SOIL EROSION IN ICELAND - RESULTS

Summary Erosion in Iceland is summarized in this map. This is the first overview of this problem for the whole country based on an actual survey, but the results are preliminary. Land with very severe erosion is shown red on the map, and occurs on 7% of the country. Severe erosion is orange and land with considerable erosion is yellow. Other parts of the country, where erosion is mostly within tolerable levels, are colored green. The numeric information indicates that erosion classes 3, 4 and 5 cover about half of the country, while areas with tolerable levels of erosion cover the other half.

Erosion grade km2 % 0 No erosion 4.148 4,0 1 Litle erosion 7.466 7,3 2 Slight erosion 26.698 26,0 3 Considerable erosion 23.106 22,5 4 Severe erosion 11.322 11,0 5 Extremely severe erosion 6.375 6,2 Mountains 9.794 9,5 Glaciers 11.361 11,1 Rivers and lakes 1.436 1,4 No data 1.010 1,0 Equal 102.721 100

 

Erosion associated with loss of vegetated areas - overview The database can be used to show various kinds of information, such as where the erosion is associated with the loss of continuous vegetation cover, or the formation of new barren lands. This map shows where erosion is currently destroying vegetated ecosystems, which are priority areas for land reclamation in Iceland. Picture A few of the erosion forms that cause the loss of continuous vegetated land (Rofabards, Erosion spots, solifluction slopes, and landslides) are discussed in more detail.

 

Deserts- overview. Most of the severe erosion is associated with the deserts, particularly the sandy deserts. This maps shows the extent of the Icelandic deserts with erosion severity 3 (yellow), 4 (orange), and 5 (red). The deserts are closely linked to the active volcanic belt that runs from SW to NE Iceland, and the glacier margins. Picture Two desert types (Melar, Sandy deserts) are discussed in more detail below. See also: Arnalds, O. and J. Kimble 2001. Andisols of Deserts in Iceland. Soil Science Society of America Journal, 65:1778-1786. Arnalds, O., F.O. Gisladottir, and H. Sigurjonsson. 2001. Sandy deserts of Iceland: an overview. Jour. of Arid Environments 47: 359-371.

 

Rofabards As an example of how the database can be used to retrieve geomorphological information, "rofabards" (erosion escarpments) are taken as an example. As can be seen on the map, they are common in Iceland. Farmers throughout the country are currently making a good effort to halt erosion of this kind. The erosion escarpments are very prominent on the landscape where they occur. Picture  Reference: O. Arnalds, 2000. The Icelandic "rofabard" soil erosion features. Earth Surface Processes and Landforms 25:17-28.

 

Erosion spots Erosion spots are the most common erosion form in Iceland, but erosion is seldom severe where they dominate. They are often a direct result of the interaction between too much grazing and cryoturbation (and the formation of hummocks). Erosion spots on slopes and solifluction Soils on most slopes are quite unstable. Solifluction features such as terraces and lobes are common. When erosion spots form on slopes such as these, rapid erosion occur. Many slopes that are now totally barren were previously covered with vegetation.   Landslides Landslides are very common in Iceland as elsewhere in volcanic regions where the surface is not covered with dense vegetation.   Melar (Lag gravel surfaces) The lag gravel surfaces are extremely common in Iceland. These surfaces were in many cases previously covered with rich Andosols and vegetation, especially in the lowlands. Less can be said about the highlands.   Sandy areas of Iceland Sandy deserts are very common in Iceland. The sources of the sand are glaciers (and glacial rivers) and volcanic ash. The sand can travel long distances before it settles in depression areas or vegetation. Sand encroachment is a severe problem in many areas in Iceland, but the Soil Conservation Service has developed methods that can stop the advancement of the sand.

Edited by Olafur Arnalds and Einar Gretarsson Agricultural Research Institute of Iceland. www.rala.is Last updated on 29/3/2000 by EG