Managem ent Process for Realization of River Basin Control tow ards the Creation of the Urbanized Hydrological System to be W ell-balanced Asian Science and Technology Sem inar ( ASTS) in Thailand March 1 1 , 2 0 0 8 Masahiro I m be Association for Rainwater Storage and Infiltration Technology ( ARSI T) A R S I T 1
Outline of this Presentation � Introduction � Outline of Study Area � Feature of Master Plan � Development of Procedure for Action Plan � Future Aspects � Conclusions 2
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
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 2002 5
Extraction of Problems in Shingasi River Basin Contour lines of unconfined groundwater level and saturated hydraulic conductvities 6
Precipitation Subjected Items of Evaporation Evaporation Analysis Irrigation River Surface Runoff Water Supply Well Un-saturated Layer Sewerage Unconfined Aquifer Pressurized Layer Artesian Aquifer 7
Extraction of Problems in Shingasi River Basin � Physically based distributed model Surface Runoff: 1D Kinematic Wave Infiltration: Unsaturated Flow (Richards Equation) Groundwater Flow: Darcy’s Law River Evapotranspiration: Harmon’s Empirical Formula 8
Extraction of Problems in Study Area Increase of flood volume a. annual direct runoff (Shingasi River) 500 409 400 290 (mm/yr) 300 206 200 100 0 past present future (in 1945) (in 2025) 9
Extraction of Problems in Study Area Increase of water demand b. annual water supply (Shingasi Basin) 1,123 1,200 1,000 775 (mm/yr) 800 600 400 200 22 0 past present future (in 1945) (in 2025) 10
Extraction of Problems in Study Area Deterioration of water quality c. Water quality (BOD) of dominant rivers in Shingasi river basin name observation observed name observation observed point value(mg/ l) point value(mg/ l) Furo Furo Bridge 28.7 Shingasi Asahi Bridge 9.1 River River Yanase Sakae Bridge 11.2 Sasame Bridge 8 River Kurome Azuma Bridge 12 Shimo Bridge 6.4 River Shirako Ochiai Bridge 6.4 River The target value recommended by the government is 10 mg/ l in this river basin) 11
Extraction of Problems in Study Area Decrease of base runoff d. annual base runoff (Furo River) 250 217 200 (mm/yr) 150 100 61 24 50 0 past present future (in 1945) (in 2025) 12
Extraction of Problems in Shingasi River Basin Decline of ground water level and dry-up of e. spring water annual spring water discharge average groundwater level(Shingasi Basin) (Shingasi Basin) 45 500 400 315 41.14 40.66 255 (mm/yr) 300 (m) 183 40 200 38.78 100 0 35 past present future past present future (in 1945) (in 2025) (in 1945) (in 2025) 13
Extraction of Problems in Shingasi River Basin Change of climate f. annual evaporation (Shingasi Basin) 447 500 360 400 287 (mm/yr) 300 200 100 0 past present future (1945) (2025) 14
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
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) com prehensive m aster plans should be drafted for urbanized areas Yanase River Basin (as a pilot project) 16
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 1945 630,000 in 2003 � Ratio of Urban Areas: 54.3% in 1994 � Ratio of Sewerage Propagation : 60 % in 2000 17
Outline of Study Area Photo image of Yanase River � 18
Outline of Study Area Photo image of Yanase River � Yanase River Main Flow Low er Reach of Yanase Confluence Point Children having a fun Main Flow from Left Yanase River from Right 19
Outline of Study Area Photo image of Yanase River � Upper Reach of Yanase River Covered w ith Rich Green at Riverside 20
Outline of Study Area Photo image of Yanase River � Azum a River Typical Conventional Revetm ent Azum a River ( Tributary) Flow ing in the City Area Typical Deteriorated Condition of Urban River 21
Feature of Master Plan 200 ７ 2000 2005 Master Plan Action Plan � The Master Plan investigative committee ・ academic advisors ・ government officers ・ representative citizens 22
Basic Concept and Policy Authorized for Master Plan 23
Basic Concept and Policy Authorized for Master Plan CONCEPT FUNDAMENTAL POLICY Conservation of Implementaion of Measures Involvement of Relevant Hydrological System which succeed to the Future People which pursue deteriorated by to make a well -balance of the cooperative society Urbanization Flood Control, regarding water i n terms of Water Utilization 1.Flood and Aqua-Environment which describes the social 2.Ordinary Flow activities such as education , 3.Underground Water and which describes the policy for clean up, festival, seminar Spring Water practical measures to be done etc. 4.Water Quality by governments and inhabitants . which describes the well - balanced hydrological system regarding water quantity and quality. 24
Basic Idea for Setting up Project Goal � Two types of viewpoints � Quantitative index (Engineering approach) � Environmental condition (understandable for ordinary inhabitants) 25
Basic Idea for Setting up Project Goal Detailed Procedure for Decision Making of Project Goal Investigation of Setting up Implemented or Planned Image of Project Goal Measures by Local Governments Setting up Measures Reconsideration to be Considered Numerical Simulation Setting up to estimate Effectiveness of Quantitative Targets Proposed Measures No Good Comparison OK to Next Sheet 26
N.G. Comparison O.K. Proposition of Project Goal N.G. Estimation of Necessity Possibility of Implementation O.K. Consensus Building for Project Goal Target Values Measures Allotment of Responsibility 27
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
Co-operative System for Drafting Master Plan � For building the consensus of the plan 29
Co-operative System for Drafting Master Plan � For building the consensus of the plan 30
31 Setting up the Image for Desirable River Basin Towards the river where children can get in and safely have a fun Catchphrase Ex.
32 Towards the river which tempts people to go Setting up the Image for Desirable River Basin Catchphrase fishing. Ex.
33 Setting up the Image for Desirable River Basin sensitive to environmental change can live Towards the river where domestic species Catchphrase Ex.
Precipitation Subjected Items of Evaporation Evaporation Analysis Irrigation River Surface Runoff Water Supply Well Un-saturated Layer Sewerage Unconfined Aquifer Pressurized Layer Artesian Aquifer 34
Setting up target values at check points and correlated fundamental measures Water supply from another basin Evapotranspiration ① Conservation of green zone and agricultural land Precipitation Rain water use Conservation of Water reuse agricultural land Surface runoff Conservation of forest ③ Implementation of Infiltration Paddy facilities River channel sewerage system field improvements improvement Discharge Sewage ② Promotion of Discharge rainwater storage and infiltration facilities Discharge Sewage plant Ground water use 35 Ground water use
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