Difference between revisions of "Altusried test case"

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(Created page with "Category:Test cases {{Fact box for Altusried}} {{Relevant Altusried}} =Introduction= The river Iller is located in the far south-western part of Germany. It flows into th...")
 
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===Pressures on the water body's ecosystem===
 
===Pressures on the water body's ecosystem===
Several dams with different purposes upstream and downstream of the two HPPs pose a problem for the continuity of the water body and thereby for fish migration. The native fish species are in decline and several alien species are appearing and/or increasing in number. The flow is highly regulated for irrigation and hydropower uses and there are a lot of artificial lentil habitats due to the presence of dams, which has an effect on the hydrology. There is a heavy agricultural use in the area with a significant use of agrotoxins, which leak into the water. Several dams block the sediment transport, especially since there is no law that enforces an improvement of the situation.
+
The main pressures on the water body are effluents from a water treatment plant, hydrology, and, to a small extent, the spillover from storm water overflows and morphology. The formerly high pressure continuity, has been reduced through fish bypass channels which were built in 2014.  
 +
 
 +
The pressures are mainly caused of morphological issues which are results of the HPP. There is a lack of important habitats such as juvenile habitats, spawning habitats and the reophilic interstitial. The BEW is working on this problems with two restauration programmes, the Illerstrategie 2020 and the EU-found program ISOBEL.
  
 
=Test case topics=
 
=Test case topics=
 
===Fish population===
 
===Fish population===
The river is dominated by small and medium size reophilic native cyprinids like Iberian barbel (Luciobarbus bocagei), northern straight-mouth nase (Pseudochondrostoma duriense), Northern Iberian chub (Squalius carolitertii) and Pyrenean gudgeon (Gobio lozanoi). All of them are suffering a decrease in their populations (specially nase, wich is an endemic species) and allien species are increasing their presence (mainly Alburnus alburnus)
+
The river is dominated by reophilic and potamodroumous species. The main species are greyling, barbel, nase, brown trout, danube salmon, chub and several small fish species. In the reservoir basins, typical lake fish species such as tench, rudd, carp and pike can also be found. Since 2016 the LEW together with the University of Augsburg are investigating what types and numbers of fish using the fish passes constructed by LEW on the 5 hydropower plants of (from downstream to upstream) Lautrach, Maria Steinbach, Legau, Fluhmühle and Altusried. Every fish swimming through a fish pass is caught in a catch construction upstream in the fish pass. The catch construction (called counting pool) is evaluated nearly daily and fish that are caught are measured (length) and marked. The mark is a blue dot on their belly near the left or right pectoral, pelvic or caudal fin, depending on the fish ladder they were passing. In this way, migratory route of marked fish can be evaluated.
  
 
===Migration devices===
 
===Migration devices===
 
The Bragado weir does not have a fish pass for either upstream or downstream fish migration. Such device was considered unnecessary by the Portuguese authorities since the HPP is placed in a reach of the Avelames River with reduced natural longitudinal connectivity, due to the occurrence of natural falls. Furthermore, migratory fish species requiring long distance movements to reproduce do not occur in this river.
 
The Bragado weir does not have a fish pass for either upstream or downstream fish migration. Such device was considered unnecessary by the Portuguese authorities since the HPP is placed in a reach of the Avelames River with reduced natural longitudinal connectivity, due to the occurrence of natural falls. Furthermore, migratory fish species requiring long distance movements to reproduce do not occur in this river.
 +
 +
==Downstream migration==
 +
Downstream migration is possible during weir overflow or while the bottom outlets are opened. Thrash racks in front of the turbines, with a spacing of 20 mm between the racks, prevent fish from swimming into the turbines.
  
 
===Upstream migration===
 
===Upstream migration===
The main facilities for upstream migration are the fishways built on each dam (all native species are potamodromous). At Guma, it is a pool and weir fishway, with submerged notch with bottom orifice. It has a slope of 8.77 % and covers a trial height of 8.85 m. Vadocondes has a vertical slot fish pass with a trial height of 3.75 m. Both have supplementary attraction flow into the fishway entrance.
+
The upstream migration facility, which was built in 2014, consists of a fish bypass channel with a length of 700 m and a flow of 1 m3/s. To also fulfill a compensation habitat function, juvenile and spawning habitats have been built into the fish-bypass channel.
  
 
===E-flow===
 
===E-flow===
Due to the hydropower plant type (over the dam and run-of-river type), there is no legal requirement for ecological flow. Nonetheless, fishways always must have enough flow for operating and therefore the downstream by-pass of the river always maintains a minimum flow of 0.25-0.50 m3/s.
+
The minimum outflow of the turbines is 9.0 m³/s, during the whole year. This regulation is part of the “Illerstrategie 2020” of the BEW. It is based on the natural minimum flow of the river Iller.
  
 
=Research objectives and tasks=
 
=Research objectives and tasks=
This hydropower plant type (run of river) is quite common on the main Spanish river basins. The work at the Test Case sites aims at improving the knowledge on the impacts this type of HPP has on fish migration and location of ascent paths. Different flow configurations through the turbines and fishway-attraction flow will be tested to maximize the relationship between fish upstream movement and hydropower production. Also, fish passage through turbines and their survival using different turbine configurations will be an important result about HPP management and impact.
+
At the Test Case Altusried, the ways fish are finding the downstream entry of fish bypass channels is being studies. For this, fish tagging and [[acoustic telemetry]] is used to follow the ways of fish into the bypass channel. Additionally, Flow measurements are conducted in the outflow area of the fish ladder.  This information is used to develop an agent-based fish movement model incorporated in the fish habitat simulation model [[CASiMiR]]. The research work is implemented by LEW, SJE, INBO and TUT.
  
 
===Research tasks===
 
===Research tasks===
The research tasks and field studies conducted at Guma and Vadocondes are:
+
The research tasks and field studies conducted at the HPP on the river Iller are:  
  
 +
* Telemetry studies
 +
* Velocity fluctuation measurements using the Lateral Line Probe
 +
* 2D hydrodynamic model and CASiMiR migration model
 
* Population and habitat analysis
 
* Population and habitat analysis
* Analysis of the conceptual solutions and facilities for fish migration
 
* Assessment and improvement of fish mortality in the turbines
 
* Spawning areas and hydro-morphology to attain self-sustainable populations
 
* Migration facilities and attraction flow
 
* Hydraulic modelling of attraction flow
 
  
 
=Results=
 
=Results=
 +
===Population and habitat analysis===
 +
The impact of the newly created fish-bypass channels and habitat measures have been monitored with electro fishing campaigns from 2016 – 2019 that are carried out twice a year on a length of 1500m downstream at both shorelines against the flow and in the middle of the river with the flow. The results of the electro fishing campaigns indicate the presence of all characteristic fish species in the Iller and thus an improvement of the formerly poor fish community status. Especially barbell, Danube salmon, grayling, chub and brown trout were caught in gratifying numbers, both in juvenile and adult stages. In spring 2018 even 6 young Danube Salmon were found. Only the population of nase is still in a rather poor condition.
 +
 +
===Acoustic 2D telemetry fish tracking===
 +
The Vemco Positioning System (VPS) was applied to track fish swimming behaviour in 2D. Through the fish telemetry study, 15 million fish positions of 47 wild fish, 25 grayling and 22 barbel were collected. The tagged fish stayed in the VPS network between 2 and 92 days, whereby barbel resided on average for longer in the area than grayling. A detailed analysis is under way. The fish detections of the hydrophones in the fish pass already indicate that 12 tagged grayling and 8 tagged barbel found the entrance of the fish ladder at least once and swum up at least half way. Of these, 10 grayling and 6 barbel then also found their way upstream into the counting pool.
 +
 +
===Hydrodynamic modelling===
 +
A hydrodynamic model has been set up using Hydro-As_2D to derive flow velocities and water depth as input parameter for the developed migration model. To cover the wide flow range that can occur during migration periods, the flow scenarios considered in the model range from 10 m³/s to 80 m³/s. The results from the hydrodynamic model show that for a low flow situation with 10 m³/s the flow velocities are increased close to the area of the fish ladder outlet. Usually this zone of increased flow velocities is considered to have a guiding function for fish searching the fish ladder entrance. But even for the low flow situation the increased flow velocities can only be detected in the direct vicinity of the fish ladder entrance. For higher flows the extension of the higher flow velocity area is much less distinct.
 +
 +
===Migration model===
 +
An extension of the habitat simulation system CASiMiR is being developed with input from the Test Cases. This new CASiMiR-Migration model is designed to simulate the migration behaviour of fish. For Altusried, the model has been applied to a lower flow velocity threshold of 0.15 m/s and an upper threshold of 1.5 m/s. When positioning the virtual fish equally over the river width in the lower part of the river stretch 10% of fish find the fish ladder entrance with flow velocities of 10 m³/s, 7% in with 20 m³/s and 5 % in with 60 m³/s in the river. I.e. the higher the flow in river the less distinct is the attraction flow when considering only flow magnitude and direction. By a first evaluation of the fish tracks it is already clear that the percentage of fish finding the fish ladder entrance is much higher than these values. This indicates that the current model has to consider additional parameters as mentioned before.

Revision as of 09:25, 27 January 2020

Fact box: Altusried
Country Germany
River Iller
Operator LEW
Capacity 4 MW
Head 9 m
Inter-annual discharge 46.5 m3/s
Turbine(s) 2 Kaplan turbines
Detailed report Click for pdf

Template:Relevant Altusried

Introduction

The river Iller is located in the far south-western part of Germany. It flows into the river Danube near the city Ulm. The river Iller originates from the confluence of the three rivers Stillach, Breitach and Trettach near the city Oberstdorf in the “Allgäuer Alps”, south Germany.

It’s catchment area has a size of 2152 km². The HPP Altusried is the first HPP after the source of the river Iller. The last HPP of the BEW is near Memmingen. In the downstream area of the BEW HPP chain there are an additional 8 HPPs.

The hydrology of the Iller is characterized by a sustained flows in winter, high water levels in spring due to snow melting and low water period from August to October. At Altusried, the main Test Case HPP at the Iller, the mean interannual discharge is estimated to be 46.6 m3/s.

About the hydropower plants

The HPP at Altusried is a run-of-river HPP with an installed capacity of 4 MW and a mean annual output of 30 million kWh. The HPP has two Kaplan turbines, each with a flow rate of 50 m³/s and a drop height of 9 m. The hydropeaking operation mode has been minimized since 2014.

Layout

There is a big reservoir in the upstream area of the Hydropower plant. In the downstream area of the HPP the river Iller is still flowing. After a free flowing area of round 1500 the root of the next reservoir starts. The BEW has built a fish bypass channel around the HPP in 2015. It is 700 m long and has a mean flow of 1 m³/s.

The Operator: LEW Wasserkraft GmbH (LEW)

The LEW is a 100 % subsidiary of the Lechwerke AG. It runs and maintains 36 HPPs at the rivers Danube, Günz, Lech and Iller and is thereby one of the leading HPP operator in Bavaria, Germany. The company produces over 1 billion kWh energy out of regenerative hydropower per year. [Read more.]

Pressures on the water body's ecosystem

The main pressures on the water body are effluents from a water treatment plant, hydrology, and, to a small extent, the spillover from storm water overflows and morphology. The formerly high pressure continuity, has been reduced through fish bypass channels which were built in 2014.

The pressures are mainly caused of morphological issues which are results of the HPP. There is a lack of important habitats such as juvenile habitats, spawning habitats and the reophilic interstitial. The BEW is working on this problems with two restauration programmes, the Illerstrategie 2020 and the EU-found program ISOBEL.

Test case topics

Fish population

The river is dominated by reophilic and potamodroumous species. The main species are greyling, barbel, nase, brown trout, danube salmon, chub and several small fish species. In the reservoir basins, typical lake fish species such as tench, rudd, carp and pike can also be found. Since 2016 the LEW together with the University of Augsburg are investigating what types and numbers of fish using the fish passes constructed by LEW on the 5 hydropower plants of (from downstream to upstream) Lautrach, Maria Steinbach, Legau, Fluhmühle and Altusried. Every fish swimming through a fish pass is caught in a catch construction upstream in the fish pass. The catch construction (called counting pool) is evaluated nearly daily and fish that are caught are measured (length) and marked. The mark is a blue dot on their belly near the left or right pectoral, pelvic or caudal fin, depending on the fish ladder they were passing. In this way, migratory route of marked fish can be evaluated.

Migration devices

The Bragado weir does not have a fish pass for either upstream or downstream fish migration. Such device was considered unnecessary by the Portuguese authorities since the HPP is placed in a reach of the Avelames River with reduced natural longitudinal connectivity, due to the occurrence of natural falls. Furthermore, migratory fish species requiring long distance movements to reproduce do not occur in this river.

Downstream migration

Downstream migration is possible during weir overflow or while the bottom outlets are opened. Thrash racks in front of the turbines, with a spacing of 20 mm between the racks, prevent fish from swimming into the turbines.

Upstream migration

The upstream migration facility, which was built in 2014, consists of a fish bypass channel with a length of 700 m and a flow of 1 m3/s. To also fulfill a compensation habitat function, juvenile and spawning habitats have been built into the fish-bypass channel.

E-flow

The minimum outflow of the turbines is 9.0 m³/s, during the whole year. This regulation is part of the “Illerstrategie 2020” of the BEW. It is based on the natural minimum flow of the river Iller.

Research objectives and tasks

At the Test Case Altusried, the ways fish are finding the downstream entry of fish bypass channels is being studies. For this, fish tagging and acoustic telemetry is used to follow the ways of fish into the bypass channel. Additionally, Flow measurements are conducted in the outflow area of the fish ladder. This information is used to develop an agent-based fish movement model incorporated in the fish habitat simulation model CASiMiR. The research work is implemented by LEW, SJE, INBO and TUT.

Research tasks

The research tasks and field studies conducted at the HPP on the river Iller are:

  • Telemetry studies
  • Velocity fluctuation measurements using the Lateral Line Probe
  • 2D hydrodynamic model and CASiMiR migration model
  • Population and habitat analysis

Results

Population and habitat analysis

The impact of the newly created fish-bypass channels and habitat measures have been monitored with electro fishing campaigns from 2016 – 2019 that are carried out twice a year on a length of 1500m downstream at both shorelines against the flow and in the middle of the river with the flow. The results of the electro fishing campaigns indicate the presence of all characteristic fish species in the Iller and thus an improvement of the formerly poor fish community status. Especially barbell, Danube salmon, grayling, chub and brown trout were caught in gratifying numbers, both in juvenile and adult stages. In spring 2018 even 6 young Danube Salmon were found. Only the population of nase is still in a rather poor condition.

Acoustic 2D telemetry fish tracking

The Vemco Positioning System (VPS) was applied to track fish swimming behaviour in 2D. Through the fish telemetry study, 15 million fish positions of 47 wild fish, 25 grayling and 22 barbel were collected. The tagged fish stayed in the VPS network between 2 and 92 days, whereby barbel resided on average for longer in the area than grayling. A detailed analysis is under way. The fish detections of the hydrophones in the fish pass already indicate that 12 tagged grayling and 8 tagged barbel found the entrance of the fish ladder at least once and swum up at least half way. Of these, 10 grayling and 6 barbel then also found their way upstream into the counting pool.

Hydrodynamic modelling

A hydrodynamic model has been set up using Hydro-As_2D to derive flow velocities and water depth as input parameter for the developed migration model. To cover the wide flow range that can occur during migration periods, the flow scenarios considered in the model range from 10 m³/s to 80 m³/s. The results from the hydrodynamic model show that for a low flow situation with 10 m³/s the flow velocities are increased close to the area of the fish ladder outlet. Usually this zone of increased flow velocities is considered to have a guiding function for fish searching the fish ladder entrance. But even for the low flow situation the increased flow velocities can only be detected in the direct vicinity of the fish ladder entrance. For higher flows the extension of the higher flow velocity area is much less distinct.

Migration model

An extension of the habitat simulation system CASiMiR is being developed with input from the Test Cases. This new CASiMiR-Migration model is designed to simulate the migration behaviour of fish. For Altusried, the model has been applied to a lower flow velocity threshold of 0.15 m/s and an upper threshold of 1.5 m/s. When positioning the virtual fish equally over the river width in the lower part of the river stretch 10% of fish find the fish ladder entrance with flow velocities of 10 m³/s, 7% in with 20 m³/s and 5 % in with 60 m³/s in the river. I.e. the higher the flow in river the less distinct is the attraction flow when considering only flow magnitude and direction. By a first evaluation of the fish tracks it is already clear that the percentage of fish finding the fish ladder entrance is much higher than these values. This indicates that the current model has to consider additional parameters as mentioned before.