3Heavy Precipitation Input Compacts the groundBlocks pores with dustReduced infiltrationMore overland flow (which is rapid(more soil erosion)Heavy rain passes through drainage basin quicklyGradual rain infiltrates more (and passage is therefore slowed)
4Heavy PrecipitationAnd Interception(Storage)water can be delivered too quickly for the plants to accommodatea larger proportion of low intensity precipitation will be intercepted as the storage capacity is created by drippage and stemflow
5Interception StorageLeaf cover / breaks fallConifers and deciduous treesInterception slows water passageLeaf drip / stem flowMore likely to infiltrate
7Surface storagePuddles fill up when it rains (slows passage)Can infiltrate if ground porous/permeableCan run-off as overland flow if too much rainor if ground impermeableCan evaporate if weather improvesHere the puddle is frozen
8Infiltration rates (flow) Infiltration into the soilRate may change over timeRate may vary according to type of vegetationIf infiltration capacity exceededThen overland flow occurs
9Emerging from an underground research facility for studying interflow during storms. Throughflow (interflow)
12Overland flow (Flow)Impervious surfaces include any surface, paved or compacted, that does not allow infiltration of water.
13Overland flow on pavement Water flows over the surface of the compacted soil or pavement, picking up pollutants as it moves. The contaminated water will enter a natural drainage, a man-made drainage, or a storm drain. In all three cases, the water ends up in a water body with no treatment for pollutants.
14UrbanisationMany people think of parking lots when they think of impervious surfaces.
15urbanisationMost of the land in this photo could be considered to be impervious surface. Impervious cover ranges from 20% or less on single family large-lot (1-acre +) properties, to 85% or more in commercial sites.
19Vegetation StorageGREEN GARDENING advice from WESSEX WATERCertain plants are particularly well suited to dry conditions, such as succulents, sedums and cacti which have thick waxy leaves to store water. Some plants and grasses have fleshy roots and others such as poppies, reach deep into moist areas in the soil.