[et_pb_section fb_built=”1″ fullwidth=”on” _builder_version=”4.20.4″ _module_preset=”default” background_image=”https:\/\/jmsc6110a.com\/capstone2023\/wp-content\/uploads\/2023\/05\/Happy-Valley-underground-stormwater-storage-tank-by-Feifan-Yu-1.jpg” parallax=”on” da_disable_devices=”off|off|off” global_colors_info=”{}” da_is_popup=”off” da_exit_intent=”off” da_has_close=”on” da_alt_close=”off” da_dark_close=”off” da_not_modal=”on” da_is_singular=”off” da_with_loader=”off” da_has_shadow=”on”][et_pb_fullwidth_header title=”Below Ground” subhead=”A Deeper Look at Our City’s Drainage System” text_orientation=”center” header_fullscreen=”on” _builder_version=”4.20.4″ _module_preset=”default” title_font=”Georgia|700||on|||||” title_text_align=”center” title_text_color=”#FFFFFF” title_font_size=”88px” title_letter_spacing=”1px” content_font=”Lato||||||||” content_text_align=”center” content_text_color=”#FFFFFF” content_letter_spacing=”0.5px” subhead_font=”Lato||||||||” subhead_text_align=”center” subhead_text_color=”#FFFFFF” subhead_font_size=”24px” subhead_letter_spacing=”1px” subhead_line_height=”2.4em” background_color=”RGBA(255,255,255,0)” background_image=”https:\/\/jmsc6110a.com\/capstone2023\/wp-content\/uploads\/2023\/05\/Happy-Valley-underground-stormwater-storage-tank-by-Feifan-Yu-1.jpg” background_size=”stretch” module_alignment=”center” custom_padding=”||17px||false|false” title_text_shadow_style=”preset1″ content_text_shadow_style=”preset1″ subhead_text_shadow_style=”preset1″ global_colors_info=”{}”]<\/p>\n
by Feifan Yu<\/p>\n
[\/et_pb_fullwidth_header][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.20.4″ _module_preset=”default” min_height=”523.2px” custom_margin=”||-40px||false|false” da_disable_devices=”off|off|off” global_colors_info=”{}” da_is_popup=”off” da_exit_intent=”off” da_has_close=”on” da_alt_close=”off” da_dark_close=”off” da_not_modal=”on” da_is_singular=”off” da_with_loader=”off” da_has_shadow=”on”][et_pb_row _builder_version=”4.20.4″ _module_preset=”default” width=”50%” module_alignment=”center” min_height=”486.2px” custom_padding=”||100px||false|false” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.20.4″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.20.4″ _module_preset=”default” text_font=”Lato||||||||” text_orientation=”justified” custom_margin=”||||false|false” global_colors_info=”{}”]When you walk down the streets of Hong Kong, you pass by many roadside gullies and manhole covers with radial patterns. That means there is a stormwater drainpipe beneath your feet. <\/p>\n
These underground drain pipes make up the whole stormwater drainage system of Hong Kong, which totals more than 2,800 kilometers. That is longer than the distance from Hong Kong to Beijing.<\/p>\n
With an average annual rainfall of about 2400mm, Hong Kong has one of the highest rainfalls in the Pacific Rim. During exceptionally heavy rainfall, flooding may occur in low-lying areas and natural flood plains in the rural areas of the northern part of the New Territories.<\/p>\n
Hong Kong also suffers from severe flooding during typhoon season, which is usually from April to October. In 1995, there were about 90 flooding black spots in Hong Kong, with serious ones larger than 100 hectares, the size of 14 soccer fields, resulting in substantial socio-economic losses.<\/p>\n
The Drainage Services Department (DSD) was established by the government in September 1989 to provide effective approaches to deal with flooding issues. To protect the city from flooding, they built and kept improving the network of tunnels and dikes, hidden just below the streets.[\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.20.4″ _module_preset=”default” custom_padding=”||0px|||” da_disable_devices=”off|off|off” global_colors_info=”{}” da_is_popup=”off” da_exit_intent=”off” da_has_close=”on” da_alt_close=”off” da_dark_close=”off” da_not_modal=”on” da_is_singular=”off” da_with_loader=”off” da_has_shadow=”on”][et_pb_row _builder_version=”4.20.4″ _module_preset=”default” width=”50%” min_height=”1144px” custom_margin=”-126px|auto|-50px|auto|false|false” custom_padding=”50px||||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″][et_pb_column type=”4_4″ _builder_version=”4.20.4″ _module_preset=”default” global_colors_info=”{}”][et_pb_text admin_label=”How does it work” _builder_version=”4.20.4″ _module_preset=”default” text_font=”Georgia|700|||||||” text_font_size=”31px” header_font=”Georgia|600|||||||” header_text_align=”left” custom_margin=”||||false|false” global_colors_info=”{}”]<\/p>\n
How does the system work?<\/p>\n
[\/et_pb_text][et_pb_text _builder_version=”4.20.4″ _module_preset=”default” text_font=”Lato||||||||” text_orientation=”justified” min_height=”348.4px” custom_margin=”||||false|false” global_colors_info=”{}”]The DSD is responsible for flood prevention. The work includes processing daily reports of blockage in public drains, regular inspection of electrical, mechanical, and structural works, rehabilitation of aged and damaged stormwater channels, and desilting drainage facilities.<\/p>\n
However, drainage improvement in urban areas faces another type of construction problem. <\/p>\n
Since most of the roads in Hong Kong are densely packed with utilities, such as cables, telephone lines, and gas pipes, traditional drainage works with excavation techniques inevitably require construction under existing underground utilities, thus affecting traffic and causing inconvenience to the public.<\/p>\n
Therefore, the DSD tries to reduce such work. In addition to the broader use of trenchless excavation techniques to lay drainage pipes, they have adopted more innovative improvement options, including the use of stormwater drainage tunnels to intercept and convey stormwater and the construction of underground flood storage tanks for the temporary storage of stormwater.[\/et_pb_text][et_pb_image src=”https:\/\/jmsc6110a.com\/capstone2023\/wp-content\/uploads\/2023\/05\/Three-pronged-Flood-Prevention-Strategy-01-scaled.jpg” alt=”Three-pronged Flood Prevention Strategy” title_text=”Three-pronged Flood Prevention Strategy” show_bottom_space=”off” align=”center” _builder_version=”4.20.4″ _module_preset=”default” module_alignment=”center” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″][\/et_pb_image][et_pb_text admin_label=”Caption” _builder_version=”4.20.4″ _module_preset=”default” text_font=”Lato||on||||||” custom_margin=”||||false|false” global_colors_info=”{}”]Three-pronged Flood Prevention Strategy. Source: Drainage Services Department.[\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.20.4″ _module_preset=”default” custom_padding=”||27px|||” da_disable_devices=”off|off|off” global_colors_info=”{}” da_is_popup=”off” da_exit_intent=”off” da_has_close=”on” da_alt_close=”off” da_dark_close=”off” da_not_modal=”on” da_is_singular=”off” da_with_loader=”off” da_has_shadow=”on”][et_pb_row _builder_version=”4.20.4″ _module_preset=”default” width=”50%” min_height=”1131px” custom_margin=”-111px|auto|-90px|auto|false|false” custom_padding=”50px||||false|false” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.20.4″ _module_preset=”default” global_colors_info=”{}”][et_pb_text admin_label=”Stormwater drainage tunnel” _builder_version=”4.20.4″ _module_preset=”default” text_font=”Georgia|700|||||||” text_font_size=”31px” header_font=”Georgia|600|||||||” header_text_align=”left” custom_margin=”||||false|false” global_colors_info=”{}”]<\/p>\n
Stormwater drainage tunnel<\/p>\n
[\/et_pb_text][et_pb_text _builder_version=”4.20.4″ _module_preset=”default” text_font=”Lato||||||||” text_orientation=”justified” custom_margin=”||||false|false” global_colors_info=”{}”]At present, there are four giant stormwater drainage tunnels throughout Hong Kong, including the Hong Kong Island West, Lai Chi Kok, Tsuen Wan stormwater drainage tunnels, and the Kai Tak Stormwater Transfer Scheme.<\/p>\n
Those large tunnels can intercept rainwater midway and directly discharge it to the sea, reducing the upstream flow to the downstream urban runoff.<\/p>\n
The Hong Kong Island West drainage tunnel, the longest and largest one with a length of 11 kilometers from Tai Hang to Cyberport, can drain away nearly 7,500 cubic meters \u2014 equivalent to three standard swimming pools of rainwater in a minute.[\/et_pb_text][et_pb_image src=”https:\/\/jmsc6110a.com\/capstone2023\/wp-content\/uploads\/2023\/05\/Lai-Chi-Kok-Drainage-Tunnel-by-DSD.jpg” alt=”Lai Chi Kok Drainage Tunnel” title_text=”Lai Chi Kok Drainage Tunnel” show_bottom_space=”off” align=”center” _builder_version=”4.20.4″ _module_preset=”default” module_alignment=”center” custom_margin=”||||false|false” custom_padding=”10px||||false|false” global_colors_info=”{}”][\/et_pb_image][et_pb_text admin_label=”Caption” _builder_version=”4.20.4″ _module_preset=”default” text_font=”Lato||on||||||” custom_margin=”||||false|false” global_colors_info=”{}”]Lai Chi Kok Drainage Tunnel. Source: Drainage Services Department.[\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.20.4″ _module_preset=”default” custom_padding=”18px||26px|||” da_disable_devices=”off|off|off” global_colors_info=”{}” da_is_popup=”off” da_exit_intent=”off” da_has_close=”on” da_alt_close=”off” da_dark_close=”off” da_not_modal=”on” da_is_singular=”off” da_with_loader=”off” da_has_shadow=”on”][et_pb_row _builder_version=”4.20.4″ _module_preset=”default” width=”50%” custom_padding=”||21px|||” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.20.4″ _module_preset=”default” global_colors_info=”{}”][et_pb_text admin_label=”Underground flood storage tank” _builder_version=”4.20.4″ _module_preset=”default” text_font=”Georgia|700|||||||” text_font_size=”31px” header_font=”Georgia|600|||||||” header_text_align=”left” custom_margin=”|0px||0px|false|false” global_colors_info=”{}”]<\/p>\n
Underground flood storage tank<\/p>\n
[\/et_pb_text][et_pb_text _builder_version=”4.20.4″ _module_preset=”default” text_font=”Lato||||||||” text_orientation=”justified” custom_margin=”||52px||false|false” global_colors_info=”{}”]Another method is to build a large underground water storage tank. These tanks can temporarily store rainwater upstream so that when the rain subsides, rainwater can be pumped out and the downstream drainage system has enough time to drain, which reduces the risk of flooding.<\/p>\n
The construction of flood storage tanks underneath Happy Valley Stadium began in 2012 and was opened in March 2017. The first and second phases of the underground flood storage tank with a total capacity of 60,000 cubic meters is equivalent to 24 standard swimming pools. <\/p>\n
After its operation, the flood discharge capacity of Happy Valley and the neighboring Wan Chai area was increased to withstand a 50-year rainstorm, protecting the lives and property of the people in the area.[\/et_pb_text][et_pb_gallery gallery_ids=”2646,2652,2657,2663″ posts_number=”5″ _builder_version=”4.20.4″ _module_preset=”default” title_level=”h1″ title_font=”Lato||on||||||” title_text_align=”left” title_font_size=”13px” caption_font=”Lato||||||||” caption_text_align=”left” caption_font_size=”11px” pagination_font=”Georgia||||||||” module_alignment=”center” custom_margin=”-20px||||false|false” global_colors_info=”{}”][\/et_pb_gallery][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.20.4″ _module_preset=”default” custom_padding=”23px||25px|||” da_disable_devices=”off|off|off” global_colors_info=”{}” da_is_popup=”off” da_exit_intent=”off” da_has_close=”on” da_alt_close=”off” da_dark_close=”off” da_not_modal=”on” da_is_singular=”off” da_with_loader=”off” da_has_shadow=”on”][et_pb_row _builder_version=”4.20.4″ _module_preset=”default” width=”50%” custom_padding=”41px|||||” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.20.4″ _module_preset=”default” global_colors_info=”{}”][et_pb_text admin_label=”River Management” _builder_version=”4.20.4″ _module_preset=”default” text_font=”Georgia|700|||||||” text_font_size=”31px” text_letter_spacing=”0.5px” header_font=”Georgia|600|||||||” header_text_align=”left” custom_margin=”||||false|false” global_colors_info=”{}”]River Management[\/et_pb_text][et_pb_text _builder_version=”4.20.4″ _module_preset=”default” text_font=”Lato||||||||” text_orientation=”justified” custom_margin=”||||false|false” global_colors_info=”{}”]The capacity of natural rivers can only cope with river flooding about once every two years. <\/p>\n
In order to increase the capacity of the river to cope with the expected extreme conditions, the rivers need to be straightened, widened, deepened, and laminated. <\/p>\n
After the completion of the river management projects in Shenzhen River, Wutong River, Shuangye River, Shanbei River, Kam Tin River, and Plain River, the risk of flooding in most flood-prone areas has been greatly reduced.<\/p>\n
The Yuen Long Drainage Bypass was specially built to divert stormwater from Yuen Long Town Center. In addition to expanding the capacity of the river, river training projects will also grow many plants on both sides of the river, and even build artificial wetlands to provide a living environment for wildlife.[\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.20.4″ _module_preset=”default” custom_padding=”18px|||||” da_disable_devices=”off|off|off” global_colors_info=”{}” da_is_popup=”off” da_exit_intent=”off” da_has_close=”on” da_alt_close=”off” da_dark_close=”off” da_not_modal=”on” da_is_singular=”off” da_with_loader=”off” da_has_shadow=”on”][et_pb_row _builder_version=”4.20.4″ _module_preset=”default” width=”50%” custom_padding=”22px|||||” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.20.4″ _module_preset=”default” global_colors_info=”{}”][et_pb_text admin_label=”Maintenance” _builder_version=”4.20.4″ _module_preset=”default” text_font=”Georgia|700|||||||” text_font_size=”31px” text_letter_spacing=”0.5px” header_font=”Georgia|600|||||||” header_text_align=”left” custom_margin=”||||false|false” global_colors_info=”{}”]Maintenance[\/et_pb_text][et_pb_text _builder_version=”4.20.4″ _module_preset=”default” text_font=”Lato||||||||” text_orientation=”justified” min_height=”615px” custom_margin=”||||false|false” global_colors_info=”{}”]The effectiveness of a drainage system is easily affected by many factors. Sediments can be slowly deposited in drains and drainage channels, affecting their capacity. Debris, bulky objects and leaves, and branches can be washed into drainage channels, severely blocking the drainage system. And land development can affect the flow path, causing more flow than expected at some points in the drainage system.<\/p>\n
Since the rainy season in Hong Kong runs from April to October, it is not easy to complete the desilting, maintenance, and repair work for the drainage facilities within such a tight time frame.<\/p>\n
DSD Secretary for Development Wong Wai Lum said every year they remove up to 500 tons of sand and silt from the four drainage tunnels and four flood storage ponds, which is equivalent to the weight of about 34 double-decker buses.<\/p>\n
Since 1995, the Drainage Services Department has eliminated a total of 127 flooding black spots. Now, only four flooding black spots remain, one of which is Chatham Road South. Its flood control project is expected to start in the third quarter of this year in hopes that this flooding black spot can eventually be removed from the list.<\/p>\n
The large scale of flood prevention facilities now includes over 2,400 km of underground stormwater drains, over 360 km of man-made watercourses, four underground flood storage ponds with a total capacity of over 180,000 m\u00b3 (equivalent to 72 standard swimming pools), and four stormwater drainage tunnels with a total length of about 21 km.<\/p>\n
With these large-scale long-term structural measures completed one after another, Hong Kong’s flooding black spots will be eliminated someday. These major underground projects will also help Hong Kong cope with the increased and more devastating natural disasters that climate change brings in the future.[\/et_pb_text][et_pb_image src=”https:\/\/jmsc6110a.com\/capstone2023\/wp-content\/uploads\/2023\/05\/Tai-Hang-Tung-Stormwater-Storage-Tank-photo-by-DSD.jpeg” alt=”Tai Hang Tung Stormwater Storage Tank” title_text=”Tai Hang Tung Stormwater Storage Tank” show_bottom_space=”off” _builder_version=”4.20.4″ _module_preset=”default” custom_margin=”13px||||false|false” global_colors_info=”{}”][\/et_pb_image][et_pb_text admin_label=”Caption” _builder_version=”4.20.4″ _module_preset=”default” text_font=”Lato||on||||||” custom_margin=”||||false|false” global_colors_info=”{}”]<\/p>\n
Tai Hang Tung Stormwater Storage Tank. Source: Drainage Services Department.<\/p>\n
[\/et_pb_text][et_pb_divider show_divider=”off” _builder_version=”4.20.4″ _module_preset=”default” global_colors_info=”{}”][\/et_pb_divider][\/et_pb_column][\/et_pb_row][\/et_pb_section]<\/p>\n","protected":false},"excerpt":{"rendered":"
A Deeper Look at Our City’s Drainage System<\/p>\n","protected":false},"author":25,"featured_media":2636,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"on","_et_pb_old_content":"","_et_gb_content_width":"","ts_fic_featured_image_caption":"Below Ground","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[21],"tags":[43,42],"ppma_author":[20],"class_list":["post-2631","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-spaces","tag-drainage","tag-space","et-has-post-format-content","et_post_format-et-post-format-standard"],"yoast_head":"\n