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1.4 The human impact - Coggle Diagram
1.4 The human impact
Impact of Human Activities on River Processes:
Urbanisation:
Increased impervious surfaces (e.g., roads, buildings) reduce infiltration and increase surface runoff.
Enhanced runoff can lead to higher peak discharge, shorter lag times and increased flood risk.
Artificial drainage systems channel water rapidly to rivers, exacerbating flashy hydrographs.
Deforestation:
Removal of vegetation reduces interception and evaporation.
Increased surface runoff and soil erosion leads to higher sediment loads in rivers.
Reduced groundwater recharge affects baseflow.
Agricultural Practices:
Plowing and soil compaction reduce infiltration and increases surface runoff.
Use of fertilisers and pesticides can lead to water pollution.
Irrigation can lower river discharge, particularly in arid areas.
Mining and Quarrying:
Excavation activities increase sediment load, causing siltation in rivers.
Chemical runoff can pollute water sources.
River Management and Modification
Dams and Reservoirs:
Positive Impacts:
Regular discharge, reducing flood risk.
Provide water for irrigation, hydroelectric power, and domestic use.
Negative Impacts:
Disrupt sediment transport, leading to erosion downstream.
Submerge ecosystems and displace communities.
After natural flow regimes, affecting aquatic habitats.
Channelisation:
Straightening and deepening of channels to improve navigation or reduce flood risk.
Can increase velocity leading to downstream flooding and erosion.
Levees and Embankments:
Constructed to contain river flow and prevent flooding.
Can fail during extreme events, leading to catastrophic flooding.
Flood Control Schemes:
Examples include flood relief channels, wastelands, and storage areas.
Aim to manage peak discharge and protect vulnerable areas.
Water Quality and Pollution:
Sources of Pollution:
Agricultural Runoff: Fertilisers and pesticides cause eutrophication.
Industrial Discharge: Chemicals and heavy metals contaminate rivers.
Sewage Disposal: Untreated sewage introduces pathogens and depletes oxygen levels.
Consequences:
Reduced water quality affects ecosystems and human health.
Bioaccumulation of toxins impacts aquatic life and food chains.
Managment Stratigies:
Enforcement of water quality standards.
Construction of wastewater treatment plants.
Public education on reducing pollution.
Climate Change and Rivers
Impact on River Systems:
Altered precipitation patterns can lead to more frequent floods or droughts.
Rising temperatures increase evaporation, reducing river discharge in some areas.
Glacial melt may initially increase flow in rivers fed by glaciers but could reduces flows long-term.
Human. Adaptation and Mitigation
Improved flood forecasting and early warning systems.
Sustainable river management to cope with increased flood risk.
Reforestation to enhance water retention and reduce runoff.