Channel Construction

Channel Construction in Urban Areas

Environmental Consideration for Channel Construction in Urban/Sub Urban Areas

when starting  channel construction in urban areas, adequate environmental consideration and proper preventive measures will be taken for noise, vibration, air and water including  groundwater pollution. Maintaining the existing groundwater level is also an important factor for the environmental consideration.

The Environmental Impact Assessment (EIA) has to be carried out for the sub urban area that there is possibility of moderate or minor impacts to the following items:

1. Traffic congestion during the construction works
2. Waste disposal during the construction
3. Noise and vibration caused by construction works
4. Air pollution and dust during construction

The impacts related to traffic congestion would be minimized by identification of roads to be used for the material and equipment transport, type of vehicle and required traffic control measures. A traffic survey has to be carried out and the  further recommendations arising from this study would be incorporated as construction procedure to ensure the adherence to such recommendations. Notification of construction plans in advance to other road users and residents in the area will be necessitated. Impacts on roads and bridges due to transport of materials and trans-location of equipment must be mitigated by drawing up a equipment mobilization plan taking into account the condition of the bridges and culvert on which the machinery has to travel.

Regarding waste disposal, adequate stipulations would be incorporated into construction procedure to ensure safe transport of disposal material without causing inconvenience to public. Impacts of spill over of residue materials on roads would be mitigated by transporting material in dump trucks without overloading them but with a cover. Dumping of disposal material into water bodies need to be totally eliminated. For disposal of deleterious matter, such as dredge material from canals, permission has to obtained from the Central Environmental Authority considering method and sites of disposal. The sediment quality of the canals also need to be determined.

The Construction managers need to aware regarding  construction methodology  about type of equipment to be used so that noise and vibration could be minimized to acceptable levels. However, the adherence to the noise and vibration standards provided by the National Environmental Act (considering noise levels and night operations permitted in residential areas) would be a requirement

Use of well-maintained vehicles and speed control, use of water spray in dusty work sites, covering of material during transport, etc., will be adopted to minimize air pollution and dust.

Channel Construction

Channel Excavation

How to do a Channel Excavation if hard rock found. This method statements gives details for Rock Blasting…

6.0 Safety plan

6.1 Safety Management Action Plan
In order to minimize the occurrence of site accident, the provision of a safe working environment for workers to work is essential. In addition to the above, the following safety precaution must also be implemented in achieving the minimization of site accidents while roadway excavation.

6.2 Personnel Protective Equipment
All rock blasting work would be carried out in accordance with the safety plan and in addition the following procedure would be adapted if it within ROW.

6.3 Safety & Environment
In order to minimize the occurrence of site accident, the provision of a safe working environment for workers to work is essential.  Our company endeavors to make a zero accident record in each site.  In addition to the above, the following safety precaution must also be implemented in achieving the minimization of site accidents.

6.4 General Safety Control

• All new staff should receive Safety Induction conducted by the Safety Officer prior to start any work.
• Traffic Control Training would be conducted to all signalmen in accordance with EMAP.
• Regular safety induction courses and toolbox talks are arranged on site for operative and supervisory staffs and in particular for those new workers.
• Personal Protective Equipment (PPE) such as safety boots and helmets would be provided with workers.  In addition, adequate PPE (e.g. ear and eye protectors) would also be available for construction works as required.
• All machinery would be examined and certified by a competent examiner before the operations.
• Barricades with warning signs would be established all around the excavated area.
• All tools, plant, equipment and temporary facilities and all other items use to carry out the work should be in a safe, sound and good condition.
• Alcoholic drinks and other substances, which may impair judgment, must be prohibited from the Site.
• Material should not be stacked on the external scaffolding.

7.0 Rock Blasting

• Crack survey would be conducted in the nearest houses within 50meters prior to blasting.
• Two blasting signs would be erected at both ends of the road “ROCK BLASTING IN PROGRESS” prior to blasting.
• More than 4 signalmen would be deployed at both ends of the road, all sub-roads foot paths etc.
• Leaflets would be distributed prior to blasting as an awareness of rock blasting.
• Controlled rock blasting would be carried out using sufficient cover of soil, iron plates, sand bags etc.,
• A siren would be alarmed in order to warn the public and on coming vehicles.
• Four barricade boards would be placed on both ends of the road to close the area prior to blasting.
• Demolished debris would be removed prior to charging and clear the surface.
• All workers and signalmen would be conducted with rock blasting awareness course.
• Blasting would be carried out by the Mining Engineer in accordance with the GSMB regulations.
• Safety Officer would announce the massage of blasting prior to ignite the detonators.

8.0 Traffic Safety

All traffic safety arrangements shall be implemented as specified in the “Works in Manholes, etc. in Urban Areas”, in accordance with Manual on Traffic Control Devices – Part II Traffic Control Devices for Road Works published by the National Safety Secretariat – Ministry of Highways.

9.0 Environmental Precaution

Strict environmental compliance will be implemented with regard to disposal of any demolished derbies.  The debris in question shall be transported and dump in the disposal areas as specified by contractual specification. Every effort would be made to ensure no environmental pollution complaints from residents of this area with regard to air & water pollution.

Channel Construction Flood Control

Flood Control in Sri Lanka

When we discuss about flood control in Sri Lanka, The growth areas of Sri Lanka, Specially Colombo district are more often treating by natural disaster of floods even in the light rain. Recently, reasonable attention has been given by the government to mitigate disaster of flood. The construction projects of storm water drainage systems are implementing according to severity of disaster & frequency of floods occurrence. The fortune of civil engineers & peoples in Sri Lanka is least effect of natural disaster comparing other countries in South Asia & even world wide. The main reasons could be identified as unplanned urbanization, absence of soil conservative practices & bad habits of some peoples.

The population growth of the Colombo district is rapidly increased in day by day. The retention areas are greatly reducing due to construction including the illegal as well. the increment of  intensity of the paved areas are effecting to more surface run off due to less infiltration that will evenly reduced due to higher ground water table. The lower latitude of Colombo district also directly influenced to flow rate of the storm water paths. The lesser gradient indirectly influences clogging of water path even piece of garbage. The construction of storm water drainage system is somewhat difficult now in these areas & development projects may get more time & cost rather originally designed and budgeted amount.

When considering of flood control in Sri Lanka,  design of the storm water drainage systems are mainly based on the past rainfall details, catchment characteristics and many other considerations of engineering hydrology & environmental engineering .the open channel construction is widely used in Sri Lanka including underground conduit, pipes sections which are need covering road crossing, building when alternative plans are impossible. The open channels are earth, gabion, random rubble masonry & reinforced concrete, the concrete, gabion channels can be either rectangular or concrete which are basically employed when the spaces are limited. Drainage system may consist of tertiary, secondary, & main canals types according to their capacity.  The frequency of other structures like culverts, bridges, conduits, underground pipes, maintenance road are vary according to intensity of roads & buildings etc.

The construction part of drainage system is vital task within this kind of environment, has to employ extreme knowledge of construction technology. The construction technologies may depend on

Spaces available for construction work

The construction techniques has to change according to the spaces available  for the construction works such as the machinery, plants, vehicles, trucks, material has to  accessible. In commonly the spaces available along channel work that most area has to construct the full width of channel. Therefore the section by sections has to complete due to limited spaces.

Water Diversion

The water path has to be diverted from construction section. The diversion channels are formed along the channel by separating sheet pile line or shoring line or otherwise polyethylene pipe. The construction of diversion channel has to change on section to section due to variation of site condition.

Traffic Diversion & Traffic intensity

The traffic diversion plan has to decide facilitating the vehicle flow. Sometimes some of the road sections have to close permanently according to alternative roots. But in main road crossing are cannot to be closed. Therefore single pile traffic has to allow & but in most cases pre cast concrete sections are providing complete such sections as soon as possible.

Soil condition

The soil conditions near the coastel area are very loose or sandy soil available. The excavations for channel construction are critical concerning safety of near building, pedestrian access, vehicle by pass etc…Therefore the excavated area has to be firmly separated by applying sheet pile or shoring will be vary according to bed level of channel

Ground water Table

The ground water table is very high near the coastal area. Therefore seepage of water has to be control by protecting cofferdam. The usages of water pumps are critical & construction schedule has to be tight minimizing the dewatering cost.

Intensity Lateral Loads

The buildings are much closed to the construction channel even in channel reservation. The construction method has to be changed considering the loose soil conditions also.

Utility Diversion

Detection of underground utility lines is important along the construction channel and has to be diverting according to the invert levels of channel & other utility poles , lines has to be relocate according to  alignment of the construction channel.

Public Interference

Public interference is considerably too high because intensity of people is too high. The variety of peoples form higher level to lower level involving many kind of complains objections etc. Therefore some of the construction sections may get unexpected time & cost.

Pedestrian access

When construction side drains along the road, the access for the building, house has to be removing for the construction works. Therefore temporary access has to be constructing for pedestrian as well as the vehicles. But sometimes has to provide Vehicle Park somewhere else that temporary access impossible for vehicles.

The new construction methods has to be improved to implement storm water drainage systems in urban & sub urban areas effectively while construction company should have experience to be a contractor of this kind of projects. the construction company & government body that the improvement of low lands is belong to Sri Lanka Land Reclamation & Development Corporation (SLLRDC) are doing great job towards mitigating the disaster of flood control in Sri Lamka. The Colombo district municipal councils are doing their maximum efforts to maintain storm water drainage systems effectively & helping to maximize productivity of newly construction drainage systems.