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1st version – Long tunnel
2nd version – Fly-over / High bridge
3rd version - Tunnel / High bridge
Main numerical parameters
Impact on environment and properties
Versions of the Riga Northern Transport Corridor, 2nd Segment, evaluation of impact
The 2nd Segment of the Riga Northern Transport Corridor (central section) starts 1449 meters in the west from Daugavgrīvas street (end point of the segment), crosses Daugava and northern part of the Riga’s centre and ends at the central axis of the Eastern Arterial (Gustava Zemgala gatve).
Public discussions on the environment impact assessment (EIA) report of the 2nd Segment were held from 17 December 2009 till 27 January 2010. Three technical solutions of the route have been offered for public discussions.
1st version - Long tunnel
The tunnel begins 400 meters in the west from Daugavgrīvas street. The tunnel crosses Daugava in the north from the "Cemex" territory, continues at the right bank under the territory of the Riga commercial port, crosses Ganību dambis between Lugažu and Rankas streets and continues under Bukultu street. Behind Duntes street, it crosses the territory of the Hospital of Traumatology and Orthopedics, railroad and southern part of the Miķeļa cemetery. Then the route continues under Gaujas street till Gustava Zemgala gatve. The tunnel has 3 entrance-exit points – at the intersection with Daugavgrīvas street, planned northern extension of Eksporta street and Gustava Zemgala gatve.
See the map here.
Advantages and disadvantages of the 1st version:
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Advantages:
- No noise pollution problems, minimized air pollution problem;
- Lower impact on surroundings during the construction;
- Does not impact and disturb local network of street, as is located under the ground;
- Lower visual impact
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Disadvantages:
- No crossing with Duntes street, which reduces number of intersections;
- Fire in a tunnel would create a massive problem;
- Impact on groundwaters and possibly on a flow of artesian waters; connected risks of wash-out and compaction of ground;
- High construction risk, for example, compaction of a ground during the construction of the tunnel;
- Longer construction period – from 5 years and 6 month (3 tunnel-building machines) until 7 years and 9 month (1 tunnel-building machines);
- Nearly impossible to divide the construction in stages.
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2nd version – Fly-over / High bridge
Gradual rise of the fly-over road starts 1450m and bridge structure – 880m to the west from Daugavgrīvas street. Location of the bridge route matches with the location of the tunnel in the 1st version. Further east the bridge diverts from the route of 1st segment, crosses Ganību dambis, railroad and transforms into a fly-over in the vicinities of Skanstes street. The fly-over starts at Skanstes street, crosses Krišjāņa Valdemāra street, then goes along Upes street till Miera street. The railway crossing on Gaujas street is rebuilt and the fly-over ends on Gaujas street west from Aizsaules street. The route is continues on ground level from here till Gustava Zemgala gatve. The fly-over has three intersections with Skanstes, Miera streets and Gustava Zemgala gatve. Maximal height of the fly-over above the ground – 15.5 meters.
See the map here.
Advantages and disadvantages of the 2nd version.
Advantages:
- Intersection with Skanstes street – a good solution in a context of possible Hanza crossing;
- Lower construction risks contrary to tunnel options due to no risk of ground compaction;
- Comparatively lower degree of intervention in groundwater system;
- Higher chances to divide works into stages;
- Fastest construction period – around 3 years and 9 months.
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Disadvantages:
- Highest number of residential buildings to be demolished;
- Highest noise and air pollution;
- Biggest visual intrusion;
- After the completion – highest nuisance for the local traffic;
- Extended suspension of tram line Nr.11 during the construction time, which will need to be replaced by other transportation means in other routes. Suspended traffic across Brasas bridge and Upes street during the construction, extended impact of construction works on neighbouring population;
- After construction – traffic load in vicinities of Skanstes street will increase substantially;
- Sharpest turns = lower speed, higher risk of traffic accidents;
- Place just for one tram track along the cemetery;
- Facilitates fragmentation of a city;
- Higher dependence of a traffic safety from weather;
- Structure occupies the biggest area, it is difficult to find a utilization of an area under the fly-over;
- According to a poll, the least supported version by population.
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3rd version – Tunnel / High bridge
Gradual rise of the road on embankment 1450m and bridge structure – 880m to the west from Daugavgrīvas street. Location of the bridge matches with the 2nd variant. The structure of the bridge ends 440m to the east from Ganību dambis (total length 3063 m) and further route goes along Bukultu street. A tunnel starts 200m to the west from Duntes street and is located under Bukultu street, crosses the territory of the Hospital of Traumatology and Orthopedics and southern part of Miķeļa cemetery. The carriageway of Northern Corridor is located 21,3m under the ground. Then the route continues under Gaujas street, the Gustava Zemgala gatve junction and ends 630m to the east from Gustava Zemgala gatve in Ķīšezera street in the area of the 1st stage of Northern Corridor). The bridge has two junctions with Daugavgrīvas street and the planned northern extension of Eksporta street. The tunnel has the following entrance-exit points – at the intersection with Duntes street, at Gustava Zemgala gatve and in the 1st segment – at Kisezera iela. There is a potential location for intersection at Sāremas street. Height of the bridge above the Daugava River – 55m.
See the map here
Advantages and disadvantages of the 3rd version.
Advantages:
- Will relieve traffic in Riga in a most effective way;
- Was not acknowledged as the worst possible of 3 versions in any category of the evaluation;
- According to a poll, the most supported version by population.
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Disadvantages:
- Sensitive attitude of population regarding the tunnel under the cemetery.
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Main numerical parameters
Route parameters
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1st version –
Long tunnel
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2nd version –
Fly-over / High bridge
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3rd version–
Tunnel/High bridge
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Length of the route from the beginning till axis of Gustava Zemgala avenue, m |
6 490
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6 780
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6 490
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Length of the motorway and BI category road of a general use, m
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6 490
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6 780
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6 490
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Engineering structures
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Length of the bridge, m
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none
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3 250
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3 063
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Length of the fly-over, m
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None
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2 500
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None
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Length of the tunnel, m
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5 770
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None
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2 094
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Connections to main roads of the city, number
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3
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5
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5
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Number of lanes
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3+3
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3+3
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3+3
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Provision of pedestrian, cyclist and public transportation traffic
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On parallel and nearby streets
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On parallel and nearby streets
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On parallel and nearby streets
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Planned/maximal speed on a route, km/h
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80
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80 on fly-over / 100 on a bridge
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80 in a tunnel / 100 on a bridge
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Ensured access to all properties
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Yes
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Yes
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Yes
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Is construction of a route possible in several stages?
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No
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No
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No
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Duration of a construction
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5 years 6 month till 7 years 9 month – depending on amount of equipment involved in a construction
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3 years 6 month till 4 years
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4 years 6 month till 5 years9 month – depending on amount of equipment involved in a construction
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Building materials
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1st version – Long tunnel
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2nd version – Fly-over / High bridge
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3rd version– Tunnel/High bridge
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Bituminous concrete (t) |
167 550
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140 217
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159 500
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Concrete (m3)
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1 525 000
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518 000
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1 003 000
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Steel reinforcements (t)
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200 000
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87 000
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146 000
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Metal constructions (t)
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76 000
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12 000
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50 400
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Impact on environment and properties
Impact on environment
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1st version –
Long tunnel
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2nd version –
Fly-over / High bridge
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3rd version–
Tunnel/High bridge
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Noise level outside a route after installation of noise barriers |
Comparatively lowest, increased noise level only at the intersections with Daugavgrīvas street, Eksporta street and Gustava Zemgala gatve
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Comparatively highest, slightly increased noise level along the whole route, higher noise level at the Skanstes street region and intersection with Gustava Zemgala gatve
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Comparatively higher than in 1st version and lower than in 2nd version. Higher noise level near intersections with Daugavgrīvas street and Gustava Zemgala gatve, along Bukultu street
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Air pollution, nitric dioxide (NO2) example
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Pollution on a surface does not change above the tunnel; increased concentration near entrance-exit points
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Slightly increased concentration in comparatively large area along the whole route
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Pollution on a surface does not change along the tunnel; increased concentration near entrance-exit
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Possibility to include technical solutions to decrease air pollution
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Yes – at entrance-exit points of the tunnel and ventilation trunks
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No
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Yes – at entrance-exit points of the tunnel
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Crosses protected nature area
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No
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No
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No
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Impact on cultural monuments
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No
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Enters protection belt of the Riga historical centre
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No
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Impact on ecological situation in Daugava
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During construction
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No
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No
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No
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During exploitation
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No
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No
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No
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Impact on underground water regime
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During construction
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Substantial; monitoring of surrounding buildings must be performed
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Not substantial
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Not substantial
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During exploitation
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Possible; monitoring of surrounding buildings must be continued
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No
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Not substantial
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Impact on landscape
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Insignificant, only at both end-points
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Significant along the whole route, especially
significant is impact of Daugava Crossing
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Significant impact of Daugava Crossing
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Properties
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1st version –
Long tunnel
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2nd version –
Fly-over / High bridge
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3rd version–
Tunnel/High bridge
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Number of alienable plots or their parts |
16
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29
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12
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Area of alienable plots or their parts, m2
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29 161
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40 470
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18 555
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Number of non-residential buildings to be demolished
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43
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45
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39
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Number of residential buildings to be demolished
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2
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13
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2
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Versions of the 2nd Segment of the Riga Northern Transport Corridor, evaluation of impact
The draft designer „Basler&Hofmann” (Germany) and developer of the environmental impact assessment „ELLE” (Latvia) gave the following comparison of route versions.
Evaluation of „Basler&Hofmann”
22 criteria were evaluated, divided in 3 groups. Every criteria has its specific weight. Every version is evaluated, granting points from 1 to 5. Acquired points are multiplied by the specific weight of a criteria and summarized. The higher is the total amount of points (maximum possible points are 5,00), the better is the version.
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Long tunnel
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Fly-over/High bridge
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Tunnel/High bridge
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a
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Impact on population
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1,29
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0,91
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1,34
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b
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Impact on environment
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1,37
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0,56
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0,95
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c
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Impact on total economical situation, taking into
account the cost of the project
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1,03
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1,16
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1,45
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Total:
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3,69
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2,63
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3,74
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Evaluation of „ELLE”
26 criteria were evaluated, divided in 6 groups. Every criteria has its specific weight. Every version is evaluated, granting points from 1 to 5. Acquired points are multiplied by the specific weight of the criteria and summarized. The higher is the total amount of points (maximum possible points are 5,00), the better is the version
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Long tunnel
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Fly-over/High bridge
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Tunnel/High bridge
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a
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Traffic organisation, compliance with Riga’s plans
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0,405
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0,27
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0,375
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b
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Impact on hydrological/geological processes
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0,445
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0,475
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0,405
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c
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Pollution
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0,63
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0,355
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0,485
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d
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Impact on environment/landscape
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0,59
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0,27
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0,41
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e
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Impact on population, culture heritage
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0,58
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0,38
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0,455
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f
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Impact during the construction
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0,42
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0,38
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0,42
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Total:
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3,07
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2,13
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2,55
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