2.3 Assessment of implementation results and City’s orientation for the upcoming period
In general, planning, programs, schemes, projects implemented lately in Ho Chi Minh City have focus, priority, contribution to elimination and significant mitigation of flood, especially in center area of the City. Among which, highlights are completion of Environment Sanitation Project – Nhieu Loc Thi Nghe basin (phase 1), putting Nhieu Loc Thi Nghe tide control station into operation, installation of 248 km long sewers of various sizes and 1077 tidal flap valves at outfalls,…
However, due to economy difficulties in past years, budget does not meet the need of fund, which leads to the fact that the implementation of those planning-based projects is still slow. Present length of sewers in the City only makes up 60% meaning that another 2,500 km of sewers is required according to the Master Plan of drainage system in Ho Chi Minh City to the year 2020 (total length of sewers in 6,000km); and only 1 of 10 tide control stations and 64 of 149 river dikes are constructed according to Water Resources Planning for flood prevention in Ho Chi Minh City.
On basis of initial positive results and planning, schemes approve by the Prime Minister, in the upcoming time the City will speed up and prioritize capital for completion and putting into operation of works under water drainage and anti-flood plan, closely manage construction planning, protect present equalization lakes and reservoirs, speed up construction of new equalization lakes for actively reserving water, dredge and clear obstacles in channels, canals for fast drainage in order to shorten flooding duration in heavy rains.
2.4 Proposed solutions in accordance with orientation, known plans and projects in order to improve the efficiency of flood elimination and reduction in background of climate change
Beside positive results of projects on drainage and flood reduction, which operate effectively and draw agreement and praise from the City’s people, but as a role of managers, experts and scientists working in the field of water drainage, we are obligated to make a joint comprehensive re-assessment from all angles, therefore specific proposals, scientific solutions will be found in order to improve, supplement plans, projects to be implemented in the upcoming time.
One of the focused issues the authors think we should concentrate for study, implement intensively in the upcoming time is level and ability to apply purpose-built informatic technology, program/software to improve efficiency, validity of drainage data management, support in the making of and make optimal operation and maintenance plan, predict scenarios corresponding to expected weather conditions which are complicated and hard to predict when climate change strongly has been effecting the City in past years and in future.
According to above figures, we wonder why exist the rather great difference between input data for calculating design frequency of sewers and weather development with precipitation, tidal water level in the last 5 year? Among which, it is partly due to effect of climate change, this is popular trend worldwide, not only Ho Chi Minh City suffers, therefore, internal challenges and subjectiveness have driven us in making plans, implementing projects. Methods of managing and operating components of drainage system, daily working and production operation now show many unsound issues that need to be solved.
The facts show that there will be no good orientation and plans without good input data which help to relatively correctly predict possible scenarios in short-term and long-term vision; there will be no effective projects without good method of steering, management and operation of the system. Therefore, the City’s works and infrastructure facilities for drainage and flood reduction are on the defensive and not able to effectively adapt to adverse weather development when climate change becomes more and more complicated. To overcome present unsound issues and to prevent limitations from happening in future, it is an unavoidable trend to utilize and exploit thoroughly scientific progress, informatic technologies for the following:
For storage, collection, comprehensive - adequate - accurate management of database of drainage system (sewers, manholes, outfalls, pumping stations and tide control stations, tidal valves/stop logs, data of rain and tide, information of flood points, collection sewer lines and wastewater treatment plants,…); support in making decisions, operation and maintenance plan for components of the system.
The data collected, measured, standardized will be valuable and reliable source of input data which is combined with hydraulic software to properly separate areas and network, assess drainage capability of drainage basin in Ho Chi Minh City, then establish projects, coordination method, method of shifting water flow in case of heavy rain causing flood among catchment areas in a basin and among basins in the City. Meanwhile, model based calculated results are scientific evidence with high reliability and accuracy, which contribute to assessment, prediction of scenarios, situations that may happen in future, support effectively in making of plans for projects, schemes of drainage and flood reduction in the City.
About solution for adaptation to flood through research, experience and angle of view, many experts, scientists and sector top managers have shared the same point of view that method using construction works to thoroughly solve flood in climate change is not the optimal solution but extremely costly; we should build up solutions towards “living in peace” with water, establish schemes, scripts of emergency response according to model-based prediction of storms, flood, reservoir discharge, heavy rains and high water rise in order to minimize damages to the City.
Use of results from above solutions (completion in 03 – 05 years to come), coming to stage of management, monitoring, steering, operation of works, system of drainage, valves, stop logs, pumping stations, tide control stations,… in the manner of automation, control via camera, through internet and sensors fixed at sites for the whole network. When coming to the stage, it is understood that all components for drainage purpose are integrated in a system, and present trend that developed countries are investing to develop is Internet of Things
Then operators can control drainage system (close/open 1 or more tidal valves, stop logs, close/open pumping stations, tide control stations or system for shifting water among catchment areas in a basin,…), all are done through internet by smart devices such as computers, tablets, smart phones.
Use of hydraulic model in Nhieu Loc Thi Nghe basin (invested and implemented by Ho Chi Minh City Urban Drainage Company Limited) to gradually solve problems raised according to schedule and solutions mentioned above is initially successful in digitalizing all data of drainage system and of drainage works into a software (ArcGIS), re-assessing present conditions, drainage capability of basins, from which catchment areas can be properly separated and calculation modeling (Mike Flood) can be established to simulate the development of and predict flood situations according to scenarios of different rains and tide conditions.
Cameras for monitoring development of rain and flood
in some streets of Ho Chi Minh City
Based on implementation results in Nhieu Loc Thi Nghe basin, continue to prepare adequate accurate detailed data and start naming components of the whole drainage system in the basin, invest in equipment, machines and human resource capable of establishing, managing and operating the system “Internet of Things for drainage – IoT drainage”. Assess, draw experience and multiply the model to other basins in HO Chi Minh City.
Ho Chi Minh City in progress of construction, development and integration cannot be out of the common rule with trend to apply informatic science and technology to all aspects of life, especially for modernization of state management in which urban management, management of environment, infrastructure works, traffic,… are in urgent need to be implemented as soon as possible in the upcoming time.
