2.3 Flow in Waterfalls

Indicator 2.3 - Flow in Waterfalls


Studlafoss-toppmyndA report was issued in 2008 (only in Icelandic) on the impact of Kárahnjúkavirkjun power plant on waterfalls. The report contains interesting information and numerous pictures of waterfalls some of which have disappeared while others remain unchanged.

The image shows Stuðlafoss waterfall in Laugará river.  Laugará river was not harnessed.



Results

Ufsárlón reservoir and Jökulsárgöng tunnel came into use in the fall of 2008. Filling of Ufsárlón reservoir started on September 11 2008 and the valve of Jökulsárgöng tunnel was opened on October 16 2008, at which time Fljótsdalur Power Station started utilizing water from Hraunasvæði area. Final preparation of the overflow channel in Ufsárlón reservoir was done in the summer of 2009 and finished on August 10 the same year. In beginning of September the same year improvement work was done on the bottom duct of Ufsárlón reservoir. Operations in the area finished in September 2010.

In an average year discharge will be controlled to the waterfalls in Jökulsá í Fljótsdal river from August 10 to October 1.

From June 16 to October 17 2016 discharge was contolled to Jökulsá í Fljótsdal river.  Water conditions in Fljótsdalsstöð power station were below median in the beginning of summer but went above median in the middle of August.

Figure 1 shows flow of Jökulsá í Fljótsdal river by Hóll farm and Hrakstrandarfoss waterfall compared to average flow.


Table 1. Number of days with controlled discharge in waterfalls.

  Year
Tunnel opened 
        (date)
Number of days with
controlled discharge
Tunnel closed 
       (date)
 Average year
     August 10
               52     October 1
     2010      July 16
               67     September 21
     2011      August 18
               58     October 15
     2012      May 31
               129     October 7
     2013      July 18                59     September 15
     2014      June 13
               95     September 25
     2015      -                 0      -
     2016      June 16
               121
    October 18


The summer water flow of Jökulsá í Fljótsdal river can be seen on Landsvirkjun's web .


Figure 1. Summer water flow of Jökulsá í Fljótsdal river in 2016.

Labels:

  • Lág- og hárennsli: The blue background shows the estimated maximum and minimum water flow by Hrakstrandarfoss waterfall in the period 1958-2014.
  • Meðalrennsli: The red line shows the estimated average flow by Hrakstrandarfoss waterfall in the period 1958-2014.
  • Rennsli við Hrakstrandarfoss: The green line shows the discharge through the overflow and bottom duct of Ufsarlón reservoir just above Hrakstrandarfoss waterfall, which is the upmost waterfall of a series of waterfalls in Fljótsdalur valley.
  • Rennsli við Hól: The blue line shows the water flow of the river by Hóll farm. The flowmeter is located above Fljótsdalsstöð power Station before the discharge from the power station merges with Jökulsá í  Fljótsdal river.

At present, some flow can be expected by Hrakstrandarfoss waterfall in late summer when Hálslón reservoir has been filled. Still, there may be some water flow in early summer due to thaw. Figures showing summer water flow 2010-2016 can be downloaded here.


                       Figure 2.  Measuring stations by Jökulsá í Fljótsdal river.


Updated:  August 2 2017
Source:   Landsvirkjun 2015-2017

Metrics, Targets and Monitoring Protocol


What is measured?

Number of days with controlled discharge in waterfalls (Project effect: Indirect).


Monitoring Protocol

Part of regular operation of the power station. Information is gathered simultaneously.


Targets

During average year controlled discharge will be in waterfalls in Jökulsá í Fljótsdal river from August 10 to October 1.

The ruling of Minister for the Environment from  December 20 2001, sets 20 preconditions for the operation of Kárahnjúkavirkjun power plant. Condition no.10 stipulates that the project developer shall utilize overflow water systematically during the tourist season and endeavor to maintain average water flow in Jökulsá í Fljótsdal river and Kelduá river in July and August in years when water is enough. In years with less water, the developer shall place emphasis on having water flowing in the channel of Jökulsá í Fljótsdal river and Kelduá river, during the tourist season as overflow water allows.


Possible countermeasures

Water flow in waterfalls is maintained as close to normal as possible.

Updatet: 22.07.2016 reviewed August 2 2017


Changes to indicator and metrics

At annual meeting of the initiative, May 6th 2015 following change was approved:

What is measured?

Original text
Changed text 
Number of days with normal discharge in waterfalls
Number of days with controlled discharge in waterfalls

Rationale for change:
According to the monitoring protocol the number of days with normal discharge in waterfalls will be measured. There is no normal discharge in the waterfalls. All flow and discharge in the waterfalls is under control and therefore its right to use the word controlled.

In the fourth phase of the sustainability project it was decided to change the numbers of the indicators. This indicator was originally number 30.1 and is referenced as 30.1 in early documents of the project.

Baseline


Landsvirkjun has published a report on the effects of Kárahnjúkavirkjun power plant on waterfalls (see here - only available in Icelandic). This report provides support for the baseline studies.

Generally, a waterfall is defined as water falling vertically from an edge, usually made of rock. In rapids, the water falls down a slope or ledges that are not high enough for the water to fall vertically. The report (above) does not distinguish between waterfalls and rapids and uses the term waterfall for both. It varies how intensely the waterfalls have been studied in the rivers covered. Three rivers, Kelduá river, and Innri- and Ytri Sauðá rivers, have been researched quite thoroughly and all waterfalls and many rapids have been photographed up to certain geodetic height defined in the report.

In the other rivers, waterfalls have not been counted and registered as thoroughly, but Landsvirkjun relies on information from people with local knowledge. No river has been researched all the way up to the glacier edge. With easier access to these rivers, because of new roads in the area, it will be easier than before to gather information about waterfalls and rapids in this area.

The initial harnessing plan for Kárahnjúkavirkjun power plant included the following rivers: Jökulsá á Dal, small rivers that fall into Hálslón reservoir, Grjótá in Vesturöræfi wilderness, Þuríðarstaðadalsá, Hölkná, Laugará, Bessastaðaá, Jökulsá í Fljótsdal, Hafursá, Kelduá, Grjótá á Hraunum, Innri Sauðá, Ytri Sauðá, Fellsá and Sultarranaá.

The ruling of Minister for the Environment on the Environmental Impact Assessment (EIA) for the Kárahnjúkar Hydro project, reduced the scope of the project - causing the following rivers to be excluded from the plan: Grjótá á Vesturöræfum, Þuríðarstaðadalsá,  Hölkná, Laugará, Bessastaðaá, Hafursá, Fellsá and Sultarranaá.

In October 2008, Landsvirkjun administration decided to put the harnessing of Ytri- and Innri Sauðá on hold for an undefined period.


 
The information in table 1 comes from previously mentioned Landsvirkjun report LV-2008/089. It includes all rivers from the initial harnessing plan. The number of waterfalls refers to the number that will be, or could have been affected according to the original harnessing plan.

Table 1: Rivers and waterfalls possibly affected by the Kárahnjúkar project.

Name of river
No. of waterfalls
Harnessing plans
Comments
Jökulsá á Dal 1 River now harnessed
One waterfall created with the harnessing of the river
Small rivers flowing
into Hálslón reservoir
6 River now harnessed Waterfalls disappear
Jökulsá í Fljótsdal 20 River now harnessed Waterfalls higher than 2 m up to altitude of 626 m
Kelduá
33 River now harnessed All waterfalls and rapids up to altitude of 620 m
Grjótá á Hraunum 3 River now harnessed Photos missing from report
          
Innri Sauðá 5 Harnessing postponed
Photos of two waterfalls in report
Ytri Sauðá 11 Harnessing postponed All waterfalls and rapids up to altitude of 691 m
       
Grjótá á Vesturöræfum 1 Min. for the Environment's decision: River not harnessed
Further research recommended
Þuríðarstaðadalsá ? Min. for the Environment's decision: River not harnessed Further research recommended
Hölkná
1 Min. for the Environment's decision: River not harnessed Further research recommended
Laugará 2 Min. for the Environment's decision: River not harnessed Further research recommended
Bessastaðaá 4 Min. for the Environment's decision: River not harnessed Further research recommended
Hafursá 1 Min. for the Environment's decision: River not harnessed Further research recommended
Fellsá 2 Min. for the Environment's decision: River not harnessed Further research recommended
Sultarranaá 1 Min. for the Environment's decision: River not harnessed Further research recommended

According to table 1, the Kárahjúkar Hydro project affects at least 63 waterfalls. Seven waterfalls dissappear but one is created. The discharge in 56 waterfalls is reduced for the main part of every year. The harnessing of two rivers has been postponed. These two rivers contain at least 16 waterfalls.

Harnessing plans for seven rivers have been abandoned (Grjótá and Þuríðarstaðadalsá are two names for the same river. The upper part of the river is called Grjótá and the lower part Þuríðarstaðadalsá). These rivers contain at least 12 waterfalls. The total number of waterfalls in rivers in the original harnessing plan is at least 91.

Rationale for Indicator Selection


A number of waterfalls are affected by the Kárahnjúkar power plant and Fljótsdalsstöð Power Station.

In the river Jökulsá í Fljótsdal, there are many waterfalls along a 30 km stretch from Eyjabakkar to Norðurdalur valley where the river drops by 600 meters. Amongst them are the waterfalls Eyjabakkafoss, Tungufoss, Kirkjufoss, Faxafoss and Gjögurfoss.

On a 20 km stretch from Eyjabakkar to Kleif farm in Fljótsdalur valley, there are 15 waterfalls more than 30 m high. There are also waterfalls in Kelduá river and other rivers in the Hraun area from which water will be diverted to the power plant. In  Jökulsá á Dal river there are no waterfalls but in some of its tributaries there are waterfalls such as Sauðárfoss in Sauðá river and Kringilsárfoss (alias Töfrafoss) in Kringilsá river.

Kárahnjúkar Power Plant will impacts waterfalls in several ways. Some waterfalls will disappear, for instance Sauðárfoss and Kringilsárfoss waterfalls, that will be submerged in the reservoir formed by the damming of Jökulsá á Dal river. Other waterfalls that are not submerged will change due to control of discharge and storage of water in reservoirs.

This applies to the majority of waterfalls in the rivers Jökulsá í Fljótsdal and Kelduá river. Those waterfalls will have reduced water flow while the reservoirs are filling. After the filling of Hálslón reservoir (before mid August in an average year), the operation of the power plant will be managed so that the discharge in the waterfalls in Jökulsá í Fljótsdal river and Kelduá river will resemble natural conditions.


Further reading

Landsvirkjun report LV - 2008 (only in Icelandic).