The correct option is (d).
Explanation
Lakes are vital components of the hydrological cycle and drainage systems. Whether natural or artificial (reservoirs), they perform essential functions related to water flow regulation, energy generation, and ecological balance.Statement 1 is Correct: Lakes help to regulate the flow of a river. During periods of heavy rainfall, they act as storage basins, absorbing excess water and preventing flooding in downstream areas.
Statement 2 is Correct: During dry seasons or lean periods, the stored water in lakes can be released to maintain a steady and even flow in the river, ensuring water availability for downstream needs.
Statement 3 is Correct: Lakes, particularly those created by dams or situated at high elevations, provide the hydraulic head (potential energy) necessary for developing hydroelectric power (hydel power).
Statement 4 is Correct: Large water bodies influence the local microclimate. They moderate the temperature of the surroundings (lowering temperatures in summer and keeping them warmer in winter) and help maintain the aquatic ecosystem.
Key Takeaway: Lakes are multi-purpose resources that regulate river flow (flood control and dry-season maintenance), support hydropower generation, and moderate the local climate.