ｚ Urban drainage : drainage Urban Urban Drainage constructed by SLLRDC and to be Local to transferred Authorities (Engineer) Regional Office Regional Kirimandara Mawatha AGM Urban drainage : scheme, Place Unity West Torrington scheme, and other minor drains inthe coverage area Deputy GeneralManager

： DGM Maintenance ofUrban Drainage New organizationNew proposed inthe Master Plan Note: AGM: Assistant General Manager General Assistant AGM: (Engineer) North Colombo Regional Office Regional Urban drainage : scheme, Serpentine scheme, St. and scheme, Sebastian other minor drains in the coverage area Canals : Canals (Engineer) Regional Office Kirimandara Mawatha Kolonnawa Ela South, Kotte canals, HeenEla, Torrington canal, other lake, Parliament canals constructed by SLLRDC and to be Local to transferred Authorities (Engineer) Colombo South Regional Office Regional Canals : Canals Dehiwela canal, Wellawatta canal, Kirilapone canal, canal(north), Bolgoda canal, mawatha Bhatiya Other minorcanals AGM DGM Canal Maintenance Canal Office (Engineer) Canal Development Maintenance and Development Canal Attidiya Regional Canals : canal Bolgoda (south), Other minor canals Proposed section forO&M ofmain rivers/canals, secondary canalsandretention areas Proposed section forO&M ofurban drains and therelated facilities tobe transferred toLocal Authorities (Engineer) Colombo North Regional Office Regional Canals : Canals canal, Sebastian St. north, Ela Kolonnawa Ela, Dematagoda Mahawatta MainDrain, Other minor Ela, canals Legend

Canal AGM Activities Development Canal Development

The Study on Storm Water Drainage Plan Figure 4.72 for the Colombo Metropolitan Region Proposed Sections of SLLRDC (CD&M in the Democratic Socialist Republic of Division) for O&M of the Project JAPAN INTERNATIONAL COOPERATION AGENCY

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Preliminary (6 days) Information

Scoping

(30 days) IEE required IEE or EIA? EIA required (14 days) Set TOR Preliminary Information Accepted as IEE Preparation of EIA Report No

Set TOR Adequacy of Report Preparation Further Yes of IEE Report Information No Yes

(30 days) Public Notice

Forward Comments to (6 days) Project Proponent(PP)

Response to Comments by PP

Decision (IEE: 6 days, EIA: 30 days) Approved Not Approved with Conditions

Notice to Public Appeal

Note: Bracketed figures indicate maximum number of days to complete necessary procedure. Source: This figure is rearranged based on the “Guide for Implementing the EIA Process, No.1, 1998. Central Environmental Agency, Sri Lanka”.

The Study on Storm Water Drainage Plan Figure 6.1 for the Colombo Metropolitan Region in the Democratic Socialist Republic of Sri Lanka EIA Process JAPAN INTERNATIONAL COOPERATION AGENCY

F - 113 Cost Component Project 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 (million Rs.) 1. Ja Ela Basin Stormwater Drainage Plan 1) Ja Ela Channel Improvement D/D Construction 1,102 (B=60m, L=7km) Procurement 2) Dandungam Oya Channel Improvement 2,342 (B=80m, L=9.9km) 3) Storm Water Retention Area 235 (Lower Area =500ha, Upper Area=376ha) 2. Kalu Oya Basin Stormwater Drainage Plan 1) Old Canal Improvement 648 ((B=40m,B=40m ,L=4.5km) L=4.2km ) 2) Kalu Oya Channel Improvement 1,515 (B=50m, L=5km) 3) Storm Water Retention Area 300 (Lower Area =360ha, Upper Area=89ha) 3. Greater Colombo Basin Stormwater Drainage Plan 1) Restoration of the Existing Mutwal Tunnel 86 (D=1.8m, L=554m) 2) Construction of Madiwela South Diversion 3,361 Canal (B=40m, L=8.8km) 3) New Mutwal Tunnel Construction (D=4m, 861 L=740m)) 4) Storm Water Retention Area (Kolonnawa, Kotte and Heen Marshes and Parliament Lake 81 Area = 380ha in total) 4. Bolgoda Basin Storm Water Drainage Plan 1) Weras Ganga Scheme (B=40m, L=5.5km), -Rattanapitiya Scheme(5.5km), 3,274 Bolgoda Scheme (2.7km)(2.4km) and - 2) North (2.9km),(3.1km) Boralesgamuwa South (1km) and Maha Ela 1,035 Scheme (4.5km)(4.3km) 3) Storm Water Retention Area in Weras Ganga 793 Basin (295ha) 4) Storm Water Retention Area in Lowlands of - North and South Bolgoda Lakes 5. Non-structural Measures 1) Storm Water Retention Area Management - Institutional and Legislative Arrangement - - Implementation 2) Development Control in Urban Development Area - - Institutional and Legislative Arrangement - Implementation 3) Land Use Regulation in Lowland Area - Institutional and Legislative Arrangement - - Implementation 4) Dissemination of Flood Information - Institutional and Legislative Arrangement - - Implementation 5) Flood-proofing of buildings in Frlood-prone - Area 6. Institutional Development Plan 1) Demarcation of Responsibilities on Storm - Water Drainage Sector among Related 2) Lowland Management by SLLRDC - Institutional and Legislative Arrangement - - Implementation 7. Operation and Maintenance Plan 1) Organizational Set-up and Staff Arrangement - (SLLRDC and Relevant Local Authorities) 2) Procurement of O&M equipment -

8. Human Resources Development Plan 1) Implementation of O&M Training Program for - SLLRDC and Local Authorities 2) Implementation of Overall Training Program for Human Resources Development for Storm - Water Drainage Sector

The Study on Storm Water Drainage Plan Figure 9.1 for the Colombo Metropolitan Region Overall Implementation Schedule of Storm in the Democratic Socialist Republic of Sri Lanka Water Drainage Master Plan JAPAN INTERNATIONAL COOPERATION AGENCY

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Nugegoda-Rattanapitiya Sub-basin (8.2 km2)

Boralesgamuwa North Sub-basin (4.9 km2)

Boralesgamuwa South 2 Bolgoda Canal Sub-basin (4.0 km )

Bolgoda Canal 2 Weras Ganga Sub-basin (7.7 km ) Maha Ela Sub-basin (20.4 km2)

Thumbowila Sub-basin (2.2 km2) Ratmalana- Sub-basin (8.1 km2)

North Bolgoda Lake

Scale Legend Boundary of Weras Ganga Basin 0 1 2 km Sub-basin Boundary

The Study on Storm Water Drainage Plan Figure 13.1 for the Colombo Metropolitan Region Weras Ganga Basin in the Democratic Socialist Republic of Sri Lanka JAPAN INTERNATIONAL COOPERATION AGENCY

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Legend Ground Elevation (above MSL) Below 0.5 m 0.5 m ~ 1.0 m 1.0 m ~ 1.5 m Scale 1.5 m ~ 2.0 m 0 1 2 3km N

Bellanwila-Attidiya Marsh Area

Ctp

Study Area (Weras Ganga Basin)

Bolgoda Ganga

Panadura Ganga

5 fathom

Legend

Geomorphological Unit Geology Brb Barrier Bar Unconsolidated Coastal Deposits Ctp Coastal Plain Alluvium Ps Planation Surface Granitic Gneiss Scale L Former Lagoon - 0 1 2 km Source: Wetland Site Report and Conservation Management Plan ,Ministry of Environment and Parliamentary Affairs, 1993

The Study on Storm Water Drainage Plan Figure 13.3 for the Colombo Metropolitan Region in the Democratic Socialist Republic of Sri Lanka Geology and Geomorphology of JAPAN INTERNATIONAL COOPERATION AGENCY the Bolgoda Basin (Wilson, 1992)

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