Management Process for Realization of River Basin Control towards the Creation of the Urbanized Hydrological System to be Well-balanced

Transcription

1 Management Process for Realization of River Basin Control towards the Creation of the Urbanized Hydrological System to be Well-balanced Asian Science and Technology Seminar (ASTS) in Thailand March 11, 2008 Masahiro Imbe Association for Rainwater Storage and Infiltration Technology (ARSIT) 1

2 Outline of this Presentation Introduction Outline of Study Area Feature of Master Plan Development of Procedure for Action Plan Future Aspects Conclusions 2

3 Introduction Impact on Hydrological System in Urban Areas Urbanization Expansion of urban area Improvement of lifestyles High population density High grade of land utilization Impact on hydrological system Expansion of impermeable area Increase in water demand Increase in waste water Reduction of water areas and green spaces 3

4 Location of Study Area 4

5 Outline of Shingasi River Basin runs from north-west to south-east into Tokyo Bay has been urbanized since the 1960s Basin area : 390 km2 River length : 34.6km Population : 2,440,000 (As of 2003) Ratio of Urbanization Area 13% in 1961 increase to be 49% in 2002 Ratio of Sewerage Propagation : 89.6% in

6 Extraction of Problems in Shingasi River Basin Contour lines of unconfined groundwater level and saturated hydraulic conductvities 6

7 Subjected Items of Analysis Evaporation Precipitation Evaporation Water Supply Surface Runoff River Irrigation Well Un-saturated Layer Sewerage Unconfined Aquifer Pressurized Layer Artesian Aquifer 7

8 Extraction of Problems in Shingasi River Basin Physically based distributed model Surface Runoff: 1D Kinematic Wave Infiltration: Unsaturated Flow (Richards Equation) River Groundwater Flow: Darcy s Law Evapotranspiration: Harmon s Empirical Formula 8

9 Extraction of Problems in Study Area a. Increase of flood volume annual direct runoff (Shingasi River) (mm/yr) past present future (in 1945) (in 2025) 9

10 Extraction of Problems in Study Area b. Increase of water demand annual water supply (Shingasi Basin) (mm/yr) 1,200 1, , past present future (in 1945) (in 2025) 10

11 Extraction of Problems in Study Area c. Deterioration of water quality Water quality (BOD) of dominant rivers in Shingasi river basin name Furo River Yanase River Kurome River Shirako River observation point observed value(mg/l) name observation point observed value(mg/l) Furo Bridge 28.7 Shingasi Asahi Bridge 9.1 River Sakae Bridge 11.2 Sasame Bridge 8 Azuma Bridge 12 Shimo Bridge 6.4 Ochiai Bridge 6.4 The target value recommended by the government is 10 mg/l in this river basin) 11

12 Extraction of Problems in Study Area d. Decrease of base runoff annual base runoff (Furo River) (mm/yr) past present future (in 1945) (in 2025) 12

13 Extraction of Problems in Shingasi River Basin e. Decline of ground water level and dry-up of spring water (m) average groundwater level(shingasi Basin) past present future (mm/yr) annual spring water discharge (Shingasi Basin) past present future (in 1945) (in 2025) (in 1945) (in 2025) 13

14 Extraction of Problems in Shingasi River Basin f. Change of climate annual evaporation (Shingasi Basin) (mm/yr) past present future (1945) (2025) 14

15 Extraction of Problems in Shingasi River Basin Problems in Shingasi River Basin Increase of flood volume Increase of water demand Deterioration of water quality Decrease of base runoff Decline of groundwater level and dry-up of spring water Change of climate 15

16 Introduction An interim report How should the well-balanced hydrological system be in river basins. (the Sub-committee of Water Cycle, the River Council for river control,july 1998) comprehensive master plans should be drafted for urbanized areas Yanase River Basin (as a pilot project) 16

17 Outline of Study Area The Yanase River Basin biggest tributary of the Shingashi River Basin runs north-west of Tokyo has been urbanized since the 1960s Basin area :100km 2 River length:27km Population:222,000 in ,000 in 2003 Ratio of Urban Areas: 54.3% in 1994 Ratio of Sewerage Propagation: 60 % in

18 Outline of Study Area Photo image of Yanase River 18

19 Outline of Study Area Photo image of Yanase River Main Flow Yanase River Confluence Point Main Flow from Left Yanase River from Right Lower Reach of Yanase Children having a fun 19

20 Outline of Study Area Photo image of Yanase River Upper Reach of Yanase River Covered with Rich Green at Riverside 20

21 Outline of Study Area Photo image of Yanase River Azuma River Typical Conventional Revetment Azuma River (Tributary) Flowing in the City Area Typical Deteriorated Condition of Urban River 21

22 Feature of Master Plan Master Plan Action Plan The Master Plan investigative committee academic advisors government officers representative citizens 22

23 Basic Concept and Policy Authorized for Master Plan 23

24 Basic Concept and Policy Authorized for Master Plan CONCEPT FUNDAMENTAL POLICY Conservation of Hydrological System deteriorated by Urbanization in terms of 1.Flood 2.Ordinary Flow 3.Underground Water and Spring Water 4.Water Quality which describes the wellbalanced hydrological system regarding water quantity and quality. Implementaion of Measures which succeed to the Future to make a well-balance of Flood Control, Water Utilization and Aqua-Environment which describes the policy for practical measures to be done by governments and inhabitants. Involvement of Relevant People which pursue the cooperative society regarding water which describes the social activities such as education, clean up, festival, seminar etc. 24

25 Basic Idea for Setting up Project Goal Two types of viewpoints Quantitative index (Engineering approach) Environmental condition (understandable for ordinary inhabitants) 25

26 Basic Idea for Setting up Project Goal Detailed Procedure for Decision Making of Project Goal Investigation of Implemented or Planned Measures by Local Governments Setting up Measures to be Considered Numerical Simulation to estimate Effectiveness of Proposed Measures Setting up Image of Project Goal Reconsideration Setting up Quantitative Targets Comparison No Good OK to Next Sheet 26

27 Comparison N.G. O.K. Proposition of Project Goal Estimation of Necessity Possibility of Implementation N.G. O.K. Consensus Building for Project Goal Target Values Measures Allotment of Responsibility 27

28 Setting up the Image for Desirable River Basin Project goal in Two conditions For Flooding river improvement plan by relevant local governments For usual time using the catchphrases and pictures 28

29 Co-operative System for Drafting Master Plan For building the consensus of the plan 29

30 Co-operative System for Drafting Master Plan For building the consensus of the plan 30

31 Setting up the Image for Desirable River Basin Ex. Catchphrase Towards the river where children can get in and safely have a fun 31

32 Setting up the Image for Desirable River Basin Ex. Catchphrase Towards the river which tempts people to go fishing. 32

33 Setting up the Image for Desirable River Basin Ex. Catchphrase Towards the river where domestic species sensitive to environmental change can live 33

34 Subjected Items of Analysis Evaporation Precipitation Evaporation Water Supply Surface Runoff River Irrigation Well Un-saturated Layer Sewerage Unconfined Aquifer Pressurized Layer Artesian Aquifer 34

35 Setting up target values at check points and correlated fundamental measures Conservation of green zone and agricultural land Precipitation Water supply from another basin Water reuse Rain water use Evapotranspiration Conservation of agricultural land River channel improvements Surface runoff Conservation of forest Implementation of Paddy sewerage field system improvement Infiltration facilities Discharge Discharge Discharge Ground water use Sewage Promotion of rainwater storage and infiltration facilities Sewage plant Ground water use 35

36 Establishment of Promotion Council Development Establishment of Promotion Council of Procedure & Working Group Discussion Session & Working Group Organized by Government Organized by Government for Action Plan Discussion with Residents Session with Residents Formulation of Action Plan Existing Measures Monitoring Program Newly Developed Program Election of Representatives Condition Assessment Progress Assessment every year Establishment of Investigative Sessions Trial Implementation at Model Areas Planning, Assessment on Monitoring and Planning, Establishment Assessment of New on Monitoring Session and Establishment of New Session every 5 years Assessment of Master Plan and Action Plan Assessment and Review of Master of Both Plan Plans and Action Plan and Review of Both Plans Cooperation Opinion Opinion Setting up of Citizen's Network 36

37 Future Aspects Conservation of green zone and agricultural land Funding system 37

38 Future Aspects Promotion of rainwater storage and infiltration facilities create the ordinance 38

39 Conclusions & Future Subjects Conclusion indicates the investigative procedure and consideration to draw up the Master plan and the Action plan Future subjects to make Action plans understandable, reasonable, and sympathy Producing the positive activity of the co-operative system in which local governments, inhabitants and companies get involved 39

40 Thank you for your attention 40