Hello, my young geographers! Buckle up because today we're about to dive into the incredible world of storm hydrographs. Picture a water slide with its ups and downs; that's exactly how a river channel reacts to rain!

A storm hydrograph is a chart that tells us how quickly rain falling on a drainage basin reaches the river channel. It's like a speedometer for water!

• Rising Limb: This is like the uphill part of a roller coaster. It shows how much water is getting into the river and how quickly it's increasing. If it's very steep, that means we have a flash flood or the drainage basin is small and the response is rapid. Imagine a city during heavy rain; water quickly rushes to the drains due to the concrete landscape, making the limb steep.

• Peak Flow or Discharge: This is the highest point in the roller coaster where all the adrenaline hits. If the basin is large or the terrain is steep, the peak gets higher because water can't infiltrate the ground quickly. Imagine a big mountain during heavy rain; the water will rush down its sides, causing a high peak in the hydrograph.

• Lag Time: This is the scary pause at the top of a roller coaster before the drop. It's the time between the heaviest rainfall and when the river reaches peak discharge. If the terrain is flat, water takes longer to reach the river, leading to a longer lag time.

• Recessional Limb: This is the speedy downhill ride on a roller coaster after the peak. It shows how the water levels in the river decrease. If the basin is large or the land is flat, this decrease will be slow, like a gentle slope.

• Base Flow: Imagine a slow leaky faucet; that's your base flow. It's the groundwater seeping into the river channel, and it's especially significant where rocks have a lot of space for water (high pore space).

• Run-off Curve: This shows the relationship between surface run-off (water flowing over the ground) and throughflow (water flowing through the soil). For instance, in a parking lot during a storm (low infiltration, high surface impermeability, and strong rainfall), surface run-off will dominate.

• Hydrograph Size: Imagine a bathtub filling up with water; the higher the rainfall, the greater the discharge (more water in the river). Similarly, a larger drainage basin will hold more water, thus increasing discharge.

Rock type greatly influences a storm hydrograph. Impermeable rocks like clay make water run-off quickly, leading to a shorter lag time and a higher peak flow, like a mini flash flood after a rainstorm in a clay-rich area. This is evident in the River Ock, which flows over clay.

Contrastingly, the River Kennet flows over permeable rocks like sands and gravels. This allows water to infiltrate and the river to drain a larger area, leading to a different hydrograph pattern compared to River Ock.

A river's flow isn't the same all year round. We call this pattern of ups and downs the river regime. For example, Arctic streams become raging rivers in the spring due to snowmelt, whereas monsoonal rivers experience peak flows after summer floods.

Factors influencing these seasonal variations include precipitation, temperature and evapotranspiration, vegetation cover changes, rock and soil types, and the size and shape of the drainage basin. Among these, seasonal changes in climate have the most significant impact on river flow, just like how the flow of a tropical river changes drastically between dry and wet seasons.

There you have it, the dramatic life of a river, all explained with hydrographs! Remember, geography isn't just about learning, it's about understanding our Earth, and you're on the right path! Happy studying!