Cuspate Foreland - Impacts and Management

Impacts and Management

There are different management issues with regard to cuspate forelands depending on their formation. If a cuspate foreland has formed from deposition, it may be vulnerable if human interference alters the transport of sediments from the shoreline. However if the cuspate foreland is a relic of a past feature that has eroded, human interference with longshore sediment movement will not have a significant impact on the cuspate foreland. For a cuspate foreland to be maintained, the input of sediment must be greater than output of sediment. Activities such as coastal development or engineering must be regulated for sediment to continue moving towards the foreland where it can be deposited. Development along cuspate forelands is risky due to erosion and the vulnerability to storms and sea level rise. As sea levels rise, cuspate forelands are likely to be at risk as they could move inland.

At Point Pelee, approximately 1,900 hectares of former agricultural land on the cuspate foreland is now under water as a result of wind erosion and compaction of organic soils on the foreland. This foreland is particularly vulnerable to erosion when high lake levels are combined with spring and autumn cyclonic activity. Erosion can also occur as spring storms cause ice to scour the lake bottom at the edge of the foreland. Because there is uncertainty about its formation, there is uncertainty with regard to management, although Parks Canada realises the importance of including Point Pelee National Park in management plans.

When there is an aquifer present under a cuspate foreland, regulation of water removal is required. At Dungeness, water restrictions have been put in place to maintain the aquifer level.

The management of coastlines needs to take into account the natural processes that occur on cuspate forelands since many provide a habitat for birds. Alternative ways of managing coastal erosion is needed, such as the use of ‘soft’ defences instead of high impact defences such as sea walls. Some cuspate forelands naturally do not contain any vegetation due to a high level of disturbance from physical factors such as wave action. However with the frequency of storms arising from climate change, the effect on forelands and their associated vegetation needs to be effectively managed.