Jökull


Jökull - 01.12.1990, Page 123

Jökull - 01.12.1990, Page 123
Groundwater from glacial areas in Iceland FREYSTEINN SIGURÐSSON Orkustofnun (National Energy Authority) Grensásvegi 9,108 Reykjavík, Iceland. abstract The major glaciers of Iceland are, at least par- tially, situated on permeable rock formations. These conditions are favourable for the infiltration of groundwater from the base of the glaciers, although dependent on the permeability of the bedrock. From the glacier Langjökull area (= 1,000 km2) 50-80 m3/s are infiltrated but from the glacier Hofsjökull (of a similar size) only 10 m3ls. The total groundwater runoff from the glaciers discussed in the present article (Langjökull, Hofs- jökull, NW- and W-Vatnajökull, N-Mýrdalsjökull) is estimated to be 130-220 rrv’/s. Groundwater from the other glaciers and glacial groundwater flowing at great depths wouldprobably increase the total glacial groundwater runoffto 200-300 rrv’/s. New maps ofthe distribution ofsome major chem- ical components in the groundwater in lceland are presented in the article. The glacial groundwater ap- pears to be characterized by low temperatures and low chemical content, especially in the mineral com- ponents which are normally dissolved from the host rock in the groundwater systems. The glacial groundwater is demonstrated to con- stitute a major component in some shallow aquifers extendingfor some kilometres away from the glaciers. In some fissure zones it can similarily be traced for some tens of kilometres. The dilution of the glacial groundwater is apparently the less the higher the con- finityand the anisotropy ofthe aquifers are. INTRODUCTION Groundwater plays an important role in the hydro- logical regime of Iceland and in the economical activ- ities and prospects of the inhabitants of the country. It supplies freshwater for most of the public water works and for many industrial enterprises, as well as consti- tuting the mainstay of the base flow of the numerous rivers, which are potential sources of hydropower, or even already hamessed for production of electricity. Part of this groundwater is released tardily from soils and rocks, often with considerable seasonal vari- ations and at a low discharge rate per area unit, but part of it is discharged in effluent springs, often grouped together in narrow areas. The latter have usually a rather constant flow, temperature and chemical com- position, indicating a drainage from a larger area and over a long time. (Fig. 1). Some of this groundwater might originate from the glaciers, covering more than one-tenth of the country (Bjömsson, 1979). The precipitation is thought to be exceptionally high on the glaciers (Einarsson, 1976) and substantialparts of them are situated on permeable rock formations, possibly permitting a considerable infiltration into the bedrock. The ice mass of the glaciers acts as a groundwater reservoir, although in a way somewhat different from that of the rocks. There are hydrological differences between the glaciers and the icefree surroundings. On the glaciers the composition of the precipitation is different from the surrounding areas, due to the higher altitude of the surface. The release of the water bound in ice and snow on the glaciers occurs in a relatively short time, compared to the lower surroundings. The hydrologi- cal properties of the glaciers are different from those of most Icelandic rocks. The chemistry of the circulating water is influenced in a different way on the glaciers. It is therefore of interest to consider whether the glacial JÖKULL, No. 40, 1990 119
Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20
Page 21
Page 22
Page 23
Page 24
Page 25
Page 26
Page 27
Page 28
Page 29
Page 30
Page 31
Page 32
Page 33
Page 34
Page 35
Page 36
Page 37
Page 38
Page 39
Page 40
Page 41
Page 42
Page 43
Page 44
Page 45
Page 46
Page 47
Page 48
Page 49
Page 50
Page 51
Page 52
Page 53
Page 54
Page 55
Page 56
Page 57
Page 58
Page 59
Page 60
Page 61
Page 62
Page 63
Page 64
Page 65
Page 66
Page 67
Page 68
Page 69
Page 70
Page 71
Page 72
Page 73
Page 74
Page 75
Page 76
Page 77
Page 78
Page 79
Page 80
Page 81
Page 82
Page 83
Page 84
Page 85
Page 86
Page 87
Page 88
Page 89
Page 90
Page 91
Page 92
Page 93
Page 94
Page 95
Page 96
Page 97
Page 98
Page 99
Page 100
Page 101
Page 102
Page 103
Page 104
Page 105
Page 106
Page 107
Page 108
Page 109
Page 110
Page 111
Page 112
Page 113
Page 114
Page 115
Page 116
Page 117
Page 118
Page 119
Page 120
Page 121
Page 122
Page 123
Page 124
Page 125
Page 126
Page 127
Page 128
Page 129
Page 130
Page 131
Page 132
Page 133
Page 134
Page 135
Page 136
Page 137
Page 138
Page 139
Page 140
Page 141
Page 142
Page 143
Page 144
Page 145
Page 146
Page 147
Page 148
Page 149
Page 150
Page 151
Page 152
Page 153
Page 154
Page 155
Page 156
Page 157
Page 158
Page 159
Page 160
Page 161
Page 162
Page 163
Page 164
Page 165
Page 166
Page 167
Page 168
Page 169
Page 170
Page 171
Page 172
Page 173
Page 174
Page 175
Page 176
Page 177
Page 178
Page 179
Page 180
Page 181
Page 182
Page 183
Page 184
Page 185
Page 186
Page 187
Page 188
Page 189
Page 190
Page 191
Page 192
Page 193
Page 194
Page 195
Page 196
Page 197
Page 198
Page 199
Page 200
Page 201
Page 202
Page 203
Page 204
Page 205
Page 206

x

Jökull

Direct Links

If you want to link to this newspaper/magazine, please use these links:

Link to this newspaper/magazine: Jökull
https://timarit.is/publication/1155

Link to this issue:

Link to this page:

Link to this article:

Please do not link directly to images or PDFs on Timarit.is as such URLs may change without warning. Please use the URLs provided above for linking to the website.