The Ecological Restoration Potential (ERP) of River Reaches after Hydropower Dam Construction

Transcription

1 The Ecological Restoration Potential (ERP) of River Reaches after Hydropower Dam Construction Hui Zhao School of Environment, Beijing Normal University 11th International Riversymposium Brisbane, 1-4 September 2008

2 Content 1 Introduction 2 Background 3 Method 4 Result and discussion

3 Introduction Construction of cascade hydropower stations Operation of cascade hy dropower stations Ecological disturbance Unbalance, degeneration

4 Introduction Construction of cascade hydropower stations Operation of cascade hy dropower stations Ecological disturbance Restoration steps Self-design Artificial design Health river system

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8 Objective of Restoration: Restore or rebuild health ecosystem -the self-sustaining and self-resilient river Management objective of governments

9 Introduction Problems? How to restore health river ecosystem? Which ecological characteristic is the key one River ecological conditions before and after dams or other projects

10 Introduction Solution Assessment of Ecological Restoration Potential Possibility of ecological restoration of dammed river Changes of typical ecological characteristics

11 Introduction ERP: Determine natural restorable degree for damaged river ecosystem Find key ecological characteristics to restoration Reduce the blindness of restoration projects

12 Background- case study

13 Manwan dam 1984 Study Site The first period The second period Dachaoshan dam 1997

14 Background - Basic circumstances of study sites R Manwan Reservoir (MR) Monitoring sections Upstream Section of Manwan dam (USM) Downstream Section of Manwan dam (DSM) Dachaoshan Reservoir (DR) Upstream Section of Dachaoshan dam (USD) Downstream Section of Dachaoshan dam (DSD)

15 Background - Date resources Current condition Field visits, 2006 Experimental analysis Historical condition Regional hydrologic bureau,

16 Method Integrative fuzzy hierarchical assessment (FHA) model Assessment indices framework of ERP Grading, standardization and quantification of ERP indices Calculation of the loss rate of ERP Assessment value - Natural value 100% Natural value

17 Assessment indices framework of ERP - 1 Element (E) Regional climate conditions (E 1 ) Index (I) Annual average air temperature (I 1 )/ Annual rainfall (I 2 )/mm Annual average water flow (I 3 )/(m 3 /s) Hydrological conditions (E 2 ) Surface water temperature (I 4 )/ Average sediment concentration (I 5 )/ kg/m 3 ) Water quality condition /(I 6 ) Degree of river channelization(i 7 )

18 Assessment indices framework of ERP - 2 Riparian soil conditions (E 3 ) Soil organic matter (I 8 )g/kg Soil heavy metal (C d ) (I 9 )mg/kg Soil ph (I 10 ) Total coverage of plant(i 11 ) Biological conditions (E 4 ) Plant diversity(i 12 ) The integrity of hydrobiology species (I 13 )

19 Results and Discussion Spatical distribution of ERP - total ERP (no unit) a) The first period MR USM- ñdsm- ñ E1 E2 E3 E b) The second period MR- ò USM- ò DSM- ò DR USD DSD

20 Spatical distribution of ERP Hydrological conditions (E 2 ) 0.00 Riparian conditions (E 3 ) Loss rate of ERP(%) Loss rate of ERP(%) MR- ñ USM- ñ DSM- ñ MR- ò USM- ò DSM- ò DR USD DSD MR- ñ USM- ñ DSM- ñ MR- ò USM- ò DSM- ò DR USD DSD Increasing channelization and sediment Heavy metals pollution Soil erosion

21 Spatical distribution of ERP - 4 Loss rate of ERP(%) Biological conditions (E 4 ) MR- ñ USM- ñ DSM- ñ MR- ò USM- ò DSM- ò DR USD DSD Better restoration effect Key restoration elements: Hydrological conditions (E 2 ), Riparian conditions (E 3 )

22 Manwan section Average loss rates of ERP- 1 Average loss rate of ERP /% E2 E3 E4 Elements Manwan- ñ(the first period Manwan- ò

23 Average loss rates of ERP - 2 Dachaoshan section Average loss rate of ERP /% E2 E3 E4 Elements Manwan- ñ(the first period Manwan- ò Dachaoshan Disturbance from the second dam is larger.

24 Average loss rates of ERP- 3 Total study area: Average loss rate of ERP /% E2 E3 E4 Elements Manwan- ñ(the first period The second period Natural self-restoration < New Dam Construction Disturbance

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