|Stormwater Drainage and Land Reclamation for Urban Development (HABITAT, 1991, 94 p.)|
The key to good maintenance is frequent inspection. Inspection followed by proper care of channels, structures and mechanical equipment will avoid major maintenance at a later date. Proper maintenance demands close and continuous examination of system facilities by experienced personnel, followed by timely repair and replacement programmes.
The timing of some recurring maintenance needs can sometimes be predicted. However, in general maintenance needs can only be determined by careful on-site observation. It is therefore necessary to arrange for periodic inspection of all system facilities at regular intervals. The results of these inspections must be recorded so that the performance can be tracked. With the advent of computer technology and the development of smart software, this recording of information in databases for easy access and management reporting can expose trends in the extent of the maintenance effort required by various sections of the drainage system. This information system can then be used to direct the available maintenance funds to those areas.
As untreated or uncorrected minor maintenance needs can grow rapidly into major and costly maintenance problems, inspections should be made frequently. The interval between subsequent inspections may then be determined as performance dictates.
Three procedures which have been developed for the implementation of an inspection programme are:
(i) Initial inspection. When construction is essentially completed, a formal inspection of all work is made and any uncompleted items and deficiencies listed. This defines the work remaining to be accomplished and provides an opportunity for all concerned to be better informed on the condition of the system at the time control is taken over. The inspection should be made by a team representing the design, construction and operation and maintenance agencies.
(ii) Operation and maintenance instructions and criteria. A detailed manual for operation and maintenance of major structures covering all important features of the operation and maintenance of the structure should be prepared. The designers' operating criteria should be published to cover the technical operations of equipment and structures and the requirements for maintenance. This helps to ensure that the facilities will be operated as the designers intended, thus avoiding damage and extending the life of the facility.
(iii) Periodic review of maintenance. These reviews should be in the form of a thorough inspection of all facilities. The inspection team should include an engineer from the design organization, a senior representative from the operating agency, and key maintenance personnel. The principal purposes of the review are to verify the safety of the structure; to determine the level of maintenance and conditions that might cause failure of operation; to note the extent of deterioration as a basis for planning maintenance, repair or rehabilitation work; and to obtain operating experience data for improvement of future design, construction, maintenance and operation practices.
Reports prepared for all review of maintenance inspection should include the current findings, comparisons with previous inspections, and a summary of conclusions and recommendations. To provide guidance in planning and performing repairs, they should also include adequate photographs and drawings to illustrate conditions found. It is suggested that recommended repairs and operating procedures be grouped into categories according to the importance of problems involved. These might be:
Category 1: recommendations involving matters of great importance which must be acted upon within a prescribed period;
Category 2: recommendations covering a wide range of important problems that should be solved;
Category 3: recommendations for modification of the inspection, operation and maintenance procedures.