the development of a storm hydrograph will vary depending on several factors including the shape of the river valley (a steep sided valley will get rain into the river much quicker than a shallow one) and as you mention the local geography
of the three examples you have given there will be three very distinctive hydrographs.
A river in an urban setting will have a very steep but short hydrograph because when it rains the rainwater can flow very quickly off tarmac and other impermeable barriers and through drains to reach the river in a short time frame. however as minimal amounts of rainfall gets into the ground the duration is very short.
in a woodland setting you will get a shallow but drawn out hydrograph because a large percentage of rainfall will be intercepted by trees or taken up through roots. The rainfall which gets through will cause a small rise in the hydrograph and over time this will be topped up by the rainfall which eventually gets through the tree canopy. Finally the rise in groundwater levels caused by the rainfall will also increase the storm hydrograph but after a reasonable length of time.
An agricultural setting will result in a hydrograph somewhere between the other two. you will get a relatively steep rise soon after the start of the rainfall event as a result of direct run-off from the fields. However you will often also get a second lower rise later on after the rainfall event has finished as a result of a rise in groundwater levels.
of the three examples you have given there will be three very distinctive hydrographs.
A river in an urban setting will have a very steep but short hydrograph because when it rains the rainwater can flow very quickly off tarmac and other impermeable barriers and through drains to reach the river in a short time frame. however as minimal amounts of rainfall gets into the ground the duration is very short.
in a woodland setting you will get a shallow but drawn out hydrograph because a large percentage of rainfall will be intercepted by trees or taken up through roots. The rainfall which gets through will cause a small rise in the hydrograph and over time this will be topped up by the rainfall which eventually gets through the tree canopy. Finally the rise in groundwater levels caused by the rainfall will also increase the storm hydrograph but after a reasonable length of time.
An agricultural setting will result in a hydrograph somewhere between the other two. you will get a relatively steep rise soon after the start of the rainfall event as a result of direct run-off from the fields. However you will often also get a second lower rise later on after the rainfall event has finished as a result of a rise in groundwater levels.