Ecosystem Service Accounts - Flood Control Analysis 2025

Supply of the flood control ecosystem service

The extent of economic assets in floodplains which benefitted from flood control by upstream ecosystems was 142,000 ha. The ecosystem which contributed the most was Inland Wetlands, which provided flood control to 64,800 hectares of economic assets in downstream floodplains. This was followed by Forests & Woodlands (37,400 hectares), Grasslands (31,200 hectares), and Heathlands & Shrubs (7,600 hectares) whereas Settlements & Other Artificial Areas and Croplands each contributed less than 1000 hectares. See Figure 3.1, Table 3.1.

Use of the flood control ecosystem service

The use table shows the area of economic units that use the flood control service (see Table 3.2). The table further divides the use among each economic unit into the ecosystem types which make up the Service Demanding Area. These are: Settlements & Other Artificial Areas, Croplands, and Sown Pastures & Other Grass. Industries were the largest user of the service (134,900 hectares), followed by Governments (4,100 hectares) and Households (2,900 hectares). See Figure 3.2, Table 3.2.

Ecosystems capable of supplying the flood control ecosystem service

The extent of ecosystems which were capable of supplying the flood control ecosystem service was 3.1 million hectares. Grasslands were the largest ecosystem in this area (1.2 million hectares), followed by Inland Wetlands (969,000 hectares), Forests & Woodlands (715,000 hectares), Heathlands & Shrubs (121,400 hectares), Settlements & Other Artificial Areas (75,800 hectares), and Croplands (16,600 hectares). See Figure 3.3, Table 3.3.

Demand & Unmet Demand of the flood control ecosystem service

Demand

There were 262,800 hectares of economic assets in floodplains. This represents 5% of the 4.9 million hectares of the total extent of economic assets. These economic assets comprised of Sown Pastures & Other Grass (232,200 hectares), Croplands (16,400 hectares), and Settlements & Other Artificial Areas (14,200 hectares). See Figure 3.4, Table 3.4.

Unmet Demand

Of the 262,800 hectares of economic assets in floodplains there were 120,900 hectares which did not benefit from any form of flood control from upstream ecosystems. See Figure 3.4, Table 3.4.

It must be stated that the unmet demand area does not represent economic assets in floodplains which have a higher risk of flooding. This is due to the fact that the geospatial model used to calculate this area does not consider existing flood defence measures. Therefore, artificial flood control infrastructure may be providing flood control to economic assets within the unmet demand area. This quantity only shows that there are economic assets in floodplains which do not benefit from flood control provided by upstream ecosystems.