Soft engineering involves the use of the natural environment surrounding a river, and the schemes often work with the river's natural processes. It is mostly less costly than hard engineering.

Forecasts and Warnings:

We use forecasts and Warnings to find out when and where a storm may hit, so we can prepare for the worst that may happen (flooding). Nevertheless this process doesn't prevent the flooding but only gives us an idea how to prepare for it with processes such as flood abatement, contour ploughing and so on.

Flood abatement:

Flood abatement aims to reduce flooding downstream by changing land use upstream. An example of flood abatement would be afforestation - when trees are planted in the upper course of the river valley to intercept the precipitation before it enters the river.

Advantages: It can prevent flooding from the source of the river, it is often cheap.

Disadvantages: The gradient of the land cannot be changed, therefore water is still going to run off into the river when rainfall is heavy. Geology of the land cannot be changed, therefore if the land has impermeable rock, no matter how many trees you plant, the water intercepted is eventually going to hit the impermeable rock and enter the river as through flow. 

Contour Ploughing:

This involves ploughing across a slope following its contour lines rather than down a slope (which would create channels for the water to flow down). It creates a series of stepped ridges which reduce the flow of run off across the land surface, thus reducing the amount of water running into a river.

Advantages: Increased water infiltration and soil moisture storage, therefore less water running off into the river. It is easily manageable and is a cheap solution.

Disadvantages: There is still the problem or heavy rain, which causes the ground to become saturated therefore when there is peak rainfall the precipitation just hits the ground and runs off into the river. Also, the gradient of the slope helps to increase the velocity of the run-off as it hits the ground (so flooding is not completely prevented). Finally, there is the problem of getting the land owner to agree to plough their land along the contours.

Land use management on the floodplain (floodplain zoning):

There are 3 zones:

• Zone 1 - the prohibitive zone, where no further development is allowed except for essential waterfront facilities.
• Zone 2 - the restrictive zone, where only essential development and recreational activities are permitted. All the buildings should be waterproof. 
• Zone 3 - the warning zone, where inhabitants receive warnings of impending floods and are reminded regularly of the flood hazard.

Advantages: people can live close to a river but not be affected by flood unless extreme floods occur. Also, the cost of the scheme is minimal and once put into place, does not take a lot of management.

Disadvantages: there are no hard structures to prevent the flood water, therefore the scheme is flawed in situations such as when there is heavy rain and the river has a high velocity. Also, the scheme can only be put into place in an area of the river which has not been built up, i.e. it cannot be used in areas where the floodplain has already been built on.

Wetland and Riverbank conservation:

Wetlands are areas that are deliberately allowed to flood at times of high discharge. They can reduce flooding to settlements by allowing the water to overflow into them instead of a town. River conservation is the removing of hard management therefore allowing the river to follow its natural course and processes.

Advantages: it is not costly to allow land to be left for wetland, and the conservation of rivers can be good for the natural environment and animal habitats. Also, wetlands and river conservation prevent flood damage to settlements.

Disadvantages: there are no hard structures that can prevent flooding in severe conditions. The most fertile land - the wetlands - cannot be used, furthermore wetlands can often take up a lot of land. Finally, the cost of removing hard engineering can sometimes be a large sum.

River Restoration:

River restoration schemes aim to restore the river's natural processes of erosion and deposition; the involve the use of a floodplain for the water to overflow into.

Advantages: New meanders can hold more water, therefore reducing the risk of floods as there is more room in the river for the floodwater. Also, the scheme is cheap.

Disadvantages: the main problem lies in having to leave space for a large floodplain, also flooding can still occur when the water is traveling at a very high velocity