3. summary of the main human interventions in the hydrological cycle

3. Summary of the Main Human Interventions in the Hydrological Cycle

This section gives a summary of the main human interventions identified from the information collected in this study. The interventions have been divided into three main categories:

1. River, lake and estuary regulation;

2. Water abstraction; and,

3. Activities in the catchment’

Each human interventions have been classified into one these categories: some interventions inevitably occur in more than one category but the classification was considered to be appropriate for this investigation and for ease of description. Section 4 gives an overview of each of the 3 categories. More detailed descriptions and examples of the main categories and sub-classes are given in Appendix B.

Tables 3.1 to 3.3 give a summary of the most significant interventions in the hydrological cycle identified by the contributing partners according to biogeographic region.

It appears from the information obtained that the most common and significant human interventions in the hydrological cycle are:

1. Groundwater abstraction for public water supply and for irrigation purposes (in the Atlantic, Continental and Mediterranean regions).

2. Damming for generating hydroelectricity (in the Alpine, Continental and Mediterranean regions and in Norway).

3. Land sealing arising from urbanisation, and land drainage for the purposes of cultivation, occur in each biogeographic region and seem to be as significant as the other interventions described above.

4. Damming for public water supply and irrigation, river channelisation for flood control, drainage purposes and high intensity agriculture obviously exert a major impact on the hydrological cycle.

Examined more closely, and considering that the selection of the interventions is restricted to a relatively small number of countries, it can be seen that a number of human interventions occur in the same regions.

1. Land sealing by urbanisation and land drainage for cultivation occur in all regions but damming for public water supply and for irrigation seem to be typical interventions in the Atlantic and Mediterranean regions.

2. In the Atlantic and the Continental regions the following interventions are common:

• Damming for flood control and fish farming;

• Dredging of river channels to drain land;

• Surface water abstraction for fish farming;

• Wet cuts;

• River channelisation for drainage and agriculture.

3. Groundwater abstraction for public water supply and irrigation purposes are significant interventions mainly in the Atlantic, Continental and Mediterranean regions.

4. Dredging of river channels for mining river bed gravel and surface water abstractions for hydropower and for inter-basin water transfers seem to be typical only for the Alpine region and Norway.

Table 3.1 Major human interventions in the hydrological cycle regarding to category A "River, lake and estuary regulation".

Alp. Alpine region
A Austria
Atl. Atlantic region
DK Denmark
Cont. Continental region
F France
Med. Mediterranean region
N Norway
P Portugal
FI Finland

Part of the Atlantic region in France:
F_n Northern part
F_nw North-western part
F_sw South-western part

Table 3.2 Major human interventions in the hydrological cycle regarding to category B "Water abstraction".

Alp. Alpine region
A Austria
Atl. Atlantic region
DK Denmark
Cont. Continental region 
Med. Mediterranean region
N Norway
P Portugal

Part of the Atlantic region in France:
F_n Northern part
F France
F_nw North-western part
F_sw South-western part

Table 3.3 Major human interventions in the hydrological cycle regarding to category C "Activities in the catchment".

Alp. Alpine region
A Austria
Atl. Atlantic region
DK Denmark
Cont. Continental region 
Med. Mediterranean region
N Norway
P Portugal
F France
FI Finland

Part of the Atlantic region in France:
F_n Northern part
F_nw North-western part
F_sw South-western part

Because different human interventions in the hydrological cycle are made for similar reasons, the results of the contributions have been regrouped. The following table shows the intended purpose of an intervention in the hydrological cycle in the contributing countries.

Table 3.4 Intended reasons of human interventions in the hydrological cycle

Table 3.4 continued

Alp. Alpine region
A Austria
Atl. Atlantic region
DK Denmark
Cont. Continental region 
F France
Med. Mediterranean region
N Norway
P Portugal

Part of the Atlantic region in France:
F_n Northern part
F_nw North-western part
F_sw South-western part