Ecological benefits of side channels
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- Samuel Shepherd
- 5 years ago
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1 Ecological benefits of side channels in relation to their hydromorphological characteristics Margriet Schoor vreugderijkerwaard, oct 2009 Kolloquium bfg & BAW, Magdeburg 24 maart 2010
2 Introduction Rhine in the Netherlands Navigable rivers in western Europe Connects the port Rotterdam with the rest of Europe 2 Ecological benefits of side channels 24 maart 2010
3 Introduction Why side channels? Ecological rehabilitation Flood prevention fish macro invertebrates water plants 3 Ecological benefits of side channels 24 maart 2010
4 Introduction Challenges in design Navigation: no hinder due to sedimentation Maintenance side channel: managable 4 Ecological benefits of side channels 24 maart 2010
5 Introduction Side channels along the Rhine vreugderijkerwaard Vreugderijkerwaard Bakenhof Beneden Leeuwen Gameren Opijnen Klompenwaard 5 Ecological benefits of side channels 24 maart 2010
6 Introduction Monitoring 2009 vreugderijkerwaard Vreugderijkerwaard Bakenhof Beneden Leeuwen Gameren Opijnen Klompenwaard 6 Ecological benefits of side channels 24 maart 2010
7 Introduction Monitoring data Hydromorphology Vreugdenrijkerwaard construction Period monitoring and available data Macrophytes Macro invertebrates Fish Bakenhof Klompenwaard Gameren , , 2009 Opijnen Beneden - Leeuwen , , , 1996, , , , 1994, , , 1995, 1997, 1998, 2009 Preliminary results : Marianne Greijdanus, Arjan Sieben, Eddy Lammens, Johan van Essen, Adri Wagener,,Alfred ten Brinke Deltares: Leon van Kouwen, Gertjan Geerling, Tom Buijse, Gerben van Geest Limers Divergens: Nils van Kessel, Martijn Dorenbosch Bureau Waardenburg Bureau Drift: Bart Peters, Gijs Kurstjens DHV 7 Ecological benefits of side channels 24 maart 2010
8 Photo impression 1. Opijnen: small channel in groyne fields Opijnen photo: B. Boekhoven 8 Ecological benefits of side channels 24 maart 2010
9 Photo impression 2. Beneden Leeuwen: sand- and clay pits connected 9 Ecological benefits of side channels 24 maart 2010
10 Photo impression 3. Gameren: 3 side channels clay used for dike reconstruction 10 Ecological benefits of side channels 24 maart 2010
11 Photo impression 3. Gameren West channel East channel Big side channel 11 Ecological benefits of side channels 24 maart 2010
12 Photo impression 3a. Gameren - big channel View from bridge to the east View from bridge to the west construction with bridge limits the discharge 12 Ecological benefits of side channels 24 maart 2010
13 Photo impression 3b. Gameren - East channel Partially sanded up semi permanent flow 13 Ecological benefits of side channels 24 maart 2010
14 Photo impression 3c. Gameren-west channel View upstream Inlet work limits discharge less than designed View downstream After first flood: sand bar 2009: Last groyne became island 14 Ecological benefits of side channels 24 maart 2010
15 Photo impression 4. Klompenwaard Waal 15 Ecological benefits of side channels 24 maart 2010
16 Photo impression Klompenwaard clay used for dike reconstruction sill 16 Ecological benefits of side channels 24 maart 2010
17 Photo impression Klompenwaard 17 Ecological benefits of side channels 24 maart 2010
18 Photo impression Klompenwaard when ships pass, water flows in, High sill (stones) prevents sedimentation in the navigation channel High turbidity and out. 18 Ecological benefits of side channels 24 maart 2010
19 Photo impression Low water oct vreugderijkerwaard (IJssel) Permanent discharge in side channel 19 Ecological benefits of side channels 24 maart 2010
20 Photo impression vreugderijkerwaard Inlet construction Shallow water 20 Ecological benefits of side channels 24 maart 2010 Very many birds
21 Photo impression 6. Bakenhof IJssel Nederrijn 21 Ecological benefits of side channels 24 maart 2010
22 Photo impression Bakenhof Dike re-location for flood prevention 22 Ecological benefits of side channels 24 maart 2010
23 Photo impression Bakenhof June 2009 Flooded, march Ecological benefits of side channels 24 maart 2010
24 Photo impression Bakenhof sept 2009 Construction in inlet Nearly dry with extreme low water June 2009 Mean water level 24 Ecological benefits of side channels 24 maart 2010
25 Hydromorphology Laser altimetry and multibeamdata Klompenwaard 2009/ Ecological benefits of side channels 24 maart 2010
26 Hydromorpology Hydrology in relation with height of the sill 26 Ecological benefits of side channels 24 maart 2010
27 water plants Macrophytes - connectivity and ecology A B C D Not the best place for water plants few characteristic rheophilic species WFD-goal habitat for macrofana and fish potamogetum Schiemer et al Ecological benefits of side channels 24 maart 2010
28 water plants Macrophytes - results Vreugderijkerwaard 2009 Abundant water plants Flow velocity maps not ready yet 28 Ecological benefits of side channels 24 maart 2010
29 water plants Macrophytes results Gameren 2009 First water plants in 2006 (after 7 years) Species of flowing water Species of standing water 29 Ecological benefits of side channels 24 maart 2010
30 water plants Macrophytes - results Klompenwaard & Bakenhof Klompenwaard: Bakenhof: no macrophytes very very few macrophytes 30 Ecological benefits of side channels 24 maart 2010
31 water plants Germination April-june Important: flowing water in germination period Hydrology & macrophytes 31 Ecological benefits of side channels 24 maart 2010
32 water plants Results macrophytes 32 Ecological benefits of side channels 24 maart 2010
33 water plants Results: limiting factors for macrophytes Water level fluctiations in summer Flow velocity -> species composition Transparency (no re-suspension of silt) Extreme geese gobble Limitation of dispersion (problem for Waal & Rijn) few water level fluctuations 33 Ecological benefits of side channels 24 maart 2010
34 Macro fauna Macro invertbrates - connectivity and ecology A B C D Goal: rheophilic fauna species rich (divers habitat) abundant catch larval drift Schiemer et al Ecological benefits of side channels 24 maart 2010
35 Macro invertebrates Macro invertebrates Results 2009 Macrofauna resultaten monitoring 2009 abundency Gameren (individuels/per m 2 ) Polychaeta Oligochaeta Hirudinea Crustacea Diptera Overige insecten Gastropoda Bivalvia Overigen Big channel, east Big channel, west West channel handnet handnet handnet handnet grote geul oost grote geul west westgeul kribvak 2 A lot more in side channels than in groyne fields big side channel -> habitat diversity Gameren Groyne field 27 april 2010
36 Macro invertebrates Macro invertebrates - results 2009 species diversity #taxa Groyne field Groyne field Groyne field A lot more in side channles than in groyne fields Vreugderijkerwaard most taxa 36 Ecological benefits of side channels 24 maart 2010
37 Macro invertebrates Macro invertebrates results 2009 flow preference of taxa More rheofilic sp. in side schannel Vreugderijkerwaard the most Less exotics in side channel Exotics;unknow preference Groyne field Groyne field! Groyne field 37 Ecological benefits of side channels 24 maart 2010
38 Macro invertebrates Macro invertebrates results 1. Compared with the groyne fields in the main channel, in side channels: Abundance higher Higher species richness less exotic species 2. Abundance and species diversity the highest on Mud Vegetation in shallow slow flowing water 3. Best Worst: Vreugderijkerwaard - Bakenhof & Gameren Klompenwaard 38 Ecological benefits of side channels 24 maart 2010
39 Macro invertebrates Macro invertebrates - results 39 Ecological benefits of side channels 24 maart 2010
40 Macro invertebrates Larval drift feb-may Yearround flowing water Hydrology & macro invertebrates 40 Ecological benefits of side channels 24 maart 2010
41 Fish Fish - connectivity and ecology A B C D Goal: rheophilic fish catch larval drift juvenile fish Habiat diversity -> species diversity Schiemer et al Ecological benefits of side channels 24 maart 2010
42 Fish Fish - results Young fish abundance on sand (net fishery) 41 locations along Rhine and Meuse on structures (electro fishery) rheofiel limno fiel mean abundance (n/100 m2) mean abundance (n/100 m2) eurytoop 0 groyne field side channel back water isolated water 0 groyne field side channel back water isolated water Dorenbosch, van Kessel & Spikmans, Ecological benefits of side channels 24 maart 2010
43 Fish Fish - Results Young fish species richness on sand (net fishery) 41 locations along Rhine and Meuse on structures (electro fishery) 12 rheofiel 12 limnofiel 10 eurytoop 10 number of species (n/100 m2) number of species (n/100 m2) groyne field side channel back water isolated water 0 groyne field side channel back water isolated water Dorenbosch, van Kessel & Spikmans, Ecological benefits of side channels 24 maart 2010
44 Fish Fish - results Young fish relative abundance 100% 80% on sand (net fishery) 5 side channels rheofiel limnofiel eurytoop relativ e abundance 60% 40% 20% 0% Bakenhof Klompenwaard Dorenbosch, van Kessel & Spikmans, 2009 Opijnen Ga meren Vreugderijkerwaard 44 Ecological benefits of side channels 24 maart 2010
45 Fish Low flow Flow velocity and habitat suitability for rheofilic fish 50% Gameren 2000 Depth (cm) Flow velocity (cm/s) eurytope rheophil young bankfull rheophil older phases not suitable for young fish Jans et al, Ecological benefits of side channels 24 maart 2010
46 Fish Larval drift mar-june Hydrology & fish 10 months flowing water 46 Ecological benefits of side channels 24 maart 2010
47 Fish Results Fish Reophilic young fish many location Explanation + Explanation - Gameren Opijnen Vreugdenrijkerwaard Shallow slow flowing water Habitat diversity few Klompenwaard High sill, almost no flow Bakenhof Weirs Nederrijn Flow velocity low, channel bed mud 47 Ecological benefits of side channels 24 maart 2010
48 Fish Fish - Results In side channels: Abundancy young fish is highest of all watertypes Rheofilic fish mostly spawn upstream (gravel beds), side channels catch larval drift For other species (Winde) adjacend flooded graslands are important spawning grounds Habitat diversity and flow velocity are both important Side channels with 50% flowing water are still interesting for some rheophillic species (east channel Gameren) More results when flow velocity maps are ready 48 Ecological benefits of side channels 24 maart 2010
49 Use of the results Future More side channels to disign and construct Why: flood prevention, river ecology & navigation Challenge: ecological good design ánd acceptable for navigation needs and sediment management. Use results of this study for it Case Gendtse waard (Waal) 49 Ecological benefits of side channels 24 maart 2010
50 Use of the results Case Gendtse Waard (Waal) side channel for ecology and flood control 50 Ecological benefits of side channels 24 maart 2010
51 Use of the results Km 872 Case Gendtse Waard (Waal) morphological effect navigation channel Calculation morphological effect: sedimentation in navigation channel up to 50 cm Km Duurzame Rivierkunde, 2009 Ecological benefits of side channels 24 maart 2010
52 Use of the results Navigation depth Waal near Gendt Problem situation Ecological benefits of side channels 24 maart 2010
53 Use of the results 2010: Finetune design Flow velocity 30cm/s Wet profile smaller Constructions near inlet Flow 11 month/yr 50% morphological effects 53 Ecological benefits of side channels 24 maart 2010
54 Thanks for your attention! 54 Ecological benefits of side channels 24 maart 2010