Indicator 2.3 - Flow in Waterfalls

This indicator applies only to Landsvirkjun.

A number of waterfalls are affected by the Hálslón reservoir and Fljótsdalur Power Station.

In the river Jökulsá in Fljótsdal, there are many waterfalls along a 30 km stretch from Eyjabakkar to Nordurdalur 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 in Fljotsdalur, there are 15 waterfalls more than 30 m high. There are also waterfalls in the river Kelduá and other rivers in the Hraun area from which water is diverted to the power plant.

In the river Jokulsá in Dal there are no waterfalls but in some of its tributaries there are waterfalls such as Sauðárfoss in the river Sauðá and Kringilsárfoss (alias Töfrafoss) in the river Kringilsá. Some waterfalls will disappear and others will change due to control of discharge and storage of water in reservoirs.

The purpose of this indicator is to monitor how the waterfalls change because of the power station.

The photo above is not connected with the projects.

Performance

Ufsárlón reservoir and Jökulsárgöng tunnel were started in the fall of 2008. Filling of the reservoir started on 11 September 2008 and the valve of the tunnel was opened on 16 October 2008, at which time Fljótsdalur Power Station started utilizing water from the Hraun area. Finalising of the overflow channel in Ufsárlón was done in the summer of 2009 and finished on August 10th the same year. This part of the Kárahnjúkar project - the Hraun area - was finished in September 2010.

a. Number of days with normal discharge in waterfalls.

On the 18th of August 2011, the flow through Jökulsárgöng tunnel was cut off, and therefore, the river Jökulsá in Fljótsdalur flowed normally. On the 15th of October 2011, the tunnel was opened again. The chart below shows the flow by Hóll in the summer of 2011, as compared with the average flow.

Chart 1: Summer flow of Jökulsá river in Fljótsdalur in 2011.

The chart shows the summer flow of Jökulsá river in Fljótsdalur in two places in 2011. It also shows the estimated mean flow and the span of minimum and maximum flow from 1950-2004.

• The violet line shows the discharge through the overflow and bottom duct of Ufsarlón reservoir above Hrakstrandarfoss waterfall, which is the upmost waterfall of a series of waterfalls in Fljótsdalur.
  
• The red line shows the flow of the river by Hóll. The flowmeter is located above Fljótsdalur Power Station before Jökulsá in Fljótsdalur and the discharge from the power station are combined.
• The blue line shows the estimated average flow by Hrakstrandar waterfall in the period 1950-2004.
• The blue background shows the estimated maximum and minimum flow by Hrakstrandar waterfall in the period 1950-2004.
  

At present, some flow can be expected by Hrakstrandarfoss waterfall in late summer when Hálslón has been filled. Still, there may be some water flow in early summer due to thaw. You can view a map showing these two measuring stations (blue dots) by clicking here.

Metrics, Targets and Monitoring Protocol

a. Number of days with normal discharge in waterfalls. (Project effect: indirect).

Targets

a. During average year normal discharge will be in waterfalls in Jokulsa in Fljotsdal from August 10^th to October 1^st.

The Minister for the Environment's decision from 20 December 2001 sets 20 conditions for the operation of Kárahjúkar Hydroelectric Plant. Condition No. 10 stipulates that the project developer shall utilize overflow water systematically during the tourist season to get a normal water flow of Jökulsá in Fljótsdalur and Kelduá in July and August in "good water years." In lesser water years, the developer shall take care to keep the water flowin these two rivers during the tourist season as overflow water allows.

Monitoring Protocol

a. Part of regular operation of the hydro station. Information is gathered simultaneously.

Rationale for Indicator Selection

A number of waterfalls are affected by the Kárahnjúkar reservoir and Fljótsdalur Power Station.

In the river Jokulsa in Fljotsdal, there are many waterfalls along a 30 km stretch from Eyjabakkar to Nordurdalur 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 in Fljotsdalur, there are 15 waterfalls more than 30 m high. There are also waterfalls in the river Kelduá and other rivers in the Hraun area from which water will be diverted to the power plant. In the river Jokulsá in Dal there are no waterfalls but in some of its tributaries there are waterfalls such as Sauðárfoss in the river Sauðá and Kringilsárfoss (alias Töfrafoss) in the river Kringilsá.

The Kárahnjúkar Hydroelectric Plant will impact waterfalls in several ways. Some waterfalls will disappear, for instance Saudárfoss and Kringilsárfoss that will be submerged in the reservoir formed by the damming of Jokulsa in Dal. 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 Jokulsá in Fljótsdalur and Kelduá. Those waterfalls will have reduced water flow while the reservoirs are filling. After the filling of Halslón (before mid August in an average year), the operation of the power plant will be managed so that the discharge in the waterfalls in Jokulsá in Fljótsdal and Kelduá will resemble natural conditions.

Baseline studies

The rivers in the area affected by the Karahnjukar Hydroelectric Plant have been mapped and the waterfalls photographed and registered. Discharge in all rivers in the area of the Karahnjukar Hydroelectric Plant has been modelled on a daily basis in a hydrological runoff model over a 51 year period from 1950 – 2001.

Landsvirkjun has published a report on the effects of the Kárahnjúkar Hydroelectric plant on waterfalls (see here - only available in Icelandic). This report provides support for the baseline studies. You may just want to see it for the nice pictures of waterfalls!

Generally, a waterfall is defined as water falling vertically from an edge, usually a cliff. In rapids, the water falls down a slope or ledges that are not high enough for the water to fall vertically. Landsvirkjuns report (above) does not separate waterfalls and rapids and uses the term waterfall for both. It varies how intensely the waterfalls have been studied in the rivers covered here. Three rivers, Kelduá, and Innri and Ytri Sauðá, have been researched quite thoroughly and all waterfalls and many rapids have been photographed.

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

The initial harnessing plan that Landsvirkjun made, included the following rivers: Jökulsá in Dal, small rivers that fall into Hálslón reservoir, Grjótá in Vesturöræfum, Thurídarstadadalsá,  Hölkná, Laugará, Bessastaðaá, Jökulsá in Fljótsdal, Hafursá, Kelduá, Grjótá in Hraunum, Innri Sauðá , Ytri Sauðá, Fellsá and Sultarranaá.

The Minister for the Environment's decision on the Environmental Impact Assessment (EIA) for the Kárahnjúkar Hydro project, reduced the scope of the project - which meant that the following rivers were excluded from the plan: Grjótá in Vesturöræfum, Thurídarstadadalsá,  Hölkná, Laugará, Bessastaðaá, Hafursá, Fellsá and Sultarranaá.

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

Table 1: Rivers and waterfalls possibly affected by the Kárahnjúkar project.
 
The information in this table comes from Landsvirkjun's report (see above). It includes all rivers which the original plans assumed to harness. The number of waterfalls means the number that will be, or could have been affected according to the original harnessing plan.

According to this table, the Kárahjúkar Hydro project has now affected at least 63 waterfalls. Seven waterfalls dissappear and 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 Thurídarstadadalsá are two names for the same river. The upper part of the river is called Grjótá and the lower part Thurídarstadadalsá). These rivers contain at least 12 waterfalls. The total number of waterfalls in rivers in the original harnessing plan is at least 91.