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Chapter 4 OBSERVATIONS & DATA COLLECTION

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Chapter 4 OBSERVATIONS & DATA COLLECTION Chapter 4 OBSERVATIONS & DATA COLLECTION 4.1 General The objective of chapter 4 is to present the observations and the data collection such as existing physical conditions, navigability, clearance and headroom of the waterway network in the three separate systems. It also presents the data on travel times along the selected canals and river systems. 4.2 Physical Condition of Waterways 4.2.1 The Northern CMR The waterway system in Northern Colombo Metropolitan Region extending from Kelani River up to Maha Oya via Hamilton Canal, Negambo Lagoon and Dutch Canal (between lagoon and Maha Oya) creates an alternate corridor from Colombo to Kochikade. (Fig. 4.1). The system up to Negambo town from Colombo is navigable where the main users being the fishermen. :7 < , , Fig. 4.1 Map of Northern Colombo metropolitan Region 28 4.2.1.1 Kelani River The Kelani River is the widest and one of the major rivers in the country falls to the sea at Modara. The river flows all year, and the depth stands around 1.2m to 1.5m in the navigable channel. The stream velocity, range between 0.15 to 0.6 m/s in the dry season but can rise up to 0.9 to 2.0 m/s after heavy rains to the catchments (UDA, 1996) The river is navigable from the estuary at Modara up to Hanwella in the Kaduwella DS division, at which point formations of rock outcrops hinder the navigability. The main water intake at Ambatale (Fig 4.1) for the Greater Colombo water treatment plant is 15 km upstream from the estuary. Any kind of motorised navigation is avoided in this region, due to the concern on the environmental impact. 4.2.1.2 Hamilton Canal The Hamilton Canal extends 14.5 km from Kelani River to Negambo Lagoon. It runs parallel and 3.8km west of the existing Colombo- Negambo highway. The width at water level is about 15m and the banks are partially protected along the length with gabions and rubble walls. The average depth at the centre of the canal stands at 1.5m & 2m at low and high tide respectively. The canal is presently used for parking of the boats of deep-sea fishermen (Fig. A1.3 of Appendix 1) and also for some, recreational activities organised by tourist hotels in Uswetakeyyawa Area. A minor road runs parallel to the canal half of its length. There are 8 highway bridges and 4 foot bridges across Hamilton canal, all having sufficient vertical and horizontal clearance for navigation. The minimum clearance on each bridge is tabulated in Table 4.1. 29 Table 4.1 Minimum Clearances of bridges across Hamilton Canal Dist. From Min. Hori. Min. Vert. Bridge the Kelani Clearance Clearance River (Km) (m) (m) Palliyawatte Highway Bridge 14.01 13.50 2.85 Elakanda Foot Bridge 13.36 10.50 2.45 Dikowita Bridge 11.86 8.50 2.90 Uswettakeyyawa Highway Bridge 9.60 12.00 3.10 Palliya Road Bridge (Near Convent) 7.65 8.50 2.90 Kadalawala Foot Bridge 5.85 7.00 3.65 Mottanpandura Foot Bridge 4.90 7.50 2.90 Pulluhena Road Bridge 4.30 7.50 3.10 Indigaslanda Road Bridge 3.25 8.80 3.50 Pamunugama Foot Bridge 2.10 8.00 3.30 Pamunugama Highway Bridge 1.75 8.70 3.20 Ambagahawatte Bridge 0.65 8.60 3.00 4.2.1.3 Negambo Lagoon The lagoon is open to the sea at its north end and the navigation channel is about 12 km in length up to the Negambo town. The depth varies from 0.75m to 2.3 m. Presently it is extensively used for shallow water fishing and also for recreational activities by the tourist hotels in the vicinity. The Katunayake International Airport and the Free Trade Zone borders the lagoon in the eastern side. 4.2.1.4 Old Negambo Canal The Old Negambo Canal runs between Kelani River and Ja-Ela parallel and interior to the Hamilton canal. The entire section is non-navigable due to insufficient depths, widths and growth of water hyacinth (Fig. A1.7 of Appendix 1). In some areas the width reduces up to 3m which makes the canal non navigable. A sluice blocks the end at Ja- Ela. The canal is presently non-existing at Nedurupitiya due to the 30 sand fill for Colombo-Katunayake Expressway construction (Fig. A1.8 of Appendix 1). 4.2.1.5 Canal Between Maha Oya and Negambo Lagoon The canal is also known as the Dutch canal. The first 1.6km of the canal runs through the Negambo town on brick retaining walls and is navigable by small boats. The width is around 7 to 9 m. Mainly boats with outboard engine owned by fishermen are parked, along the side on this section of the canal. (Fig A 1.5 & Fig A 1.6 of Appendix 1). The remaining 5.6 km to Maha Oya has steep banks and the depths are insufficient for navigation. The water level width is around 12m and the bridges across the entire section do not present any obstructions for navigation. 4.2.2 The Central CMR The Central Colombo Metropolitan Region has the most potential water bodies for public transport solely because of the amount of passenger movement within the area. Colombo being the business and administrative capital attracted 1,678,651 people on a normal working day in 1995 (Kumarage, 1999). The Beira Lake in the heart of the city and the Wellawatte-Kirillapone canal are the main water bodies that pose the potential for public transport. The feasibility of these two waterways as a mode of public transport would be looked in to in the next chapter. The Central CMR is connected to the Northern CMR and Southern CMR by St. Sebastian canal and Bolgoda Canal respectively (Fig 4.2), both being non navigable due to siltation. Dehiwela canal, which is connected to Wellawatte canal, has the sufficient widths but lack of depth and polluted state hinders any potential navigation. 31 Fig. 4.2 Map of Central Colombo Metropolitan Region 32 4.2.2.1 Beira Lake The Beira is located in the heart of the city of Colombo. The Lake covers 65.4 hectares and has mean depth of 2m. The water level is maintained at 1.8 MSL by couple of locks in the East Lake and the spillway constructed near the Secretariat at Galle Face. It comprises four main basins; the East Lake, the Galle Face Lake, the West Lake and the South West Lake. The East Lake is the largest and the deepest basin with extent of 43.2 hectares and a maximum depth of 5.6 m and accounts for more than 60% of the total lake surface, while the other three basins are much smaller and shallower with a total of 23.2 hectares and a maximum depth of 3.4 m. The Galle Face Lake (2.7 ha) is adjacent to both East and West lakes, and the lake discharge (spillway) is located at the western most section of this basin. With a surface area of only 8.1 ha, the West Lake consists mostly of a narrow passage that connects the Galle Face Lake to the South West Lake (Fig. Al.ll of Appendix 1). The surface area of the latter basin is approximately of 11.4 ha, and a small island is located at its centre (UDA, 1996). The Galle Face Lake and South West Lake are presently navigable but navigation between them is hampered by the silted and stagnated narrow passage of the West Lake. Further, the West Lake borders the Sri Lanka Army Headquarters, where any public navigation is prohibited due to security concerns. East Lake is currently used for recreational activities such as rowing; floating restaurants and it is navigable almost up to its south most end. 4.2.2.2 Wellawatte - Kirillapone Canal The navigable channel is 8.1 km in length from Diyawanna Oya up to the sea outfall at Wellawatte. It passes through 4 major highways 33 making it one of the most potential waterways for public transport as it acts as a transverse link for all the radial links available. The section from Battaramulla end to the Marine drive bridge at Wellawatte, have 7 highway bridges, a Railway Bridge and an over pass of a water line cross the canal. The minimum vertical clearance at high tide is 1.76 m at the Open University Bridge at Nawala (Table 4.2). The horizontal clearances of all the bridges are sufficient for navigation of a boat. The mean depth of the section is around 1.5 m. Table 4.2 Minimum vertical clearances across Wellawatte-Kirillapone Canal Minimum Vertical Clearance Bridge (m) At Low Tide At High Tide Ethul Kotte near Dommino's Pizza 2.87 2.58 Water line Over pass > 4.0 > 4.0 Open University - Nawala 2.05 1.76 Open University - Narahenpita Rd 2.09 1.80 Railway Bridge > 4.0 > 4.0 Baseline Road - Polhengoda 2.19 1.90 Havelock Road near Weaving Mills 2.29 2.00 Duplication Road near St. Peters College 3.29 3.00 Galle Road near Savoy Cinema > 4.0 > 4.0 Sethsiripaya at Battaramulla is a work based trip attractor while, number of private hospitals at Narahenpita including Apollo, Asiri, Oasis and Schools such as St. Peters College, Veluwana College, British School and Royal Institute; Open University; Savoy cinema are all trip attractors that are within the canal influence zone (Fig.
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