstream areas.
Example: Building dams to regulate discharge during heavy rains.
Allows water retention upstream, reducing downstream flooding risks.
Human Behavior in Flood Conditions:
People often underestimate flood risks, attempting risky crossings in swollen rivers.
Increased water speed and depth can lead to dangerous situations.
Many fatalities occur due to misjudgment of river conditions.
Education and Awareness: Important in preparing and protecting communities from flooding dangers.
Environmental Engineering Response:
Companies like CPCL help clean spills and execute flood prevention strategies.
Flood Probability Metrics:
Terms used:
10-year flood: Represents a 10% chance in a given year.
50-year flood, 100-year flood: Longer return periods indicating lower probabilities.
Challenges exist in predicting these metrics accurately across different river sections (reaches).
Impact of Geography on Flooding:
Wide valleys vs. narrow gorges:
Width influences how water spreads and rises. In a wide valley, flood levels may rise minimally, while in a gorge, small increases in discharge can cause dramatic increases in height.
Use of Digital Elevation Models: Visual tools used to assess historical flood risk areas.
Example: Flood risk maps for specific rivers (e.g., Sackville River).
Encouragement to research local rivers for their flood risk metrics based on geographical data over time.
Sediment Management:
Sediment accumulation in rivers can change their morphologies and affect flood risks over millennia.
Importance of understanding sedimentary processes for future flood risk management.